Imported from libpng-1.0.7beta12.tar

ANNOUNCE

@@ -0,0 +1,72 @@
+
+Libpng 1.0.7beta12 - May 12, 2000
+
+This is a public release of libpng, intended for use in production codes.
+
+Changes since the last public release (1.0.6):
+
+  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
+  Added data_length parameter to png_decompress_chunk() function
+  Revised documentation to remove reference to abandoned png_free_chnk functions
+  Fixed an error in png_rgb_to_gray_fixed()
+  Revised example.c, usage of png_destroy_write_struct().
+  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
+  Added a check for info_ptr->free_me&PNG_FREE_TEXT when free'ing text in png.c
+  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
+  Added png_data_freer() function.
+  In the code that checks for over-length tRNS chunks, added check of
+    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
+  Check for existing data and free it if the free_me flag is set, in png_set_*()
+    and png_handle_*().
+  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
+    is defined.
+  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
+    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
+  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
+  Add checks in png_set_text() for NULL members of the input text structure.
+  Removed superfluous prototype for png_set_itxt from png.h
+  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
+  Changed several png_errors about malformed ancillary chunks to png_warnings.
+  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
+  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
+    and other revisions (Matthias Benckmann)
+  Relocated info_ptr->free_me to restore binary compatibility with libpng-1.0.5
+    (breaks compatibility with libpng-1.0.6).
+  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
+    png_ptr members to restore binary compatibility with libpng-1.0.5
+    (breaks compatibility with libpng-1.0.6).
+  Rearranged some members at the end of png_info and png_struct, to put
+    unknown_chunks_num and free_me within the original size of the png_structs
+    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
+    because some old applications allocate the structs directly instead of
+    using png_create_*().
+  Added documentation of user memory functions in libpng.txt/libpng.3
+  Modified png_read_png so that it will use user_allocated row_pointers
+    if present, unless free_me directs that it be freed, and added description
+    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
+  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
+    1.00) members of png_struct and png_info, to regain binary compatibility
+    when you define this macro.  Capabilities lost in this event
+    are user transforms (new in version 1.0.0),the user transform pointer
+    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
+    the high-level interface, and unknown chunks support (all new in 1.0.6).
+    This was necessary because of old applications that allocate the structs
+    directly as authors were instructed to do in libpng-0.88 and earlier,
+    instead of using png_create_*(). 
+  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
+  Overloaded png_read_init() and png_write_init() with macros that convert
+    calls to png_read_init_2() or png_write_init_2() that check the version
+    and structure sizes.
+  Made PNG_NO_ITXT_SUPPORTED the default setting, to avoid memory overrun
+    when old applications fill the info_ptr->text structure directly.
+  Added PNGAPI macro, and added it to the definitions of all exported functions.
+  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
+  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
+  Added png_access_version_number() function.
+  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
+  Expanded libpng.3/libpng.txt information about png_data_freer().
+
+Send comments/corrections/commendations to
+png-implement@ccrc.wustl.edu or to randeg@alum.rpi.edu
+
+Glenn R-P

CHANGES

@@ -1,169 +1,752 @@
-pngchange.txt - changes for libpng
+CHANGES - changes for libpng
 
 version 0.2
-   added reader into png.h
-   fixed small problems in stub file
+  added reader into png.h
+  fixed small problems in stub file
 version 0.3
-   added pull reader
-   split up pngwrite.c to several files
-   added pnglib.txt
-   added example.c
-   cleaned up writer, adding a few new tranformations
-   fixed some bugs in writer
-   interfaced with zlib 0.5
-   added K&R support
-   added check for 64 KB blocks for 16 bit machines
+  added pull reader
+  split up pngwrite.c to several files
+  added pnglib.txt
+  added example.c
+  cleaned up writer, adding a few new tranformations
+  fixed some bugs in writer
+  interfaced with zlib 0.5
+  added K&R support
+  added check for 64 KB blocks for 16 bit machines
 version 0.4
-   cleaned up code and commented code
-   simplified time handling into png_time
-   created png_color_16 and png_color_8 to handle color needs
-   cleaned up color type defines
-   fixed various bugs
-   made various names more consistant
-   interfaced with zlib 0.71
-   cleaned up zTXt reader and writer (using zlib's Reset functions)
-   split transformations into pngrtran.c and pngwtran.c
+  cleaned up code and commented code
+  simplified time handling into png_time
+  created png_color_16 and png_color_8 to handle color needs
+  cleaned up color type defines
+  fixed various bugs
+  made various names more consistant
+  interfaced with zlib 0.71
+  cleaned up zTXt reader and writer (using zlib's Reset functions)
+  split transformations into pngrtran.c and pngwtran.c
 version 0.5
-   interfaced with zlib 0.8
-   fixed many reading and writing bugs
-   saved using 3 spaces instead of tabs
+  interfaced with zlib 0.8
+  fixed many reading and writing bugs
+  saved using 3 spaces instead of tabs
 version 0.6
-   added png_large_malloc() and png_large_free()
-   added png_size_t
-   cleaned up some compiler warnings
-   added png_start_read_image()
+  added png_large_malloc() and png_large_free()
+  added png_size_t
+  cleaned up some compiler warnings
+  added png_start_read_image()
 version 0.7
-   cleaned up lots of bugs
-   finished dithering and other stuff
-   added test program
-   changed name from pnglib to libpng
+  cleaned up lots of bugs
+  finished dithering and other stuff
+  added test program
+  changed name from pnglib to libpng
 version 0.71 [June, 1995]
-   changed pngtest.png for zlib 0.93
-   fixed error in libpng.txt and example.c
+  changed pngtest.png for zlib 0.93
+  fixed error in libpng.txt and example.c
 version 0.8
-   cleaned up some bugs
-   added png_set_filler()
-   split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
-   added #define's to remove unwanted code
-   moved png_info_init() to png.c
-   added old_size into png_realloc()
-   added functions to manually set filtering and compression info
-   changed compression parameters based on image type
-   optimized filter selection code
-   added version info
-   changed external functions passing floats to doubles (k&r problems?)
-   put all the configurable stuff in pngconf.h
-   enabled png_set_shift to work with paletted images on read
-   added png_read_update_info() - updates info structure with
-      transformations
+  cleaned up some bugs
+  added png_set_filler()
+  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
+  added #define's to remove unwanted code
+  moved png_info_init() to png.c
+  added old_size into png_realloc()
+  added functions to manually set filtering and compression info
+  changed compression parameters based on image type
+  optimized filter selection code
+  added version info
+  changed external functions passing floats to doubles (k&r problems?)
+  put all the configurable stuff in pngconf.h
+  enabled png_set_shift to work with paletted images on read
+  added png_read_update_info() - updates info structure with
+     transformations
 version 0.81 [August, 1995]
-   incorporated Tim Wegner's medium model code (thanks, Tim)
+  incorporated Tim Wegner's medium model code (thanks, Tim)
 version 0.82 [September, 1995]
-   [unspecified changes]
+  [unspecified changes]
 version 0.85 [December, 1995]
-   added more medium model code (almost everything's a far)
-   added i/o, error, and memory callback functions
-   fixed some bugs (16 bit, 4 bit interlaced, etc.)
-   added first run progressive reader (barely tested)
+  added more medium model code (almost everything's a far)
+  added i/o, error, and memory callback functions
+  fixed some bugs (16 bit, 4 bit interlaced, etc.)
+  added first run progressive reader (barely tested)
 version 0.86 [January, 1996]
-   fixed bugs
-   improved documentation
+  fixed bugs
+  improved documentation
 version 0.87 [January, 1996]
-   fixed medium model bugs
-   fixed other bugs introduced in 0.85 and 0.86
-   added some minor documentation
+  fixed medium model bugs
+  fixed other bugs introduced in 0.85 and 0.86
+  added some minor documentation
 version 0.88 [January, 1996]
-   fixed progressive bugs
-   replaced tabs with spaces
-   cleaned up documentation
-   added callbacks for read/write and warning/error functions
+  fixed progressive bugs
+  replaced tabs with spaces
+  cleaned up documentation
+  added callbacks for read/write and warning/error functions
 version 0.89 [July, 1996]
-   added new initialization API to make libpng work better with shared libs
-      we now have png_create_read_struct(), png_create_write_struct(),
-      png_create_info_struct(), png_destroy_read_struct(), and
-      png_destroy_write_struct() instead of the separate calls to
-      malloc and png_read_init(), png_info_init(), and png_write_init()
-   changed warning/error callback functions to fix bug - this means you
-      should use the new initialization API if you were using the old
-      png_set_message_fn() calls, and that the old API no longer exists
-      so that people are aware that they need to change their code
-   changed filter selection API to allow selection of multiple filters
-      since it didn't work in previous versions of libpng anyways
-   optimized filter selection code    
-   fixed png_set_background() to allow using an arbitrary RGB color for
-      paletted images
-   fixed gamma and background correction for paletted images, so
-      png_correct_palette is not needed unless you are correcting an
-      external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
-      in pngconf.h) - if nobody uses this, it may disappear in the future.
-   fixed bug with Borland 64K memory allocation (Alexander Lehmann)
-   fixed bug in interlace handling (Smarasderagd, I think)
-   added more error checking for writing and image to reduce invalid files
-   separated read and write functions so that they won't both be linked
-      into a binary when only reading or writing functionality is used
-   new pngtest image also has interlacing and zTXt
-   updated documentation to reflect new API
+  added new initialization API to make libpng work better with shared libs
+     we now have png_create_read_struct(), png_create_write_struct(),
+     png_create_info_struct(), png_destroy_read_struct(), and
+     png_destroy_write_struct() instead of the separate calls to
+     malloc and png_read_init(), png_info_init(), and png_write_init()
+  changed warning/error callback functions to fix bug - this means you
+     should use the new initialization API if you were using the old
+     png_set_message_fn() calls, and that the old API no longer exists
+     so that people are aware that they need to change their code
+  changed filter selection API to allow selection of multiple filters
+     since it didn't work in previous versions of libpng anyways
+  optimized filter selection code
+  fixed png_set_background() to allow using an arbitrary RGB color for
+     paletted images
+  fixed gamma and background correction for paletted images, so
+     png_correct_palette is not needed unless you are correcting an
+     external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
+     in pngconf.h) - if nobody uses this, it may disappear in the future.
+  fixed bug with Borland 64K memory allocation (Alexander Lehmann)
+  fixed bug in interlace handling (Smarasderagd, I think)
+  added more error checking for writing and image to reduce invalid files
+  separated read and write functions so that they won't both be linked
+     into a binary when only reading or writing functionality is used
+  new pngtest image also has interlacing and zTXt
+  updated documentation to reflect new API
 version 0.90 [January, 1997]
-   made CRC errors/warnings on critical and ancillary chunks configurable
-   libpng will use the zlib CRC routines by (compile-time) default
-   changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
-   added external C++ wrapper statements to png.h (Gilles Dauphin)
-   allow PNG file to be read when some or all of file signature has already
-      been read from the beginning of the stream.  ****This affects the size
-      of info_struct and invalidates all programs that use a shared libpng****
-   fixed png_filler() declarations
-   fixed? background color conversions
-   fixed order of error function pointers to match documentation
-   current chunk name is now available in png_struct to reduce the number
-      of nearly identical error messages (will simplify multi-lingual
-      support when available)
-   try to get ready for unknown-chunk callback functions:
-      - previously read critical chunks are flagged, so the chunk handling
-        routines can determine if the chunk is in the right place
-      - all chunk handling routines have the same prototypes, so we will
-        be able to handle all chunks via a callback mechanism
-   try to fix Linux "setjmp" buffer size problems
+  made CRC errors/warnings on critical and ancillary chunks configurable
+  libpng will use the zlib CRC routines by (compile-time) default
+  changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
+  added external C++ wrapper statements to png.h (Gilles Dauphin)
+  allow PNG file to be read when some or all of file signature has already
+     been read from the beginning of the stream.  ****This affects the size
+     of info_struct and invalidates all programs that use a shared libpng****
+  fixed png_filler() declarations
+  fixed? background color conversions
+  fixed order of error function pointers to match documentation
+  current chunk name is now available in png_struct to reduce the number
+     of nearly identical error messages (will simplify multi-lingual
+     support when available)
+  try to get ready for unknown-chunk callback functions:
+     - previously read critical chunks are flagged, so the chunk handling
+       routines can determine if the chunk is in the right place
+     - all chunk handling routines have the same prototypes, so we will
+       be able to handle all chunks via a callback mechanism
+  try to fix Linux "setjmp" buffer size problems
+  removed png_large_malloc, png_large_free, and png_realloc functions.
 version 0.95 [March, 1997]
-   fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
-   fixed bug in PNG file signature compares when start != 0
-   changed parameter type of png_set_filler(...filler...) from png_byte
-      to png_uint_32
-   added test for MACOS to ensure that both math.h and fp.h are not #included
-   added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
-   added "packswap" transformation, which changes the endianness of
-      packed-pixel bytes (Kevin Bracey)
-   added "strip_alpha" transformation, which removes the alpha channel of
-      input images without using it (not neccesarily a good idea)
-   added "swap_alpha" transformation, which puts the alpha channel in front
-      of the color bytes instead of after
-   removed all implicit variable tests which assume NULL == 0 (I think)
-   changed several variables to "png_size_t" to show 16/32-bit limitations
-   added new pCAL chunk read/write support
-   added experimental filter selection weighting (Greg Roelofs)
-   removed old png_set_rgbx() and png_set_xrgb() functions that have been
-      obsolete for about 2 years now (use png_set_filler() instead)
-   added macros to read 16- and 32-bit ints directly from buffer, to be
-      used only on those systems that support it (namely PowerPC and 680x0)
-      With some testing, this may become the default for MACOS/PPC systems.
-   only calculate CRC on data if we are going to use it
-   added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
-   added macros for simple libpng debugging output selectable at compile time
-   removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
-   more description of info_struct in libpng.txt and png.h
-   more instructions in example.c
-   more chunk types tested in pngtest.c
-   renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
-      png_set_<chunk>.  We now have corresponding png_get_<chunk>
-      functions in pngget.c to get infomation in info_ptr.  This isolates
-      the application from the internal organization of png_info_struct
-      (good for shared library implementations).
+  fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
+  fixed bug in PNG file signature compares when start != 0
+  changed parameter type of png_set_filler(...filler...) from png_byte
+     to png_uint_32
+  added test for MACOS to ensure that both math.h and fp.h are not #included
+  added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
+  added "packswap" transformation, which changes the endianness of
+     packed-pixel bytes (Kevin Bracey)
+  added "strip_alpha" transformation, which removes the alpha channel of
+     input images without using it (not neccesarily a good idea)
+  added "swap_alpha" transformation, which puts the alpha channel in front
+     of the color bytes instead of after
+  removed all implicit variable tests which assume NULL == 0 (I think)
+  changed several variables to "png_size_t" to show 16/32-bit limitations
+  added new pCAL chunk read/write support
+  added experimental filter selection weighting (Greg Roelofs)
+  removed old png_set_rgbx() and png_set_xrgb() functions that have been
+     obsolete for about 2 years now (use png_set_filler() instead)
+  added macros to read 16- and 32-bit ints directly from buffer, to be
+     used only on those systems that support it (namely PowerPC and 680x0)
+     With some testing, this may become the default for MACOS/PPC systems.
+  only calculate CRC on data if we are going to use it
+  added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
+  added macros for simple libpng debugging output selectable at compile time
+  removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
+  more description of info_struct in libpng.txt and png.h
+  more instructions in example.c
+  more chunk types tested in pngtest.c
+  renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
+     png_set_<chunk>.  We now have corresponding png_get_<chunk>
+     functions in pngget.c to get infomation in info_ptr.  This isolates
+     the application from the internal organization of png_info_struct
+     (good for shared library implementations).
 version 0.96 [May, 1997]
-   fixed serious bug with < 8bpp images introduced in 0.95
-   fixed 256-color transparency bug (Greg Roelofs)
-   fixed up documentation (Greg Roelofs, Laszlo Nyul)
-   fixed "error" in pngconf.h for Linux setjmp() behaviour
-   fixed DOS medium model support (Tim Wegner)
-   fixed png_check_keyword() for case with error in static string text
-   added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
-   added typecasts to quiet compiler errors
-   added more debugging info
+  fixed serious bug with < 8bpp images introduced in 0.95
+  fixed 256-color transparency bug (Greg Roelofs)
+  fixed up documentation (Greg Roelofs, Laszlo Nyul)
+  fixed "error" in pngconf.h for Linux setjmp() behaviour
+  fixed DOS medium model support (Tim Wegner)
+  fixed png_check_keyword() for case with error in static string text
+  added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
+  added typecasts to quiet compiler errors
+  added more debugging info
+version 0.97 [January, 1998]
+  removed PNG_USE_OWN_CRC capability
+  relocated png_set_crc_action from pngrutil.c to pngrtran.c
+  fixed typecasts of "new_key", etc. (Andreas Dilger)
+  added RFC 1152 [sic] date support
+  fixed bug in gamma handling of 4-bit grayscale
+  added 2-bit grayscale gamma handling (Glenn R-P)
+  added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
+  minor corrections in libpng.txt
+  added simple sRGB support (Glenn R-P)
+  easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
+     all configurable options can be selected from command-line instead
+     of having to edit pngconf.h (Glenn R-P)
+  fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
+  added more conditions for png_do_background, to avoid changing
+     black pixels to background when a background is supplied and
+     no pixels are transparent
+  repaired PNG_NO_STDIO behaviour
+  tested NODIV support and made it default behaviour (Greg Roelofs)
+  added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
+  regularized version numbering scheme and bumped shared-library major
+     version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
+version 0.98 [January, 1998]
+  cleaned up some typos in libpng.txt and in code documentation
+  fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
+  cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
+  changed recommendation about file_gamma for PC images to .51 from .45,
+     in example.c and libpng.txt, added comments to distinguish between
+     screen_gamma, viewing_gamma, and display_gamma.
+  changed all references to RFC1152 to read RFC1123 and changed the
+     PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
+  added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
+  changed srgb_intent from png_byte to int to avoid compiler bugs
+version 0.99 [January 30, 1998]
+  free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
+  fixed a longstanding "packswap" bug in pngtrans.c
+  fixed some inconsistencies in pngconf.h that prevented compiling with
+     PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
+  fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
+  changed recommendation about file_gamma for PC images to .50 from .51 in
+     example.c and libpng.txt, and changed file_gamma for sRGB images to .45
+  added a number of functions to access information from the png structure
+     png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
+  added TARGET_MACOS similar to zlib-1.0.8
+  define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
+  added type casting to all png_malloc() function calls
+version 0.99a [January 31, 1998]
+  Added type casts and parentheses to all returns that return a value.(Tim W.)
+version 0.99b [February 4, 1998]
+  Added type cast png_uint_32 on malloc function calls where needed.
+  Changed type of num_hist from png_uint_32 to int (same as num_palette).
+  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
+  Renamed makefile.elf to makefile.lnx.
+version 0.99c [February 7, 1998]
+  More type casting.  Removed erroneous overflow test in pngmem.c.
+  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
+  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
+version 0.99d [February 11, 1998]
+  Renamed "far_to_near()" "png_far_to_near()"
+  Revised libpng.3
+  Version 99c "buffered" operations didn't work as intended.  Replaced them
+    with png_memcpy_check() and png_memset_check().
+  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
+    unused png_ptr, mostly in pngget.c and pngset.c.
+  Check for overlength tRNS chunk present when indexed-color PLTE is read.
+  Cleaned up spelling errors in libpng.3/libpng.txt
+  Corrected a problem with png_get_tRNS() which returned undefined trans array
+version 0.99e [February 28, 1998]
+  Corrected png_get_tRNS() again.
+  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
+  Touched up example.c to make more of it compileable, although the entire
+    file still can't be compiled (Willem van Schaik)
+  Fixed a bug in png_do_shift() (Bryan Tsai)
+  Added a space in png.h prototype for png_write_chunk_start()
+  Replaced pngtest.png with one created with zlib 1.1.1
+  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
+  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
+version 0.99f [March 5, 1998]
+  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
+  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
+  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
+  Added pointers to "note on libpng versions" in makefile.lnx and README
+  Added row callback feature when reading and writing nonprogressive rows
+     and added a test of this feature in pngtest.c
+  Added user transform callbacks, with test of the feature in pngtest.c
+version 0.99g [March 6, 1998, morning]
+  Minor changes to pngtest.c to suppress compiler warnings.
+  Removed "beta" language from documentation.
+version 0.99h [March 6, 1998, evening]
+  Minor changes to previous minor changes to pngtest.c
+  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
+  and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
+  Added user transform capability
+version 1.00 [March 7, 1998]
+  Changed several typedefs in pngrutil.c
+  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
+  replaced "while(1)" with "for(;;)"
+  added PNGARG() to prototypes in pngtest.c and removed some prototypes
+  updated some of the makefiles (Tom Lane)
+  changed some typedefs (s_start, etc.) in pngrutil.c
+  fixed dimensions of "short_months" array in pngwrite.c
+  Replaced ansi2knr.c with the one from jpeg-v6
+version 1.0.0 [March 8, 1998]
+  Changed name from 1.00 to 1.0.0 (Adam Costello)
+  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
+version 1.0.0a [March 9, 1998]
+  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
+  (Greg Roelofs)
+  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
+  for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
+  Tom Lane)
+  Make months range from 1-12 in png_convert_to_rfc1123
+version 1.0.0b [March 13, 1998]
+  Quieted compiler complaints about two empty "for" loops in pngrutil.c
+  Minor changes to makefile.s2x
+  Removed #ifdef/#endif around a png_free() in pngread.c
+version 1.0.1 [March 14, 1998]
+  Changed makefile.s2x to reduce security risk of using a relative pathname
+  Fixed some typos in the documentation (Greg).
+  Fixed a problem with value of "channels" returned by png_read_update_info()
+version 1.0.1a [April 21, 1998]
+  Optimized Paeth calculations by replacing abs() function calls with intrinsics
+  plus other loop optimizations. Improves avg decoding speed by about 20%.
+  Commented out i386istic "align" compiler flags in makefile.lnx.
+  Reduced the default warning level in some makefiles, to make them consistent.
+  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
+  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
+  Added grayscale and 16-bit capability to png_do_read_filler().
+  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
+    too large when writing an image with bit_depth < 8 (Bob Dellaca).
+  Corrected some bugs in the experimental weighted filtering heuristics.
+  Moved a misplaced pngrutil code block that truncates tRNS if it has more
+    than num_palette entries -- test was done before num_palette was defined.
+  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
+  Changed compiler flags in makefile.wat for better optimization (Pawel Mrochen).
+version 1.0.1b [May 2, 1998]
+  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
+  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
+  Added makefile.sco (contributed by Mike Hopkirk).
+  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
+  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
+  More work on the Paeth-filtering, achieving imperceptible speedup (A Kleinert).
+  More work on loop optimization which may help when compiled with C++ compilers.
+  Added warnings when people try to use transforms they've defined out.
+  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
+  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
+version 1.0.1c [May 11, 1998]
+  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
+    filler bytes should have been 0xff instead of 0xf.
+  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
+  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
+    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
+  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
+    for consistency, in pngconf.h
+  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
+    to remove unwanted capabilities via the compile line
+  Made some corrections to grammar (which, it's) in documentation (Greg).
+  Corrected example.c, use of row_pointers in png_write_image().
+version 1.0.1d [May 24, 1998]
+  Corrected several statements that used side effects illegally in pngrutil.c
+    and pngtrans.c, that were introduced in version 1.0.1b
+  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
+  More corrections to example.c, use of row_pointers in png_write_image()
+    and png_read_rows().
+  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
+    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
+  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
+  Changed several loops from count-down to count-up, for consistency.
+version 1.0.1e [June 6, 1998]
+  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
+    added warnings when people try to set png_read_fn and png_write_fn in
+    the same structure.
+  Added a test such that png_do_gamma will be done when num_trans==0
+    for truecolor images that have defined a background.  This corrects an
+    error that was introduced in libpng-0.90 that can cause gamma processing
+    to be skipped.
+  Added tests in png.h to include "trans" and "trans_values" in structures
+    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
+  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
+  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
+  Added capability for user-provided malloc_fn() and free_fn() functions,
+    and revised pngtest.c to demonstrate their use, replacing the
+    PNGTEST_DEBUG_MEM feature.
+  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
+version 1.0.2 [June 14, 1998]
+  Fixed two bugs in makefile.bor .
+version 1.0.2a [December 30, 1998]
+  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
+  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
+    the left-most pixel of each row (Kevin Bracey).
+  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
+    in pngtest.c (Duncan Simpson).
+  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
+    even when no tIME chunk was present in the source file.
+  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
+  Fixed a problem in png_read_push_finish_row(), which would not skip some
+    passes that it should skip, for images that are less than 3 pixels high.
+  Interchanged the order of calls to png_do_swap() and png_do_shift()
+    in pngwtran.c (John Cromer).
+  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
+  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
+  Fixed a documentation error about default filtering with 8-bit indexed-color.
+  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
+    (L. Peter Deutsch).
+  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
+  Added png_get_copyright() and png_get_header_version() functions.
+  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
+  Added information about debugging in libpng.txt and libpng.3 .
+  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and makefile.sco.
+  Removed lines after Dynamic Dependencies" in makefile.aco .
+  Revised makefile.dec to make a shared library (Jeremie Petit).
+  Removed trailing blanks from all files. 
+version 1.0.2a [January 6, 1999]
+  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
+  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
+  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
+  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
+    which is obsolete.
+version 1.0.3 [January 14, 1999]
+  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
+  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
+version 1.0.3a [August 12, 1999]
+  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
+     if an attempt is made to read an interlaced image when it's not supported.
+  Added check if png_ptr->trans is defined before free'ing it in pngread.c
+  Modified the Y2K statement to include versions back to version 0.71
+  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
+  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
+  Replaced leading blanks with tab characters in makefile.hux
+  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
+  Changed (float)red and (float)green to (double)red, (double)green
+     in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
+  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
+  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
+  Updated documentation to refer to the PNG-1.2 specification.
+  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
+    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
+  Fixed bugs in calculation of the length of rowbytes when adding alpha
+    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
+  Added function png_set_user_transform_info() to store user_transform_ptr,
+    user_depth, and user_channels into the png_struct, and a function
+    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
+  Added function png_set_empty_plte_permitted() to make libpng useable
+    in MNG applications.
+  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
+  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
+    consistent with PNG-1.2, and allow variance of 500 before complaining.
+  Added assembler code contributed by Intel in file pngvcrd.c and modified
+    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation, Gilles Vollant)
+  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
+  Added some aliases for png_set_expand() in pngrtran.c, namely
+    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
+    (Greg Roelofs, in "PNG: The Definitive Guide").
+  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
+version 1.0.3b [August 26, 1999]
+  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
+  Changed leading blanks to tabs in all makefiles.
+  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
+  Made alternate versions of  png_set_expand() in pngrtran.c, namely
+    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
+    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
+  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
+  Revised calculation of num_blocks in pngmem.c to avoid a potentially
+    negative shift distance, whose results are undefined in the C language.
+  Added a check in pngset.c to prevent writing multiple tIME chunks.
+  Added a check in pngwrite.c to detect invalid small window_bits sizes.
+version 1.0.3d [September 4, 1999]
+  Fixed type casting of igamma in pngrutil.c
+  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
+  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
+version 1.0.4 [September 24, 1999]
+  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
+  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
+  Made several minor corrections to pngtest.c
+  Renamed the makefiles with longer but more user friendly extensions.
+  Copied the PNG copyright and license to a separate LICENSE file.
+  Revised documentation, png.h, and example.c to remove reference to
+    "viewing_gamma" which no longer appears in the PNG specification.
+  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
+  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
+  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
+    assembler code) and makefile.vcwin32 (doesn't).
+  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
+  Added a copy of pngnow.png to the distribution.
+version 1.0.4a [September 25, 1999]
+  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
+  Changed several division operations to right-shifts in pngvcrd.c
+version 1.0.4b [September 30, 1999]
+  Added parentheses in line 3732 of pngvcrd.c
+  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
+version 1.0.4c [October 1, 1999]
+  Added a "png_check_version" function in png.c and pngtest.c that will generate
+    a helpful compiler error if an old png.h is found in the search path.
+  Changed type of png_user_transform_depth|channels from int to png_byte.
+version 1.0.4d [October 6, 1999]
+  Changed 0.45 to 0.45455 in png_set_sRGB()
+  Removed unused PLTE entries from pngnow.png
+  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
+version 1.0.4e [October 10, 1999]
+  Fixed sign error in pngvcrd.c (Greg Roelofs)
+  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
+version 1.0.4f [October 15, 1999]
+  Surrounded example.c code with #if 0 .. #endif to prevent people from
+    inadvertently trying to compile it.
+  Changed png_get_header_version() from a function to a macro in png.h
+  Added type casting mostly in pngrtran.c and pngwtran.c
+  Removed some pointless "ptr = NULL" in pngmem.c
+  Added a "contrib" directory containing the source code from Greg's book.
+version 1.0.5 [October 15, 1999]
+  Minor editing of the INSTALL and README files.
+version 1.0.5a [October 23, 1999]
+  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
+  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
+  Further optimization and bugfix of pngvcrd.c
+  Revised pngset.c so that it does not allocate or free memory in the user's
+    text_ptr structure.  Instead, it makes its own copy.
+  Created separate write_end_info_struct in pngtest.c for a more severe test.
+  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
+version 1.0.5b [November 23, 1999]
+  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
+    PNG_FLAG_WROTE_tIME from flags to mode.
+  Added png_write_info_before_PLTE() function.
+  Fixed some typecasting in contrib/gregbook/*.c
+  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
+    and contrib/pngminus (Martin Zinser)
+version 1.0.5c [November 26, 1999]
+  Moved png_get_header_version from png.h to png.c, to accomodate ansi2knr.
+  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
+    accomodate making DLL's: Moved usr_png_ver from global variable to function
+    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
+    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
+    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
+    png_CHNK and png_pass arrays to be "const".  Made the global arrays
+    available to applications (although none are used in libpng itself) when
+    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
+  Removed some extraneous "-I" from contrib/pngminus/makefile.std
+  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
+  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
+version 1.0.5d [November 29, 1999]
+  Add type cast (png_const_charp) two places in png.c
+  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
+  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
+    to applications a macro "PNG_USE_LOCAL_ARRAYS".
+  #ifdef out all the new declarations when PNG_USE_GLOBAL_ARRAYS is defined.
+  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
+version 1.0.5e [November 30, 1999]
+  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
+    structure; refactored the inflate/deflate support to make adding new chunks
+    with trailing compressed parts easier in the future, and added new functions
+    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
+    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
+  NOTE: Applications that write text chunks MUST define png_text->lang
+    before calling png_set_text(). It must be set to NULL if you want to
+    write tEXt or zTXt chunks.  If you want your application to be able to
+    run with older versions of libpng, use
+
+      #ifdef PNG_iTXt_SUPPORTED
+         png_text[i].lang = NULL;
+      #endif
+
+  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
+    offsets (Eric S. Raymond).
+  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
+    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
+    macros, leaving the separate macros also available.
+  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
+version 1.0.5f [December 6, 1999]
+  Changed makefile.solaris to issue a warning about potential problems when
+    the ucb "ld" is in the path ahead of the ccs "ld".
+  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
+  Added sCAL chunk support (Eric S. Raymond).
+version 1.0.5g [December 7, 1999]
+  Fixed "png_free_spallettes" typo in png.h
+  Added code to handle new chunks in pngpread.c
+  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
+  Added "translated_key" to png_text structure and png_write_iTXt().
+  Added code in pngwrite.c to work around a newly discovered zlib bug.
+version 1.0.5h [December 10, 1999]
+  NOTE: regarding the note for version 1.0.5e, the following must also
+    be included in your code:
+        png_text[i].translated_key = NULL;
+  Unknown chunk handling is now supported.
+  Option to eliminate all floating point support was added.  Some new
+    fixed-point functions such as png_set_gAMA_fixed() were added.
+  Expanded tabs and removed trailing blanks in source files.
+version 1.0.5i [December 13, 1999]
+  Added some type casts to silence compiler warnings.
+  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
+  Removed leading blanks from a #define in pngvcrd.c
+  Added some parameters to the new png_set_keep_unknown_chunks() function.
+  Added a test for up->location != 0 in the first instance of writing
+    unknown chunks in pngwrite.c
+  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
+    prevent recursion.
+  Added png_free_hIST() function.
+  Various patches to fix bugs in the sCAL and integer cHRM processing,
+    and to add some convenience macros for use with sCAL.
+version 1.0.5j [December 21, 1999]
+  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
+    around buggy compilers.
+  Added new type "png_fixed_point" for integers that hold float*100000 values
+  Restored backward compatibility of tEXt/zTXt chunk processing:
+    Restored the first four members of png_text to the same order as v.1.0.5d.
+    Added members "lang_key" and "itxt_length" to png_text struct.  Set
+    text_length=0 when "text" contains iTXt data.  Use the "compression"
+    member to distinguish among tEXt/zTXt/iTXt types.  Added
+    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
+    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
+    longer applies.
+  Fixed png_read|write_iTXt() to read|write parameters in the right order,
+    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
+  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
+  Reversed the order of trying to write floating-point and fixed-point gAMA.
+version 1.0.5k [December 27, 1999]
+  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
+  Added png_handle_as_unknown() function (Glenn)
+  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
+    of png_ptr.
+  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
+  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
+    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
+  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
+  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
+  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
+version 1.0.5l [January 1, 2000]
+  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
+    for setting a callback function to handle unknown chunks and for
+    retrieving the associated user pointer (Glenn).
+version 1.0.5m [January 7, 2000]
+  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
+version 1.0.5n [January 9, 2000]
+  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
+    own memory for info_ptr->palette.  This makes it safe for the calling
+    application to free its copy of the palette any time after it calls
+    png_set_PLTE().
+version 1.0.5o [January 20, 2000]
+  Cosmetic changes only (removed some trailing blanks and TABs)
+version 1.0.5p [January 31, 2000]
+  Renamed pngdll.mak to makefile.bd32
+  Cosmetic changes in pngtest.c
+version 1.0.5q [February 5, 2000]
+  Relocated the makefile.solaris warning about PATH problems.
+  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
+  Revised makefile.gcmmx
+  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
+version 1.0.5r [February 7, 2000]
+  Removed superfluous prototype for png_get_itxt from png.h
+  Fixed a bug in pngrtran.c that improperly expanded the background color.
+  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
+    of png_get_text() in libpng.txt/libpng.3.
+version 1.0.5s [February 18, 2000]
+  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
+    new error handler that's planned for the next libpng release, and changed
+    example.c, pngtest.c, and contrib programs to use this macro.
+  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
+  Fixed a bug in png_read_png() that caused it to fail to expand some images
+    that it should have expanded.
+  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
+    in pngget.c
+  Changed the allocation of palette, history, and trans arrays back to
+    the version 1.0.5 method (linking instead of copying) which restores
+    backward compatibility with version 1.0.5.  Added some remarks about
+    that in example.c.  Added "free_me" member to info_ptr and png_ptr
+    and added png_free_data() function.
+  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
+  Made cosmetic changes to pngasmrd.h
+  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
+  Modified png_read_png() to allocate info_ptr->row_pointers only if it
+    hasn't already been allocated.
+version 1.0.5t [March 4, 2000]
+  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
+  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
+  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
+    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
+  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
+    a 24-bit visual if one is available, and to allow abbreviated options.
+  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
+  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
+version 1.0.5u [March 5, 2000]
+  Simplified the code that detects old png.h in png.c and pngtest.c
+  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
+  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
+    added png_set_rgb_to_gray_fixed() function.
+  Added makefile.bc32 (32-bit Borland C++, C mode)
+version 1.0.5v [March 11, 2000]
+  Added some parentheses to the png_jmpbuf macro definition.
+  Updated references to the zlib home page, which has moved to freesoftware.com.
+  Corrected bugs in documentation regarding png_read_row() and png_write_row().
+  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
+  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
+    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
+version 1.0.6 [March 20, 2000]
+  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
+  Added makefile.sggcc (SGI IRIX with gcc)
+version 1.0.6d [April 7, 2000]
+  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
+  Added data_length parameter to png_decompress_chunk() function
+  Revised documentation to remove reference to abandoned png_free_chnk functions
+  Fixed an error in png_rgb_to_gray_fixed()
+  Revised example.c, usage of png_destroy_write_struct().
+  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
+  Added a check for info_ptr->free_me&PNG_FREE_TEXT when free'ing text in png.c
+  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
+version 1.0.6e [April 9, 2000]
+  Added png_data_freer() function.
+  In the code that checks for over-length tRNS chunks, added check of
+    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
+  Minor revisions of libpng.txt/libpng.3.
+  Check for existing data and free it if the free_me flag is set, in png_set_*()
+    and png_handle_*().
+  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
+    is defined.
+  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
+    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
+version 1.0.6f [April 14, 2000]
+  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
+  Add checks in png_set_text() for NULL members of the input text structure.
+  Revised libpng.txt/libpng.3.
+  Removed superfluous prototype for png_set_itxt from png.h
+  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
+  Changed several png_errors about malformed ancillary chunks to png_warnings.
+version 1.0.6g [April 24, 2000]
+  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
+  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
+    and other revisions (Matthias Benckmann)
+  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
+    png_ptr members to restore binary compatibility with libpng-1.0.5
+    (breaks compatibility with libpng-1.0.6).
+version 1.0.6h [April 24, 2000]
+  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
+    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
+    This is a temporary change for test purposes.
+version 1.0.6i [May 2, 2000]
+  Rearranged some members at the end of png_info and png_struct, to put
+    unknown_chunks_num and free_me within the original size of the png_structs
+    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
+    because some old applications allocate the structs directly instead of
+    using png_create_*().
+  Added documentation of user memory functions in libpng.txt/libpng.3
+  Modified png_read_png so that it will use user_allocated row_pointers
+    if present, unless free_me directs that it be freed, and added description
+    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
+  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
+    1.00) members of png_struct and png_info, to regain binary compatibility
+    when you define this macro.  Capabilities lost in this event
+    are user transforms (new in version 1.0.0),the user transform pointer
+    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
+    the high-level interface, and unknown chunks support (all new in 1.0.6).
+    This was necessary because of old applications that allocate the structs
+    directly as authors were instructed to do in libpng-0.88 and earlier,
+    instead of using png_create_*(). 
+  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
+    can be used to detect codes that directly allocate the structs, and
+    code to check these modes in png_read_init() and png_write_init() and
+    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
+    was not defined.
+  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
+version 1.0.6j [May 3, 2000]
+  Overloaded png_read_init() and png_write_init() with macros that convert
+    calls to png_read_init_2() or png_write_init_2() that check the version
+    and structure sizes.
+version 1.0.7beta11 [May 7, 2000]
+  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
+    which are no longer used.
+  Eliminated the three new members of png_text when PNG_NO_iTXt_SUPPORTED
+    or PNG_LEGACY_SUPPORTED is defined.
+  Made PNG_NO_ITXT_SUPPORTED the default setting, to avoid memory overrun
+    when old applications fill the info_ptr->text structure directly.
+  Added PNGAPI macro, and added it to the definitions of all exported functions.
+version 1.0.7beta12 [May 12, 2000]
+  Revised pngset.c to avoid a problem with expanding the png_debug macro.
+  Deleted some extraneous defines from pngconf.h
+  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
+  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
+  Added png_access_version_number() function.
+  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
+  Expanded libpng.3/libpng.txt information about png_data_freer().
+
+Send comments/corrections/commendations to
+png-implement@ccrc.wustl.edu or to randeg@alum.rpi.edu
+
+Glenn R-P

INSTALL

@@ -0,0 +1,118 @@
+
+Installing libpng version 1.0.7beta12 - May 12, 2000
+
+Before installing libpng, you must first install zlib.  zlib
+can usually be found wherever you got libpng.  zlib can be
+placed in another directory, at the same level as libpng.
+Note that your system might already have a preinstalled
+zlib, but you will still need to have access to the
+zlib.h and zconf.h include files that correspond to the
+version of zlib that's installed.
+
+You can rename the directories that you downloaded (they
+might be called "libpng-1.0.7beta12" or "lpng106" and "zlib-1.1.3"
+or "zlib113") so that you have directories called "zlib" and "libpng".
+
+Your directory structure should look like this:
+
+   ..       (the parent directory)
+      libpng  (this directory)
+          INSTALL (this file)
+          README
+          *.h
+          *.c
+          contrib
+             gregbook
+             pngminus
+             pngsuite
+          scripts
+             makefile.*
+          pngtest.png
+          etc.
+      zlib
+          README
+          *.h
+          *.c
+          contrib
+          etc.
+
+If the line endings in the files look funny, you may wish to get the other
+distribution of libpng.  It is available in both tar.gz (UNIX style line
+endings) and zip (DOS style line endings) formats.
+
+First enter the zlib directory and follow the instructions in zlib/README.
+Then come back here and choose the appropriate makefile.sys in the scripts
+directory.  
+The files that are presently available in the scripts directory
+include
+
+ makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
+ makefile.linux    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.7beta12)
+ makefile.gcmmx    =>  Linux/ELF makefile (gcc, creates libpng.so.2.1.0.7beta12,
+                       uses assembler code tuned for Intel MMX platform)
+ makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
+ makefile.knr      =>  Archaic UNIX Makefile that converts files with
+                       ansi2knr (Requires ansi2knr.c from
+                       ftp://ftp.cs.wisc.edu/ghost)
+ makefile.dec      =>  DEC Alpha UNIX makefile
+ makefile.hpux     =>  HPUX (10.20 and 11.00) makefile
+ makefile.ibmc     =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
+ libpng.icc        =>  Project file for IBM VisualAge/C++ version 4.0 or later
+ makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
+ makefile.sggcc    =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.7beta12)
+ makefile.sunos    =>  Sun makefile
+ makefile.solaris  =>  Solaris 2.X makefile (gcc, creates libpng.so.2.1.0.7beta12)
+ makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
+ makefile.mips     =>  MIPS makefile
+ makefile.acorn    =>  Acorn makefile
+ makefile.amiga    =>  Amiga makefile
+ smakefile.ppc     =>  AMIGA smakefile for SAS C V6.58/7.00 PPC compiler
+                       (Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)
+ makefile.atari    =>  Atari makefile
+ makefile.beos     =>  BEOS makefile for X86
+ makefile.bor      =>  Borland makefile (uses bcc)
+ makefile.bc32     =>  32-bit Borland C++ (all modules compiled in C mode)
+ makefile.bd32     =>  To make a png32bd.dll with Borland C++ 4.5
+ makefile.tc3      =>  Turbo C 3.0 makefile
+ makefile.dj2      =>  DJGPP 2 makefile
+ makefile.msc      =>  Microsoft C makefile
+ makefile.vcawin32 =>  makefile for Microsoft Visual C++ 5.0 and later (uses
+                       assembler code tuned for Intel MMX platform)
+ makefile.vcwin32  =>  makefile for Microsoft Visual C++ 4.0 and later (does
+                       not use assembler code)
+ makefile.os2      =>  OS/2 Makefile (gcc and emx, requires pngos2.def)
+ pngos2.def        =>  OS/2 module definition file used by makefile.os2
+ makefile.watcom   =>  Watcom 10a+ Makefile, 32-bit flat memory model
+ makevms.com       =>  VMS build script
+ descrip.mms       =>  VMS makefile for MMS or MMK
+ pngdef.pas        =>  Defines for a png32bd.dll with Borland C++ 4.5
+ SCOPTIONS.ppc     =>  Used with smakefile.ppc
+
+Copy the file (or files) that you need from the
+scripts directory into this directory, for example
+
+   MSDOS example: copy scripts\makefile.msc makefile
+   UNIX example:    cp scripts/makefile.std makefile
+
+Read the makefile to see if you need to change any source or
+target directories to match your preferences.
+
+Then read pngconf.h to see if you want to make any configuration
+changes.
+
+Then just run "make test" which will create the libpng library in
+this directory and run a quick test that reads the "pngtest.png"
+file and writes a "pngout.png" file that should be identical to it.
+Look for "9782 zero samples" in the output of the test.  For more
+confidence, you can run another test by typing "pngtest pngnow.png"
+and looking for "289 zero samples" in the output.  Also, you can
+run "pngtest -m *.png" in the "contrib/pngsuite" directory and compare
+your output with the result shown in contrib/pngsuite/README.
+
+Most of the makefiles will allow you to run "make install" to
+put the library in its final resting place (if you want to
+do that, run "make install" in the zlib directory first if necessary).
+
+Further information can be found in the README and libpng.txt
+files, in the individual makefiles, in png.h, and the manual pages
+libpng.3 and png.5.

KNOWNBUG

@@ -0,0 +1,132 @@
+
+Known bugs and suggested enhancements in libpng-1.0.6
+
+1. April 24, 2000 -- BUG -- binary incompatibility
+
+   Libpng-1.0.6 is binary incompatible with old applications that
+   allocate the png_struct and png_info structures themselves instead
+   of using png_create_*().  They do not allocate enough space for
+   the structures because they have an incorrect notion of
+   sizeof(png_struct) and sizeof(png_info).  Although such applications
+   should be considered broken rather than considering libpng to be broken,
+   they are numerous and include products of the PNG group, such
+   as gif2png and pnmtopng-2.36 (pnmtopng-2.37 is OK), so libpng will
+   be fixed in version 1.0.7 to work around this problem.
+
+   Applications that use png_create_*() instead of png_ptr=malloc(...)
+   are immune to this problem.
+
+   STATUS:  Fixed in libpng-1.0.6ad, libpng-1.0.6j, and patch-d
+   which are currently being tested by the PNG group.
+   The fix necessarily reintroduces a binary incompatibility with any
+   application that makes direct access to the png_info and
+   png_struct members that deal with the pCAL chunk, palette_lookup,
+   dither_index, time_buffer, or weighted filtering, i.e., any members
+   coming after the new "free_me" member of either structure.  It
+   is believed that applications affected by this reintroduced binary
+   incompatibility are rare (none are known to the PNG group). An
+   effective  workaround for this and the next bug is to recompile the
+   old applications with the installed version of libpng.
+
+2. April 23, 2000 -- BUG -- binary incompatibility
+
+   Libpng-1.0.6 introduced binary incompatibility for applications that
+   make direct access to members of the png_struct and png_info structures,
+   due to the insertion of the free_me member ahead of some previously
+   existing members.
+
+   Applications that use png_set_*(), png_get_*() are immune to this
+   problem, but people are still to this day writing applications that
+   make ill-advised direct access to members of the png_struct and
+   png_info structures, so libpng-1.0.6 will be patched to work around
+   this problem.
+
+   STATUS:  Fixed in libpng-1.0.6j and patch-d, which are currently being
+   tested by the PNG group.  Users can work around the problem without
+   patching libpng by recompiling their applications.
+
+3. April 15, 2000 -- BUG -- pnggccrd.c
+
+   If PNG_NO_GLOBAL_ARRAYS is defined, pnggccrd.c will not compile.
+
+   STATUS: Fixed in libpng-1.0.6g
+
+4. April 1, 2000 -- BUG
+
+   Under some circumstances old applications that make direct access to
+   the info_ptr->text and its members might free the same memory that
+   is also free'ed by libpng during the png_destroy_struct process.
+
+   Fixed in libpng-1.0.6-patch-c and libpng-1.0.6d.  The PNG_FREE_TEXT flag
+   bit in info_ptr->free_me is now checked to make sure libpng is responsible
+   for freeing the memory.
+
+5. April 1, 2000 -- BUG
+
+   The non-ISO-C "strdup()" function is used in png.c
+
+   STATUS: The function has been simplified and no longer uses strdup()
+   in libpng-1.0.6-patch-c and libpng-1.0.6d.
+
+6. March 24, 2000 -- BUG
+
+   The png_set_rgb_to_gray_fixed() function is setting incorrect weighting
+   factors.
+
+   STATUS: Fixed in libpng-1.0.6-patch-b and libpng-1.0.6d.
+
+7. March 22, 2000 -- BUG
+
+   There are some printf() and fprintf() statements active in pngwutil.c
+   when PNG_NO_STDIO and PNG_sCAL_SUPPORTED are both defined.
+
+   STATUS: Fixed in libpng-1.0.6-patch-a and libpng-1.0.6d.  The strcpy()
+   function is used instead.
+
+8. March 22, 2000 -- BUG
+
+   The length of the iCCP chunk data is calculated incorrectly; because
+   it can contain zeroes, strlen() doesn't work.
+
+   STATUS: Fixed in libpng-1.0.6-patch-a and libpng-1.0.6d by adding a
+   data_length parameter to the png_decompress_chunk() function.
+
+9. March 15, 1998 -- OPTIMIZATION -- Kevin Bracey
+
+   Loops need to be optimized everywhere
+
+   Make them count down instead of up -- Kevin Bracey
+
+   Optimizing compilers don't need this, and making
+   the change would be error prone -- Tom Lane, Glenn R-P
+
+   Question whether i-- or --i is better.
+
+   STATUS: Under investigation, postponed until after
+   libpng-1.1.0.  About 160 loops will be turned around
+   in libpng-1.1.Nn, for testing.
+
+10. July 4, 1998 -- ENHANCEMENT -- Glenn R-P
+
+   libpng-1.0.5 and earlier transform colors to gamma=1.0 space for
+   merging with background, and then back to the image's gamma.  The
+   bit_depth of the intermediate (gamma=1.0) representation is probably
+   not sufficient.  In the typical gamma=1/2.2 situation, the linear
+   pixels need about 4 more bits than the gamma-encoded ones, to avoid
+   loss of precision.  A similar situation exists with the rgb_to_gray
+   operation.
+
+   STATUS: under development.
+
+11. September 1999 -- ENHANCEMENT --
+
+   It should be possible to use libpng without floating-point aritmetic.
+
+   STATUS: Under investigation, implementation postponed until after
+   libpng-1.0.6.  The application interface will change because replacements
+   for the png_set_gAMA(), png_set_cHRM(), and corresponding png_get_()
+   functions will be needed.
+
+   Much of this was completed in libpng-1.0.6, but gamma compensation
+   is not yet done in fixed-point arithmetic.
+

LICENSE

@@ -0,0 +1,71 @@
+COPYRIGHT NOTICE:
+
+Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+(libpng versions 0.5, May 1995, through 0.89c, May 1996)
+Copyright (c) 1996, 1997 Andreas Dilger
+(libpng versions 0.90, December 1996, through 0.96, May 1997)
+Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+(libpng versions 0.97, January 1998, through 1.0.7beta12, May 12, 2000)
+
+For the purposes of this copyright and license, "Contributing Authors"
+is defined as the following set of individuals:
+
+   John Bowler
+   Kevin Bracey
+   Sam Bushell
+   Andreas Dilger
+   Magnus Holmgren
+   Tom Lane
+   Dave Martindale
+   Glenn Randers-Pehrson
+   Eric S. Raymond
+   Greg Roelofs
+   Guy Eric Schalnat
+   Paul Schmidt
+   Tom Tanner
+   Willem van Schaik
+   Tim Wegner
+
+The PNG Reference Library is supplied "AS IS".  The Contributing Authors
+and Group 42, Inc. disclaim all warranties, expressed or implied,
+including, without limitation, the warranties of merchantability and of
+fitness for any purpose.  The Contributing Authors and Group 42, Inc.
+assume no liability for direct, indirect, incidental, special, exemplary,
+or consequential damages, which may result from the use of the PNG
+Reference Library, even if advised of the possibility of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute this
+source code, or portions hereof, for any purpose, without fee, subject
+to the following restrictions:
+
+ 1. The origin of this source code must not be
+    misrepresented.
+
+ 2. Altered versions must be plainly marked as such
+    and must not be misrepresented as being the
+    original source.
+
+ 3. This Copyright notice may not be removed or
+    altered from any source or altered source
+    distribution.
+
+The Contributing Authors and Group 42, Inc. specifically permit, without
+fee, and encourage the use of this source code as a component to
+supporting the PNG file format in commercial products.  If you use this
+source code in a product, acknowledgment is not required but would be
+appreciated.
+
+A "png_get_copyright" function is available, for convenient use in "about"
+boxes and the like:
+
+   printf("%s",png_get_copyright(NULL));
+
+Also, the PNG logo (in PNG format, of course) is supplied in the
+file "pngnow.png".
+
+Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
+certification mark of the Open Source Initiative.
+
+Glenn Randers-Pehrson
+randeg@alum.rpi.edu
+May 12, 2000

README

@@ -1,16 +1,26 @@
-README for libpng 0.96
+README for libpng 1.0.7beta12 - May 12, 2000 (shared library 2.1)
+See the note about version numbers near the top of png.h
 
-This is the sixth (and hopefully last) beta release of libpng 1.0.
-The changes from libpng-0.90 include bug fixes, a C++ wrapper for
-png.h, some additions to the API, as well as internal changes to
-the library.  See "CHANGES" for a detailed list of differences.
+See INSTALL for instructions on how to install libpng.
+
+Libpng comes in two distribution formats.  Get libpng-*.tar.gz if you
+want UNIX-style line endings in the text files, or lpng*.zip if you want
+DOS-style line endings.
+
+Version 0.89 was the first official release of libpng.  Don't let the
+fact that it's the first release fool you.  The libpng library has been in
+extensive use and testing since mid-1995.  By late 1997 it had
+finally gotten to the stage where there hadn't been significant
+changes to the API in some time, and people have a bad feeling about
+libraries with versions < 1.0.  Version 1.0.0 was released in
+March 1998.
 
 ****
 Note that some of the changes to the png_info structure render this
 version of the library binary incompatible with libpng-0.89 or
 earlier versions if you are using a shared library.  The type of the
 "filler" parameter for png_set_filler() has changed from png_byte to
-png_uint_32, which will affect shared-library applications which use
+png_uint_32, which will affect shared-library applications that use
 this function.
 
 To avoid problems with changes to the internals of png_info_struct,
@@ -19,6 +29,12 @@ access to info_ptr.  These functions are the png_set_<chunk> and
 png_get_<chunk> functions.  These functions should be used when
 accessing/storing the info_struct data, rather than manipulating it
 directly, to avoid such problems in the future.
+
+It is important to note that the APIs do not make current programs
+that access the info struct directly incompatible with the new
+library.  However, it is strongly suggested that new programs use
+the new APIs (as shown in example.c and pngtest.c), and older programs
+be converted to the new format, to facilitate upgrades in the future.
 ****
 
 Additions since 0.90 include the ability to compile libpng as a
@@ -38,8 +54,9 @@ to set different actions based on whether the CRC error occurred in a
 critical or an ancillary chunk.
 
 The changes made to the library, and bugs fixed are based on discussions
-on the PNG implementation mailing list <png-implement@dworking.wustl.edu>
-and not on material submitted to Guy.
+on the PNG implementation mailing list <png-implement@ccrc.wustl.edu>
+and not on material submitted privately to Guy, Andreas, or Glenn.  They will
+forward any good suggestions to the list.
 
 For a detailed description on using libpng, read libpng.txt.  For
 examples of libpng in a program, see example.c and pngtest.c.  For usage
@@ -65,7 +82,7 @@ If not, it should be at ftp.uu.net in /graphics/png
 Eventually, it will be at ftp.uu.net in /pub/archiving/zip/zlib
 
 You may also want a copy of the PNG specification.  It is available
-as an Internet Draft, and RFC, and a W3C Recommendation.  Failing
+as an RFC and a W3C Recommendation.  Failing
 these resources you can try ftp.uu.net in the /graphics/png directory.
 
 This code is currently being archived at ftp.uu.net in the
@@ -85,19 +102,19 @@ Finally, if you get any warning messages when compiling libpng
 fix.  Please mention "libpng" somewhere in the subject line.  Thanks.
 
 This release was created and will be supported by myself (of course
-based in a large way on Guy's earlier work), and the PNG group.
+based in a large way on Guy's and Andreas' earlier work), and the PNG group.
 
-adilger@enel.ucalgary.ca
-png-implement@dworkin.wustl.edu
+randeg@alum.rpi.edu
+png-implement@ccrc.wustl.edu
 
-You can reach Guy, the original libpng author, at (internet preferred):
-
-internet: schalnat@group42.com
-CompuServe: 75501,1625
+You can't reach Guy, the original libpng author, at the addresses
+given in previous versions of this document.  He and Andreas will read mail
+addressed to the png-implement list, however.
 
 Please do not send general questions about PNG.  Send them to
-the address in the specification.  At the same time, please do
-not send libpng questions to that address, send them to me.  I'll
+the address in the specification (png-group@w3.org).  At the same
+time, please do not send libpng questions to that address, send them to me
+or to png-implement@ccrc.wustl.edu.  I'll
 get them in the end anyway.  If you have a question about something
 in the PNG specification that is related to using libpng, send it
 to me.  Send me any questions that start with "I was using libpng,
@@ -105,39 +122,33 @@ and ...".  If in doubt, send questions to me.  I'll bounce them
 to others, if necessary.
 
 Please do not send suggestions on how to change PNG.  We have
-been discussing PNG for a couple years now, and it is official and
+been discussing PNG for three years now, and it is official and
 finished.  If you have suggestions for libpng, however, I'll
 gladly listen.  Even if your suggestion is not used for version
 1.0, it may be used later.
 
 Files in this distribution:
 
+      ANNOUNCE      =>  Announcement of this version, with recent changes
       CHANGES       =>  Description of changes between libpng versions
+      KNOWNBUG      =>  List of known bugs and deficiencies
+      LICENSE       =>  License to use and redistribute libpng
       README        =>  This file
       TODO          =>  Things not implemented in the current library
-      ansi2knr.c    =>  Converts files to K&R style function declarations
-      build.bat     =>  MS-DOS batch file for Borland compiler
-      descrip.mms   =>  VMS project file
+      Y2KINFO       =>  Statement of Y2K compliance
       example.c     =>  Example code for using libpng functions
+      libpng.3      =>  manual page for libpng (includes libpng.txt)
       libpng.txt    =>  Description of libpng and its functions
-      makefile      =>  Default Unixish makefile
-      makefile.aco  =>  ACORN makefile
-      makefile.ama  =>  Amiga makefile
-      makefile.atr  =>  Atari makefile
-      makefile.bor  =>  Borland makefile
-      makefile.dj2  =>  DJGPP 2 makefile
-      makefile.elf  =>  Unix ELF makefile
-      makefile.knr  =>  Makefile which calls ansi2knr to convert files
-      makefile.mip  =>  MIPS makefile
-      makefile.msc  =>  Microsoft C makefile
-      makefile.std  =>  Standard Unix makefile
-      makefile.tc   =>  Turbo C makefile
-      makevms.com   =>  VMS make program
+      libpngpf.3    =>  manual page for libpng's private functions
+      png.5         =>  manual page for the PNG format
       png.c         =>  Basic interface functions common to library
       png.h         =>  Library function and interface declarations
       pngconf.h     =>  System specific library configuration
+      pngasmrd.h    =>  Header file for assembler-coded functions
       pngerror.c    =>  Error/warning message I/O functions
+      pngget.c      =>  Functions for retrieving info from struct
       pngmem.c      =>  Memory handling functions
+      pngnow.png    =>  PNG logo
       pngpread.c    =>  Progressive reading functions
       pngread.c     =>  Read data/helper high-level functions
       pngrio.c      =>  Lowest-level data read I/O functions
@@ -151,16 +162,70 @@ Files in this distribution:
       pngwrite.c    =>  High-level write functions
       pngwtran.c    =>  Write data transformations
       pngwutil.c    =>  Write utility functions
+      contrib       =>  Contributions
+       gregbook         =>  source code for PNG reading and writing, from
+                            Greg Roelofs' "PNG: The Definitive Guide",
+                            O'Reilly, 1999
+       pngminus     =>  Simple pnm2png and png2pnm programs
+       pngsuite     =>  Test images
+      scripts       =>  Directory containing scripts for building libpng:
+       descrip.mms      =>  VMS makefile for MMS or MMK
+       makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
+       makefile.linux   =>  Linux/ELF makefile
+                            (gcc, creates libpng.so.2.1.0.7beta12)
+       makefile.gcmmx   =>  Linux/ELF makefile (gcc, creates
+                            libpng.so.2.1.0.7beta12, uses assembler code
+                            tuned for Intel MMX platform)
+       makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
+       makefile.knr     =>  Archaic UNIX Makefile that converts files with
+                            ansi2knr (Requires ansi2knr.c from
+                            ftp://ftp.cs.wisc.edu/ghost)
+       makefile.dec     =>  DEC Alpha UNIX makefile
+       makefile.hpux    =>  HPUX (10.20 and 11.00) makefile
+       makefile.ibmc    =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
+       libpng.icc       =>  Project file, IBM VisualAge/C++ 4.0 or later
+       makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
+       makefile.sggcc   =>  Silicon Graphics (gcc, creates libpng.so.2.1.0.7beta12)
+       makefile.sunos   =>  Sun makefile
+       makefile.solaris =>  Solaris 2.X makefile
+                            (gcc, creates libpng.so.2.1.0.7beta12)
+       makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
+       makefile.mips    =>  MIPS makefile
+       makefile.acorn   =>  Acorn makefile
+       makefile.amiga   =>  Amiga makefile
+       smakefile.ppc    =>  AMIGA smakefile for SAS C V6.58/7.00 PPC
+                            compiler (Requires SCOPTIONS, copied from
+                            scripts/SCOPTIONS.ppc)
+       makefile.atari   =>  Atari makefile
+       makefile.beos    =>  BEOS makefile for X86
+       makefile.bor     =>  Borland makefile (uses bcc)
+       makefile.bc32    =>  32-bit Borland C++ (all modules compiled in C mode)
+       makefile.bd32    =>  To make a png32bd.dll with Borland C++ 4.5
+       makefile.tc3     =>  Turbo C 3.0 makefile
+       makefile.dj2     =>  DJGPP 2 makefile
+       makefile.msc     =>  Microsoft C makefile
+       makefile.vcawin32 => makefile for Microsoft Visual C++ 5.0 and
+                            later (uses assembler code tuned for Intel MMX
+                            platform)
+       makefile.vcwin32 =>  makefile for Microsoft Visual C++ 4.0 and
+                            later (does not use assembler code)
+       makefile.os2     =>  OS/2 Makefile (gcc and emx, requires pngos2.def)
+       pngos2.def       =>  OS/2 module definition file used by makefile.os2
+       makefile.watcom  =>  Watcom 10a+ Makefile, 32-bit flat memory model
+       makevms.com      =>  VMS build script
+       pngdef.pas       =>  Defines for a png32bd.dll with Borland C++ 4.5
+       SCOPTIONS.ppc    =>  Used with smakefile.ppc
 
 Good luck, and happy coding.
 
+-Glenn Randers-Pehrson
+ Internet: randeg@alum.rpi.edu
+ Web: http://www.rpi.edu/~randeg/index.html
+
 -Andreas Eric Dilger
  Internet: adilger@enel.ucalgary.ca
  Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/
 
 -Guy Eric Schalnat
- Group 42, Inc.
- Internet: schalnat@group42.com
- CompuServe: 75501,1625
- Web: http://www.group42.com/
-
+ (formerly of Group 42, Inc)
+ Internet: gschal@infinet.com

TODO

@@ -1,19 +1,19 @@
-pngtodo.txt - list of things to do for libpng
+TODO - list of things to do for libpng:
 
-add "grayscale->palette" transformation and "palette->grayscale" detection
-improved dithering
-multi-lingual error and warning message support
-cHRM transformation
-sRGB chunk handling
-man pages for function calls
-high-level API for reading images
-final bug fixes
-better documentation
-better filter selection
-   (counting huffman bits/precompression?  filter inertia?  filter costs?)
-optional palette creation
-histogram creation
-support for application-defined chunk handlers
-keep up with public chunks
-better C++ wrapper/full C++ implementation?
-text conversion between different code pages (Latin-1 -> Mac and DOS)
+Final bug fixes.
+Improve API by hiding the png_struct and png_info structs.
+Finish work on the no-floating-point version (including gamma compensation)
+Better C++ wrapper/full C++ implementation?
+Fix problem with C++ and EXTERN "C".
+cHRM transformation.
+Improve setjmp/longjmp usage or remove it in favor of returning error codes.
+Add "grayscale->palette" transformation and "palette->grayscale" detection.
+Improved dithering.
+Multi-lingual error and warning message support.
+Complete sRGB transformation (presently it simply uses gamma=0.45455).
+Man pages for function calls.
+Better documentation.
+Better filter selection
+   (counting huffman bits/precompression?  filter inertia?  filter costs?).
+Histogram creation.
+Text conversion between different code pages (Latin-1 -> Mac and DOS).

Y2KINFO

@@ -0,0 +1,55 @@
+   Y2K compliance in libpng:
+   =========================
+
+      May 12, 2000
+
+      Since the PNG Development group is an ad-hoc body, we can't make
+      an official declaration.
+
+      This is your unofficial assurance that libpng from version 0.71 and
+      upward through 1.0.7beta12 are Y2K compliant.  It is my belief that earlier
+      versions were also Y2K compliant.
+
+      Libpng only has three year fields.  One is a 2-byte unsigned integer
+      that will hold years up to 65535.  The other two hold the date in text
+      format, and will hold years up to 9999.
+
+      The integer is
+          "png_uint_16 year" in png_time_struct.
+
+      The strings are
+          "png_charp time_buffer" in png_struct and
+          "near_time_buffer", which is a local character string in png.c.
+
+      There are seven time-related functions:
+
+          png_convert_to_rfc_1123() in png.c
+            (formerly png_convert_to_rfc_1152() in error)
+          png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
+          png_convert_from_time_t() in pngwrite.c
+          png_get_tIME() in pngget.c
+          png_handle_tIME() in pngrutil.c, called in pngread.c
+          png_set_tIME() in pngset.c
+          png_write_tIME() in pngwutil.c, called in pngwrite.c
+
+      All appear to handle dates properly in a Y2K environment.  The
+      png_convert_from_time_t() function calls gmtime() to convert from system
+      clock time, which returns (year - 1900), which we properly convert to
+      the full 4-digit year.  There is a possibility that applications using
+      libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
+      function, or that they are incorrectly passing only a 2-digit year
+      instead of "year - 1900" into the png_convert_from_struct_tm() function,
+      but this is not under our control.  The libpng documentation has always
+      stated that it works with 4-digit years, and the APIs have been
+      documented as such.
+
+      The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
+      integer to hold the year, and can hold years as large as 65535.
+
+      zlib, upon which libpng depends, is also Y2K compliant.  It contains
+      no date-related code.
+
+
+         Glenn Randers-Pehrson
+         libpng maintainer
+         PNG Development Group

ansi2knr.c

@@ -1,488 +0,0 @@
-/* Copyright (C) 1989, 1991, 1993 Aladdin Enterprises. All rights reserved. */
-
-/* ansi2knr.c */
-/* Convert ANSI function declarations to K&R syntax */
-
-/*
-ansi2knr is distributed in the hope that it will be useful, but
-WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
-to anyone for the consequences of using it or for whether it serves any
-particular purpose or works at all, unless he says so in writing.  Refer
-to the GNU General Public License for full details.
-
-Everyone is granted permission to copy, modify and redistribute
-ansi2knr, but only under the conditions described in the GNU
-General Public License.  A copy of this license is supposed to have been
-given to you along with ansi2knr so you can know your rights and
-responsibilities.  It should be in a file named COPYING.  Among other
-things, the copyright notice and this notice must be preserved on all
-copies.
-*/
-
-/*
----------- Here is the GNU GPL file COPYING, referred to above ----------
------ These terms do NOT apply to the JPEG software itself; see README ------
-
-		    GHOSTSCRIPT GENERAL PUBLIC LICENSE
-		    (Clarified 11 Feb 1988)
-
- Copyright (C) 1988 Richard M. Stallman
- Everyone is permitted to copy and distribute verbatim copies of this
- license, but changing it is not allowed.  You can also use this wording
- to make the terms for other programs.
-
-  The license agreements of most software companies keep you at the
-mercy of those companies.  By contrast, our general public license is
-intended to give everyone the right to share Ghostscript.  To make sure
-that you get the rights we want you to have, we need to make
-restrictions that forbid anyone to deny you these rights or to ask you
-to surrender the rights.  Hence this license agreement.
-
-  Specifically, we want to make sure that you have the right to give
-away copies of Ghostscript, that you receive source code or else can get
-it if you want it, that you can change Ghostscript or use pieces of it
-in new free programs, and that you know you can do these things.
-
-  To make sure that everyone has such rights, we have to forbid you to
-deprive anyone else of these rights.  For example, if you distribute
-copies of Ghostscript, you must give the recipients all the rights that
-you have.  You must make sure that they, too, receive or can get the
-source code.  And you must tell them their rights.
-
-  Also, for our own protection, we must make certain that everyone finds
-out that there is no warranty for Ghostscript.  If Ghostscript is
-modified by someone else and passed on, we want its recipients to know
-that what they have is not what we distributed, so that any problems
-introduced by others will not reflect on our reputation.
-
-  Therefore we (Richard M. Stallman and the Free Software Foundation,
-Inc.) make the following terms which say what you must do to be allowed
-to distribute or change Ghostscript.
-
-
-			COPYING POLICIES
-
-  1. You may copy and distribute verbatim copies of Ghostscript source
-code as you receive it, in any medium, provided that you conspicuously
-and appropriately publish on each copy a valid copyright and license
-notice "Copyright (C) 1989 Aladdin Enterprises.  All rights reserved.
-Distributed by Free Software Foundation, Inc." (or with whatever year is
-appropriate); keep intact the notices on all files that refer to this
-License Agreement and to the absence of any warranty; and give any other
-recipients of the Ghostscript program a copy of this License Agreement
-along with the program.  You may charge a distribution fee for the
-physical act of transferring a copy.
-
-  2. You may modify your copy or copies of Ghostscript or any portion of
-it, and copy and distribute such modifications under the terms of
-Paragraph 1 above, provided that you also do the following:
-
-    a) cause the modified files to carry prominent notices stating
-    that you changed the files and the date of any change; and
-
-    b) cause the whole of any work that you distribute or publish,
-    that in whole or in part contains or is a derivative of Ghostscript
-    or any part thereof, to be licensed at no charge to all third
-    parties on terms identical to those contained in this License
-    Agreement (except that you may choose to grant more extensive
-    warranty protection to some or all third parties, at your option).
-
-    c) You may charge a distribution fee for the physical act of
-    transferring a copy, and you may at your option offer warranty
-    protection in exchange for a fee.
-
-Mere aggregation of another unrelated program with this program (or its
-derivative) on a volume of a storage or distribution medium does not bring
-the other program under the scope of these terms.
-
-  3. You may copy and distribute Ghostscript (or a portion or derivative
-of it, under Paragraph 2) in object code or executable form under the
-terms of Paragraphs 1 and 2 above provided that you also do one of the
-following:
-
-    a) accompany it with the complete corresponding machine-readable
-    source code, which must be distributed under the terms of
-    Paragraphs 1 and 2 above; or,
-
-    b) accompany it with a written offer, valid for at least three
-    years, to give any third party free (except for a nominal
-    shipping charge) a complete machine-readable copy of the
-    corresponding source code, to be distributed under the terms of
-    Paragraphs 1 and 2 above; or,
-
-    c) accompany it with the information you received as to where the
-    corresponding source code may be obtained.  (This alternative is
-    allowed only for noncommercial distribution and only if you
-    received the program in object code or executable form alone.)
-
-For an executable file, complete source code means all the source code for
-all modules it contains; but, as a special exception, it need not include
-source code for modules which are standard libraries that accompany the
-operating system on which the executable file runs.
-
-  4. You may not copy, sublicense, distribute or transfer Ghostscript
-except as expressly provided under this License Agreement.  Any attempt
-otherwise to copy, sublicense, distribute or transfer Ghostscript is
-void and your rights to use the program under this License agreement
-shall be automatically terminated.  However, parties who have received
-computer software programs from you with this License Agreement will not
-have their licenses terminated so long as such parties remain in full
-compliance.
-
-  5. If you wish to incorporate parts of Ghostscript into other free
-programs whose distribution conditions are different, write to the Free
-Software Foundation at 675 Mass Ave, Cambridge, MA 02139.  We have not
-yet worked out a simple rule that can be stated here, but we will often
-permit this.  We will be guided by the two goals of preserving the free
-status of all derivatives of our free software and of promoting the
-sharing and reuse of software.
-
-Your comments and suggestions about our licensing policies and our
-software are welcome!  Please contact the Free Software Foundation,
-Inc., 675 Mass Ave, Cambridge, MA 02139, or call (617) 876-3296.
-
-		       NO WARRANTY
-
-  BECAUSE GHOSTSCRIPT IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY
-NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW.  EXCEPT
-WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC, RICHARD
-M. STALLMAN, ALADDIN ENTERPRISES, L. PETER DEUTSCH, AND/OR OTHER PARTIES
-PROVIDE GHOSTSCRIPT "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
-EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE
-ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF GHOSTSCRIPT IS WITH
-YOU.  SHOULD GHOSTSCRIPT PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
-NECESSARY SERVICING, REPAIR OR CORRECTION.
-
-  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M.
-STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., L. PETER DEUTSCH, ALADDIN
-ENTERPRISES, AND/OR ANY OTHER PARTY WHO MAY MODIFY AND REDISTRIBUTE
-GHOSTSCRIPT AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING
-ANY LOST PROFITS, LOST MONIES, OR OTHER SPECIAL, INCIDENTAL OR
-CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
-(INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED
-INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR A FAILURE OF THE
-PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) GHOSTSCRIPT, EVEN IF YOU
-HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM
-BY ANY OTHER PARTY.
-
--------------------- End of file COPYING ------------------------------
-*/
-
-
-#include <stdio.h>
-#include <ctype.h>
-
-#ifdef BSD
-#include <strings.h>
-#else
-#ifdef VMS
-	extern int strlen(), strncmp();
-#else
-#include <string.h>
-#endif
-#endif
-
-/* malloc and free should be declared in stdlib.h, */
-/* but if you've got a K&R compiler, they probably aren't. */
-#ifdef MSDOS
-#include <malloc.h>
-#else
-#ifdef VMS
-     extern char *malloc();
-     extern void free();
-#else
-     extern char *malloc();
-     extern int free();
-#endif
-#endif
-
-/* Usage:
-	ansi2knr input_file [output_file]
- * If no output_file is supplied, output goes to stdout.
- * There are no error messages.
- *
- * ansi2knr recognizes functions by seeing a non-keyword identifier
- * at the left margin, followed by a left parenthesis,
- * with a right parenthesis as the last character on the line.
- * It will recognize a multi-line header provided that the last character
- * of the last line of the header is a right parenthesis,
- * and no intervening line ends with a left brace or a semicolon.
- * These algorithms ignore whitespace and comments, except that
- * the function name must be the first thing on the line.
- * The following constructs will confuse it:
- *	- Any other construct that starts at the left margin and
- *	    follows the above syntax (such as a macro or function call).
- *	- Macros that tinker with the syntax of the function header.
- */
-
-/* Scanning macros */
-#define isidchar(ch) (isalnum(ch) || (ch) == '_')
-#define isidfirstchar(ch) (isalpha(ch) || (ch) == '_')
-
-/* Forward references */
-char *skipspace();
-int writeblanks();
-int test1();
-int convert1();
-
-/* The main program */
-main(argc, argv)
-    int argc;
-    char *argv[];
-{	FILE *in, *out;
-#define bufsize 5000			/* arbitrary size */
-	char *buf;
-	char *line;
-	switch ( argc )
-	   {
-	default:
-		printf("Usage: ansi2knr input_file [output_file]\n");
-		exit(0);
-	case 2:
-		out = stdout; break;
-	case 3:
-		out = fopen(argv[2], "w");
-		if ( out == NULL )
-		   {	fprintf(stderr, "Cannot open %s\n", argv[2]);
-			exit(1);
-		   }
-	   }
-	in = fopen(argv[1], "r");
-	if ( in == NULL )
-	   {	fprintf(stderr, "Cannot open %s\n", argv[1]);
-		exit(1);
-	   }
-	fprintf(out, "#line 1 \"%s\"\n", argv[1]);
-	buf = malloc(bufsize);
-	line = buf;
-	while ( fgets(line, (unsigned)(buf + bufsize - line), in) != NULL )
-	   {	switch ( test1(buf) )
-		   {
-		case 1:			/* a function */
-			convert1(buf, out);
-			break;
-		case -1:		/* maybe the start of a function */
-			line = buf + strlen(buf);
-			if ( line != buf + (bufsize - 1) ) /* overflow check */
-				continue;
-			/* falls through */
-		default:		/* not a function */
-			fputs(buf, out);
-			break;
-		   }
-		line = buf;
-	   }
-	if ( line != buf ) fputs(buf, out);
-	free(buf);
-	fclose(out);
-	fclose(in);
-	return 0;
-}
-
-/* Skip over space and comments, in either direction. */
-char *
-skipspace(p, dir)
-    register char *p;
-    register int dir;			/* 1 for forward, -1 for backward */
-{	for ( ; ; )
-	   {	while ( isspace(*p) ) p += dir;
-		if ( !(*p == '/' && p[dir] == '*') ) break;
-		p += dir;  p += dir;
-		while ( !(*p == '*' && p[dir] == '/') )
-		   {	if ( *p == 0 ) return p;	/* multi-line comment?? */
-			p += dir;
-		   }
-		p += dir;  p += dir;
-	   }
-	return p;
-}
-
-/*
- * Write blanks over part of a string.
- */
-int
-writeblanks(start, end)
-    char *start;
-    char *end;
-{	char *p;
-	for ( p = start; p < end; p++ ) *p = ' ';
-	return 0;
-}
-
-/*
- * Test whether the string in buf is a function definition.
- * The string may contain and/or end with a newline.
- * Return as follows:
- *	0 - definitely not a function definition;
- *	1 - definitely a function definition;
- *	-1 - may be the beginning of a function definition,
- *		append another line and look again.
- */
-int
-test1(buf)
-    char *buf;
-{	register char *p = buf;
-	char *bend;
-	char *endfn;
-	int contin;
-	if ( !isidfirstchar(*p) )
-		return 0;		/* no name at left margin */
-	bend = skipspace(buf + strlen(buf) - 1, -1);
-	switch ( *bend )
-	   {
-	case ')': contin = 1; break;
-	case '{':
-	case ';': return 0;		/* not a function */
-	default: contin = -1;
-	   }
-	while ( isidchar(*p) ) p++;
-	endfn = p;
-	p = skipspace(p, 1);
-	if ( *p++ != '(' )
-		return 0;		/* not a function */
-	p = skipspace(p, 1);
-	if ( *p == ')' )
-		return 0;		/* no parameters */
-	/* Check that the apparent function name isn't a keyword. */
-	/* We only need to check for keywords that could be followed */
-	/* by a left parenthesis (which, unfortunately, is most of them). */
-	   {	static char *words[] =
-		   {	"asm", "auto", "case", "char", "const", "double",
-			"extern", "float", "for", "if", "int", "long",
-			"register", "return", "short", "signed", "sizeof",
-			"static", "switch", "typedef", "unsigned",
-			"void", "volatile", "while", 0
-		   };
-		char **key = words;
-		char *kp;
-		int len = endfn - buf;
-		while ( (kp = *key) != 0 )
-		   {	if ( strlen(kp) == len && !strncmp(kp, buf, len) )
-				return 0;	/* name is a keyword */
-			key++;
-		   }
-	   }
-	return contin;
-}
-
-int
-convert1(buf, out)
-    char *buf;
-    FILE *out;
-{	char *endfn;
-	register char *p;
-	char **breaks;
-	unsigned num_breaks = 2;	/* for testing */
-	char **btop;
-	char **bp;
-	char **ap;
-	/* Pre-ANSI implementations don't agree on whether strchr */
-	/* is called strchr or index, so we open-code it here. */
-	for ( endfn = buf; *(endfn++) != '('; ) ;
-top:	p = endfn;
-	breaks = (char **)malloc(sizeof(char *) * num_breaks * 2);
-	if ( breaks == 0 )
-	   {	/* Couldn't allocate break table, give up */
-		fprintf(stderr, "Unable to allocate break table!\n");
-		fputs(buf, out);
-		return -1;
-	   }
-	btop = breaks + num_breaks * 2 - 2;
-	bp = breaks;
-	/* Parse the argument list */
-	do
-	   {	int level = 0;
-		char *end = NULL;
-		if ( bp >= btop )
-		   {	/* Filled up break table. */
-			/* Allocate a bigger one and start over. */
-			free((char *)breaks);
-			num_breaks <<= 1;
-			goto top;
-		   }
-		*bp++ = p;
-		/* Find the end of the argument */
-		for ( ; end == NULL; p++ )
-		   {	switch(*p)
-			   {
-			case ',': if ( !level ) end = p; break;
-			case '(': level++; break;
-			case ')': if ( --level < 0 ) end = p; break;
-			case '/': p = skipspace(p, 1) - 1; break;
-			default: ;
-			   }
-		   }
-		p--;			/* back up over terminator */
-		/* Find the name being declared. */
-		/* This is complicated because of procedure and */
-		/* array modifiers. */
-		for ( ; ; )
-		   {	p = skipspace(p - 1, -1);
-			switch ( *p )
-			   {
-			case ']':	/* skip array dimension(s) */
-			case ')':	/* skip procedure args OR name */
-			   {	int level = 1;
-				while ( level )
-				 switch ( *--p )
-				   {
-				case ']': case ')': level++; break;
-				case '[': case '(': level--; break;
-				case '/': p = skipspace(p, -1) + 1; break;
-				default: ;
-				   }
-			   }
-				if ( *p == '(' && *skipspace(p + 1, 1) == '*' )
-				   {	/* We found the name being declared */
-					while ( !isidfirstchar(*p) )
-						p = skipspace(p, 1) + 1;
-					goto found;
-				   }
-				break;
-			default: goto found;
-			   }
-		   }
-found:		if ( *p == '.' && p[-1] == '.' && p[-2] == '.' )
-		   {	p++;
-			if ( bp == breaks + 1 )	/* sole argument */
-				writeblanks(breaks[0], p);
-			else
-				writeblanks(bp[-1] - 1, p);
-			bp--;
-		   }
-		else
-		   {	while ( isidchar(*p) ) p--;
-			*bp++ = p+1;
-		   }
-		p = end;
-	   }
-	while ( *p++ == ',' );
-	*bp = p;
-	/* Make a special check for 'void' arglist */
-	if ( bp == breaks+2 )
-	   {	p = skipspace(breaks[0], 1);
-		if ( !strncmp(p, "void", 4) )
-		   {	p = skipspace(p+4, 1);
-			if ( p == breaks[2] - 1 )
-			   {	bp = breaks;	/* yup, pretend arglist is empty */
-				writeblanks(breaks[0], p + 1);
-			   }
-		   }
-	   }
-	/* Put out the function name */
-	p = buf;
-	while ( p != endfn ) putc(*p, out), p++;
-	/* Put out the declaration */
-	for ( ap = breaks+1; ap < bp; ap += 2 )
-	   {	p = *ap;
-		while ( isidchar(*p) ) putc(*p, out), p++;
-		if ( ap < bp - 1 ) fputs(", ", out);
-	   }
-	fputs(")  ", out);
-	/* Put out the argument declarations */
-	for ( ap = breaks+2; ap <= bp; ap += 2 ) (*ap)[-1] = ';';
-	fputs(breaks[0], out);
-	free((char *)breaks);
-	return 0;
-}

build.bat

@@ -1,2 +0,0 @@
-make -fmakefile.bor -B -DMODEL=m %1 %2 %3 libpng >buildm.out
-make -fmakefile.bor -B -DMODEL=l %1 %2 %3 libpng >buildl.out

configure

@@ -0,0 +1,6 @@
+echo "
+  There is no \"configure\" script for Libpng-1.0.7beta12.  Instead, please
+  copy the appropriate makefile for your system from the \"scripts\"
+  directory.  Read the INSTALL file for more details.
+"
+

contrib/gregbook/LICENSE

@@ -0,0 +1,26 @@
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------

contrib/gregbook/Makefile.unx

@@ -0,0 +1,104 @@
+# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
+# Greg Roelofs
+# Last modified:  28 February 2000
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
+#	and family, too.  (Not that this is a blatant plug or anything.)
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#	make -f Makefile.unx
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are both installed in /usr/local/{include,lib} (as indicated by the
+# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIB, ZINC and ZLIB lines.
+#
+# This makefile builds statically linked executables (against libpng and zlib,
+# that is), but that can be changed by uncommenting the appropriate PNGLIB and
+# ZLIB lines.
+
+
+# macros --------------------------------------------------------------------
+
+PNGINC = -I/usr/local/include
+#PNGLIB = -L/usr/local/lib -lpng	# dynamically linked against libpng
+PNGLIB = /usr/local/lib/libpng.a	# statically linked against libpng
+# or:
+#PNGINC = -I../..
+#PNGLIB = -L../.. -lpng
+#PNGLIB = ../../libpng.a
+
+ZINC = -I/usr/local/include
+#ZLIB = -L/usr/local/lib -lz		# dynamically linked against zlib
+ZLIB = /usr/local/lib/libz.a		# statically linked against zlib
+#ZINC = -I../zlib
+#ZLIB = -L../zlib -lz
+#ZLIB = ../../../zlib/libz.a
+
+#XINC = -I/usr/include/X11		# old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11
+#XINC = -I/usr/openwin/include/X11	# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
+WLIBS = $(PNGLIB) $(ZLIB)
+
+CC = gcc
+LD = gcc
+RM = rm -f
+CFLAGS = -O -Wall $(INCS)
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic and -W can also be used]
+LDFLAGS =
+O = .o
+E =
+
+RPNG  = rpng-x
+RPNG2 = rpng2-x
+WPNG  = wpng
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)

contrib/gregbook/Makefile.w32

@@ -0,0 +1,112 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
+# Greg Roelofs
+# Last modified:  16 February 1999
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
+#	and family, too.  (Not that this is a blatant plug or anything.)
+#
+# Invoke this makefile from a DOS prompt window via:
+#
+#	%devstudio%\vc\bin\vcvars32.bat
+#	nmake -nologo -f Makefile.w32
+#
+# where %devstudio% is the installation directory for MSVC / DevStudio.  If
+# you get "environment out of space" errors, create a desktop shortcut with
+# "c:\windows\command.com /e:4096" as the program command line and set the
+# working directory to this directory.  Then double-click to open the new
+# DOS-prompt window with a bigger environment and retry the commands above.
+# 
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds statically linked executables, but that can be changed by uncom-
+# menting the appropriate PNGLIB and ZLIB lines.
+
+!include <ntwin32.mak>
+
+
+# macros --------------------------------------------------------------------
+
+PNGPATH = ../..
+PNGINC = -I$(PNGPATH)
+#PNGLIB = $(PNGPATH)/pngdll.lib
+PNGLIB = $(PNGPATH)/libpng.lib
+
+ZPATH = ../../../zlib
+ZINC = -I$(ZPATH)
+#ZLIB = $(ZPATH)/zlibdll.lib
+ZLIB = $(ZPATH)/zlibstat.lib
+
+WINLIBS = -defaultlib:user32.lib gdi32.lib
+# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
+
+INCS = $(PNGINC) $(ZINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
+WLIBS = $(PNGLIB) $(ZLIB)
+
+CC = cl
+LD = link
+RM = del
+CFLAGS = -nologo -O -W3 $(INCS) $(cvars)
+# [note that -Wall is an MSVC-specific compilation flag ("all warnings on")]
+# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
+O = .obj
+E = .exe
+
+RLDFLAGS = -nologo -subsystem:windows
+WLDFLAGS = -nologo
+
+RPNG  = rpng-win
+RPNG2 = rpng2-win
+WPNG  = wpng
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+#	ideally we could just do this:
+#	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
+#	...but the Windows "DEL" command is none too bright, so:
+	$(RM) r*$(E)
+	$(RM) w*$(E)
+	$(RM) r*$(O)
+	$(RM) w*$(O)

contrib/gregbook/README

@@ -0,0 +1,183 @@
+                     ===========================
+                      PNG: The Definitive Guide
+                     ===========================
+
+                             Source Code
+
+Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
+cross-platform demo programs that show how to use the libpng reference
+library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
+a very simple example that that shows how a standard file-viewer might use
+libpng, while the second is designed to process streaming data and shows
+how a web browser might be written.  wpng is a simple command-line program
+that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
+of PBMPLUS/NetPBM) and converts them to PNG.
+
+The source code for all three demo programs currently compiles under
+Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
+zinser@decus.de, for making the necessary changes for OpenVMS and for
+providing an appropriate build script.)  Build instructions can be
+found below.
+
+Files:
+
+   README             this file
+   README.w32         additional Windows-specific information
+   LICENSE            terms of distribution and reuse (BSD-like)
+
+   Makefile.unx       Unix makefile
+   Makefile.w32       Windows (MSVC) makefile
+   makevms.com        OpenVMS build script
+
+   rpng-win.c         Windows front end for the basic viewer
+   rpng-x.c           X Window System (Unix, OpenVMS) front end
+   readpng.c          generic back end for the basic viewer
+   readpng.h          header file for the basic viewer
+
+   rpng2-win.c        Windows front end for the progressive viewer
+   rpng2-x.c          X front end for the progressive viewer
+   readpng2.c         generic back end for the progressive viewer
+   readpng2.h         header file for the progressive viewer
+
+   wpng.c             generic (text) front end for the converter
+   writepng.c         generic back end for the converter
+   writepng.h         header file for the converter
+
+   toucan.png         transparent PNG for testing (by Stefan Schneider)
+
+Note that the programs are designed to be functional, but their primary
+purpose is to demonstrate how to use libpng to add PNG support to other
+programs.  As such, their user interfaces are crude and definitely not
+intended for everyday use.
+
+Please see http://www.cdrom.com/pub/png/pngbook.html for further infor-
+mation and links to the latest version of the source code, and Chapters
+13-15 of the book for detailed discussion of the three programs.
+
+Greg Roelofs
+19 March 2000
+
+
+BUILD INSTRUCTIONS
+
+ - Prerequisites:
+
+      - zlib		ftp://ftp.cdrom.com/pub/infozip/zlib/zlib.html
+      - libpng		http://www.cdrom.com/pub/png/pngcode.html
+      - pngbook		http://www.cdrom.com/pub/png/book/sources.html
+
+     The pngbook demo programs are explicitly designed to demonstrate proper
+     coding techniques for using the libpng reference library.  As a result,
+     you need to download and build both zlib (on which libpng depends) and
+     libpng.  A common build setup is to place the zlib, libpng and pngbook
+     subdirectory trees ("folders") in the same parent directory.  Then the
+     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
+     and similarly for the pngbook build.
+
+     Note that all three packages are designed to be built from a command
+     line by default; those who wish to use a graphical or other integrated
+     development environments are on their own.
+
+
+ - Unix:
+
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a directory and change into that directory.
+
+     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
+     appropriately (possibly also the X* variables if necessary).
+
+     make
+
+     There is no "install" target, so copy the three executables somewhere
+     in your path or run them from the current directory.  All three will
+     print a basic usage screen when run without any command-line arguments;
+     see the book for more details.
+
+
+ - Windows:
+
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a folder, open a "DOS shell" or "command prompt"
+     or equivalent command-line window, and cd into the folder where you
+     unpacked the source code.
+
+     For MSVC, set up the necessary environment variables by invoking
+ 
+        %devstudio%\vc\bin\vcvars32.bat
+
+     where where %devstudio% is the installation directory for MSVC /
+     DevStudio.  If you get "environment out of space" errors under 95/98,
+     create a desktop shortcut with "c:\windows\command.com /e:4096" as
+     the program command line and set the working directory to the pngbook
+     directory.  Then double-click to open the new DOS-prompt window with
+     a bigger environment and retry the commands above.
+
+     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
+     appropriately (possibly also the "INC" and "LIB" variables if needed).
+     Note that the names of the dynamic and static libpng and zlib libraries
+     used in the makefile may change in later releases of the libraries.
+     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
+     This makefile therefore builds statically linked executables, but if
+     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
+     and ZLIB lines will build dynamically linked executables instead.
+
+     Do the build by typing
+
+        nmake
+
+     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
+     and wpng.exe.  Copy them somewhere in your PATH or run them from the
+     current folder.  Unlike the Unix versions, the two windowed programs
+     (rpng and rpng2) do not display a usage screen when invoked without
+     command-line arguments; see README.w32 for brief help or the book for
+     details.  Note that the programs use the Unix-style "-" character to
+     specify options, instead of the more common DOS/Windows "/" character.
+
+
+ - OpenVMS:
+
+     Unpack the pngbook sources into a subdirectory and change into that
+     subdirectory.
+
+     Edit makevms.com appropriately, specifically the zpath and pngpath
+     variables.
+
+     @makevms
+
+     To run the programs, they probably first need to be set up as "foreign
+     symbols," with "disk" and "dir" set appropriately:
+
+     $ rpng == "$disk:[dir]rpng-x.exe"
+     $ rpng2 == "$disk:[dir]rpng2-x.exe"
+     $ wpng == "$disk:[dir]wpng.exe"
+
+     All three will print a basic usage screen when run without any command-
+     line arguments; see the book for more details.  Note that the options
+     style is Unix-like, i.e., preceded by "-" rather than "/".
+
+
+RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
+
+     rpng is a simple PNG viewer that can display transparent PNGs with a
+     specified background color; for example,
+
+	rpng -bgcolor #ff0000 toucan.png
+
+     would display the image with a red background.  rpng2 is a progressive
+     viewer that simulates a web browser in some respects; it can display
+     images against either a background color or a dynamically generated
+     background image.  For example:
+
+	rpng2 -bgpat 16 toucan.png
+
+     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
+     format (.pgm or .ppm) to PNG; for example,
+
+	wpng -time < toucan.ppm > toucan.png
+
+     would convert the specified PPM file (using redirection) to PNG, auto-
+     matically setting the PNG modification-time chunk.
+
+     All options can be abbreviated to the shortest unique value; for example,
+     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.

contrib/gregbook/README.w32

@@ -0,0 +1,53 @@
+See the main README file for basic instructions on compiling and running
+the programs.  See http://www.cdrom.com/pub/png/pngbook.html for further
+information and links to the source code, and Chapters 13-15 of the book
+for detailed discussion of the three programs.
+
+Since the two viewers, rpng and rpng2, are both designed to write infor-
+mation to the console (i.e., a DOS-window command line) while displaying
+the image in a graphical window--and since I haven't yet figured out how
+to do that under Windows--here are the usage screens for the two programs:
+
+
+rpng-win 1.02 of 19 March 2000:  Simple PNG Viewer for Windows
+   Compiled with libpng 1.0.5; using libpng 1.0.5.
+   Compiled with zlib 1.1.3; using zlib 1.1.3.
+
+Usage:  rpng-win [-gamma exp] [-bgcolor bg] file.png
+    exp 	transfer-function exponent (``gamma'') of the display
+		  system in floating-point format (e.g., ``2.2''); equal
+		  to the product of the lookup-table exponent (varies)
+		  and the CRT exponent (usually 2.2); must be positive
+    bg  	desired background color in 7-character hex RGB format
+		  (e.g., ``#ff7f00'' for orange:  same as HTML colors);
+		  used with transparent images
+
+Press Q, Esc or mouse button 1 after image is displayed to quit.
+
+
+rpng2-win 1.04 of 19 March 2000:  Progressive PNG Viewer for Windows
+   Compiled with libpng 1.0.5; using libpng 1.0.5.
+   Compiled with zlib 1.1.3; using zlib 1.1.3.
+
+Usage:  rpng2-win [-gamma exp] [-bgcolor bg | -bgpat pat] [-timing] file.png
+
+    exp 	transfer-function exponent (``gamma'') of the display
+		  system in floating-point format (e.g., ``2.2''); equal
+		  to the product of the lookup-table exponent (varies)
+		  and the CRT exponent (usually 2.2); must be positive
+    bg  	desired background color in 7-character hex RGB format
+		  (e.g., ``#ff7f00'' for orange:  same as HTML colors);
+		  used with transparent images; overrides -bgpat
+    pat 	desired background pattern number (1-16); used with
+		  transparent images; overrides -bgcolor
+    -timing	enables delay for every block read, to simulate modem
+		  download of image (~36 Kbps)
+
+Press Q, Esc or mouse button 1 after image is displayed to quit.
+
+
+The usage screen for the third (non-windowed) program, wpng, can be seen
+simply by invoking it without any parameters (``wpng'').
+
+Greg Roelofs
+19 March 2000

contrib/gregbook/makevms.com

@@ -0,0 +1,118 @@
+$!------------------------------------------------------------------------------
+$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
+$!
+$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
+$! for standalone pngbook source distribution.
+$!
+$!
+$!    Set locations where zlib and libpng sources live.
+$!
+$ zpath = "[-.zlib]"
+$ pngpath = "[-.libpng]"
+$!
+$! USE THESE INSTEAD if building from libpng's [.contrib.gregbook] directory:
+$! zpath = "[---.zlib]"
+$! pngpath = "[--]"
+$!
+$!    Look for the compiler used.
+$!
+$ ccopt="/include=(''zpath',''pngpath')"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "''pngpath'libpng.olb/lib"
+$ write lopt "''zpath'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$!
+$!    Build 'em.
+$!
+$ write sys$output "Compiling PNG book programs ..."
+$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
+	readpng.c readpng.h
+$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
+	readpng2.c readpng2.h
+$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
+	writepng.c writepng.h
+$   write sys$output "Building rpng-x..."
+$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
+	rpng-x.c readpng.h
+$   call make rpng-x.exe -
+	"LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
+	rpng-x.obj readpng.obj
+$   write sys$output "Building rpng2-x..."
+$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
+	rpng2-x.c readpng2.h
+$   call make rpng2-x.exe -
+	"LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
+	rpng2-x.obj readpng2.obj
+$   write sys$output "Building wpng..."
+$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
+	wpng.c writepng.h
+$   call make wpng.exe -
+	"LINK wpng,writepng,lib.opt/opt" -
+	wpng.obj writepng.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE

contrib/gregbook/readpng.c

@@ -0,0 +1,280 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readpng.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "png.h"        /* libpng header; includes zlib.h */
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+
+/* future versions of libpng will provide this macro: */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
+#endif
+
+
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+
+png_uint_32  width, height;
+int  bit_depth, color_type;
+uch  *image_data = NULL;
+
+
+void readpng_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+
+
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    uch sig[8];
+
+
+    /* first do a quick check that the file really is a PNG image; could
+     * have used slightly more general png_sig_cmp() function instead */
+
+    fread(sig, 1, 8, infile);
+    if (!png_check_sig(sig, 8))
+        return 1;   /* bad signature */
+
+
+    /* could pass pointers to user-defined error handlers instead of NULLs: */
+
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    png_init_io(png_ptr, infile);
+    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
+
+    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
+
+
+    /* alternatively, could make separate calls to png_get_image_width(),
+     * etc., but want bit_depth and color_type for later [don't care about
+     * compression_type and filter_type => NULLs] */
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+      NULL, NULL, NULL);
+    *pWidth = width;
+    *pHeight = height;
+
+
+    /* OK, that's all we need for now; return happy */
+
+    return 0;
+}
+
+
+
+
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    png_color_16p pBackground;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
+        return 1;
+
+    /* it is not obvious from the libpng documentation, but this function
+     * takes a pointer to a pointer, and it always returns valid red, green
+     * and blue values, regardless of color_type: */
+
+    png_get_bKGD(png_ptr, info_ptr, &pBackground);
+
+
+    /* however, it always returns the raw bKGD data, regardless of any
+     * bit-depth transformations, so check depth and adjust if necessary */
+
+    if (bit_depth == 16) {
+        *red   = pBackground->red   >> 8;
+        *green = pBackground->green >> 8;
+        *blue  = pBackground->blue  >> 8;
+    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+        if (bit_depth == 1)
+            *red = *green = *blue = pBackground->gray? 255 : 0;
+        else if (bit_depth == 2)
+            *red = *green = *blue = (255/3) * pBackground->gray;
+        else /* bit_depth == 4 */
+            *red = *green = *blue = (255/15) * pBackground->gray;
+    } else {
+        *red   = (uch)pBackground->red;
+        *green = (uch)pBackground->green;
+        *blue  = (uch)pBackground->blue;
+    }
+
+    return 0;
+}
+
+
+
+
+/* display_exponent == LUT_exponent * CRT_exponent */
+
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    double  gamma;
+    png_uint_32  i, rowbytes;
+    png_bytepp  row_pointers = NULL;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+
+
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+    if (bit_depth == 16)
+        png_set_strip_16(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+
+    /* unlike the example in the libpng documentation, we have *no* idea where
+     * this file may have come from--so if it doesn't have a file gamma, don't
+     * do any correction ("do no harm") */
+
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, display_exponent, gamma);
+
+
+    /* all transformations have been registered; now update info_ptr data,
+     * get rowbytes and channels, and allocate image memory */
+
+    png_read_update_info(png_ptr, info_ptr);
+
+    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
+
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        free(image_data);
+        image_data = NULL;
+        return NULL;
+    }
+
+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+
+
+    /* set the individual row_pointers to point at the correct offsets */
+
+    for (i = 0;  i < height;  ++i)
+        row_pointers[i] = image_data + i*rowbytes;
+
+
+    /* now we can go ahead and just read the whole image */
+
+    png_read_image(png_ptr, row_pointers);
+
+
+    /* and we're done!  (png_read_end() can be omitted if no processing of
+     * post-IDAT text/time/etc. is desired) */
+
+    free(row_pointers);
+    row_pointers = NULL;
+
+    png_read_end(png_ptr, NULL);
+
+    return image_data;
+}
+
+
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (png_ptr && info_ptr) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        png_ptr = NULL;
+        info_ptr = NULL;
+    }
+}

contrib/gregbook/readpng.h

@@ -0,0 +1,64 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readpng.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+
+/* prototypes for public functions in readpng.c */
+
+void readpng_version_info(void);
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
+
+int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
+
+uch *readpng_get_image(double display_exponent, int *pChannels,
+                       ulg *pRowbytes);
+
+void readpng_cleanup(int free_image_data);

contrib/gregbook/readpng2.c

@@ -0,0 +1,424 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                 readpng2.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>     /* for exit() prototype */
+
+#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
+#include "readpng2.h"   /* typedefs, common macros, public prototypes */
+
+
+/* local prototypes */
+
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                 png_uint_32 row_num, int pass);
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
+
+
+
+
+void readpng2_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+
+
+
+
+int readpng2_check_sig(uch *sig, int num)
+{
+    return png_check_sig(sig, num);
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
+
+int readpng2_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+
+
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+      readpng2_error_handler, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or exit immediately, so here we are: */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    /* instead of doing png_init_io() here, now we set up our callback
+     * functions for progressive decoding */
+
+    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
+      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
+
+
+    /* make sure we save our pointers for use in readpng2_decode_data() */
+
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+
+
+    /* and that's all there is to initialization */
+
+    return 0;
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* hand off the next chunk of input data to libpng for decoding */
+
+    png_process_data(png_ptr, info_ptr, rawbuf, length);
+
+    return 0;
+}
+
+
+
+
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+    int  color_type, bit_depth;
+    double  gamma;
+
+
+    /* setjmp() doesn't make sense here, because we'd either have to exit(),
+     * longjmp() ourselves, or return control to libpng, which doesn't want
+     * to see us again.  By not doing anything here, libpng will instead jump
+     * to readpng2_decode_data(), which can return an error value to the main
+     * program. */
+
+
+    /* retrieve the pointer to our special-purpose struct, using the png_ptr
+     * that libpng passed back to us (i.e., not a global this time--there's
+     * no real difference for a single image, but for a multithreaded browser
+     * decoding several PNG images at the same time, one needs to avoid mixing
+     * up different images' structs) */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+    if (mainprog_ptr == NULL) {         /* we be hosed */
+        fprintf(stderr,
+          "readpng2 error:  main struct not recoverable in info_callback.\n");
+        fflush(stderr);
+        return;
+        /*
+         * Alternatively, we could call our error-handler just like libpng
+         * does, which would effectively terminate the program.  Since this
+         * can only happen if png_ptr gets redirected somewhere odd or the
+         * main PNG struct gets wiped, we're probably toast anyway.  (If
+         * png_ptr itself is NULL, we would not have been called.)
+         */
+    }
+
+
+    /* this is just like in the non-progressive case */
+
+    png_get_IHDR(png_ptr, info_ptr, &mainprog_ptr->width,
+      &mainprog_ptr->height, &bit_depth, &color_type, NULL, NULL, NULL);
+
+
+    /* since we know we've read all of the PNG file's "header" (i.e., up
+     * to IDAT), we can check for a background color here */
+
+    if (mainprog_ptr->need_bgcolor &&
+        png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
+    {
+        png_color_16p pBackground;
+
+        /* it is not obvious from the libpng documentation, but this function
+         * takes a pointer to a pointer, and it always returns valid red,
+         * green and blue values, regardless of color_type: */
+        png_get_bKGD(png_ptr, info_ptr, &pBackground);
+
+        /* however, it always returns the raw bKGD data, regardless of any
+         * bit-depth transformations, so check depth and adjust if necessary */
+        if (bit_depth == 16) {
+            mainprog_ptr->bg_red   = pBackground->red   >> 8;
+            mainprog_ptr->bg_green = pBackground->green >> 8;
+            mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
+        } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+            if (bit_depth == 1)
+                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                  mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
+            else if (bit_depth == 2)
+                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                  mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
+            else /* bit_depth == 4 */
+                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                  mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
+        } else {
+            mainprog_ptr->bg_red   = (uch)pBackground->red;
+            mainprog_ptr->bg_green = (uch)pBackground->green;
+            mainprog_ptr->bg_blue  = (uch)pBackground->blue;
+        }
+    }
+
+
+    /* as before, let libpng expand palette images to RGB, low-bit-depth
+     * grayscale images to 8 bits, transparency chunks to full alpha channel;
+     * strip 16-bit-per-sample images to 8 bits per sample; and convert
+     * grayscale to RGB[A] */
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+    if (bit_depth == 16)
+        png_set_strip_16(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+
+    /* Unlike the basic viewer, which was designed to operate on local files,
+     * this program is intended to simulate a web browser--even though we
+     * actually read from a local file, too.  But because we are pretending
+     * that most of the images originate on the Internet, we follow the recom-
+     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
+     * chunk) as existing in the sRGB color space.  That is, we assume that
+     * such images have a file gamma of 0.45455, which corresponds to a PC-like
+     * display system.  This change in assumptions will have no effect on a
+     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
+     * identity lookup table, it will darken unlabelled images, which effec-
+     * tively favors images from PC-like systems over those originating on
+     * the local platform.  Note that mainprog_ptr->display_exponent is the
+     * "gamma" value for the entire display system, i.e., the product of
+     * LUT_exponent and CRT_exponent. */
+
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
+    else
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
+
+
+    /* we'll let libpng expand interlaced images, too */
+
+    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
+
+
+    /* all transformations have been registered; now update info_ptr data and
+     * then get rowbytes and channels */
+
+    png_read_update_info(png_ptr, info_ptr);
+
+    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
+    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
+
+
+    /* Call the main program to allocate memory for the image buffer and
+     * initialize windows and whatnot.  (The old-style function-pointer
+     * invocation is used for compatibility with a few supposedly ANSI
+     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
+
+    (*mainprog_ptr->mainprog_init)();
+
+
+    /* and that takes care of initialization */
+
+    return;
+}
+
+
+
+
+
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                  png_uint_32 row_num, int pass)
+{
+    mainprog_info  *mainprog_ptr;
+
+
+    /* first check whether the row differs from the previous pass; if not,
+     * nothing to combine or display */
+
+    if (!new_row)
+        return;
+
+
+    /* retrieve the pointer to our special-purpose struct so we can access
+     * the old rows and image-display callback function */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+
+    /* save the pass number for optional use by the front end */
+
+    mainprog_ptr->pass = pass;
+
+
+    /* have libpng either combine the new row data with the existing row data
+     * from previous passes (if interlaced) or else just copy the new row
+     * into the main program's image buffer */
+
+    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
+      new_row);
+
+
+    /* finally, call the display routine in the main program with the number
+     * of the row we just updated */
+
+    (*mainprog_ptr->mainprog_display_row)(row_num);
+
+
+    /* and we're ready for more */
+
+    return;
+}
+
+
+
+
+
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+
+
+    /* retrieve the pointer to our special-purpose struct */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+
+    /* let the main program know that it should flush any buffered image
+     * data to the display now and set a "done" flag or whatever, but note
+     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
+     * NOT call readpng2_cleanup() either here or in the finish_display()
+     * routine; wait until control returns to the main program via
+     * readpng2_decode_data() */
+
+    (*mainprog_ptr->mainprog_finish_display)();
+
+
+    /* all done */
+
+    return;
+}
+
+
+
+
+
+void readpng2_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+    if (png_ptr && info_ptr)
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+    mainprog_ptr->png_ptr = NULL;
+    mainprog_ptr->info_ptr = NULL;
+}
+
+
+
+
+
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+
+    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
+    fflush(stderr);
+
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}

contrib/gregbook/readpng2.h

@@ -0,0 +1,86 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                 readpng2.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+typedef struct _mainprog_info {
+    double display_exponent;
+    ulg width;
+    ulg height;
+    void *png_ptr;
+    void *info_ptr;
+    void (*mainprog_init)(void);
+    void (*mainprog_display_row)(ulg row_num);
+    void (*mainprog_finish_display)(void);
+    uch *image_data;
+    uch **row_pointers;
+    jmp_buf jmpbuf;
+    int passes;              /* not used */
+    int pass;
+    int rowbytes;
+    int channels;
+    int need_bgcolor;
+    int done;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+
+
+/* prototypes for public functions in readpng2.c */
+
+void readpng2_version_info(void);
+
+int readpng2_check_sig(uch *sig, int num);
+
+int readpng2_init(mainprog_info *mainprog_ptr);
+
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
+
+void readpng2_cleanup(mainprog_info *mainprog_ptr);

contrib/gregbook/rpng-win.c

@@ -0,0 +1,620 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                             rpng-win.c
+
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for 32-bit Windows; it may compile under 16-bit Windows
+   with a little tweaking (or maybe not).
+
+   to do:
+    - stdout/stderr don't work!  need message window (maybe scrollable?)
+    - handle quoted command-line args (especially filenames with spaces)
+    - have minimum window width:  oh well
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.00:  initial public release
+    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng-win"
+#define LONGNAME  "Simple PNG Viewer for Windows"
+#define VERSION   "1.02 of 19 March 2000"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <windows.h>
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+/* local prototypes */
+static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
+static int        rpng_win_display_image(void);
+static void       rpng_win_cleanup(void);
+LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;     /* GRR:  not (yet) used */
+static char *filename;
+static FILE *infile;
+
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+
+static double display_exponent;
+
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+
+/* Windows-specific variables */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+
+static HWND global_hwnd;
+
+
+
+
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char *p, *q, **argv = args;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+
+
+    filename = (char *)NULL;
+
+
+    /* First set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+
+
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename) {
+        ++error;
+    } else if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n",
+                      filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    /* usage screen */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+         "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
+         "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+         "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+         "\t\t  to the product of the lookup-table exponent (varies)\n"
+         "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+         "    bg  \tdesired background color in 7-character hex RGB format\n"
+         "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+         "\t\t  used with transparent images\n"
+         "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+         "\n", PROGNAME, default_display_exponent);
+        exit(1);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+
+    if (have_bg)
+        sscanf(bgstr+1, "%2x%2x%2x", &bg_red, &bg_green, &bg_blue);
+    else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+
+
+    /* do the basic Windows initialization stuff, make the window and fill it
+     * with the background color */
+
+    if (rpng_win_create_window(hInst, showmode))
+        exit(2);
+
+
+    /* decode the image, all at once */
+
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+
+
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+
+    readpng_cleanup(FALSE);
+    fclose(infile);
+
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+
+
+    /* display image (composite with background if requested) */
+
+    Trace((stderr, "calling rpng_win_display_image()\n"))
+    if (rpng_win_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_win_display_image()\n"))
+
+
+    /* wait for the user to tell us when to quit */
+
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+
+
+    /* OK, we're done:  clean up all image and Windows resources and go away */
+
+    rpng_win_cleanup();
+
+    return msg.wParam;
+}
+
+
+
+
+
+static int rpng_win_create_window(HINSTANCE hInst, int showmode)
+{
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+
+    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
+
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*image_height)))
+    {
+        return 4;   /* fail */
+    }
+
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = image_width;
+    bmih->biHeight = -((long)image_height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+
+/*---------------------------------------------------------------------------
+    Fill in background color (black by default); data are in BGR order.
+  ---------------------------------------------------------------------------*/
+
+    for (j = 0;  j < image_height;  ++j) {
+        dest = wimage_data + j*wimage_rowbytes;
+        for (i = image_width;  i > 0;  --i) {
+            *dest++ = bg_blue;
+            *dest++ = bg_green;
+            *dest++ = bg_red;
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+
+    memset(&wndclass, 0, sizeof(wndclass));
+
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng_win_wndproc;
+    wndclass.hInstance = hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+
+    RegisterClassEx(&wndclass);
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
+      image_height+extra_height, NULL, NULL, hInst, NULL);
+
+    ShowWindow(global_hwnd, showmode);
+    UpdateWindow(global_hwnd);
+
+    return 0;
+
+} /* end function rpng_win_create_window() */
+
+
+
+
+
+static int rpng_win_display_image()
+{
+    uch *src, *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow;
+    RECT rect;
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
+      image_width, image_rowbytes, wimage_rowbytes))
+
+
+/*---------------------------------------------------------------------------
+    Blast image data to buffer.  This whole routine takes place before the
+    message loop begins, so there's no real point in any pseudo-progressive
+    display...
+  ---------------------------------------------------------------------------*/
+
+    for (lastrow = row = 0;  row < image_height;  ++row) {
+        src = image_data + row*image_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        if (image_channels == 3) {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dest++ = b;
+                *dest++ = g;   /* note reverse order */
+                *dest++ = r;
+            }
+        } else /* if (image_channels == 4) */ {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (a == 255) {
+                    *dest++ = b;
+                    *dest++ = g;
+                    *dest++ = r;
+                } else if (a == 0) {
+                    *dest++ = bg_blue;
+                    *dest++ = bg_green;
+                    *dest++ = bg_red;
+                } else {
+                    /* this macro (copied from png.h) composites the
+                     * foreground and background values and puts the
+                     * result into the first argument; there are no
+                     * side effects with the first argument */
+                    alpha_composite(*dest++, b, a, bg_blue);
+                    alpha_composite(*dest++, g, a, bg_green);
+                    alpha_composite(*dest++, r, a, bg_red);
+                }
+            }
+        }
+        /* display after every 16 lines */
+        if (((row+1) & 0xf) == 0) {
+            rect.left = 0L;
+            rect.top = (LONG)lastrow;
+            rect.right = (LONG)image_width;      /* possibly off by one? */
+            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
+            InvalidateRect(global_hwnd, &rect, FALSE);
+            UpdateWindow(global_hwnd);     /* similar to XFlush() */
+            lastrow = row + 1;
+        }
+    }
+
+    Trace((stderr, "calling final image-flush routine\n"))
+    if (lastrow < image_height) {
+        rect.left = 0L;
+        rect.top = (LONG)lastrow;
+        rect.right = (LONG)image_width;      /* possibly off by one? */
+        rect.bottom = (LONG)image_height;    /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);     /* similar to XFlush() */
+    }
+
+/*
+    last param determines whether or not background is wiped before paint
+    InvalidateRect(global_hwnd, NULL, TRUE);
+    UpdateWindow(global_hwnd);
+ */
+
+    return 0;
+}
+
+
+
+
+
+static void rpng_win_cleanup()
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+
+
+
+
+
+LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+                    /*                    dest                          */
+            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
+                    /*                    source                        */
+                                    0, 0, image_width, image_height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                    /*              iUsage: no clue                     */
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {      /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:     /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+
+        case WM_LBUTTONDOWN:   /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}

contrib/gregbook/rpng-x.c

@@ -0,0 +1,843 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                               rpng-x.c
+
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for the X Window System (tested by author under Unix and
+   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
+
+   to do:
+    - 8-bit support
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng-x"
+#define LONGNAME  "Simple PNG Viewer for X"
+#define VERSION   "1.11 of 19 March 2000"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+#include "readpng.h"   /* typedefs, common macros, readpng prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+/* local prototypes */
+static int  rpng_x_create_window(void);
+static int  rpng_x_display_image(void);
+static void rpng_x_cleanup(void);
+static int  rpng_x_msb(ulg u32val);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *filename;
+static FILE *infile;
+
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+
+static double display_exponent;
+
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+/*
+ulg numcolors=0, pixels[256];
+ush reds[256], greens[256], blues[256];
+ */
+
+
+
+
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;               /* just the lookup table */
+    double CRT_exponent = 2.2;         /* just the monitor */
+    double default_display_exponent;   /* whole display system */
+    XEvent e;
+    KeySym k;
+
+
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+
+
+    /* First set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error; 
+                else 
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename) {
+        ++error;
+    } else if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n",
+                      filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng_cleanup(TRUE);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    /* usage screen */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n"
+          "\n", PROGNAME, default_display_exponent);
+        exit(1);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+
+
+    /* do the basic X initialization stuff, make the window and fill it
+     * with the background color */
+
+    if (rpng_x_create_window())
+        exit(2);
+
+
+    /* decode the image, all at once */
+
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+
+
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+
+    readpng_cleanup(FALSE);
+    fclose(infile);
+
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+
+
+    /* display image (composite with background if requested) */
+
+    Trace((stderr, "calling rpng_x_display_image()\n"))
+    if (rpng_x_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_x_display_image()\n"))
+
+
+    /* wait for the user to tell us when to quit */
+
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+
+    do
+        XNextEvent(display, &e);
+    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
+           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
+             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
+
+
+    /* OK, we're done:  clean up all image and X resources and go away */
+
+    rpng_x_cleanup();
+
+    return 0;
+}
+
+
+
+
+
+static int rpng_x_create_window(void)
+{
+    uch *xdata;
+    int need_colormap = FALSE;
+    int screen, pad;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XSizeHints *size_hints;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XWMHints *wm_hints;
+
+
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+
+#if 0
+/* GRR:  add 8-bit support */
+    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
+        fprintf(stderr,
+          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
+          depth);
+        return 2;
+    }
+
+    XMatchVisualInfo(display, screen, depth,
+      (depth == 8)? PseudoColor : TrueColor, &visual_info);
+    visual = visual_info.visual;
+#else
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+#endif
+
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng_x_msb(GMask);
+        BShift = 15 - rpng_x_msb(BMask);
+    } else if (depth > 16) {
+#define NO_24BIT_MASKS
+#ifdef NO_24BIT_MASKS
+        RShift = rpng_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng_x_msb(GMask) - 7;
+        BShift = rpng_x_msb(BMask) - 7;
+#else
+        RShift = 7 - rpng_x_msb(RMask);     /* these are right-shifts, too */
+        GShift = 7 - rpng_x_msb(GMask);
+        BShift = 7 - rpng_x_msb(BMask);
+#endif
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+
+    window = XCreateWindow(display, root, 0, 0, image_width, image_height, 0,
+      depth, InputOutput, visual, attrmask, &attr);
+
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+
+    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
+
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)image_width;
+        size_hints->min_height = size_hints->max_height = (int)image_height;
+    }
+
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, NULL);
+
+    XMapWindow(display, window);
+
+    gc = XCreateGC(display, window, 0, &gcvalues);
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        bg_pixel = ((ulg)bg_red   << RShift) |
+                   ((ulg)bg_green << GShift) |
+                   ((ulg)bg_blue  << BShift);
+    } else if (depth == 16) {
+        bg_pixel = ((((ulg)bg_red   << 8) >> RShift) & RMask) |
+                   ((((ulg)bg_green << 8) >> GShift) & GMask) |
+                   ((((ulg)bg_blue  << 8) >> BShift) & BMask);
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    XSetForeground(display, gc, bg_pixel);
+    XFillRectangle(display, window, gc, 0, 0, image_width, image_height);
+
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush.
+  ---------------------------------------------------------------------------*/
+
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+
+    XFlush(display);
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*image_width*image_height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*image_width*image_height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(image_width*image_height);
+        pad = 8;
+    }
+
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, image_width, image_height, pad, 0);
+
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (like Linux/x86, old VAXen, etc.)--this is not the most
+     * efficient approach (the giant if-test would be better), but in the
+     * interest of clarity, we take the easy way out... */
+
+    ximage->byte_order = MSBFirst;
+
+    return 0;
+
+} /* end function rpng_x_create_window() */
+
+
+
+
+
+static int rpng_x_display_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+/*  int bpp = ximage->bits_per_pixel;  */
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %ld, ximage_rowbytes = %d)\n",
+      image_width, image_rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG:  this assumes bpp == 32, but may be 24: */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#endif
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < image_height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, image_width, image_height-lastrow);
+        XFlush(display);
+    }
+
+    return 0;
+}
+
+
+
+
+static void rpng_x_cleanup(void)
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+
+    XFreeGC(display, gc);
+
+    if (have_window)
+        XDestroyWindow(display, window);
+
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+
+
+
+
+
+static int rpng_x_msb(ulg u32val)
+{
+    int i;
+
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}

contrib/gregbook/wpng.c

@@ -0,0 +1,816 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                                 wpng.c
+
+   This program converts certain NetPBM binary files (grayscale and RGB,
+   maxval = 255) to PNG.  Non-interlaced PNGs are written progressively;
+   interlaced PNGs are read and written in one memory-intensive blast.
+   Thanks to Jean-loup Gailly for providing the necessary trick to read
+   interactive text from the keyboard while stdin is redirected.
+
+   NOTE:  includes provisional support for PNM type "8" (portable alphamap)
+          images, presumed to be a 32-bit interleaved RGBA format; no pro-
+          vision for possible interleaved grayscale+alpha (16-bit) format.
+          THIS IS UNLIKELY TO BECOME AN OFFICIAL NETPBM ALPHA FORMAT!
+
+   to do:
+    - delete output file if quit before calling any writepng routines
+    - process backspace with -text option under DOS/Win? (currently get ^H)
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options
+    - 1.03:  removed extraneous character from usage screen; fixed bug in
+              command-line parsing
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "wpng"
+#define VERSION   "1.03 of 19 March 2000"
+#define APPNAME   "Simple PGM/PPM/PAM to PNG Converter"
+
+#if defined(__MSDOS__) || defined(__OS2__)
+#  define DOS_OS2_W32
+#elif defined(_WIN32) || defined(__WIN32__)
+#  define DOS_OS2_W32
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>     /* for jmpbuf declaration in writepng.h */
+#include <time.h>
+
+#ifdef DOS_OS2_W32
+#  include <io.h>       /* for isatty(), setmode() prototypes */
+#  include <fcntl.h>    /* O_BINARY for fdopen() without text translation */
+#  ifdef __EMX__
+#    ifndef getch
+#      define getch() _read_kbd(0, 1, 0)    /* need getche() */
+#    endif
+#  else /* !__EMX__ */
+#    ifdef __GO32__
+#      include <pc.h>
+#      define getch() getkey()  /* GRR:  need getche() */
+#    else
+#      include <conio.h>        /* for getche() console input */
+#    endif
+#  endif /* ?__EMX__ */
+#  define FGETS(buf,len,stream)  dos_kbd_gets(buf,len)
+#else
+#  include <unistd.h>           /* for isatty() prototype */
+#  define FGETS fgets
+#endif
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+/* #define FORBID_LATIN1_CTRL  :  this requires the user to re-enter any
+   text that includes control characters discouraged by the PNG spec; text
+   that includes an escape character (27) must be re-entered regardless */
+
+#include "writepng.h"   /* typedefs, common macros, writepng prototypes */
+
+
+
+/* local prototypes */
+
+static int  wpng_isvalid_latin1(uch *p, int len);
+static void wpng_cleanup(void);
+
+#ifdef DOS_OS2_W32
+   static char *dos_kbd_gets(char *buf, int len);
+#endif
+
+
+
+static mainprog_info wpng_info;   /* lone global */
+
+
+
+int main(int argc, char **argv)
+{
+#ifndef DOS_OS2_W32
+    FILE *keybd;
+#endif
+#ifdef sgi
+    FILE *tmpfile;      /* or we could just use keybd, since no overlap */
+    char tmpline[80];
+#endif
+    char *inname = NULL, outname[256];
+    char *p, pnmchar, pnmline[256];
+    char *bgstr, *textbuf = NULL;
+    ulg rowbytes;
+    int rc, len = 0;
+    int error = 0;
+    int text = FALSE;
+    int maxval;
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    double default_gamma = 0.0;
+
+
+    wpng_info.infile = NULL;
+    wpng_info.outfile = NULL;
+    wpng_info.image_data = NULL;
+    wpng_info.row_pointers = NULL;
+    wpng_info.filter = FALSE;
+    wpng_info.interlaced = FALSE;
+    wpng_info.have_bg = FALSE;
+    wpng_info.have_time = FALSE;
+    wpng_info.have_text = 0;
+    wpng_info.gamma = 0.0;
+
+
+    /* First get the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  If the PNM image
+     * looks correct on the user's display system, its file gamma is the
+     * inverse of this value.  (Note that this is not an exhaustive list
+     * of LUT values--e.g., OpenStep has a lot of weird ones--but it should
+     * cover 99% of the current possibilities.  This section must ensure
+     * that default_display_exponent is positive.) */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    tmpfile = fopen("/etc/config/system.glGammaVal", "r");
+    if (tmpfile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, tmpfile);
+        fclose(tmpfile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL) {
+        double exponent = atof(p);
+
+        if (exponent > 0.0)
+            default_gamma = 1.0 / exponent;
+    }
+
+    if (default_gamma == 0.0)
+        default_gamma = 1.0 / default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNM filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-i", 2)) {
+            wpng_info.interlaced = TRUE;
+        } else if (!strncmp(*argv, "-time", 3)) {
+            wpng_info.modtime = time(NULL);
+            wpng_info.have_time = TRUE;
+        } else if (!strncmp(*argv, "-text", 3)) {
+            text = TRUE;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                wpng_info.gamma = atof(*argv);
+                if (wpng_info.gamma <= 0.0)
+                    ++error;
+                else if (wpng_info.gamma > 1.01)
+                    fprintf(stderr, PROGNAME
+                      " warning:  file gammas are usually less than 1.0\n");
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    unsigned r, g, b;  /* this way quiets compiler warnings */
+
+                    sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+                    wpng_info.bg_red   = (uch)r;
+                    wpng_info.bg_green = (uch)g;
+                    wpng_info.bg_blue  = (uch)b;
+                    wpng_info.have_bg = TRUE;
+                }
+            }
+        } else {
+            if (**argv != '-') {
+                inname = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+
+    /* open the input and output files, or register an error and abort */
+
+    if (!inname) {
+        if (isatty(0)) {
+            fprintf(stderr, PROGNAME
+              ":  must give input filename or provide image data via stdin\n");
+            ++error;
+        } else {
+#ifdef DOS_OS2_W32
+            /* some buggy C libraries require BOTH setmode() and fdopen(bin) */
+            setmode(fileno(stdin), O_BINARY);
+            setmode(fileno(stdout), O_BINARY);
+#endif
+            if ((wpng_info.infile = fdopen(fileno(stdin), "rb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdin in binary mode\n");
+                ++error;
+            } else
+            if ((wpng_info.outfile = fdopen(fileno(stdout), "wb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdout in binary mode\n");
+                fclose(wpng_info.infile);
+                ++error;
+            } else
+                wpng_info.filter = TRUE;
+        }
+    } else if ((len = strlen(inname)) > 250) {
+        fprintf(stderr, PROGNAME ":  input filename is too long [%d chars]\n",
+          len);
+        ++error;
+    } else if (!(wpng_info.infile = fopen(inname, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open input file [%s]\n", inname);
+        ++error;
+    }
+
+    if (!error) {
+        fgets(pnmline, 256, wpng_info.infile);
+        if (pnmline[0] != 'P' || ((pnmchar = pnmline[1]) != '5' &&
+            pnmchar != '6' && pnmchar != '8'))
+        {
+            fprintf(stderr, PROGNAME
+              ":  input file [%s] is not a binary PGM, PPM or PAM file\n",
+              inname);
+            ++error;
+        } else {
+            wpng_info.pnmtype = (int)(pnmchar - '0');
+            if (wpng_info.pnmtype != 8)
+                wpng_info.have_bg = FALSE;  /* no need for bg if opaque */
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* lose any comments */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%ld %ld", &wpng_info.width, &wpng_info.height);
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* more comment lines */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%d", &maxval);
+            if (wpng_info.width <= 0L || wpng_info.height <= 0L ||
+                maxval != 255)
+            {
+                fprintf(stderr, PROGNAME
+                  ":  only positive width/height, maxval == 255 allowed \n");
+                ++error;
+            }
+            wpng_info.sample_depth = 8;  /* <==> maxval 255 */
+
+            if (!wpng_info.filter) {
+                /* make outname from inname */
+                if ((p = strrchr(inname, '.')) == NULL ||
+                    (p - inname) != (len - 4))
+                {
+                    strcpy(outname, inname);
+                    strcpy(outname+len, ".png");
+                } else {
+                    len -= 4;
+                    strncpy(outname, inname, len);
+                    strcpy(outname+len, ".png");
+                }
+                /* check if outname already exists; if not, open */
+                if ((wpng_info.outfile = fopen(outname, "rb")) != NULL) {
+                    fprintf(stderr, PROGNAME ":  output file exists [%s]\n",
+                      outname);
+                    fclose(wpng_info.outfile);
+                    ++error;
+                } else if (!(wpng_info.outfile = fopen(outname, "wb"))) {
+                    fprintf(stderr, PROGNAME ":  can't open output file [%s]\n",
+                      outname);
+                    ++error;
+                }
+            }
+        }
+        if (error) {
+            fclose(wpng_info.infile);
+            wpng_info.infile = NULL;
+            if (wpng_info.filter) {
+                fclose(wpng_info.outfile);
+                wpng_info.outfile = NULL;
+            }
+        }
+    }
+
+
+    /* if we had any errors, print usage and die horrible death...arrr! */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, APPNAME);
+        writepng_version_info();
+        fprintf(stderr, "\n"
+"Usage:  %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] pnmfile\n"
+"or: ... | %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] | ...\n"
+         "    exp \ttransfer-function exponent (``gamma'') of the image in\n"
+         "\t\t  floating-point format (e.g., ``%.5f''); if image looks\n"
+         "\t\t  correct on given display system, image gamma is equal to\n"
+         "\t\t  inverse of display-system exponent, i.e., 1 / (LUT * CRT)\n"
+         "\t\t  (where LUT = lookup-table exponent and CRT = CRT exponent;\n"
+         "\t\t  first varies, second is usually 2.2, all are positive)\n"
+         "    bg  \tdesired background color for alpha-channel images, in\n"
+         "\t\t  7-character hex RGB format (e.g., ``#ff7700'' for orange:\n"
+         "\t\t  same as HTML colors)\n"
+         "    -text\tprompt interactively for text info (tEXt chunks)\n"
+         "    -time\tinclude a tIME chunk (last modification time)\n"
+         "    -interlace\twrite interlaced PNG image\n"
+         "\n"
+"pnmfile or stdin must be a binary PGM (`P5'), PPM (`P6') or (extremely\n"
+"unofficial and unsupported!) PAM (`P8') file.  Currently it is required\n"
+"to have maxval == 255 (i.e., no scaling).  If pnmfile is specified, it\n"
+"is converted to the corresponding PNG file with the same base name but a\n"
+"``.png'' extension; files read from stdin are converted and sent to stdout.\n"
+"The conversion is progressive (low memory usage) unless interlacing is\n"
+"requested; in that case the whole image will be buffered in memory and\n"
+"written in one call.\n"
+         "\n", PROGNAME, PROGNAME, default_gamma);
+        exit(1);
+    }
+
+
+    /* prepare the text buffers for libpng's use; note that even though
+     * PNG's png_text struct includes a length field, we don't have to fill
+     * it out */
+
+    if (text &&
+#ifndef DOS_OS2_W32
+        (keybd = fdopen(fileno(stderr), "r")) != NULL &&
+#endif
+        (textbuf = (char *)malloc((5 + 9)*75)) != NULL)
+    {
+        int i, valid, result;
+
+        fprintf(stderr,
+          "Enter text info (no more than 72 characters per line);\n");
+        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
+        /* note:  just <Enter> leaves len == 1 */
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_TITLE_OFFSET;
+            fprintf(stderr, "  Title: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.title = p;
+                wpng_info.have_text |= TEXT_TITLE;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_TITLE;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_TITLE;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_AUTHOR_OFFSET;
+            fprintf(stderr, "  Author: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.author = p;
+                wpng_info.have_text |= TEXT_AUTHOR;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_AUTHOR;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_AUTHOR;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_DESC_OFFSET;
+            fprintf(stderr, "  Description (up to 9 lines):\n");
+            for (i = 1;  i < 10;  ++i) {
+                fprintf(stderr, "    [%d] ", i);
+                fflush(stderr);
+                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
+                    p += len;   /* now points at NULL; char before is newline */
+                else
+                    break;
+            }
+            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
+                if (p[-1] == '\n') {
+                    p[-1] = '\0';
+                    --len;
+                }
+                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
+                wpng_info.have_text |= TEXT_DESC;
+                p = textbuf + TEXT_DESC_OFFSET;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_DESC;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_DESC;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_COPY_OFFSET;
+            fprintf(stderr, "  Copyright: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.copyright = p;
+                wpng_info.have_text |= TEXT_COPY;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_COPY;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_COPY;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_EMAIL_OFFSET;
+            fprintf(stderr, "  E-mail: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.email = p;
+                wpng_info.have_text |= TEXT_EMAIL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_EMAIL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_EMAIL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_URL_OFFSET;
+            fprintf(stderr, "  URL: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.url = p;
+                wpng_info.have_text |= TEXT_URL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_URL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_URL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+#ifndef DOS_OS2_W32
+        fclose(keybd);
+#endif
+
+    } else if (text) {
+        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
+        text = FALSE;
+        wpng_info.have_text = 0;
+    }
+
+
+    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */
+
+    if ((rc = writepng_init(&wpng_info)) != 0) {
+        switch (rc) {
+            case 2:
+                fprintf(stderr, PROGNAME
+                  ":  libpng initialization problem (longjmp)\n");
+                break;
+            case 4:
+                fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                break;
+            case 11:
+                fprintf(stderr, PROGNAME
+                  ":  internal logic error (unexpected PNM type)\n");
+                break;
+            default:
+                fprintf(stderr, PROGNAME
+                  ":  unknown writepng_init() error\n");
+                break;
+        }
+        exit(rc);
+    }
+
+
+    /* free textbuf, since it's a completely local variable and all text info
+     * has just been written to the PNG file */
+
+    if (text && textbuf) {
+        free(textbuf);
+        textbuf = NULL;
+    }
+
+
+    /* calculate rowbytes on basis of image type; note that this becomes much
+     * more complicated if we choose to support PBM type, ASCII PNM types, or
+     * 16-bit-per-sample binary data [currently not an official NetPBM type] */
+
+    if (wpng_info.pnmtype == 5)
+        rowbytes = wpng_info.width;
+    else if (wpng_info.pnmtype == 6)
+        rowbytes = wpng_info.width * 3;
+    else /* if (wpng_info.pnmtype == 8) */
+        rowbytes = wpng_info.width * 4;
+
+
+    /* read and write the image, either in its entirety (if writing interlaced
+     * PNG) or row by row (if non-interlaced) */
+
+    fprintf(stderr, "Encoding image data...\n");
+    fflush(stderr);
+
+    if (wpng_info.interlaced) {
+        long i;
+        ulg bytes;
+        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */
+
+        wpng_info.image_data = (uch *)malloc(image_bytes);
+        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
+        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        for (i = 0;  i < wpng_info.height;  ++i)
+            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
+        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
+        if (bytes != image_bytes) {
+            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
+              image_bytes, bytes);
+            fprintf(stderr, "  (continuing anyway)\n");
+        }
+        if (writepng_encode_image(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME
+              ":  libpng problem (longjmp) while writing image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+
+    } else /* not interlaced:  write progressively (row by row) */ {
+        long j;
+        ulg bytes;
+
+        wpng_info.image_data = (uch *)malloc(rowbytes);
+        if (wpng_info.image_data == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        error = 0;
+        for (j = wpng_info.height;  j > 0L;  --j) {
+            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
+            if (bytes != rowbytes) {
+                fprintf(stderr, PROGNAME
+                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
+                  bytes, wpng_info.height-j);
+                ++error;
+                break;
+            }
+            if (writepng_encode_row(&wpng_info) != 0) {
+                fprintf(stderr, PROGNAME
+                  ":  libpng problem (longjmp) while writing row %ld\n",
+                  wpng_info.height-j);
+                ++error;
+                break;
+            }
+        }
+        if (error) {
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+        if (writepng_encode_finish(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+    }
+
+
+    /* OK, we're done (successfully):  clean up all resources and quit */
+
+    fprintf(stderr, "Done.\n");
+    fflush(stderr);
+
+    writepng_cleanup(&wpng_info);
+    wpng_cleanup();
+
+    return 0;
+}
+
+
+
+
+
+static int wpng_isvalid_latin1(uch *p, int len)
+{
+    int i, result = -1;
+
+    for (i = 0;  i < len;  ++i) {
+        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
+            continue;           /* character is completely OK */
+        if (result < 0 || (p[result] != 27 && p[i] == 27))
+            result = i;         /* mark location of first questionable one */
+    }                           /*  or of first escape character (bad) */
+
+    return result;
+}
+
+
+
+
+
+static void wpng_cleanup(void)
+{
+    if (wpng_info.outfile) {
+        fclose(wpng_info.outfile);
+        wpng_info.outfile = NULL;
+    }
+
+    if (wpng_info.infile) {
+        fclose(wpng_info.infile);
+        wpng_info.infile = NULL;
+    }
+
+    if (wpng_info.image_data) {
+        free(wpng_info.image_data);
+        wpng_info.image_data = NULL;
+    }
+
+    if (wpng_info.row_pointers) {
+        free(wpng_info.row_pointers);
+        wpng_info.row_pointers = NULL;
+    }
+}
+
+
+
+
+#ifdef DOS_OS2_W32
+
+static char *dos_kbd_gets(char *buf, int len)
+{
+    int ch, count=0;
+
+    do {
+        buf[count++] = ch = getche();
+    } while (ch != '\r' && count < len-1);
+
+    buf[count--] = '\0';        /* terminate string */
+    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
+        buf[count] = '\n';
+
+    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
+    fflush(stderr);
+
+    return buf;
+}
+
+#endif /* DOS_OS2_W32 */

contrib/gregbook/writepng.c

@@ -0,0 +1,368 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                             writepng.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>     /* for exit() prototype */
+
+#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
+#include "writepng.h"   /* typedefs, common macros, public prototypes */
+
+
+/* local prototype */
+
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
+
+
+
+void writepng_version_info(void)
+{
+  fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+    PNG_LIBPNG_VER_STRING, png_libpng_ver);
+  fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+    ZLIB_VERSION, zlib_version);
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
+ *  unexpected pnmtype; note that outfile might be stdout */
+
+int writepng_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+    int color_type, interlace_type;
+
+
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+      writepng_error_handler, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_write_struct(&png_ptr, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* setjmp() must be called in every function that calls a PNG-writing
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or exit immediately, so here we go: */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 2;
+    }
+
+
+    /* make sure outfile is (re)opened in BINARY mode */
+
+    png_init_io(png_ptr, mainprog_ptr->outfile);
+
+
+    /* set the compression levels--in general, always want to leave filtering
+     * turned on (except for palette images) and allow all of the filters,
+     * which is the default; want 32K zlib window, unless entire image buffer
+     * is 16K or smaller (unknown here)--also the default; usually want max
+     * compression (NOT the default); and remaining compression flags should
+     * be left alone */
+
+    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+/*
+    >> this is default for no filtering; Z_FILTERED is default otherwise:
+    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
+    >> these are all defaults:
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+ */
+
+
+    /* set the image parameters appropriately */
+
+    if (mainprog_ptr->pnmtype == 5)
+        color_type = PNG_COLOR_TYPE_GRAY;
+    else if (mainprog_ptr->pnmtype == 6)
+        color_type = PNG_COLOR_TYPE_RGB;
+    else if (mainprog_ptr->pnmtype == 8)
+        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+    else {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 11;
+    }
+
+    interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
+                                               PNG_INTERLACE_NONE;
+
+    png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
+      mainprog_ptr->sample_depth, color_type, interlace_type,
+      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+    if (mainprog_ptr->gamma > 0.0)
+        png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
+
+    if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
+        png_color_16  background;
+
+        background.red = mainprog_ptr->bg_red;
+        background.green = mainprog_ptr->bg_green;
+        background.blue = mainprog_ptr->bg_blue;
+        png_set_bKGD(png_ptr, info_ptr, &background);
+    }
+
+    if (mainprog_ptr->have_time) {
+        png_time  modtime;
+
+        png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
+        png_set_tIME(png_ptr, info_ptr, &modtime);
+    }
+
+    if (mainprog_ptr->have_text) {
+        png_text  text[6];
+        int  num_text = 0;
+
+        if (mainprog_ptr->have_text & TEXT_TITLE) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Title";
+            text[num_text].text = mainprog_ptr->title;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_AUTHOR) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Author";
+            text[num_text].text = mainprog_ptr->author;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_DESC) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Description";
+            text[num_text].text = mainprog_ptr->desc;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_COPY) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Copyright";
+            text[num_text].text = mainprog_ptr->copyright;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_EMAIL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "E-mail";
+            text[num_text].text = mainprog_ptr->email;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_URL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "URL";
+            text[num_text].text = mainprog_ptr->url;
+            ++num_text;
+        }
+        png_set_text(png_ptr, info_ptr, text, num_text);
+    }
+
+
+    /* write all chunks up to (but not including) first IDAT */
+
+    png_write_info(png_ptr, info_ptr);
+
+
+    /* if we wanted to write any more text info *after* the image data, we
+     * would set up text struct(s) here and call png_set_text() again, with
+     * just the new data; png_set_tIME() could also go here, but it would
+     * have no effect since we already called it above (only one tIME chunk
+     * allowed) */
+
+
+    /* set up the transformations:  for now, just pack low-bit-depth pixels
+     * into bytes (one, two or four pixels per byte) */
+
+    png_set_packing(png_ptr);
+/*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
+
+
+    /* make sure we save our pointers for use in writepng_encode_image() */
+
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+
+
+    /* OK, that's all we need to do for now; return happy */
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+
+int writepng_encode_image(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* and now we just write the whole image; libpng takes care of interlacing
+     * for us */
+
+    png_write_image(png_ptr, mainprog_ptr->row_pointers);
+
+
+    /* since that's it, we also close out the end of the PNG file now--if we
+     * had any text or time info to write after the IDATs, second argument
+     * would be info_ptr, but we optimize slightly by sending NULL pointer: */
+
+    png_write_end(png_ptr, NULL);
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 if succeeds, 2 if libpng problem */
+
+int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* image_data points at our one row of image data */
+
+    png_write_row(png_ptr, mainprog_ptr->image_data);
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 if succeeds, 2 if libpng problem */
+
+int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* close out PNG file; if we had any text or time info to write after
+     * the IDATs, second argument would be info_ptr: */
+
+    png_write_end(png_ptr, NULL);
+
+    return 0;
+}
+
+
+
+
+
+void writepng_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+    if (png_ptr && info_ptr)
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+}
+
+
+
+
+
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+
+    fprintf(stderr, "writepng libpng error: %s\n", msg);
+    fflush(stderr);
+
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "writepng severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}

contrib/gregbook/writepng.h

@@ -0,0 +1,109 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                             writepng.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2000 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+#define TEXT_TITLE    0x01
+#define TEXT_AUTHOR   0x02
+#define TEXT_DESC     0x04
+#define TEXT_COPY     0x08
+#define TEXT_EMAIL    0x10
+#define TEXT_URL      0x20
+
+#define TEXT_TITLE_OFFSET        0
+#define TEXT_AUTHOR_OFFSET      72
+#define TEXT_COPY_OFFSET     (2*72)
+#define TEXT_EMAIL_OFFSET    (3*72)
+#define TEXT_URL_OFFSET      (4*72)
+#define TEXT_DESC_OFFSET     (5*72)
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+typedef struct _mainprog_info {
+    double gamma;
+    long width;
+    long height;
+    time_t modtime;
+    FILE *infile;
+    FILE *outfile;
+    void *png_ptr;
+    void *info_ptr;
+    uch *image_data;
+    uch **row_pointers;
+    char *title;
+    char *author;
+    char *desc;
+    char *copyright;
+    char *email;
+    char *url;
+    int filter;    /* command-line-filter flag, not PNG row filter! */
+    int pnmtype;
+    int sample_depth;
+    int interlaced;
+    int have_bg;
+    int have_time;
+    int have_text;
+    jmp_buf jmpbuf;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+
+
+/* prototypes for public functions in writepng.c */
+
+void writepng_version_info(void);
+
+int writepng_init(mainprog_info *mainprog_ptr);
+
+int writepng_encode_image(mainprog_info *mainprog_ptr);
+
+int writepng_encode_row(mainprog_info *mainprog_ptr);
+
+int writepng_encode_finish(mainprog_info *mainprog_ptr);
+
+void writepng_cleanup(mainprog_info *mainprog_ptr);

contrib/pngminus/README

@@ -0,0 +1,153 @@
+PngMinus
+--------
+(copyright Willem van Schaik, 1999)
+
+
+License
+-------
+
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and
+that both that copyright notice and this permission notice appear in
+supporting documentation. This software is provided "as is" without
+express or implied warranty.
+
+
+Some history
+------------
+Soon after the creation of PNG in 1995, the need was felt for a set of
+pnmtopng / pngtopnm utilities. Independantly Alexander Lehmann and I
+(Willem van Schaik) started such a project. Luckily we discovered this
+and merged the two together into pnmtopng.tar.gz, which is available
+from a/o ftp://swrinde.nde.swri.edu/pub/png/.
+
+These two utilities have many, many options and make use of most of the
+features of PNG, like gamma, alpha, sbit, text-chunks, etc. This makes
+the utilities quite complex and by now not anymore very maintainable.
+When we wrote these programs, libpng was still in an early stage.
+Therefore, lots of the functionality that we put in our software can now
+be done using transform-functions in libpng.
+
+Finally, to compile these programs, you need to have installed and
+compiled three libraries: libpng, zlib and netpbm. Especially the latter
+makes the whole setup a bit bulky. But that's unavoidable given the many
+features of pnmtopng.
+
+
+What now
+--------
+At this moment libpng is in a very stable state and can do much of the
+work done in pnmtopng. Also, pnmtopng needs to be upgraded to the new
+interface of libpng. Hence, it is time for a rewrite from the ground up
+of pnmtopng and pngtopnm. This will happen in the near future (stay
+tuned). The new package will get a different name to distinguish it from
+the old one: PngPlus.
+
+To experiment a bit with the new interface of libpng, I started off with
+a small prototype that contains only the basic functionality. It doesn't
+have any of the options to read or write special chunks and it will do
+no gamma correction. But this makes it also a simple program that is
+quite easy to understand and can serve well as a template for other
+software developments. (By now there are of course a couple of programs,
+like Greg Roelofs' rpng/wpng, that can be used just as good.)
+
+
+Can and can not
+---------------
+As this is the small brother of the future PngPlus, I called this fellow
+PngMinus. Because I started this development in good-old Turbo-C, I
+avoided the use the netpbm library, which requires DOS extenders. Again,
+another reason to call it PngMinus (minus netpbm :-). So, part of the
+program are some elementary routines to read / write pgm- and ppm-files.
+It does not read b&w pbm-files.
+
+The downside of this approach is that you can not use them on images
+that require blocks of memory bigger than 64k (the DOS version). For
+larger images you will get an out-of-memory error.
+
+As said before, PngMinus doesn't correct for gamma. When reading
+png-files you can do this just as well by piping the output of png2pnm
+to pnmgamma, one of the standard PbmPlus tools. This same scenario will
+most probably also be followed in the full-blown future PngPlus, with
+the addition of course of the possibility to create gamma-chunks when
+writing png-files.
+
+On the other hand it supports alpha-channels. When reading a png-image
+you can write the alpha-channel into a pgm-file. And when creating an
+RGB+A png-image, you just combine a ppm-file with a corresponding
+pgm-file containing the alpha-channel. When reading, transparency chunks
+are converted into an alpha-channel and from there on treated the same
+way.
+
+Finally you can opt for writing ascii or binary pgm- and ppm-files. When
+the bit-depth is 16, the format will always be ascii.
+
+
+Using it
+--------
+To distinguish them from pnmtopng and PngPlus, the utilities are named
+png2pnm and pnm2png (2 instead of to). The input- and output-files can
+be given as parameters or through redirection. Therefore the programs
+can be part of a pipe.
+
+To list the options type "png2pnm -h" or "pnm2png -h".
+
+
+Just like Scandinavian furniture
+--------------------------------
+You have to put it together yourself. I did test the software under
+MS-DOS with Turbo-C 3.0 and under RedHat Linux 4.2 with gcc. In both
+cases I used libpng-1.0.4 and zlib-1.1.3. Later versions should be OK,
+however some older libpng versions have a bug in pngmem.c when using
+Turbo-C 3.0 (see below).
+
+You can build it using one of the two makefiles (make -f makefile.###)
+or use the batch/script files pngminus.bat / pngminus.sh. This assumes
+that you have built the libraries in ../libpng and ../zlib. Using Linux,
+make sure that you have built libpng with makefile.std and not
+makefile.linux (also called .lnx in earlier versions of libpng). The
+latter creates a .so shared-library, while the PngMinus makefile assumes
+a normal .a static library.
+
+If you create a ../pngsuite directory and then store the basn####.png
+files from PngSuite (http://www.schaik.com/pngsuite/) in there, you can
+test in one go the proper functioning of PngMinus, see png2pnm.bat and
+pnm2png.bat (or the .sh versions).
+
+
+Warranty
+-------
+Please, remember that this was just a small experiment to learn a few
+things. It will have many unforeseen features <vbg>. Who said bugs? Use
+it when you are in need for something simple or when you want to start
+developing your own stuff.
+
+
+The Turbo bug
+-------------
+** pngmem.old
+          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
+          hptr += 16L;
+** pngmem.c
+          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
+          hptr = hptr + 16L;
+**
+
+** pngmem.old
+          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
+          hptr += (png_uint_32)65536L;
+** pngmem.c
+          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
+          hptr = hptr + 65536L;
+**
+
+
+The end
+-------
+Willem van Schaik
+mailto:willem@schaik.com
+http://www.schaik.com/png/
+-------
+Oct 1999
+

contrib/pngminus/makefile.std

@@ -0,0 +1,52 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# Linux / Unix
+
+CC=cc -O
+LD=cc -O
+#CC=gcc -O
+#LD=gcc -O
+LB=ar
+RM=rm
+CP=cp
+
+PNGPATH = /usr/local
+PNGINC = $(PNGPATH)/include
+#PNGLIB = $(PNGPATH)/lib -lpng
+PNGLIB = $(PNGPATH)/lib/libpng.a
+
+ZPATH = /usr/local
+ZINC = $(ZPATH)/include
+#ZLIB = $(ZPATH)/lib -lz
+ZLIB = $(ZPATH)/lib/libz.a
+
+CCFLAGS=-I$(PNGINC) -I$(ZINC)
+LDFLAGS=-L$(PNGLIB) -L$(ZLIB)
+C=.c
+O=.o
+L=.a
+E=
+
+# dependencies
+
+all: png2pnm$(E) pnm2png$(E)
+
+png2pnm$(O): png2pnm$(C)
+	$(CC) -c $(CCFLAGS) png2pnm$(C)
+
+png2pnm$(E): png2pnm$(O)
+	$(LD) -o png2pnm$(E) png2pnm$(O) $(LDFLAGS) -lpng -lz -lm
+
+pnm2png$(O): pnm2png$(C)
+	$(CC) -c $(CCFLAGS) pnm2png$(C)
+
+pnm2png$(E): pnm2png$(O)
+	$(LD) -o pnm2png$(E) pnm2png$(O) $(LDFLAGS) -lpng -lz -lm
+
+clean:
+	$(RM) png2pnm$(O)
+	$(RM) pnm2png$(O)
+	$(RM) png2pnm$(E)
+	$(RM) pnm2png$(E)
+
+# End of makefile for png2pnm / pnm2png
+

contrib/pngminus/makefile.tc3

@@ -0,0 +1,38 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# TurboC++ 3.0
+
+CC=tcc -Ic:\tc3\inc
+LD=tcc -Lc:\tc3\lib
+LB=tlib
+RM=del
+CP=copy
+MODEL=l
+CCFLAGS=-O -m$(MODEL) -I..\libpng -I..\zlib
+LDFLAGS=-m$(MODEL) -L..\libpng -L..\zlib
+C=.c
+O=.obj
+L=.lib
+E=.exe
+
+# dependencies
+
+all: png2pnm$(E) pnm2png$(E)
+
+png2pnm$(O): png2pnm$(C)
+        $(CC) -c $(CCFLAGS) png2pnm$(C)
+
+png2pnm$(E): png2pnm$(O)
+        $(LD) $(LDFLAGS) png2pnm$(O) libpng$(L) zlib$(L)
+
+pnm2png$(O): pnm2png$(C)
+        $(CC) -c $(CCFLAGS) pnm2png$(C)
+
+pnm2png$(E): pnm2png$(O)
+        $(LD) $(LDFLAGS) pnm2png$(O) libpng$(L) zlib$(L)
+
+clean:
+        $(RM) *$(O)
+        $(RM) *$(E)
+
+# End of makefile for png2pnm / pnm2png
+

contrib/pngminus/makevms.com

@@ -0,0 +1,92 @@
+$!------------------------------------------------------------------------------
+$! make Contrib programs of libpng under OpenVMS
+$!
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[---.zlib]"
+$ ccopt="/include=(''zlibsrc',[--])"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "[--]libpng.olb/lib"
+$ write lopt "''zlibsrc'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$ write sys$output "Compiling PNG contrib programs ..."
+$   write sys$output "Building pnm2png..."
+$   CALL MAKE pnm2png.OBJ "cc ''CCOPT' pnm2png" -
+	pnm2png.c
+$   call make pnm2png.exe -
+	"LINK pnm2png,lib.opt/opt" -
+	pnm2png.obj
+$   write sys$output "Building png2pnm..."
+$   CALL MAKE png2pnm.OBJ "cc ''CCOPT' png2pnm" -
+	png2pnm.c
+$   call make pnm2png.exe -
+	"LINK pnm2png,lib.opt/opt" -
+	pnm2png.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE

contrib/pngminus/png2pnm.bat

@@ -0,0 +1,41 @@
+REM -- grayscale
+png2pnm.exe -noraw ..\pngsuite\basn0g01.png basn0g01.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g02.png basn0g02.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g04.png basn0g04.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g08.png basn0g08.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g16.png basn0g16.pgm
+REM -- full-color
+png2pnm.exe -noraw ..\pngsuite\basn2c08.png basn2c08.ppm
+png2pnm.exe -noraw ..\pngsuite\basn2c16.png basn2c16.ppm
+REM -- palletted
+png2pnm.exe -noraw ..\pngsuite\basn3p01.png basn3p01.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p02.png basn3p02.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p04.png basn3p04.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p08.png basn3p08.ppm
+REM -- gray with alpha-channel
+png2pnm.exe -noraw ..\pngsuite\basn4a08.png basn4a08.pgm
+png2pnm.exe -noraw ..\pngsuite\basn4a16.png basn4a16.pgm
+REM -- color with alpha-channel
+png2pnm.exe -noraw -alpha basn6a08.pgm ..\pngsuite\basn6a08.png basn6a08.ppm
+png2pnm.exe -noraw -alpha basn6a16.pgm ..\pngsuite\basn6a16.png basn6a16.ppm
+REM -- grayscale
+png2pnm.exe -raw ..\pngsuite\basn0g01.png rawn0g01.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g02.png rawn0g02.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g04.png rawn0g04.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g08.png rawn0g08.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g16.png rawn0g16.pgm
+REM -- full-color
+png2pnm.exe -raw ..\pngsuite\basn2c08.png rawn2c08.ppm
+png2pnm.exe -raw ..\pngsuite\basn2c16.png rawn2c16.ppm
+REM -- palletted
+png2pnm.exe -raw ..\pngsuite\basn3p01.png rawn3p01.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p02.png rawn3p02.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p04.png rawn3p04.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p08.png rawn3p08.ppm
+REM -- gray with alpha-channel
+png2pnm.exe -raw ..\pngsuite\basn4a08.png rawn4a08.pgm
+png2pnm.exe -raw ..\pngsuite\basn4a16.png rawn4a16.pgm
+REM -- color with alpha-channel
+png2pnm.exe -noraw -alpha rawn6a08.pgm ..\pngsuite\basn6a08.png rawn6a08.ppm
+png2pnm.exe -noraw -alpha rawn6a16.pgm ..\pngsuite\basn6a16.png rawn6a16.ppm
+

contrib/pngminus/png2pnm.c

@@ -0,0 +1,425 @@
+/*
+ *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
+ *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
+ *
+ *  version 1.0 - 1999.10.15 - First version.
+ *
+ *  Permission to use, copy, modify, and distribute this software and
+ *  its documentation for any purpose and without fee is hereby granted,
+ *  provided that the above copyright notice appear in all copies and
+ *  that both that copyright notice and this permission notice appear in
+ *  supporting documentation. This software is provided "as is" without
+ *  express or implied warranty.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef __TURBOC__
+#include <mem.h>
+#include <fcntl.h>
+#endif
+
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE (BOOL) 1
+#endif
+#ifndef FALSE
+#define FALSE (BOOL) 0
+#endif
+
+#ifdef __TURBOC__
+#define STDIN  0
+#define STDOUT 1
+#define STDERR 2
+#endif
+
+/* to make png2pnm verbose so we can find problems (needs to be before png.h) */
+#ifndef PNG_DEBUG
+#define PNG_DEBUG 0
+#endif
+
+#include "png.h"
+
+/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#endif
+
+/* function prototypes */
+
+int  main (int argc, char *argv[]);
+void usage ();
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);
+
+/*
+ *  main
+ */
+
+int main(int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_wr = stdout;
+  FILE *fp_al = NULL;
+  BOOL raw = TRUE;
+  BOOL alpha = FALSE;
+  int argi;
+
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'n':
+          raw = FALSE;
+          break;
+        case 'r':
+          raw = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage();
+          exit(0);
+          break;
+        default:
+          fprintf (stderr, "PNG2PNM\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage();
+          exit(1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+             fprintf (stderr, "PNG2PNM\n");
+            fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+            exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "Error:  can not create file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNG2PNM\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage();
+      exit(1);
+    }
+  } /* end for */
+
+#ifdef __TURBOC__
+  /* set stdin/stdout if required to binary */
+  if (fp_rd == stdin)
+  {
+    setmode (STDIN, O_BINARY);
+  }
+  if ((raw) && (fp_wr == stdout))
+  {
+    setmode (STDOUT, O_BINARY);
+  }
+#endif
+
+  /* call the conversion program itself */
+  if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  unsuccessful convertion of PNG-image\n");
+    exit(1);
+  }
+
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+
+  return 0;
+}
+
+/*
+ *  usage
+ */
+
+void usage()
+{
+  fprintf (stderr, "PNG2PNM\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+#ifdef __TURBOC__
+  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
+#else
+  fprintf (stderr, "   for Linux (and Unix) compilers\n");
+#endif
+  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
+  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
+  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+
+/*
+ *  png2pnm
+ */
+
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
+{
+  png_struct    *png_ptr = NULL;
+  png_info	*info_ptr = NULL;
+  png_byte      buf[8];
+  png_byte      *png_pixels = NULL;
+  png_byte      **row_pointers = NULL;
+  png_byte      *pix_ptr = NULL;
+  png_uint_32   row_bytes;
+
+  png_uint_32   width;
+  png_uint_32   height;
+  int           bit_depth;
+  int           channels;
+  int           color_type;
+  int           alpha_present;
+  int           row, col;
+  int           ret;
+  int           i;
+
+  /* read and check signature in PNG file */
+  ret = fread (buf, 1, 8, png_file);
+  if (ret != 8)
+    return FALSE;
+
+  ret = png_check_sig (buf, 8);
+  if (!ret)
+    return FALSE;
+
+  /* create png and info structures */
+
+  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
+    NULL, NULL, NULL);
+  if (!png_ptr)
+    return FALSE;   /* out of memory */
+
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_read_struct (&png_ptr, NULL, NULL);
+    return FALSE;   /* out of memory */
+  }
+
+  if (setjmp (png_jmpbuf(png_ptr)))
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+
+  /* set up the input control for C streams */
+  png_init_io (png_ptr, png_file);
+  png_set_sig_bytes (png_ptr, 8);  /* we already read the 8 signature bytes */
+
+  /* read the file information */
+  png_read_info (png_ptr, info_ptr);
+
+  /* get size and bit-depth of the PNG-image */
+  png_get_IHDR (png_ptr, info_ptr,
+    &width, &height, &bit_depth, &color_type,
+    NULL, NULL, NULL);
+
+  /* set-up the transformations */
+
+  /* transform paletted images into full-color rgb */
+  if (color_type == PNG_COLOR_TYPE_PALETTE)
+    png_set_expand (png_ptr);
+  /* expand images to bit-depth 8 (only applicable for grayscale images) */
+  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+    png_set_expand (png_ptr);
+  /* transform transparency maps into full alpha-channel */
+  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
+    png_set_expand (png_ptr);
+
+#ifdef NJET
+  /* downgrade 16-bit images to 8 bit */
+  if (bit_depth == 16)
+    png_set_strip_16 (png_ptr);
+  /* transform grayscale images into full-color */
+  if (color_type == PNG_COLOR_TYPE_GRAY ||
+    color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    png_set_gray_to_rgb (png_ptr);
+  /* only if file has a file gamma, we do a correction */
+  if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
+    png_set_gamma (png_ptr, (double) 2.2, file_gamma);
+#endif
+
+  /* all transformations have been registered; now update info_ptr data,
+   * get rowbytes and channels, and allocate image memory */
+
+  png_read_update_info (png_ptr, info_ptr);
+
+  /* get the new color-type and bit-depth (after expansion/stripping) */
+  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+    NULL, NULL, NULL);
+
+  /* check for 16-bit files */
+  if (bit_depth == 16)
+  {
+    raw = FALSE;
+#ifdef __TURBOC__
+    pnm_file->flags &= ~((unsigned) _F_BIN);
+#endif
+  }
+
+  /* calculate new number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    channels = 0; /* should never happen */
+  alpha_present = (channels - 1) % 2;
+
+  /* check if alpha is expected to be present in file */
+  if (alpha && !alpha_present)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");
+    exit (1);
+  }
+
+  /* row_bytes is the width x number of channels x (bit-depth / 8) */
+  row_bytes = png_get_rowbytes (png_ptr, info_ptr);
+
+  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+
+  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    free (png_pixels);
+    png_pixels = NULL;
+    return FALSE;
+  }
+
+  /* set the individual row_pointers to point at the correct offsets */
+  for (i = 0; i < (height); i++)
+    row_pointers[i] = png_pixels + i * row_bytes;
+
+  /* now we can go ahead and just read the whole image */
+  png_read_image (png_ptr, row_pointers);
+
+  /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
+  png_read_end (png_ptr, info_ptr);
+
+  /* clean up after the read, and free any memory allocated - REQUIRED */
+  png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL);
+
+  /* write header of PNM file */
+
+  if ((color_type == PNG_COLOR_TYPE_GRAY) ||
+      (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+  else if ((color_type == PNG_COLOR_TYPE_RGB) ||
+           (color_type == PNG_COLOR_TYPE_RGB_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+
+  /* write header of PGM file with alpha channel */
+
+  if ((alpha) &&
+      ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
+       (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+  {
+    fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
+    fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+
+  /* write data to PNM file */
+  pix_ptr = png_pixels;
+
+  for (row = 0; row < height; row++)
+  {
+    for (col = 0; col < width; col++)
+    {
+      for (i = 0; i < (channels - alpha_present); i++)
+      {
+        if (raw)
+          fputc ((int) *pix_ptr++ , pnm_file);
+        else
+          if (bit_depth == 16)
+            fprintf (pnm_file, "%ld ", ((long) *pix_ptr++ << 8) + (long) *pix_ptr++);
+          else
+            fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
+      }
+      if (alpha_present)
+      {
+        if (!alpha)
+        {
+          pix_ptr++; /* alpha */
+          if (bit_depth == 16)
+            pix_ptr++;
+        }
+        else /* output alpha-channel as pgm file */
+        {
+          if (raw)
+            fputc ((int) *pix_ptr++ , alpha_file);
+          else
+            if (bit_depth == 16)
+              fprintf (alpha_file, "%ld ", ((long) *pix_ptr++ << 8) + (long) *pix_ptr++);
+            else
+              fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
+        }
+      } /* if alpha_present */
+
+      if (!raw)
+        if (col % 4 == 3)
+          fprintf (pnm_file, "\n");
+    } /* end for col */
+
+    if (!raw)
+      if (col % 4 != 0)
+        fprintf (pnm_file, "\n");
+  } /* end for row */
+
+  if (row_pointers != (unsigned char**) NULL)
+    free (row_pointers);
+  if (png_pixels != (unsigned char*) NULL)
+    free (png_pixels);
+
+  return TRUE;
+
+} /* end of source */
+

contrib/pngminus/png2pnm.sh

@@ -0,0 +1,41 @@
+# -- grayscale
+./png2pnm -noraw ../pngsuite/basn0g01.png basn0g01.pgm
+./png2pnm -noraw ../pngsuite/basn0g02.png basn0g02.pgm
+./png2pnm -noraw ../pngsuite/basn0g04.png basn0g04.pgm
+./png2pnm -noraw ../pngsuite/basn0g08.png basn0g08.pgm
+./png2pnm -noraw ../pngsuite/basn0g16.png basn0g16.pgm
+# -- full-color
+./png2pnm -noraw ../pngsuite/basn2c08.png basn2c08.ppm
+./png2pnm -noraw ../pngsuite/basn2c16.png basn2c16.ppm
+# -- palletted
+./png2pnm -noraw ../pngsuite/basn3p01.png basn3p01.ppm
+./png2pnm -noraw ../pngsuite/basn3p02.png basn3p02.ppm
+./png2pnm -noraw ../pngsuite/basn3p04.png basn3p04.ppm
+./png2pnm -noraw ../pngsuite/basn3p08.png basn3p08.ppm
+# -- gray with alpha-channel
+./png2pnm -noraw ../pngsuite/basn4a08.png basn4a08.pgm
+./png2pnm -noraw ../pngsuite/basn4a16.png basn4a16.pgm
+# -- color with alpha-channel
+./png2pnm -noraw -alpha basn6a08.pgm ../pngsuite/basn6a08.png basn6a08.ppm
+./png2pnm -noraw -alpha basn6a16.pgm ../pngsuite/basn6a16.png basn6a16.ppm
+# -- grayscale
+./png2pnm -raw ../pngsuite/basn0g01.png rawn0g01.pgm
+./png2pnm -raw ../pngsuite/basn0g02.png rawn0g02.pgm
+./png2pnm -raw ../pngsuite/basn0g04.png rawn0g04.pgm
+./png2pnm -raw ../pngsuite/basn0g08.png rawn0g08.pgm
+./png2pnm -raw ../pngsuite/basn0g16.png rawn0g16.pgm
+# -- full-color
+./png2pnm -raw ../pngsuite/basn2c08.png rawn2c08.ppm
+./png2pnm -raw ../pngsuite/basn2c16.png rawn2c16.ppm
+# -- palletted
+./png2pnm -raw ../pngsuite/basn3p01.png rawn3p01.ppm
+./png2pnm -raw ../pngsuite/basn3p02.png rawn3p02.ppm
+./png2pnm -raw ../pngsuite/basn3p04.png rawn3p04.ppm
+./png2pnm -raw ../pngsuite/basn3p08.png rawn3p08.ppm
+# -- gray with alpha-channel
+./png2pnm -raw ../pngsuite/basn4a08.png rawn4a08.pgm
+./png2pnm -raw ../pngsuite/basn4a16.png rawn4a16.pgm
+# -- color with alpha-channel
+./png2pnm -noraw -alpha rawn6a08.pgm ../pngsuite/basn6a08.png rawn6a08.ppm
+./png2pnm -noraw -alpha rawn6a16.pgm ../pngsuite/basn6a16.png rawn6a16.ppm
+

contrib/pngminus/pngminus.bat

@@ -0,0 +1,4 @@
+make -f makefile.tc3
+call png2pnm.bat
+call pnm2png.bat
+

contrib/pngminus/pngminus.sh

@@ -0,0 +1,4 @@
+make -f makefile.std
+sh png2pnm.sh
+sh pnm2png.sh
+

contrib/pngminus/pnm2png.bat

@@ -0,0 +1,41 @@
+REM -- grayscale
+pnm2png.exe basn0g01.pgm basn0g01.png
+pnm2png.exe basn0g02.pgm basn0g02.png
+pnm2png.exe basn0g04.pgm basn0g04.png
+pnm2png.exe basn0g08.pgm basn0g08.png
+pnm2png.exe basn0g16.pgm basn0g16.png
+REM -- full-color
+pnm2png.exe basn2c08.ppm basn2c08.png
+pnm2png.exe basn2c16.ppm basn2c16.png
+REM -- palletted
+pnm2png.exe basn3p01.ppm basn3p01.png
+pnm2png.exe basn3p02.ppm basn3p02.png
+pnm2png.exe basn3p04.ppm basn3p04.png
+pnm2png.exe basn3p08.ppm basn3p08.png
+REM -- gray with alpha-channel
+pnm2png.exe -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
+pnm2png.exe -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
+REM -- color with alpha-channel
+pnm2png.exe -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
+pnm2png.exe -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
+REM -- grayscale
+pnm2png.exe rawn0g01.pgm rawn0g01.png
+pnm2png.exe rawn0g02.pgm rawn0g02.png
+pnm2png.exe rawn0g04.pgm rawn0g04.png
+pnm2png.exe rawn0g08.pgm rawn0g08.png
+pnm2png.exe rawn0g16.pgm rawn0g16.png
+REM -- full-color
+pnm2png.exe rawn2c08.ppm rawn2c08.png
+pnm2png.exe rawn2c16.ppm rawn2c16.png
+REM -- palletted
+pnm2png.exe rawn3p01.ppm rawn3p01.png
+pnm2png.exe rawn3p02.ppm rawn3p02.png
+pnm2png.exe rawn3p04.ppm rawn3p04.png
+pnm2png.exe rawn3p08.ppm rawn3p08.png
+REM -- gray with alpha-channel
+pnm2png.exe -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
+pnm2png.exe -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
+REM -- color with alpha-channel
+pnm2png.exe -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
+pnm2png.exe -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
+

contrib/pngminus/pnm2png.c

@@ -0,0 +1,533 @@
+/*
+ *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
+ *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
+ *
+ *  version 1.0 - 1999.10.15 - First version.
+ *
+ *  Permission to use, copy, modify, and distribute this software and
+ *  its documentation for any purpose and without fee is hereby granted,
+ *  provided that the above copyright notice appear in all copies and
+ *  that both that copyright notice and this permission notice appear in
+ *  supporting documentation. This software is provided "as is" without
+ *  express or implied warranty.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef __TURBOC__
+#include <mem.h>
+#include <fcntl.h>
+#endif
+
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE (BOOL) 1
+#endif
+#ifndef FALSE
+#define FALSE (BOOL) 0
+#endif
+
+#define STDIN  0
+#define STDOUT 1
+#define STDERR 2
+
+/* to make pnm2png verbose so we can find problems (needs to be before png.h) */
+#ifndef PNG_DEBUG
+#define PNG_DEBUG 0
+#endif
+
+#include "png.h"
+
+/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#endif
+
+/* function prototypes */
+
+int  main (int argc, char *argv[]);
+void usage ();
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
+void get_token(FILE *pnm_file, char *token);
+png_uint_32 get_data (FILE *pnm_file, int depth);
+png_uint_32 get_value (FILE *pnm_file, int depth);
+
+/*
+ *  main
+ */
+
+int main(int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_al = NULL;
+  FILE *fp_wr = stdout;
+  BOOL interlace = FALSE;
+  BOOL alpha = FALSE;
+  int argi;
+
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'i':
+          interlace = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "rb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  alpha-channel file %s does not exist\n",
+               argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage();
+          exit(0);
+          break;
+        default:
+          fprintf (stderr, "PNM2PNG\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage();
+          exit(1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  can not create PNG-file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNM2PNG\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage();
+      exit (1);
+    }
+  } /* end for */
+
+#ifdef __TURBOC__
+  /* set stdin/stdout to binary, we're reading the PNM always! in binary format */
+  if (fp_rd == stdin)
+  {
+    setmode (STDIN, O_BINARY);
+  }
+  if (fp_wr == stdout)
+  {
+    setmode (STDOUT, O_BINARY);
+  }
+#endif
+
+  /* call the conversion program itself */
+  if (pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha) == FALSE)
+  {
+    fprintf (stderr, "PNM2PNG\n");
+    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
+    exit (1);
+  }
+
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+
+  return 0;
+}
+
+/*
+ *  usage
+ */
+
+void usage()
+{
+  fprintf (stderr, "PNM2PNG\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+#ifdef __TURBOC__
+  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
+#else
+  fprintf (stderr, "   for Linux (and Unix) compilers\n");
+#endif
+  fprintf (stderr, "Usage:  pnm2png [options] <file>.<pnm> [<file>.png]\n");
+  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
+  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+
+/*
+ *  pnm2png
+ */
+
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha)
+{
+  png_struct    *png_ptr = NULL;
+  png_info      *info_ptr = NULL;
+  png_byte      *png_pixels = NULL;
+  png_byte      **row_pointers = NULL;
+  png_byte      *pix_ptr = NULL;
+  png_uint_32   row_bytes;
+
+  char          type_token[16];
+  char          width_token[16];
+  char          height_token[16];
+  char          maxval_token[16];
+  int           color_type;
+  png_uint_32   width, alpha_width;
+  png_uint_32   height, alpha_height;
+  png_uint_32   maxval;
+  int           bit_depth = 0;
+  int           channels;
+  int           alpha_depth = 0;
+  int           alpha_present;
+  int           row, col;
+  BOOL          raw, alpha_raw = FALSE;
+  png_uint_32   tmp16;
+  int           i;
+
+  /* read header of PNM file */
+
+  get_token(pnm_file, type_token);
+  if (type_token[0] != 'P')
+  {
+    return FALSE;
+  }
+  else if ((type_token[1] == '1') || (type_token[1] == '4'))
+  {
+    raw = (type_token[1] == '4');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    bit_depth = 1;
+  }
+  else if ((type_token[1] == '2') || (type_token[1] == '5'))
+  {
+    raw = (type_token[1] == '5');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    get_token(pnm_file, width_token);
+    sscanf (width_token, "%lu", &width);
+    get_token(pnm_file, height_token);
+    sscanf (height_token, "%lu", &height);
+    get_token(pnm_file, maxval_token);
+    sscanf (maxval_token, "%lu", &maxval);
+    if (maxval <= 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else /* if (maxval <= 65535) */
+      bit_depth = 16;
+  }
+  else if ((type_token[1] == '3') || (type_token[1] == '6'))
+  {
+    raw = (type_token[1] == '6');
+    color_type = PNG_COLOR_TYPE_RGB;
+    get_token(pnm_file, width_token);
+    sscanf (width_token, "%lu", &width);
+    get_token(pnm_file, height_token);
+    sscanf (height_token, "%lu", &height);
+    get_token(pnm_file, maxval_token);
+    sscanf (maxval_token, "%lu", &maxval);
+    if (maxval <= 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else /* if (maxval <= 65535) */
+      bit_depth = 16;
+  }
+  else
+  {
+    return FALSE;
+  }
+
+  /* read header of PGM file with alpha channel */
+
+  if (alpha)
+  {
+    if (color_type == PNG_COLOR_TYPE_GRAY)
+      color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+    if (color_type == PNG_COLOR_TYPE_RGB)
+      color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+    get_token(alpha_file, type_token);
+    if (type_token[0] != 'P')
+    {
+      return FALSE;
+    }
+    else if ((type_token[1] == '2') || (type_token[1] == '5'))
+    {
+      alpha_raw = (type_token[1] == '5');
+      get_token(alpha_file, width_token);
+      sscanf (width_token, "%lu", &alpha_width);
+      if (alpha_width != width)
+        return FALSE;
+      get_token(alpha_file, height_token);
+      sscanf (height_token, "%lu", &alpha_height);
+      if (alpha_height != height)
+        return FALSE;
+      get_token(alpha_file, maxval_token);
+      sscanf (maxval_token, "%lu", &maxval);
+      if (maxval <= 1)
+        alpha_depth = 1;
+      else if (maxval <= 3)
+        alpha_depth = 2;
+      else if (maxval <= 15)
+        alpha_depth = 4;
+      else if (maxval <= 255)
+        alpha_depth = 8;
+      else /* if (maxval <= 65535) */
+        alpha_depth = 16;
+      if (alpha_depth != bit_depth)
+        return FALSE;
+    }
+    else
+    {
+      return FALSE;
+    }
+  } /* end if alpha */
+
+  /* calculate the number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    channels = 0; /* should not happen */
+
+  alpha_present = (channels - 1) % 2;
+
+  /* row_bytes is the width x number of channels x (bit-depth / 8) */
+  row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+
+  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
+    return FALSE;
+
+  /* read data from PNM file */
+  pix_ptr = png_pixels;
+
+  for (row = 0; row < height; row++)
+  {
+    for (col = 0; col < width; col++)
+    {
+      for (i = 0; i < (channels - alpha_present); i++)
+      {
+        if (raw)
+          *pix_ptr++ = get_data (pnm_file, bit_depth);
+        else
+          if (bit_depth <= 8)
+            *pix_ptr++ = get_value (pnm_file, bit_depth);
+          else
+          {
+            tmp16 = get_value (pnm_file, bit_depth);
+            *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+            pix_ptr++;
+            *pix_ptr = (png_byte) (tmp16 & 0xFF);
+            pix_ptr++;
+          }
+      }
+
+      if (alpha) /* read alpha-channel from pgm file */
+      {
+        if (alpha_raw)
+          *pix_ptr++ = get_data (alpha_file, alpha_depth);
+        else
+          if (alpha_depth <= 8)
+            *pix_ptr++ = get_value (alpha_file, bit_depth);
+          else
+          {
+            tmp16 = get_value (alpha_file, bit_depth);
+            *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+            *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+          }
+      } /* if alpha */
+
+    } /* end for col */
+  } /* end for row */
+
+  /* prepare the standard PNG structures */
+  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  if (!png_ptr)
+  {
+    return FALSE;
+  }
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+    return FALSE;
+  }
+
+  /* setjmp() must be called in every function that calls a PNG-reading libpng function */
+  if (setjmp (png_jmpbuf(png_ptr)))
+  {
+    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+    return FALSE;
+  }
+
+  /* initialize the png structure */
+  png_init_io (png_ptr, png_file);
+
+  /* we're going to write more or less the same PNG as the input file */
+  png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
+    (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
+    PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+  /* write the file header information */
+  png_write_info (png_ptr, info_ptr);
+
+  /* if needed we will allocate memory for an new array of row-pointers */
+  if (row_pointers == (unsigned char**) NULL)
+  {
+    if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+    {
+      png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+      return FALSE;
+    }
+  }
+
+  /* set the individual row_pointers to point at the correct offsets */
+  for (i = 0; i < (height); i++)
+    row_pointers[i] = png_pixels + i * row_bytes;
+
+  /* write out the entire image data in one call */
+  png_write_image (png_ptr, row_pointers);
+
+  /* write the additional chuncks to the PNG file (not really needed) */
+  png_write_end (png_ptr, info_ptr);
+
+  /* clean up after the write, and free any memory allocated */
+  png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+
+  if (row_pointers != (unsigned char**) NULL)
+    free (row_pointers);
+  if (png_pixels != (unsigned char*) NULL)
+    free (png_pixels);
+
+  return TRUE;
+} /* end of pnm2png */
+
+/*
+ * get_token() - gets the first string after whitespace
+ */
+
+void get_token(FILE *pnm_file, char *token)
+{
+  int i = 0;
+
+  /* remove white-space */
+  do
+  {
+    token[i] = (unsigned char) fgetc (pnm_file);
+  }
+  while ((token[i] == '\n') || (token[i] == '\r') || (token[i] == ' '));
+
+  /* read string */
+  do
+  {
+    i++;
+    token[i] = (unsigned char) fgetc (pnm_file);
+  }
+  while ((token[i] != '\n') && (token[i] != '\r') && (token[i] != ' '));
+
+  token[i] = '\0';
+
+  return;
+}
+
+/*
+ * get_data() - takes first byte and converts into next pixel value,
+ *        taking as much bits as defined by bit-depth and
+ *        using the bit-depth to fill up a byte (0Ah -> AAh)
+ */
+
+png_uint_32 get_data (FILE *pnm_file, int depth)
+{
+  static int bits_left = 0;
+  static int old_value = 0;
+  static int mask = 0;
+  int i;
+  png_uint_32 ret_value;
+
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask >> 1) | 0x80;
+
+  if (bits_left <= 0)
+  {
+    old_value = fgetc (pnm_file);
+    bits_left = 8;
+  }
+
+  ret_value = old_value & mask;
+  for (i = 1; i < (8 / depth); i++)
+    ret_value = ret_value || (ret_value >> depth);
+
+  old_value = (old_value << depth) & 0xFF;
+  bits_left -= depth;
+
+  return ret_value;
+}
+
+/*
+ * get_value() - takes first (numeric) string and converts into number,
+ *         using the bit-depth to fill up a byte (0Ah -> AAh)
+ */
+
+png_uint_32 get_value (FILE *pnm_file, int depth)
+{
+  static png_uint_32 mask = 0;
+  png_byte token[16];
+  png_uint_32 ret_value;
+  int i = 0;
+
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask << 1) | 0x01;
+
+  get_token (pnm_file, (char *) token);
+  sscanf ((const char *) token, "%lu", &ret_value);
+
+  ret_value &= mask;
+
+  if (depth < 8)
+    for (i = 0; i < (8 / depth); i++)
+      ret_value = (ret_value << depth) || ret_value;
+
+  return ret_value;
+}
+
+/* end of source */
+

contrib/pngminus/pnm2png.sh

@@ -0,0 +1,41 @@
+# -- grayscale
+./pnm2png basn0g01.pgm basn0g01.png
+./pnm2png basn0g02.pgm basn0g02.png
+./pnm2png basn0g04.pgm basn0g04.png
+./pnm2png basn0g08.pgm basn0g08.png
+./pnm2png basn0g16.pgm basn0g16.png
+# -- full-color
+./pnm2png basn2c08.ppm basn2c08.png
+./pnm2png basn2c16.ppm basn2c16.png
+# -- palletted
+./pnm2png basn3p01.ppm basn3p01.png
+./pnm2png basn3p02.ppm basn3p02.png
+./pnm2png basn3p04.ppm basn3p04.png
+./pnm2png basn3p08.ppm basn3p08.png
+# -- gray with alpha-channel
+./pnm2png -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
+./pnm2png -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
+# -- color with alpha-channel
+./pnm2png -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
+./pnm2png -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
+# -- grayscale
+./pnm2png rawn0g01.pgm rawn0g01.png
+./pnm2png rawn0g02.pgm rawn0g02.png
+./pnm2png rawn0g04.pgm rawn0g04.png
+./pnm2png rawn0g08.pgm rawn0g08.png
+./pnm2png rawn0g16.pgm rawn0g16.png
+# -- full-color
+./pnm2png rawn2c08.ppm rawn2c08.png
+./pnm2png rawn2c16.ppm rawn2c16.png
+# -- palletted
+./pnm2png rawn3p01.ppm rawn3p01.png
+./pnm2png rawn3p02.ppm rawn3p02.png
+./pnm2png rawn3p04.ppm rawn3p04.png
+./pnm2png rawn3p08.ppm rawn3p08.png
+# -- gray with alpha-channel
+./pnm2png -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
+./pnm2png -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
+# -- color with alpha-channel
+./pnm2png -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
+./pnm2png -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
+

contrib/pngsuite/README

@@ -0,0 +1,85 @@
+
+pngsuite
+--------
+(c) Willem van Schaik, 1999
+
+Permission to use, copy, and distribute these images for any purpose and
+without fee is hereby granted.
+
+These 15 images are part of the much larger PngSuite test-set of 
+images, available for developers of PNG supporting software. The 
+complete set, available at http:/www.schaik.com/pngsuite/, contains 
+a variety of images to test interlacing, gamma settings, ancillary
+chunks, etc.
+
+The images in this directory represent the basic PNG color-types:
+grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
+(1-8 bit) and grayscale or color images with alpha channel. You
+can use them to test the proper functioning of PNG software.
+
+    filename      depth type
+    ------------ ------ --------------
+    basn0g01.png  1-bit grayscale
+    basn0g02.png  2-bit grayscale
+    basn0g04.png  4-bit grayscale
+    basn0g08.png  8-bit grayscale
+    basn0g16.png 16-bit grayscale
+    basn2c08.png  8-bit truecolor
+    basn2c16.png 16-bit truecolor
+    basn3p01.png  1-bit paletted
+    basn3p02.png  2-bit paletted
+    basn3p04.png  4-bit paletted
+    basn3p08.png  8-bit paletted
+    basn4a08.png  8-bit gray with alpha
+    basn4a16.png 16-bit gray with alpha
+    basn6a08.png  8-bit RGBA
+    basn6a16.png 16-bit RGBA
+
+Here is the correct result of typing "pngtest -m *.png" in
+this directory:
+
+Testing basn0g01.png: PASS (524 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g04.png: PASS (520 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g08.png: PASS (3 zero samples)
+ Filter 1 was used 9 times
+ Filter 4 was used 23 times
+Testing basn0g16.png: PASS (1 zero samples)
+ Filter 1 was used 1 times
+ Filter 2 was used 31 times
+Testing basn2c08.png: PASS (6 zero samples)
+ Filter 1 was used 5 times
+ Filter 4 was used 27 times
+Testing basn2c16.png: PASS (592 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn3p01.png: PASS (512 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p04.png: PASS (544 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p08.png: PASS (4 zero samples)
+ Filter 0 was used 32 times
+Testing basn4a08.png: PASS (32 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn4a16.png: PASS (64 zero samples)
+ Filter 0 was used 1 times
+ Filter 1 was used 2 times
+ Filter 2 was used 1 times
+ Filter 4 was used 28 times
+Testing basn6a08.png: PASS (160 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn6a16.png: PASS (1072 zero samples)
+ Filter 1 was used 4 times
+ Filter 4 was used 28 times
+libpng passes test
+
+Willem van Schaik
+<willem@schaik.com>
+October 1999

example.c

@@ -1,59 +1,79 @@
+
+#if 0 /* in case someone actually tries to compile this */
+
 /* example.c - an example of using libpng */
 
 /* This is an example of how to use libpng to read and write PNG files.
-   The file libpng.txt is much more verbose then this.  If you have not
-   read it, do so first.  This was designed to be a starting point of an
-   implementation.  This is not officially part of libpng, and therefore
-   does not require a copyright notice.
+ * The file libpng.txt is much more verbose then this.  If you have not
+ * read it, do so first.  This was designed to be a starting point of an
+ * implementation.  This is not officially part of libpng, is hereby placed
+ * in the public domain, and therefore does not require a copyright notice.
+ *
+ * This file does not currently compile, because it is missing certain
+ * parts, like allocating memory to hold an image.  You will have to
+ * supply these parts to get it to compile.  For an example of a minimal
+ * working PNG reader/writer, see pngtest.c, included in this distribution;
+ * see also the programs in the contrib directory.
+ */
 
-   This file does not currently compile, because it is missing certain
-   parts, like allocating memory to hold an image.  You will have to
-   supply these parts to get it to compile.  For an example of a minimal
-   working PNG reader/writer, see pngtest.c, included in this distribution.
-*/
+#include "png.h"
 
-#include <png.h>
+ /* The png_jmpbuf() macro, used in error handling, became available in
+  * libpng version 1.0.6.  If you want to be able to run your code with older
+  * versions of libpng, you must define the macro yourself (but only if it
+  * is not already defined by libpng!).
+  */
 
-/* Check to see if a file is a PNG file using png_check_sig().  Returns
-   non-zero if the image is a PNG, and 0 if it isn't a PNG.
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#endif
 
-   If this call is successful, and you are going to keep the file open,
-   you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
-   you have created the png_ptr, so that libpng knows your application
-   has read that many bytes from the start of the file.  Make sure you
-   don't call png_set_sig_bytes() with more than 8 bytes read or give it
-   an incorrect number of bytes read, or you will either have read too
-   many bytes (your fault), or you are telling libpng to read the wrong
-   number of magic bytes (also your fault).
-
-   Many applications already read the first 2 or 4 bytes from the start
-   of the image to determine the file type, so it would be easiest just
-   to pass the bytes to png_check_sig() or even skip that if you know
-   you have a PNG file, and call png_set_sig_bytes().
-*/
+/* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
+ * returns zero if the image is a PNG and nonzero if it isn't a PNG.
+ *
+ * The function check_if_png() shown here, but not used, returns nonzero (true)
+ * if the file can be opened and is a PNG, 0 (false) otherwise.
+ *
+ * If this call is successful, and you are going to keep the file open,
+ * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
+ * you have created the png_ptr, so that libpng knows your application
+ * has read that many bytes from the start of the file.  Make sure you
+ * don't call png_set_sig_bytes() with more than 8 bytes read or give it
+ * an incorrect number of bytes read, or you will either have read too
+ * many bytes (your fault), or you are telling libpng to read the wrong
+ * number of magic bytes (also your fault).
+ *
+ * Many applications already read the first 2 or 4 bytes from the start
+ * of the image to determine the file type, so it would be easiest just
+ * to pass the bytes to png_sig_cmp() or even skip that if you know
+ * you have a PNG file, and call png_set_sig_bytes().
+ */
 #define PNG_BYTES_TO_CHECK 4
 int check_if_png(char *file_name, FILE **fp)
 {
    char buf[PNG_BYTES_TO_CHECK];
 
    /* Open the prospective PNG file. */
-   if ((*fp = fopen(file_name, "rb")) != NULL);
+   if ((*fp = fopen(file_name, "rb")) == NULL)
       return 0;
 
-   /* Read in the signature bytes */
+   /* Read in some of the signature bytes */
    if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
       return 0;
 
-   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature. */
-   return(png_check_sig(buf, PNG_BYTES_TO_CHECK));
+   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
+      Return nonzero (true) if they match */
+
+   return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
 }
 
 /* Read a PNG file.  You may want to return an error code if the read
-   fails (depending upon the failure).  There are two "prototypes" given
-   here - one where we are given the filename, and we need to open the
-   file, and the other where we are given an open file (possibly with
-   some or all of the magic bytes read - see comments above). */
-**** prototype 1 ****
+ * fails (depending upon the failure).  There are two "prototypes" given
+ * here - one where we are given the filename, and we need to open the
+ * file, and the other where we are given an open file (possibly with
+ * some or all of the magic bytes read - see comments above).
+ */
+#ifdef open_file /* prototype 1 */
 void read_png(char *file_name)  /* We need to open the file */
 {
    png_structp png_ptr;
@@ -65,14 +85,14 @@ void read_png(char *file_name)  /* We need to open the file */
 
    if ((fp = fopen(file_name, "rb")) == NULL)
       return;
-**** prototype 2 ****
+#else no_open_file /* prototype 2 */
 void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 {
    png_structp png_ptr;
    png_infop info_ptr;
    png_uint_32 width, height;
    int bit_depth, color_type, interlace_type;
-**** only use one prototype! ****
+#endif no_open_file /* only use one prototype! */
 
    /* Create and initialize the png_struct with the desired error handler
     * functions.  If you want to use the default stderr and longjump method,
@@ -81,7 +101,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
     * was compiled with a compatible version of the library.  REQUIRED
     */
    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
-      (void *)user_error_ptr, user_error_fn, user_warning_fn);
+      png_voidp user_error_ptr, user_error_fn, user_warning_fn);
 
    if (png_ptr == NULL)
    {
@@ -90,7 +110,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    }
 
    /* Allocate/initialize the memory for image information.  REQUIRED. */
-   info_ptr = png_create_info_struct();
+   info_ptr = png_create_info_struct(png_ptr);
    if (info_ptr == NULL)
    {
       fclose(fp);
@@ -102,7 +122,8 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
     * the normal method of doing things with libpng).  REQUIRED unless you
     * set up your own error handlers in the png_create_read_struct() earlier.
     */
-   if (setjmp(png_ptr->jmpbuf))
+
+   if (setjmp(png_jmpbuf(png_ptr)))
    {
       /* Free all of the memory associated with the png_ptr and info_ptr */
       png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
@@ -112,19 +133,33 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    }
 
    /* One of the following I/O initialization methods is REQUIRED */
-**** PNG file I/O method 1 ****
+#ifdef streams /* PNG file I/O method 1 */
    /* Set up the input control if you are using standard C streams */
    png_init_io(png_ptr, fp);
 
-**** PNG file I/O method 2 ****
+#else no_streams /* PNG file I/O method 2 */
    /* If you are using replacement read functions, instead of calling
-    * png_init_io() here you would call */
+    * png_init_io() here you would call:
+    */
    png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
    /* where user_io_ptr is a structure you want available to the callbacks */
-**** Use only one I/O method! ****
+#endif no_streams /* Use only one I/O method! */
 
    /* If we have already read some of the signature */
-   png_set_sig_bytes_read(png_ptr, sig_read);
+   png_set_sig_bytes(png_ptr, sig_read);
+
+#ifdef hilevel
+   /*
+    * If you have enough memory to read in the entire image at once,
+    * and you need to specify only transforms that can be controlled
+    * with one of the PNG_TRANSFORM_* bits (this presently excludes
+    * dithering, filling, setting background, and doing gamma
+    * adjustment), then you can read the entire image (including
+    * pixels) into the info structure with this call:
+    */
+   png_read_png(png_ptr, info_ptr, png_transforms, NULL);
+#else
+   /* OK, you're doing it the hard way, with the lower-level functions */
 
    /* The call to png_read_info() gives us all of the information from the
     * PNG file before the first IDAT (image data chunk).  REQUIRED
@@ -143,29 +178,31 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    /* tell libpng to strip 16 bit/color files down to 8 bits/color */
    png_set_strip_16(png_ptr);
 
-   /* strip alpha bytes from the input data without combining with th
-    * background (not recommended) */
+   /* Strip alpha bytes from the input data without combining with the
+    * background (not recommended).
+    */
    png_set_strip_alpha(png_ptr);
 
-   /* extract multiple pixels with bit depths of 1, 2, and 4 from a single
+   /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
     * byte into separate bytes (useful for paletted and grayscale images).
     */
    png_set_packing(png_ptr);
 
-   /* change the order of packed pixels to least significant bit first
+   /* Change the order of packed pixels to least significant bit first
     * (not useful if you are using png_set_packing). */
    png_set_packswap(png_ptr);
 
-   /* expand paletted colors into true RGB triplets */
+   /* Expand paletted colors into true RGB triplets */
    if (color_type == PNG_COLOR_TYPE_PALETTE)
       png_set_expand(png_ptr);
 
-   /* expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
+   /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
       png_set_expand(png_ptr);
 
-   /* expand paletted or RGB images with transparency to full alpha channels
-    * so the data will be available as RGBA quartets */
+   /* Expand paletted or RGB images with transparency to full alpha channels
+    * so the data will be available as RGBA quartets.
+    */
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
       png_set_expand(png_ptr);
 
@@ -176,51 +213,65 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
     * use it - you should use the (solid) application background if it has one.
     */
 
-   png_color_16 my_background, *image_background);
+   png_color_16 my_background, *image_background;
 
-   if (png_get_bKGD(png_ptr, info_ptr, &image_background);
-      png_set_background(png_ptr, image_background),
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+      png_set_background(png_ptr, image_background,
                          PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
    else
       png_set_background(png_ptr, &my_background,
                          PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
 
    /* Some suggestions as to how to get a screen gamma value */
+
+   /* Note that screen gamma is the display_exponent, which includes
+    * the CRT_exponent and any correction for viewing conditions */
    if (/* We have a user-defined screen gamma value */)
    {
       screen_gamma = user-defined screen_gamma;
    }
    /* This is one way that applications share the same screen gamma value */
-   else if ((gamma_str = getenv("DISPLAY_GAMMA")) != NULL)
+   else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
    {
       screen_gamma = atof(gamma_str);
    }
    /* If we don't have another value */
    else
    {
-      screen_gamma = 2.2;  /* A good guess for PC monitors */
+      screen_gamma = 2.2;  /* A good guess for a PC monitors in a dimly
+                              lit room */
       screen_gamma = 1.7 or 1.0;  /* A good guess for Mac systems */
    }
 
-   /* Tell libpng to handle the gamma conversion for you.  The second call
+   /* Tell libpng to handle the gamma conversion for you.  The final call
     * is a good guess for PC generated images, but it should be configurable
     * by the user at run time by the user.  It is strongly suggested that
     * your application support gamma correction.
     */
-   if (png_get_gAMA(png_ptr, info_ptr, &image_gamma);
-      png_set_gamma(png_ptr, screen_gamma, image_gamma);
+
+   int intent;
+
+   if (png_get_sRGB(png_ptr, info_ptr, &intent))
+      png_set_gamma(png_ptr, screen_gamma, 0.45455);
    else
-      png_set_gamma(png_ptr, screen_gamma, 0.45);
+   {
+      double image_gamma;
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
+         png_set_gamma(png_ptr, screen_gamma, image_gamma);
+      else
+         png_set_gamma(png_ptr, screen_gamma, 0.45455);
+   }
 
    /* Dither RGB files down to 8 bit palette or reduce palettes
-      to the number of colors available on your screen */
+    * to the number of colors available on your screen.
+    */
    if (color_type & PNG_COLOR_MASK_COLOR)
    {
       png_uint_32 num_palette;
       png_colorp palette;
 
       /* This reduces the image to the application supplied palette */
-      if (we have our own palette)
+      if (/* we have our own palette */)
       {
          /* An array of colors to which the image should be dithered */
          png_color std_color_cube[MAX_SCREEN_COLORS];
@@ -229,7 +280,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
             MAX_SCREEN_COLORS, NULL, 0);
       }
       /* This reduces the image to the palette supplied in the file */
-      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette)))
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
       {
          png_color16p histogram;
 
@@ -241,7 +292,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    }
 
    /* invert monocrome files to have 0 as white and 1 as black */
-   png_set_invert(png_ptr);
+   png_set_invert_mono(png_ptr);
 
    /* If you want to shift the pixel values from the range [0,255] or
     * [0,65535] to the original [0,7] or [0,31], or whatever range the
@@ -249,14 +300,15 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
     */
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
    {
-      png_color8p sig_bit;
+      png_color_8p sig_bit;
 
       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
       png_set_shift(png_ptr, sig_bit);
    }
 
    /* flip the RGB pixels to BGR (or RGBA to BGRA) */
-   png_set_bgr(png_ptr);
+   if (color_type & PNG_COLOR_MASK_COLOR)
+      png_set_bgr(png_ptr);
 
    /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
    png_set_swap_alpha(png_ptr);
@@ -269,19 +321,19 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 
    /* Turn on interlace handling.  REQUIRED if you are not using
     * png_read_image().  To see how to handle interlacing passes,
-    * see the png_read_row() method below.
+    * see the png_read_row() method below:
     */
    number_passes = png_set_interlace_handling(png_ptr);
 
-   /* optional call to gamma correct and add the background to the palette
+   /* Optional call to gamma correct and add the background to the palette
     * and update info structure.  REQUIRED if you are expecting libpng to
     * update the palette for you (ie you selected such a transform above).
     */
    png_read_update_info(png_ptr, info_ptr);
 
-   /* allocate the memory to hold the image using the fields of info_ptr. */
+   /* Allocate the memory to hold the image using the fields of info_ptr. */
 
-   /* the easiest way to read the image */
+   /* The easiest way to read the image: */
    png_bytep row_pointers[height];
 
    for (row = 0; row < height; row++)
@@ -290,40 +342,43 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    }
 
    /* Now it's time to read the image.  One of these methods is REQUIRED */
-**** Read the entire image in one go ****
+#ifdef entire /* Read the entire image in one go */
    png_read_image(png_ptr, row_pointers);
 
-**** Read the image one or more scanlines at a time ****
-   /* the other way to read images - deal with interlacing */
+#else no_entire /* Read the image one or more scanlines at a time */
+   /* The other way to read images - deal with interlacing: */
 
    for (pass = 0; pass < number_passes; pass++)
    {
-[[[[[[[ Read the image a single row at a time ]]]]]]]
+#ifdef single /* Read the image a single row at a time */
       for (y = 0; y < height; y++)
       {
-         png_bytep row_pointers = row[y];
-         png_read_rows(png_ptr, &row_pointers, NULL, 1);
+         png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
       }
 
-[[[[[[[ Read the image several rows at a time ]]]]]]]
+#else no_single /* Read the image several rows at a time */
       for (y = 0; y < height; y += number_of_rows)
       {
-<<<<<<<<<< Read the image using the "sparkle" effect. >>>>>>>>>>
-         png_read_rows(png_ptr, row_pointers, NULL, number_of_rows);
-        
-<<<<<<<<<< Read the image using the "rectangle" effect >>>>>>>>>>
-         png_read_rows(png_ptr, NULL, row_pointers, number_of_rows);
-<<<<<<<<<< use only one of these two methods >>>>>>>>>>
+#ifdef sparkle /* Read the image using the "sparkle" effect. */
+         png_read_rows(png_ptr, &row_pointers[y], NULL, number_of_rows);
+
+         png_read_rows(png_ptr, NULL, row_pointers[y], number_of_rows);
+#else no_sparkle /* Read the image using the "rectangle" effect */
+         png_read_rows(png_ptr, NULL, &row_pointers[y], number_of_rows);
+#endif no_sparkle /* use only one of these two methods */
       }
-     
+
       /* if you want to display the image after every pass, do
          so here */
-[[[[[[[ use only one of these two methods ]]]]]]]
+#endif no_single /* use only one of these two methods */
    }
-**** use only one of these two methods ****
+#endif no_entire /* use only one of these two methods */
 
    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);
+#endif hilevel
+
+   /* At this point you have read the entire image */
 
    /* clean up after the read, and free any memory allocated - REQUIRED */
    png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
@@ -347,7 +402,7 @@ initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
     * linked libraries.
     */
    *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
-       (void *)user_error_ptr, user_error_fn, user_warning_fn);
+       png_voidp user_error_ptr, user_error_fn, user_warning_fn);
 
    if (*png_ptr == NULL)
    {
@@ -363,14 +418,17 @@ initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
       return ERROR;
    }
 
-   if (setjmp((*png_ptr)->jmpbuf))
+   if (setjmp(png_jmpbuf((*png_ptr))))
    {
       png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
       return ERROR;
    }
 
-   /* this one's new.  You will need to provide all three
+   /* This one's new.  You will need to provide all three
     * function callbacks, even if you aren't using them all.
+    * If you aren't using all functions, you can specify NULL
+    * parameters.  Even when all three functions are NULL,
+    * you need to call png_set_progressive_read_fn().
     * These functions shouldn't be dependent on global or
     * static variables if you are decoding several images
     * simultaneously.  You should store stream specific data
@@ -388,7 +446,7 @@ int
 process_data(png_structp *png_ptr, png_infop *info_ptr,
    png_bytep buffer, png_uint_32 length)
 {
-   if (setjmp((*png_ptr)->jmpbuf))
+   if (setjmp(png_jmpbuf((*png_ptr))))
    {
       /* Free the png_ptr and info_ptr memory on error */
       png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
@@ -465,11 +523,12 @@ end_callback(png_structp png_ptr, png_infop info)
 }
 
 /* write a png file */
-void write_png(char *file_name, ... other image information ...)
+void write_png(char *file_name /* , ... other image information ... */)
 {
    FILE *fp;
    png_structp png_ptr;
    png_infop info_ptr;
+   png_colorp palette;
 
    /* open the file */
    fp = fopen(file_name, "wb");
@@ -483,7 +542,7 @@ void write_png(char *file_name, ... other image information ...)
     * in case we are using dynamically linked libraries.  REQUIRED.
     */
    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
-      (void *)user_error_ptr, user_error_fn, user_warning_fn);
+      png_voidp user_error_ptr, user_error_fn, user_warning_fn);
 
    if (png_ptr == NULL)
    {
@@ -501,27 +560,36 @@ void write_png(char *file_name, ... other image information ...)
    }
 
    /* Set error handling.  REQUIRED if you aren't supplying your own
-    * error hadnling functions in the png_create_write_struct() call.
+    * error handling functions in the png_create_write_struct() call.
     */
-   if (setjmp(png_ptr->jmpbuf))
+   if (setjmp(png_jmpbuf(png_ptr)))
    {
       /* If we get here, we had a problem reading the file */
       fclose(fp);
-      png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
+      png_destroy_write_struct(&png_ptr,  (png_infopp)info_ptr);
       return;
    }
 
    /* One of the following I/O initialization functions is REQUIRED */
-**** I/O initialization method 1 ****
+#ifdef streams /* I/O initialization method 1 */
    /* set up the output control if you are using standard C streams */
    png_init_io(png_ptr, fp);
-**** I/O initialization method 2 ****
+#else no_streams /* I/O initialization method 2 */
    /* If you are using replacement read functions, instead of calling
     * png_init_io() here you would call */
    png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
       user_IO_flush_function);
    /* where user_io_ptr is a structure you want available to the callbacks */
-**** only use 1 initialization method ****
+#endif no_streams /* only use one initialization method */
+
+#ifdef hilevel
+   /* This is the easy way.  Use it if you already have all the
+    * image info living info in the structure.  You could "|" many
+    * PNG_TRANSFORM flags into the png_transforms integer here.
+    */
+   png_write_png(png_ptr, info_ptr, png_transforms, NULL);
+#else
+   /* This is the hard way */
 
    /* Set the image information here.  Width and height are up to 2^31,
     * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
@@ -535,9 +603,12 @@ void write_png(char *file_name, ... other image information ...)
       PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
    /* set the palette if there is one.  REQUIRED for indexed-color images */
-   palette = png_malloc(png_ptr, 256 * sizeof (png_color));
-   ... set palette colors ...
+   palette = (png_colorp)png_malloc(png_ptr, 256 * sizeof (png_color));
+   /* ... set palette colors ... */
    png_set_PLTE(png_ptr, info_ptr, palette, 256);
+   /* You must not free palette here, because png_set_PLTE only makes a link to
+      the palette that you malloced.  Wait until you are about to destroy
+      the png structure. */
 
    /* optional significant bit chunk */
    /* if we are dealing with a grayscale image then */
@@ -550,9 +621,10 @@ void write_png(char *file_name, ... other image information ...)
    sig_bit.alpha = true_alpha_bit_depth;
    png_set_sBIT(png_ptr, info_ptr, sig_bit);
 
-  
+
    /* Optional gamma chunk is strongly suggested if you have any guess
-    * as to the correct gamma of the image. */
+    * as to the correct gamma of the image.
+    */
    png_set_gAMA(png_ptr, info_ptr, gamma);
 
    /* Optionally write comments into the image */
@@ -565,13 +637,31 @@ void write_png(char *file_name, ... other image information ...)
    text_ptr[2].key = "Description";
    text_ptr[2].text = "<long text>";
    text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
-   png_set_text(png_ptr, info_ptr, text_ptr, 2);
+#ifdef PNG_iTXt_SUPPORTED
+   text_ptr[0].lang = NULL;
+   text_ptr[1].lang = NULL;
+   text_ptr[2].lang = NULL;
+#endif
+   png_set_text(png_ptr, info_ptr, text_ptr, 3);
 
    /* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */
+   /* note that if sRGB is present the gAMA and cHRM chunks must be ignored
+    * on read and must be written in accordance with the sRGB profile */
 
    /* Write the file header information.  REQUIRED */
    png_write_info(png_ptr, info_ptr);
 
+   /* If you want, you can write the info in two steps, in case you need to
+    * write your private chunk ahead of PLTE:
+    *
+    *   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+    *   write_my_chunk();
+    *   png_write_info(png_ptr, info_ptr);
+    *
+    * However, given the level of known- and unknown-chunk support in 1.1.0
+    * and up, this should no longer be necessary.
+    */
+
    /* Once we write out the header, the compression type on the text
     * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
     * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
@@ -579,13 +669,15 @@ void write_png(char *file_name, ... other image information ...)
     */
 
    /* set up the transformations you want.  Note that these are
-    * all optional.  Only call them if you want them. */
+    * all optional.  Only call them if you want them.
+    */
 
    /* invert monocrome pixels */
-   png_set_invert(png_ptr);
+   png_set_invert_mono(png_ptr);
 
    /* Shift the pixels up to a legal bit depth and fill in
-    * as appropriate to correctly scale the image */
+    * as appropriate to correctly scale the image.
+    */
    png_set_shift(png_ptr, &sig_bit);
 
    /* pack pixels into bytes */
@@ -595,7 +687,8 @@ void write_png(char *file_name, ... other image information ...)
    png_set_swap_alpha(png_ptr);
 
    /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
-    * RGB (4 channels -> 3 channels). The second parameter is not used. */
+    * RGB (4 channels -> 3 channels). The second parameter is not used.
+    */
    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 
    /* flip BGR pixels to RGB */
@@ -617,46 +710,59 @@ void write_png(char *file_name, ... other image information ...)
     * layout, however, so choose what fits your needs best).  You need to
     * use the first method if you aren't handling interlacing yourself.
     */
-   png_byte row_pointers[height][width];
+   png_uint_32 k, height, width;
+   png_byte image[height][width*bytes_per_pixel];
+   png_bytep row_pointers[height];
+   for (k = 0; k < height; k++)
+     row_pointers[k] = image + k*width*bytes_per_pixel;
 
    /* One of the following output methods is REQUIRED */
-**** write out the entire image data in one call ***
+#ifdef entire /* write out the entire image data in one call */
    png_write_image(png_ptr, row_pointers);
 
    /* the other way to write the image - deal with interlacing */
 
-**** write out the image data by one or more scanlines ****
+#else no_entire /* write out the image data by one or more scanlines */
    /* The number of passes is either 1 for non-interlaced images,
     * or 7 for interlaced images.
     */
    for (pass = 0; pass < number_passes; pass++)
    {
       /* Write a few rows at a time. */
-      png_write_rows(png_ptr, row_pointers, number_of_rows);
+      png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
 
       /* If you are only writing one row at a time, this works */
       for (y = 0; y < height; y++)
       {
-         png_bytep row_pointers = row[y];
-         png_write_rows(png_ptr, &row_pointers, 1);
+         png_write_rows(png_ptr, &row_pointers[y], 1);
       }
    }
-**** use only one output method ****
+#endif no_entire /* use only one output method */
 
    /* You can write optional chunks like tEXt, zTXt, and tIME at the end
-    * as well.
+    * as well.  Shouldn't be necessary in 1.1.0 and up as all the public
+    * chunks are supported and you can use png_set_unknown_chunks() to
+    * register unknown chunks into the info structure to be written out.
     */
 
    /* It is REQUIRED to call this to finish writing the rest of the file */
    png_write_end(png_ptr, info_ptr);
+#endif hilevel
 
-   /* if you malloced the palette, free it here */
-   free(info_ptr->palette);
+   /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
+      as recommended in versions 1.0.5m and earlier of this example; if
+      libpng mallocs info_ptr->palette, libpng will free it).  If you
+      allocated it with malloc() instead of png_malloc(), use free() instead
+      of png_free(). */
+   png_free(png_ptr, palette);
 
-   /* if you allocated any text comments, free them here */
+   /* Similarly, if you png_malloced any data that you passed in with
+      png_set_something(), such as a hist or trans array, free it here,
+      when you can be sure that libpng is through with it. */
+   png_free(png_ptr, trans);
 
    /* clean up after the write, and free any memory allocated */
-   png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
+   png_destroy_write_struct(&png_ptr, (png_infopp)info_ptr);
 
    /* close the file */
    fclose(fp);
@@ -665,3 +771,4 @@ void write_png(char *file_name, ... other image information ...)
    return;
 }
 
+#endif /* if 0 */

libpngpf.3

@@ -0,0 +1,549 @@
+.TH LIBPNGPF 3 "May 12, 2000"
+.SH NAME
+libpng \- Portable Network Graphics (PNG) Reference Library 1.0.7beta12
+(private functions)
+.SH SYNOPSIS
+\fB#include <png.h>\fP
+
+\fI\fB
+
+\fBvoid png_build_gamma_table (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_calculate_crc (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIptr\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_check_chunk_name (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_size_t png_check_keyword (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIkey\fP\fB, png_charpp \fInew_key\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, int \fImask\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_correct_palette (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_crc_error (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_crc_finish (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIskip\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_crc_read (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuf\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_create_struct (int \fP\fItype\fP\fB, png_malloc_ptr \fImalloc_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_voidp png_create_struct_2 (int \fItype\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_charp png_decompress_chunk (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcomp_type\fP\fB, png_charp \fP\fIchunkdata\fP\fB, png_size_t \fP\fIchunklength\fP\fB, png_size_t \fP\fIprefix_length\fP\fB, png_size_t \fI*data_length\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_destroy_struct (png_voidp \fIstruct_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_destroy_struct_2 (png_voidp \fP\fIstruct_ptr\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_background (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_16p \fP\fItrans_values\fP\fB, png_color_16p \fP\fIbackground\fP\fB, png_color_16p \fP\fIbackground_1\fP\fB, png_bytep \fP\fIgamma_table\fP\fB, png_bytep \fP\fIgamma_from_1\fP\fB, png_bytep \fP\fIgamma_to_1\fP\fB, png_uint_16pp \fP\fIgamma_16\fP\fB, png_uint_16pp \fP\fIgamma_16_from_1\fP\fB, png_uint_16pp \fP\fIgamma_16_to_1\fP\fB, int \fIgamma_shift\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_bgr (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_chop (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_dither (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fP\fIpalette_lookup\fP\fB, png_bytep \fIdither_lookup\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_expand (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_16p \fItrans_value\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_expand_palette (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_colorp \fP\fIpalette\fP\fB, png_bytep \fP\fItrans\fP\fB, int \fInum_trans\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_gamma (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fP\fIgamma_table\fP\fB, png_uint_16pp \fP\fIgamma_16_table\fP\fB, int \fIgamma_shift\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_gray_to_rgb (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_invert (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_pack (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_uint_32 \fIbit_depth\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_packswap (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_read_filler (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, png_uint_32 \fIflags\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_read_interlace (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, int \fP\fIpass\fP\fB, png_uint_32 \fItransformations\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_read_invert_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_read_swap_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_read_transformations (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_do_rgb_to_gray (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_shift (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_8p \fIbit_depth\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_strip_filler (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_uint_32 \fIflags\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_swap (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_unpack (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_unshift (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_color_8p \fIsig_bits\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_write_interlace (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, int \fIpass\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_write_invert_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_write_swap_alpha (png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_do_write_transformations (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid *png_far_to_near (png_structp png_ptr,png_voidp \fP\fIptr\fP\fB, int \fIcheck\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_flush (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fI\fB
+
+\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_IEND (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_iTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_handle_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_info_destroy (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_init_read_transformations (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_process_IDAT_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_length\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_process_some_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_check_crc (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_crc_finish (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_crc_skip (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_fill_buffer (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_handle_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_handle_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_handle_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_have_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_have_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_have_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_process_row (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_read_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_read_IDAT (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_read_sig (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_read_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_read_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_restore_buffer (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_length\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_push_save_buffer (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_filter_row (png_structp \fP\fIpng_ptr\fP\fB, png_row_infop \fP\fIrow_info\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fP\fIprev_row\fP\fB, int \fIfilter\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_finish_row (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_push_finish_row (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_start_row (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_read_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_reset_crc (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIvalues\fP\fB, int \fIcolor_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_cHRM (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fBvoid png_write_filtered_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIfiltered_row\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_find_filter (png_structp \fP\fIpng_ptr\fP\fB, png_row_infop \fIrow_info\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_finish_row (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_gAMA (png_structp \fP\fIpng_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIint_file_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_uint_16p \fP\fIhist\fP\fB, int \fInum_hist\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_charp \fP\fIprofile\fP\fB, int \fIproflen\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_IDAT (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_IEND (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fP\fIfilter_type\fP\fB, int \fIinterlace_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_iTXt (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcompression\fP\fB, png_charp \fP\fIkey\fP\fB, png_charp \fP\fIlang\fP\fB, png_charp \fP\fItranslated_key\fP\fB, png_charp \fItext)\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIx_offset\fP\fB, png_uint_32 \fP\fIy_offset\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIx_pixels_per_unit\fP\fB, png_uint_32 \fP\fIy_pixels_per_unit\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, png_uint_32 \fInum_pal\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fP\fIsbit\fP\fB, int \fIcolor_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sRGB (png_structp \fP\fIpng_ptr\fP\fB, int \fIintent\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_spalette_p \fIpalette\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_start_row (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_tEXt (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIkey\fP\fB, png_charp \fP\fItext\fP\fB, png_size_t \fItext_len\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fItrans\fP\fB, png_color_16p \fP\fIvalues\fP\fB, int \fP\fInumber\fP\fB, int \fIcolor_type\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_write_zTXt (png_structp \fP\fIpng_ptr\fP\fB, png_charp \fP\fIkey\fP\fB, png_charp \fP\fItext\fP\fB, png_size_t \fP\fItext_len\fP\fB, int \fIcompression\fP\fB);\fP
+
+\fI\fB
+
+\fBvoidpf png_zalloc (voidpf \fP\fIpng_ptr\fP\fB, uInt \fP\fIitems\fP\fB, uInt \fIsize\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_zfree (voidpf \fP\fIpng_ptr\fP\fB, voidpf \fIptr\fP\fB);\fP
+
+\fI\fB
+
+.SH DESCRIPTION
+The functions listed above are used privately by libpng
+and are not recommended for use by applications.  They
+are listed alphabetically here as an aid to libpng maintainers.
+See png.h for more information on these functions.
+
+.SH SEE ALSO
+libpng(3), png(5)
+.SH AUTHOR
+Glenn Randers-Pehrson

makefile.aco

@@ -1,221 +0,0 @@
-# Project:   libpng
-
-
-# Toolflags:
-CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah 
-C++flags = -c -depend !Depend -IC: -throwback
-Linkflags = -aif -c++ -o $@
-ObjAsmflags = -throwback -NoCache -depend !Depend
-CMHGflags = 
-LibFileflags = -c -l -o $@ 
-Squeezeflags = -o $@
-
-
-# Final targets:
-@.libpng-lib:   @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
-        @.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
-        @.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil 
-        LibFile $(LibFileflags) @.o.png @.o.pngerror @.o.pngrio @.o.pngrtran \
-        @.o.pngmem @.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngwio \
-        @.o.pngrutil @.o.pngtrans  @.o.pngwrite @.o.pngwtran @.o.pngwutil 
-@.mm-libpng-lib:   @.mm.png @.mm.pngerror @.mm.pngrio @.mm.pngwio @.mm.pngmem \
-        @.mm.pngpread @.mm.pngset @.mm.pngget @.mm.pngread @.mm.pngrtran \
-        @.mm.pngrutil @.mm.pngtrans @.mm.pngwrite @.mm.pngwtran @.mm.pngwutil 
-        LibFile $(LibFileflags) @.mm.png @.mm.pngerror @.mm.pngrio \
-        @.mm.pngwio @.mm.pngmem @.mm.pngpread @.mm.pngset @.mm.pngget \
-        @.mm.pngread @.mm.pngrtran @.mm.pngrutil @.mm.pngtrans @.mm.pngwrite \
-        @.mm.pngwtran @.mm.pngwutil 
-
-
-# User-editable dependencies:
-# (C) Copyright 1997 Tom Tanner
-Test: @.pngtest 
-        <Prefix$Dir>.pngtest
-        @remove <Prefix$Dir>.pngtest
-
-#It would be nice if you could stop "make" listing from here on!
-@.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib 
-        Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib 
-
-.SUFFIXES: .o .mm .c
-
-.c.mm:
-        MemCheck.CC cc $(ccflags) -o $@ LibPng:$<
-.c.o:
-        cc $(ccflags) -o $@ $<
-
-
-# Static dependencies:
-
-
-# Dynamic dependencies:
-o.pngtest:	c.pngtest
-o.pngtest:	h.png
-o.pngtest:	Zlib:h.zlib
-o.pngtest:	Zlib:h.zconf
-o.pngtest:	h.pngconf
-mm.png:		LibPng:c.png
-mm.png:		LibPng:h.png
-mm.png:		Zlib:h.zlib
-mm.png:		Zlib:h.zconf
-mm.png:		LibPng:h.pngconf
-mm.png:		MemCheck:ANSI.h.stdio
-mm.pngerror:	LibPng:c.pngerror
-mm.pngerror:	LibPng:h.png
-mm.pngerror:	Zlib:h.zlib
-mm.pngerror:	Zlib:h.zconf
-mm.pngerror:	LibPng:h.pngconf
-mm.pngerror:	MemCheck:ANSI.h.stdio
-mm.pngrio:	LibPng:c.pngrio
-mm.pngrio:	LibPng:h.png
-mm.pngrio:	Zlib:h.zlib
-mm.pngrio:	Zlib:h.zconf
-mm.pngrio:	LibPng:h.pngconf
-mm.pngrio:	MemCheck:ANSI.h.stdio
-mm.pngwio:	LibPng:c.pngwio
-mm.pngwio:	LibPng:h.png
-mm.pngwio:	Zlib:h.zlib
-mm.pngwio:	Zlib:h.zconf
-mm.pngwio:	LibPng:h.pngconf
-mm.pngwio:	MemCheck:ANSI.h.stdio
-mm.pngmem:	LibPng:c.pngmem
-mm.pngmem:	LibPng:h.png
-mm.pngmem:	Zlib:h.zlib
-mm.pngmem:	Zlib:h.zconf
-mm.pngmem:	LibPng:h.pngconf
-mm.pngmem:	MemCheck:ANSI.h.stdio
-mm.pngpread:	LibPng:c.pngpread
-mm.pngpread:	LibPng:h.png
-mm.pngpread:	Zlib:h.zlib
-mm.pngpread:	Zlib:h.zconf
-mm.pngpread:	LibPng:h.pngconf
-mm.pngpread:	MemCheck:ANSI.h.stdio
-mm.pngset:	LibPng:c.pngset
-mm.pngset:	LibPng:h.png
-mm.pngset:	Zlib:h.zlib
-mm.pngset:	Zlib:h.zconf
-mm.pngset:	LibPng:h.pngconf
-mm.pngset:	MemCheck:ANSI.h.stdio
-mm.pngget:	LibPng:c.pngget
-mm.pngget:	LibPng:h.png
-mm.pngget:	Zlib:h.zlib
-mm.pngget:	Zlib:h.zconf
-mm.pngget:	LibPng:h.pngconf
-mm.pngget:	MemCheck:ANSI.h.stdio
-mm.pngread:	LibPng:c.pngread
-mm.pngread:	LibPng:h.png
-mm.pngread:	Zlib:h.zlib
-mm.pngread:	Zlib:h.zconf
-mm.pngread:	LibPng:h.pngconf
-mm.pngread:	MemCheck:ANSI.h.stdio
-mm.pngrtran:	LibPng:c.pngrtran
-mm.pngrtran:	LibPng:h.png
-mm.pngrtran:	Zlib:h.zlib
-mm.pngrtran:	Zlib:h.zconf
-mm.pngrtran:	LibPng:h.pngconf
-mm.pngrtran:	MemCheck:ANSI.h.stdio
-mm.pngrutil:	LibPng:c.pngrutil
-mm.pngrutil:	LibPng:h.png
-mm.pngrutil:	Zlib:h.zlib
-mm.pngrutil:	Zlib:h.zconf
-mm.pngrutil:	LibPng:h.pngconf
-mm.pngrutil:	MemCheck:ANSI.h.stdio
-mm.pngtrans:	LibPng:c.pngtrans
-mm.pngtrans:	LibPng:h.png
-mm.pngtrans:	Zlib:h.zlib
-mm.pngtrans:	Zlib:h.zconf
-mm.pngtrans:	LibPng:h.pngconf
-mm.pngtrans:	MemCheck:ANSI.h.stdio
-mm.pngwrite:	LibPng:c.pngwrite
-mm.pngwrite:	LibPng:h.png
-mm.pngwrite:	Zlib:h.zlib
-mm.pngwrite:	Zlib:h.zconf
-mm.pngwrite:	LibPng:h.pngconf
-mm.pngwrite:	MemCheck:ANSI.h.stdio
-mm.pngwtran:	LibPng:c.pngwtran
-mm.pngwtran:	LibPng:h.png
-mm.pngwtran:	Zlib:h.zlib
-mm.pngwtran:	Zlib:h.zconf
-mm.pngwtran:	LibPng:h.pngconf
-mm.pngwtran:	MemCheck:ANSI.h.stdio
-mm.pngwutil:	LibPng:c.pngwutil
-mm.pngwutil:	LibPng:h.png
-mm.pngwutil:	Zlib:h.zlib
-mm.pngwutil:	Zlib:h.zconf
-mm.pngwutil:	LibPng:h.pngconf
-mm.pngwutil:	MemCheck:ANSI.h.stdio
-o.png:		c.png
-o.png:		h.png
-o.png:		Zlib:h.zlib
-o.png:		Zlib:h.zconf
-o.png:		h.pngconf
-o.pngerror:	c.pngerror
-o.pngerror:	h.png
-o.pngerror:	Zlib:h.zlib
-o.pngerror:	Zlib:h.zconf
-o.pngerror:	h.pngconf
-o.pngrio:	c.pngrio
-o.pngrio:	h.png
-o.pngrio:	Zlib:h.zlib
-o.pngrio:	Zlib:h.zconf
-o.pngrio:	h.pngconf
-o.pngwio:	c.pngwio
-o.pngwio:	h.png
-o.pngwio:	Zlib:h.zlib
-o.pngwio:	Zlib:h.zconf
-o.pngwio:	h.pngconf
-o.pngmem:	c.pngmem
-o.pngmem:	h.png
-o.pngmem:	Zlib:h.zlib
-o.pngmem:	Zlib:h.zconf
-o.pngmem:	h.pngconf
-o.pngpread:	c.pngpread
-o.pngpread:	h.png
-o.pngpread:	Zlib:h.zlib
-o.pngpread:	Zlib:h.zconf
-o.pngpread:	h.pngconf
-o.pngset:	c.pngset
-o.pngset:	h.png
-o.pngset:	Zlib:h.zlib
-o.pngset:	Zlib:h.zconf
-o.pngset:	h.pngconf
-o.pngget:	c.pngget
-o.pngget:	h.png
-o.pngget:	Zlib:h.zlib
-o.pngget:	Zlib:h.zconf
-o.pngget:	h.pngconf
-o.pngread:	c.pngread
-o.pngread:	h.png
-o.pngread:	Zlib:h.zlib
-o.pngread:	Zlib:h.zconf
-o.pngread:	h.pngconf
-o.pngrtran:	c.pngrtran
-o.pngrtran:	h.png
-o.pngrtran:	Zlib:h.zlib
-o.pngrtran:	Zlib:h.zconf
-o.pngrtran:	h.pngconf
-o.pngrutil:	c.pngrutil
-o.pngrutil:	h.png
-o.pngrutil:	Zlib:h.zlib
-o.pngrutil:	Zlib:h.zconf
-o.pngrutil:	h.pngconf
-o.pngtrans:	c.pngtrans
-o.pngtrans:	h.png
-o.pngtrans:	Zlib:h.zlib
-o.pngtrans:	Zlib:h.zconf
-o.pngtrans:	h.pngconf
-o.pngwrite:	c.pngwrite
-o.pngwrite:	h.png
-o.pngwrite:	Zlib:h.zlib
-o.pngwrite:	Zlib:h.zconf
-o.pngwrite:	h.pngconf
-o.pngwtran:	c.pngwtran
-o.pngwtran:	h.png
-o.pngwtran:	Zlib:h.zlib
-o.pngwtran:	Zlib:h.zconf
-o.pngwtran:	h.pngconf
-o.pngwutil:	c.pngwutil
-o.pngwutil:	h.png
-o.pngwutil:	Zlib:h.zlib
-o.pngwutil:	Zlib:h.zconf
-o.pngwutil:	h.pngconf

makefile.elf

@@ -1,86 +0,0 @@
-# makefile for libpng on (linux) ELF
-# Copyright (C) 1996, 1997 Andreas Dilger
-# For conditions of distribution and use, see copyright notice in png.h
-
-CC=gcc
-
-# Where the zlib library and include files are located
-#ZLIBLIB=/usr/local/lib
-#ZLIBINC=/usr/local/include
-ZLIBLIB=../zlib
-ZLIBINC=../zlib
-
-WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
-         -Wmissing-declarations -Wtraditional -Wcast-align \
-         -Wstrict-prototypes -Wmissing-prototypes #-Wconversion
-CFLAGS=-I$(ZLIBINC) -Wall -O2 -fPIC # $(WARNMORE) # -g -DPNG_DEBUG=3
-LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz -lm
-
-RANLIB=ranlib
-#RANLIB=echo
-
-PNGMAJ = 0
-PNGMIN = 96
-PNGVER = $(PNGMAJ).$(PNGMIN)
-
-# where make install puts libpng.a, libpng.so*, and png.h
-prefix=/usr/local
-INCPATH=$(prefix)/include
-LIBPATH=$(prefix)/lib
-
-OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
-       pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-       pngwtran.o pngmem.o pngerror.o pngpread.o
-
-all: libpng.so pngtest
-
-libpng.a: $(OBJS)
-	ar rc $@  $(OBJS)
-	$(RANLIB) $@
-
-libpng.so: libpng.so.$(PNGMAJ)
-	ln -sf libpng.so.$(PNGMAJ) libpng.so
-
-libpng.so.$(PNGMAJ): libpng.so.$(PNGVER)
-	ln -sf libpng.so.$(PNGVER) libpng.so.$(PNGMAJ)
-
-libpng.so.$(PNGVER): $(OBJS)
-	gcc -shared -Wl,-soname,libpng.so.$(PNGMAJ) -o libpng.so.$(PNGVER) $(OBJS)
-
-pngtest: pngtest.o libpng.so
-	$(CC) -o pngtest pngtest.o $(LDFLAGS)
-
-test: pngtest
-	./pngtest
-
-install: libpng.so.$(PNGVER)
-	-@mkdir $(INCPATH) $(LIBPATH)
-	cp png.h pngconf.h $(INCPATH)
-	chmod 644 $(INCPATH)/png.h $(INCPATH)/pngconf.h
-	cp libpng.so.$(PNGVER) $(LIBPATH)
-	chmod 755 $(LIBPATH)/libpng.so.$(PNGVER)
-	-@/bin/rm $(LIBPATH)/libpng.so.$(PNGMAJ) $(LIBPATH)/libpng.so
-	(cd $(LIBPATH); ln -sf libpng.so.$(PNGVER) libpng.so.$(PNGMAJ); \
-	 ln -sf libpng.so.$(PNGMAJ) libpng.so)
-
-clean:
-	rm -f *.o libpng.a libpng.so* pngtest pngout.png
-
-# DO NOT DELETE THIS LINE -- make depend depends on it.
-
-png.o: png.h pngconf.h
-pngerror.o: png.h pngconf.h
-pngrio.o: png.h pngconf.h
-pngwio.o: png.h pngconf.h
-pngmem.o: png.h pngconf.h
-pngset.o: png.h pngconf.h
-pngget.o: png.h pngconf.h
-pngread.o: png.h pngconf.h
-pngrtran.o: png.h pngconf.h
-pngrutil.o: png.h pngconf.h
-pngtest.o: png.h pngconf.h
-pngtrans.o: png.h pngconf.h
-pngwrite.o: png.h pngconf.h
-pngwtran.o: png.h pngconf.h
-pngwutil.o: png.h pngconf.h
-pngpread.o: png.h pngconf.h

png.5

@@ -0,0 +1,60 @@
+.TH PNG 5 "May 12, 2000"
+.SH NAME
+png \- Portable Network Graphics (PNG) format
+.SH DESCRIPTION
+PNG (Portable Network Graphics) is an extensible file format for the
+lossless, portable, well-compressed storage of raster images. PNG provides
+a patent-free replacement for GIF and can also replace many
+common uses of TIFF. Indexed-color, grayscale, and truecolor images are
+supported, plus an optional alpha channel. Sample depths range from
+1 to 16 bits.
+.br
+
+PNG is designed to work well in online viewing applications, such as the
+World Wide Web, so it is fully streamable with a progressive display
+option. PNG is robust, providing both full file integrity checking and
+fast, simple detection of common transmission errors. Also, PNG can store
+gamma and chromaticity data for improved color matching on heterogeneous
+platforms.
+
+.SH "SEE ALSO"
+.IR libpng(3), zlib(3), deflate(5), and zlib(5)
+.LP
+PNG 1.2 specification, July 1999:
+.IP
+.br
+http://www.cdrom.com/pub/png (moving to http://www.libpng.org)
+.br
+or ftp://ftp.uu.net/graphics/png/documents
+.LP
+PNG 1.0 specification, October 1996:
+.IP
+.br
+RFC 2083
+.IP
+.br
+ftp://ds.internic.net/rfc/rfc2083.txt
+.br
+or (as a W3C Recommendation) at
+.br
+http://www.w3.org/TR/REC-png.html
+.SH AUTHORS
+This man page: Glenn Randers-Pehrson
+.LP
+Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
+Glenn Randers-Pehrson and others (png-list@ccrc.wustl.edu).
+.LP
+Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
+Thomas Boutell and others (png-list@ccrc.wustl.edu).
+.LP
+
+
+.SH COPYRIGHT NOTICE
+The PNG-1.2 specification is copyright (c) 1999 Glenn Randers-Pehrson.
+See the specification for conditions of use and distribution.
+.LP
+The PNG-1.0 specification is copyright (c) 1996 Massachussets Institute of
+Technology.  See the specification for conditions of use and distribution.
+.LP
+.\" end of man page
+

png.c

@@ -1,43 +1,54 @@
 
-/* png.c - location for general purpose png functions
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-   */
+/* png.c - location for general purpose libpng functions
+ *
+ * libpng version 1.0.7beta12 - May 12, 2000
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ *
+ */
 
 #define PNG_INTERNAL
 #define PNG_NO_EXTERN
+#include <assert.h>
 #include "png.h"
 
-/* Version information for C files.  This had better match the version
-   string defined in png.h */
-char png_libpng_ver[] = "0.95";
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef version_1_0_7beta12 Your_png_h_is_not_version_1_0_7beta12;
 
-/* Place to hold the signiture string for a PNG file. */
+/* Version information for C files.  This had better match the version
+ * string defined in png.h.  */
+
+#ifdef PNG_USE_GLOBAL_ARRAYS
+/* png_libpng_ver was changed to a function in version 1.0.5c */
+char png_libpng_ver[12] = "1.0.7beta12";
+
+/* png_sig was changed to a function in version 1.0.5c */
+/* Place to hold the signature string for a PNG file. */
 png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 
-/* constant strings for known chunk types.  If you need to add a chunk,
-   add a string holding the name here.  If you want to make the code
-   portable to EBCDIC machines, use ASCII numbers, not characters. */
-png_byte FARDATA png_IHDR[5] = { 73,  72,  68,  82, '\0'};
-png_byte FARDATA png_IDAT[5] = { 73,  68,  65,  84, '\0'};
-png_byte FARDATA png_IEND[5] = { 73,  69,  78,  68, '\0'};
-png_byte FARDATA png_PLTE[5] = { 80,  76,  84,  69, '\0'};
-png_byte FARDATA png_bKGD[5] = { 98,  75,  71,  68, '\0'};
-png_byte FARDATA png_cHRM[5] = { 99,  72,  82,  77, '\0'};
-png_byte FARDATA png_gAMA[5] = {103,  65,  77,  65, '\0'};
-png_byte FARDATA png_hIST[5] = {104,  73,  83,  84, '\0'};
-png_byte FARDATA png_oFFs[5] = {111,  70,  70, 115, '\0'};
-png_byte FARDATA png_pCAL[5] = {112,  67,  65,  76, '\0'};
-png_byte FARDATA png_pHYs[5] = {112,  72,  89, 115, '\0'};
-png_byte FARDATA png_sBIT[5] = {115,  66,  73,  84, '\0'};
-png_byte FARDATA png_tEXt[5] = {116,  69,  88, 116, '\0'};
-png_byte FARDATA png_tIME[5] = {116,  73,  77,  69, '\0'};
-png_byte FARDATA png_tRNS[5] = {116,  82,  78,  83, '\0'};
-png_byte FARDATA png_zTXt[5] = {122,  84,  88, 116, '\0'};
+/* Invoke global declarations for constant strings for known chunk types */
+PNG_IHDR;
+PNG_IDAT;
+PNG_IEND;
+PNG_PLTE;
+PNG_bKGD;
+PNG_cHRM;
+PNG_gAMA;
+PNG_hIST;
+PNG_iCCP;
+PNG_iTXt;
+PNG_oFFs;
+PNG_pCAL;
+PNG_sCAL;
+PNG_pHYs;
+PNG_sBIT;
+PNG_sPLT;
+PNG_sRGB;
+PNG_tEXt;
+PNG_tIME;
+PNG_tRNS;
+PNG_zTXt;
 
 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
@@ -53,38 +64,38 @@ int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 /* offset to next interlace block in the y direction */
 int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 
-/* width of interlace block */
-/* this is not currently used - if you need it, uncomment it here and
-   in png.h
+/* width of interlace block (used in assembler routines only) */
+#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW
 int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
-*/
+#endif
 
-/* height of interlace block */
-/* this is not currently used - if you need it, uncomment it here and
-   in png.h
+/* Height of interlace block.  This is not currently used - if you need
+ * it, uncomment it here and in png.h
 int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
 */
 
-/* mask to determine which pixels are valid in a pass */
+/* Mask to determine which pixels are valid in a pass */
 int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 
-/* mask to determine which pixels to overwrite while displaying */
+/* Mask to determine which pixels to overwrite while displaying */
 int FARDATA png_pass_dsp_mask[] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
 
+#endif
 
 /* Tells libpng that we have already handled the first "num_bytes" bytes
  * of the PNG file signature.  If the PNG data is embedded into another
  * stream we can set num_bytes = 8 so that libpng will not attempt to read
  * or write any of the magic bytes before it starts on the IHDR.
  */
-void
+
+void PNGAPI
 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
 {
    png_debug(1, "in png_set_sig_bytes\n");
    if (num_bytes > 8)
       png_error(png_ptr, "Too many bytes for PNG signature.");
 
-   png_ptr->sig_bytes = num_bytes < 0 ? 0 : num_bytes;
+   png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
 }
 
 /* Checks whether the supplied bytes match the PNG signature.  We allow
@@ -95,42 +106,42 @@ png_set_sig_bytes(png_structp png_ptr, int num_bytes)
  * respectively, to be less than, to match, or be greater than the correct
  * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
  */
-int
+int PNGAPI
 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
 {
+   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
    if (num_to_check > 8)
       num_to_check = 8;
    else if (num_to_check < 1)
-      return 0;
+      return (0);
 
    if (start > 7)
-      return 0;
+      return (0);
 
    if (start + num_to_check > 8)
       num_to_check = 8 - start;
 
-   return (png_memcmp(&sig[start], &png_sig[start], num_to_check));
+   return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
 }
 
 /* (Obsolete) function to check signature bytes.  It does not allow one
-   to check a partial signature.  This function will be removed in the
-   future - use png_sig_cmp(). */
-int
+ * to check a partial signature.  This function might be removed in the
+ * future - use png_sig_cmp().  Returns true (nonzero) if the file is a PNG.
+ */
+int PNGAPI
 png_check_sig(png_bytep sig, int num)
 {
-  return !png_sig_cmp(sig, (png_size_t)0, (png_size_t)num);
+  return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
 }
 
-/* Function to allocate memory for zlib. */
-voidpf
+/* Function to allocate memory for zlib and clear it to 0. */
+voidpf PNGAPI
 png_zalloc(voidpf png_ptr, uInt items, uInt size)
 {
-   png_voidp ptr;
-   png_uint_32 num_bytes;
+   png_uint_32 num_bytes = (png_uint_32)items * size;
+   png_voidp ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
 
-   num_bytes = (png_uint_32)items * size;
-   ptr = png_malloc((png_structp)png_ptr, num_bytes);
-   if (num_bytes > (png_uint_32)0x8000)
+   if (num_bytes > (png_uint_32)0x8000L)
    {
       png_memset(ptr, 0, (png_size_t)0x8000L);
       png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
@@ -140,90 +151,31 @@ png_zalloc(voidpf png_ptr, uInt items, uInt size)
    {
       png_memset(ptr, 0, (png_size_t)num_bytes);
    }
-   return (voidpf)(ptr);
+   return ((voidpf)ptr);
 }
 
 /* function to free memory for zlib */
-void
+void PNGAPI
 png_zfree(voidpf png_ptr, voidpf ptr)
 {
    png_free((png_structp)png_ptr, (png_voidp)ptr);
 }
 
 /* Reset the CRC variable to 32 bits of 1's.  Care must be taken
-   in case CRC is > 32 bits to leave the top bits 0. */
-void
+ * in case CRC is > 32 bits to leave the top bits 0.
+ */
+void /* PRIVATE */
 png_reset_crc(png_structp png_ptr)
 {
-   /* set CRC to all 1's */
-#ifdef PNG_USE_OWN_CRC
-   png_ptr->crc = 0xffffffffL;
-#else
    png_ptr->crc = crc32(0, Z_NULL, 0);
-#endif
 }
 
-#ifdef PNG_USE_OWN_CRC
-/* Table of CRCs of all 8-bit messages.  By default, we use the tables made
-   by zlib, to save some memory.  If you wish to png_malloc() this
-   table, turn this into a pointer, and png_malloc() it in make_crc_table().
-   You may then want to hook it into png_struct and free it with the
-   destroy functions.  Another alternative is to pre-fill the table.  */
-static png_uint_32 crc_table[256];
-
-/* Flag: has the table been computed? Initially false. */
-static int crc_table_computed = 0;
-
-/* make the table for a fast crc */
-static void
-make_crc_table(void)
-{
-  png_uint_32 c;
-  int n, k;
-
-  for (n = 0; n < 256; n++)
-  {
-   c = (png_uint_32)n;
-   for (k = 0; k < 8; k++)
-     c = c & 1 ? 0xedb88320L ^ (c >> 1) : c >> 1;
-   crc_table[n] = c;
-  }
-  crc_table_computed = 1;
-}
-
-/* Update a running CRC with the bytes buf[0..len-1] - the CRC should be
-   initialized to all 1's, and the transmitted value is the 1's complement
-   of the final running CRC. */
-static png_uint_32
-update_crc(png_uint_32 crc, png_bytep buf, png_size_t len)
-{
-  png_uint_32 c;
-  png_bytep p;
-  png_uint_32 n;
-
-  c = crc;
-  p = buf;
-  n = len;
-
-  if (!crc_table_computed)
-  {
-   make_crc_table();
-  }
-
-  if (n > 0) do
-  {
-   c = crc_table[(png_byte)((c ^ (*p++)) & 0xff)] ^ (c >> 8);
-  } while (--n);
-
-  return c;
-}
-#endif /* PNG_USE_OWN_CRC */
-
 /* Calculate the CRC over a section of data.  We can only pass as
-   much data to this routine as the largest single buffer size.  We
-   also check that this data will actually be used before going to the
-   trouble of calculating it. */
-void
+ * much data to this routine as the largest single buffer size.  We
+ * also check that this data will actually be used before going to the
+ * trouble of calculating it.
+ */
+void /* PRIVATE */
 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
 {
    int need_crc = 1;
@@ -241,37 +193,41 @@ png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
    }
 
    if (need_crc)
-#ifdef PNG_USE_OWN_CRC
-      png_ptr->crc = update_crc(png_ptr->crc, ptr, length);
-#else
-      png_ptr->crc = crc32(png_ptr->crc, ptr, length);
-#endif
+      png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
 }
 
 /* Allocate the memory for an info_struct for the application.  We don't
-   really need the png_ptr, but it could potentially be useful in the
-   future.  This should be used in favour of malloc(sizeof(png_info))
-   and png_info_init() so that applications that want to use a shared
-   libpng don't have to be recompiled if png_info changes size. */
-png_infop
+ * really need the png_ptr, but it could potentially be useful in the
+ * future.  This should be used in favour of malloc(sizeof(png_info))
+ * and png_info_init() so that applications that want to use a shared
+ * libpng don't have to be recompiled if png_info changes size.
+ */
+png_infop PNGAPI
 png_create_info_struct(png_structp png_ptr)
 {
    png_infop info_ptr;
 
    png_debug(1, "in png_create_info_struct\n");
+   if(png_ptr == NULL) return (NULL);
+#ifdef PNG_USER_MEM_SUPPORTED
+   if ((info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
+      png_ptr->malloc_fn)) != NULL)
+#else
    if ((info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO)) != NULL)
+#endif
    {
       png_info_init(info_ptr);
    }
 
-   return info_ptr;
+   return (info_ptr);
 }
 
 /* This function frees the memory associated with a single info struct.
-   Normally, one would use either png_destroy_read_struct() or
-   png_destroy_write_struct() to free an info struct, but this may be
-   useful for some applications. */
-void
+ * Normally, one would use either png_destroy_read_struct() or
+ * png_destroy_write_struct() to free an info struct, but this may be
+ * useful for some applications.
+ */
+void PNGAPI
 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 {
    png_infop info_ptr = NULL;
@@ -284,15 +240,20 @@ png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
    {
       png_info_destroy(png_ptr, info_ptr);
 
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn);
+#else
       png_destroy_struct((png_voidp)info_ptr);
+#endif
       *info_ptr_ptr = (png_infop)NULL;
    }
 }
 
 /* Initialize the info structure.  This is now an internal function (0.89)
-   and applications using it are urged to use png_create_info_struct()
-   instead. */
-void
+ * and applications using it are urged to use png_create_info_struct()
+ * instead.
+ */
+void PNGAPI
 png_info_init(png_infop info_ptr)
 {
    png_debug(1, "in png_info_init\n");
@@ -300,36 +261,265 @@ png_info_init(png_infop info_ptr)
    png_memset(info_ptr, 0, sizeof (png_info));
 }
 
+#ifdef PNG_FREE_ME_SUPPORTED
+void PNGAPI
+png_data_freer(png_structp png_ptr, png_infop info_ptr,
+   int freer, png_uint_32 mask)
+{
+   png_debug(1, "in png_data_freer\n");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+   if(freer == PNG_DESTROY_WILL_FREE_DATA)
+      info_ptr->free_me |= mask;
+   else if(freer == PNG_USER_WILL_FREE_DATA)
+      info_ptr->free_me &= ~mask;
+   else
+      png_warning(png_ptr,
+         "Unknown freer parameter in png_data_freer.");
+}
+#endif
+
+void PNGAPI
+png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, int num)
+{
+   png_debug(1, "in png_free_data\n");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+#if defined(PNG_TEXT_SUPPORTED)
+/* free text item num or (if num == -1) all text items */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & info_ptr->free_me & PNG_FREE_TEXT)
+#else
+if (mask & PNG_FREE_TEXT)
+#endif
+{
+   if (num != -1)
+   {
+     if (info_ptr->text[num].key)
+     {
+         png_free(png_ptr, info_ptr->text[num].key);
+         info_ptr->text[num].key = NULL;
+     }
+   }
+   else if (info_ptr->text != NULL)
+   {
+     int i;
+     for (i = 0; i < info_ptr->num_text; i++)
+         png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
+     png_free(png_ptr, info_ptr->text);
+     info_ptr->text = NULL;
+     info_ptr->num_text=0;
+   }
+}
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+/* free any tRNS entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_TRNS & info_ptr->free_me)
+#else
+if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
+#endif
+{
+   if (info_ptr->valid & PNG_INFO_tRNS)
+   {
+         png_free(png_ptr, info_ptr->trans);
+       info_ptr->valid &= ~PNG_INFO_tRNS;
+   }
+}
+#endif
+
+#if defined(PNG_sCAL_SUPPORTED)
+/* free any sCAL entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_SCAL & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_SCAL)
+#endif
+{
+   if (info_ptr->valid & PNG_INFO_sCAL)
+   {
+#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
+       png_free(png_ptr, info_ptr->scal_s_width);
+       png_free(png_ptr, info_ptr->scal_s_height);
+#endif
+          info_ptr->valid &= ~PNG_INFO_sCAL;
+   }
+}
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+/* free any pCAL entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_PCAL & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_PCAL)
+#endif
+{
+   if (info_ptr->valid & PNG_INFO_pCAL)
+   {
+       png_free(png_ptr, info_ptr->pcal_purpose);
+       png_free(png_ptr, info_ptr->pcal_units);
+       if (info_ptr->pcal_params != NULL)
+       {
+           int i;
+           for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
+             {
+             png_free(png_ptr, info_ptr->pcal_params[i]);
+             }
+           png_free(png_ptr, info_ptr->pcal_params);
+       }
+       info_ptr->valid &= ~PNG_INFO_pCAL;
+   }
+}
+#endif
+
+#if defined(PNG_iCCP_SUPPORTED)
+/* free any iCCP entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_ICCP & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_ICCP)
+#endif
+{
+   if (info_ptr->valid & PNG_INFO_iCCP)
+   {
+       png_free(png_ptr, info_ptr->iccp_name);
+       png_free(png_ptr, info_ptr->iccp_profile);
+       info_ptr->valid &= ~PNG_INFO_iCCP;
+   }
+}
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+/* free a given sPLT entry, or (if num == -1) all sPLT entries */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_SPLT & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_SPLT)
+#endif
+{
+   if (num != -1)
+   {
+       png_free(png_ptr, info_ptr->splt_palettes[num].name);
+       png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+       info_ptr->valid &= ~PNG_INFO_sPLT;
+   }
+   else
+   {
+       if(info_ptr->splt_palettes_num)
+       {
+         int i;
+         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
+
+         png_free(png_ptr, info_ptr->splt_palettes);
+         info_ptr->splt_palettes_num = 0;
+       }
+   }
+}
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & info_ptr->free_me & PNG_FREE_UNKN)
+#else
+if (mask & PNG_FREE_UNKN)
+#endif
+{
+   if (num != -1)
+   {
+       png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+       info_ptr->unknown_chunks[num].data = NULL;
+   }
+   else
+   {
+       int i;
+
+       if(info_ptr->unknown_chunks_num)
+       {
+         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
+            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
+
+         png_free(png_ptr, info_ptr->unknown_chunks);
+         info_ptr->unknown_chunks_num = 0;
+       }
+   }
+}
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+/* free any hIST entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_HIST  & info_ptr->free_me)
+#else
+if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
+#endif
+{
+   if (info_ptr->valid & PNG_INFO_hIST)
+   {
+       png_free(png_ptr, info_ptr->hist);
+       info_ptr->valid &= ~PNG_INFO_hIST;
+   }
+}
+#endif
+
+/* free any PLTE entry that was internally allocated */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & PNG_FREE_PLTE & info_ptr->free_me)
+#else
+if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
+#endif
+{
+   if (info_ptr->valid & PNG_INFO_PLTE)
+   {
+       png_zfree(png_ptr, info_ptr->palette);
+       info_ptr->valid &= ~(PNG_INFO_PLTE);
+       info_ptr->num_palette = 0;
+   }
+}
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+/* free any image bits attached to the info structure */
+#ifdef PNG_FREE_ME_SUPPORTED
+if (mask & info_ptr->free_me & PNG_FREE_ROWS)
+#else
+if (mask & PNG_FREE_ROWS)
+#endif
+{
+    if(info_ptr->row_pointers)
+    {
+       int row;
+       for (row = 0; row < (int)info_ptr->height; row++)
+          png_free(png_ptr, info_ptr->row_pointers[row]);
+       png_free(png_ptr, info_ptr->row_pointers);
+       info_ptr->row_pointers=NULL;
+    }
+}
+#endif
+#ifdef PNG_FREE_ME_SUPPORTED
+   if(num == -1)
+     info_ptr->free_me &= ~mask;
+#endif
+}
+
 /* This is an internal routine to free any memory that the info struct is
  * pointing to before re-using it or freeing the struct itself.  Recall
  * that png_free() checks for NULL pointers for us.
  */
-void
+void /* PRIVATE */
 png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 {
-#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_READ_zTXt_SUPPORTED)
-   int i;
-
    png_debug(1, "in png_info_destroy\n");
-   if (info_ptr->text != NULL)
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+    
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+   if (png_ptr->num_chunk_list)
    {
-      for (i = 0; i < info_ptr->num_text; i++)
-      {
-         png_free(png_ptr, info_ptr->text[i].key);
-      }
-      png_free(png_ptr, info_ptr->text);
-   }
-#endif
-#if defined(PNG_READ_pCAL_SUPPORTED)
-   png_free(png_ptr, info_ptr->pcal_purpose);
-   png_free(png_ptr, info_ptr->pcal_units);
-   if (info_ptr->pcal_params != NULL)
-   {
-      for (i = 0; i < info_ptr->pcal_nparams; i++)
-      {
-         png_free(png_ptr, info_ptr->pcal_params[i]);
-      }
-      png_free(png_ptr, info_ptr->pcal_params);
+       png_free(png_ptr, png_ptr->chunk_list);
+       png_ptr->num_chunk_list=0;
    }
 #endif
 
@@ -337,22 +527,147 @@ png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 }
 
 /* This function returns a pointer to the io_ptr associated with the user
-   functions.  The application should free any memory associated with this
-   pointer before png_write_destroy() or png_read_destroy() are called. */
-png_voidp
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy() or png_read_destroy() are called.
+ */
+png_voidp PNGAPI
 png_get_io_ptr(png_structp png_ptr)
 {
-   return png_ptr->io_ptr;
+   return (png_ptr->io_ptr);
 }
 
 #if !defined(PNG_NO_STDIO)
 /* Initialize the default input/output functions for the PNG file.  If you
-   use your own read or write routines, you can call either png_set_read_fn()
-   or png_set_write_fn() instead of png_init_io(). */
-void
+ * use your own read or write routines, you can call either png_set_read_fn()
+ * or png_set_write_fn() instead of png_init_io().  If you have defined
+ * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
+ * necessarily available.
+ */
+void PNGAPI
 png_init_io(png_structp png_ptr, FILE *fp)
 {
    png_debug(1, "in png_init_io\n");
    png_ptr->io_ptr = (png_voidp)fp;
 }
 #endif
+
+#if defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Convert the supplied time into an RFC 1123 string suitable for use in
+ * a "Creation Time" or other text-based time string.
+ */
+png_charp PNGAPI
+png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
+{
+   static PNG_CONST char short_months[12][4] =
+        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+
+   if (png_ptr->time_buffer == NULL)
+   {
+      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
+         sizeof(char)));
+   }
+
+#ifdef USE_FAR_KEYWORD
+   {
+      char near_time_buf[29];
+      sprintf(near_time_buf, "%d %s %d %02d:%02d:%02d +0000",
+               ptime->day % 32, short_months[(ptime->month - 1) % 12],
+               ptime->year, ptime->hour % 24, ptime->minute % 60,
+               ptime->second % 61);
+      png_memcpy(png_ptr->time_buffer, near_time_buf,
+      29*sizeof(char));
+   }
+#else
+   sprintf(png_ptr->time_buffer, "%d %s %d %02d:%02d:%02d +0000",
+               ptime->day % 32, short_months[(ptime->month - 1) % 12],
+               ptime->year, ptime->hour % 24, ptime->minute % 60,
+               ptime->second % 61);
+#endif
+   return ((png_charp)png_ptr->time_buffer);
+}
+#endif /* PNG_TIME_RFC1123_SUPPORTED */
+
+#if 0
+/* Signature string for a PNG file. */
+png_bytep PNGAPI
+png_sig_bytes(void)
+{
+   return ((png_bytep)"\211\120\116\107\015\012\032\012");
+}
+#endif
+
+png_charp PNGAPI
+png_get_copyright(png_structp png_ptr)
+{
+   if (png_ptr != NULL || png_ptr == NULL)  /* silence compiler warning */
+   return ("\n libpng version 1.0.7beta12 - May 12, 2000\n\
+   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.\n\
+   Copyright (c) 1996, 1997 Andreas Dilger\n\
+   Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson\n");
+   return ("");
+}
+
+/* The following return the library version as a short string in the
+ * format 1.0.0 through 99.99.99zz.  To get the version of *.h files used
+ * with your application, print out PNG_LIBPNG_VER_STRING, which is defined
+ * in png.h.
+ */
+
+png_charp PNGAPI
+png_get_libpng_ver(png_structp png_ptr)
+{
+   /* Version of *.c files used when building libpng */
+   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
+      return("1.0.7beta12");
+   return("1.0.7beta12");
+}
+
+png_charp PNGAPI
+png_get_header_ver(png_structp png_ptr)
+{
+   /* Version of *.h files used when building libpng */
+   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
+      return(PNG_LIBPNG_VER_STRING);
+   return(PNG_LIBPNG_VER_STRING);
+}
+
+png_charp PNGAPI
+png_get_header_version(png_structp png_ptr)
+{
+   /* Returns longer string containing both version and date */
+   if(png_ptr != NULL) /* silence compiler warning about unused png_ptr */
+      return(PNG_HEADER_VERSION_STRING);
+   return(PNG_HEADER_VERSION_STRING);
+}
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+int PNGAPI
+png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
+{
+   /* check chunk_name and return "keep" value if it's on the list, else 0 */
+   int i;
+   png_bytep p;
+   if((png_ptr == NULL && chunk_name == NULL) || png_ptr->num_chunk_list<=0)
+      return 0;
+   p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
+   for (i = png_ptr->num_chunk_list; i; i--, p-=5)
+      if (!png_memcmp(chunk_name, p, 4))
+        return ((int)*(p+4));
+   return 0;
+}
+#endif
+
+/* This function, added to libpng-1.0.6g, is untested. */
+int PNGAPI
+png_reset_zstream(png_structp png_ptr)
+{
+   return (inflateReset(&png_ptr->zstream));
+}
+
+png_uint_32 PNGAPI
+png_access_version_number(void)
+{
+   /* Version of *.c files used when building libpng */
+   return((png_uint_32) 10007L);
+}

pngasmrd.h

@@ -0,0 +1,35 @@
+/* pngasmrd.h - assembler version of utilities to read a PNG file
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1999, 2000 Glenn Randers-Pehrson
+ *
+ */
+
+#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
+
+/* Set this in the makefile for VC++ on Pentium, not in pngconf.h */
+/* Platform must be Pentium.  Makefile must assemble and load pngvcrd.c .
+ * MMX will be detected at run time and used if present.
+ */
+#ifdef PNG_USE_PNGVCRD
+#  define PNG_HAVE_ASSEMBLER_COMBINE_ROW
+#  define PNG_HAVE_ASSEMBLER_READ_INTERLACE
+#  define PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
+#endif
+
+/* Set this in the makefile for gcc/as on Pentium, not in pngconf.h */
+/* Platform must be Pentium.  Makefile must assemble and load pnggccrd.c .
+ * MMX will be detected at run time and used if present.
+ */
+#ifdef PNG_USE_PNGGCCRD
+#  define PNG_HAVE_ASSEMBLER_COMBINE_ROW
+#  define PNG_HAVE_ASSEMBLER_READ_INTERLACE
+#  define PNG_HAVE_ASSEMBLER_READ_FILTER_ROW
+#endif
+/*
+    GRR notes:
+      - see pnggccrd.c for info about what is currently enabled
+ */
+
+#endif

pngerror.c

@@ -1,30 +1,34 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-
-   This file provides a location for all error handling.  Users which
-   need special error handling are expected to write replacement functions
-   and use png_set_error_fn() to use those functions.  See the instructions
-   at each function. */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ *
+ * This file provides a location for all error handling.  Users who
+ * need special error handling are expected to write replacement functions
+ * and use png_set_error_fn() to use those functions.  See the instructions
+ * at each function.
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
 
-static void png_default_error PNGARG((png_structp png_ptr,
+static void /* PRIVATE */
+png_default_error PNGARG((png_structp png_ptr,
                                       png_const_charp message));
-static void png_default_warning PNGARG((png_structp png_ptr,
+static void /* PRIVATE */
+png_default_warning PNGARG((png_structp png_ptr,
                                         png_const_charp message));
 
 /* This function is called whenever there is a fatal error.  This function
-   should not be changed.  If there is a need to handle errors differently,
-   you should supply a replacement error function and use png_set_error_fn()
-   to replace the error function at run-time. */
-void
+ * should not be changed.  If there is a need to handle errors differently,
+ * you should supply a replacement error function and use png_set_error_fn()
+ * to replace the error function at run-time.
+ */
+void PNGAPI
 png_error(png_structp png_ptr, png_const_charp message)
 {
    if (png_ptr->error_fn != NULL)
@@ -36,10 +40,11 @@ png_error(png_structp png_ptr, png_const_charp message)
 }
 
 /* This function is called whenever there is a non-fatal error.  This function
-   should not be changed.  If there is a need to handle warnings differently,
-   you should supply a replacement warning function and use
-   png_set_error_fn() to replace the warning function at run-time. */
-void
+ * should not be changed.  If there is a need to handle warnings differently,
+ * you should supply a replacement warning function and use
+ * png_set_error_fn() to replace the warning function at run-time.
+ */
+void PNGAPI
 png_warning(png_structp png_ptr, png_const_charp message)
 {
    if (png_ptr->warning_fn != NULL)
@@ -48,48 +53,115 @@ png_warning(png_structp png_ptr, png_const_charp message)
       png_default_warning(png_ptr, message);
 }
 
+/* These utilities are used internally to build an error message that relates
+ * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
+ * this is used to prefix the message.  The message is limited in length
+ * to 63 bytes, the name characters are output as hex digits wrapped in []
+ * if the character is invalid.
+ */
+#define isnonalpha(c) ((c) < 41 || (c) > 122 || ((c) > 90 && (c) < 97))
+static PNG_CONST char png_digit[16] = {
+   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+static void /* PRIVATE */
+png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp message)
+{
+   int iout = 0, iin = 0;
+
+   while (iin < 4)
+   {
+      int c = png_ptr->chunk_name[iin++];
+      if (isnonalpha(c))
+      {
+         buffer[iout++] = '[';
+         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
+         buffer[iout++] = png_digit[c & 0x0f];
+         buffer[iout++] = ']';
+      }
+      else
+      {
+         buffer[iout++] = (png_byte)c;
+      }
+   }
+
+   if (message == NULL)
+      buffer[iout] = 0;
+   else
+   {
+      buffer[iout++] = ':';
+      buffer[iout++] = ' ';
+      png_memcpy(buffer+iout, message, 64);
+      buffer[iout+63] = 0;
+   }
+}
+
+void PNGAPI
+png_chunk_error(png_structp png_ptr, png_const_charp message)
+{
+   char msg[16+64];
+   png_format_buffer(png_ptr, msg, message);
+   png_error(png_ptr, msg);
+}
+
+void PNGAPI
+png_chunk_warning(png_structp png_ptr, png_const_charp message)
+{
+   char msg[16+64];
+   png_format_buffer(png_ptr, msg, message);
+   png_warning(png_ptr, msg);
+}
+
 /* This is the default error handling function.  Note that replacements for
-   this function MUST NOT RETURN, or the program will likely crash.  This
-   function is used by default, or if the program supplies NULL for the
-   error function pointer in png_set_error_fn(). */
-static void
+ * this function MUST NOT RETURN, or the program will likely crash.  This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static void /* PRIVATE */
 png_default_error(png_structp png_ptr, png_const_charp message)
 {
-#ifndef PNG_NO_STDIO
+#ifndef PNG_NO_CONSOLE_IO
    fprintf(stderr, "libpng error: %s\n", message);
 #endif
 
-#ifdef USE_FAR_KEYWORD
+#ifdef PNG_SETJMP_SUPPORTED
+#  ifdef USE_FAR_KEYWORD
    {
       jmp_buf jmpbuf;
       png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
       longjmp(jmpbuf, 1);
    }
-#else
+#  else
    longjmp(png_ptr->jmpbuf, 1);
+# endif
+#else
+   if (png_ptr == NULL)
+     /* make compiler happy */ ;
+   PNG_ABORT();
 #endif
 }
 
 /* This function is called when there is a warning, but the library thinks
-   it can continue anyway.  Replacement functions don't have to do anything
-   here if you don't want to.  In the default configuration, png_ptr is
-   not used, but it is passed in case it may be useful. */
-static void
+ * it can continue anyway.  Replacement functions don't have to do anything
+ * here if you don't want them to.  In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+static void /* PRIVATE */
 png_default_warning(png_structp png_ptr, png_const_charp message)
 {
-   if (png_ptr == NULL)
-      return;
-
-#ifndef PNG_NO_STDIO
+#ifndef PNG_NO_CONSOLE_IO
    fprintf(stderr, "libpng warning: %s\n", message);
 #endif
+   if (png_ptr == NULL)
+      return;
 }
 
 /* This function is called when the application wants to use another method
-   of handling errors and warnings.  Note that the error function MUST NOT
-   return to the calling routine or serious problems will occur.  The return
-   method used in the default routine calls longjmp(png_ptr->jmpbuf, 1) */
-void
+ * of handling errors and warnings.  Note that the error function MUST NOT
+ * return to the calling routine or serious problems will occur.  The return
+ * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
+ */
+void PNGAPI
 png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
    png_error_ptr error_fn, png_error_ptr warning_fn)
 {
@@ -100,12 +172,13 @@ png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
 
 
 /* This function returns a pointer to the error_ptr associated with the user
-   functions.  The application should free any memory associated with this
-   pointer before png_write_destroy and png_read_destroy are called. */
-png_voidp
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
 png_get_error_ptr(png_structp png_ptr)
 {
-   return png_ptr->error_ptr;
+   return ((png_voidp)png_ptr->error_ptr);
 }
 
 

pngget.c

@@ -1,59 +1,351 @@
 
 /* pngget.c - retrieval of values from info struct
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-   */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
 
-png_uint_32
+png_uint_32 PNGAPI
 png_get_valid(png_structp png_ptr, png_infop info_ptr, png_uint_32 flag)
 {
-   if (info_ptr != NULL)
+   if (png_ptr != NULL && info_ptr != NULL)
       return(info_ptr->valid & flag);
    else
       return(0);
 }
 
-png_uint_32
+png_uint_32 PNGAPI
 png_get_rowbytes(png_structp png_ptr, png_infop info_ptr)
 {
-   if (info_ptr != NULL)
+   if (png_ptr != NULL && info_ptr != NULL)
       return(info_ptr->rowbytes);
    else
       return(0);
 }
 
-png_byte
-png_get_channels(png_structp png_ptr, png_infop info_ptr)
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+png_bytepp PNGAPI
+png_get_rows(png_structp png_ptr, png_infop info_ptr)
 {
-   if (info_ptr != NULL)
-      return(info_ptr->channels);
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->row_pointers);
    else
       return(0);
 }
+#endif
 
-png_bytep
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* easy access to info, added in libpng-0.99 */
+png_uint_32 PNGAPI
+png_get_image_width(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->width;
+   }
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_image_height(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->height;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_bit_depth(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->bit_depth;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_color_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->color_type;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_filter_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->filter_type;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_interlace_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->interlace_type;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_compression_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->compression_type;
+   }
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_pHYs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_x_pixels_per_meter");
+      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
+          return (0);
+      else return (info_ptr->x_pixels_per_unit);
+   }
+   else
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_pHYs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_y_pixels_per_meter");
+      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
+          return (0);
+      else return (info_ptr->y_pixels_per_unit);
+   }
+   else
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_pHYs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_pixels_per_meter");
+      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER ||
+         info_ptr->x_pixels_per_unit != info_ptr->y_pixels_per_unit)
+          return (0);
+      else return (info_ptr->x_pixels_per_unit);
+   }
+   else
+#endif
+   return (0);
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_pixel_aspect_ratio(png_structp png_ptr, png_infop info_ptr)
+   {
+#if defined(PNG_pHYs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_aspect_ratio");
+      if (info_ptr->x_pixels_per_unit == 0)
+         return ((float)0.0);
+      else
+         return ((float)info_ptr->y_pixels_per_unit
+            /(float)info_ptr->x_pixels_per_unit);
+   }
+   else
+#endif
+      return ((float)0.0);
+}
+#endif
+
+png_uint_32 PNGAPI
+png_get_x_offset_microns(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_oFFs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_x_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
+          return (0);
+      else return (info_ptr->x_offset);
+   }
+   else
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_y_offset_microns(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_oFFs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_y_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
+          return (0);
+      else return (info_ptr->y_offset);
+   }
+   else
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_x_offset_pixels(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_oFFs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_x_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
+          return (0);
+      else return (info_ptr->x_offset);
+   }
+   else
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_y_offset_pixels(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_oFFs_SUPPORTED)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_y_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
+          return (0);
+      else return (info_ptr->y_offset);
+   }
+   else
+#endif
+   return (0);
+}
+
+#if defined(PNG_INCH_CONVERSIONS) && defined(PNG_FLOATING_POINT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((png_uint_32)((float)png_get_pixels_per_meter(png_ptr, info_ptr)
+     *.0254 +.5);
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((png_uint_32)((float)png_get_x_pixels_per_meter(png_ptr, info_ptr)
+     *.0254 +.5);
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((png_uint_32)((float)png_get_y_pixels_per_meter(png_ptr, info_ptr)
+     *.0254 +.5);
+}
+
+float PNGAPI
+png_get_x_offset_inches(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((float)png_get_x_offset_microns(png_ptr, info_ptr)
+     *.00003937);
+}
+
+float PNGAPI
+png_get_y_offset_inches(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((float)png_get_y_offset_microns(png_ptr, info_ptr)
+     *.00003937)
+}
+
+#if defined(PNG_READ_pHYs_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_pHYs_dpi(png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "pHYs");
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+         if(unit_type == 1)
+         {
+            if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
+            if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
+         }
+      }
+   }
+   return (retval);
+}
+#endif /* PNG_READ_pHYs_SUPPORTED */
+#endif  /* PNG_INCH_CONVERSIONS && PNG_FLOATING_POINT_SUPPORTED */
+
+/* png_get_channels really belongs in here, too, but it's been around longer */
+
+#endif  /* PNG_EASY_ACCESS_SUPPORTED */
+
+png_byte PNGAPI
+png_get_channels(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->channels);
+   else
+      return (0);
+}
+
+png_bytep PNGAPI
 png_get_signature(png_structp png_ptr, png_infop info_ptr)
 {
-   if (info_ptr != NULL)
+   if (png_ptr != NULL && info_ptr != NULL)
       return(info_ptr->signature);
    else
-      return(NULL);
+      return (NULL);
 }
 
 #if defined(PNG_READ_bKGD_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_bKGD(png_structp png_ptr, png_infop info_ptr,
    png_color_16p *background)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_bKGD &&
-      background != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
+      && background != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "bKGD");
       *background = &(info_ptr->background);
@@ -64,12 +356,13 @@ png_get_bKGD(png_structp png_ptr, png_infop info_ptr,
 #endif
 
 #if defined(PNG_READ_cHRM_SUPPORTED)
-png_uint_32
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
 png_get_cHRM(png_structp png_ptr, png_infop info_ptr,
    double *white_x, double *white_y, double *red_x, double *red_y,
    double *green_x, double *green_y, double *blue_x, double *blue_y)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_cHRM)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
    {
       png_debug1(1, "in %s retrieval function\n", "cHRM");
       if (white_x != NULL)
@@ -93,13 +386,46 @@ png_get_cHRM(png_structp png_ptr, png_infop info_ptr,
    return (0);
 }
 #endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
+   png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
+   png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
+   png_fixed_point *blue_x, png_fixed_point *blue_y)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
+   {
+      png_debug1(1, "in %s retrieval function\n", "cHRM");
+      if (white_x != NULL)
+         *white_x = info_ptr->int_x_white;
+      if (white_y != NULL)
+         *white_y = info_ptr->int_y_white;
+      if (red_x != NULL)
+         *red_x = info_ptr->int_x_red;
+      if (red_y != NULL)
+         *red_y = info_ptr->int_y_red;
+      if (green_x != NULL)
+         *green_x = info_ptr->int_x_green;
+      if (green_y != NULL)
+         *green_y = info_ptr->int_y_green;
+      if (blue_x != NULL)
+         *blue_x = info_ptr->int_x_blue;
+      if (blue_y != NULL)
+         *blue_y = info_ptr->int_y_blue;
+      return (PNG_INFO_cHRM);
+   }
+   return (0);
+}
+#endif
+#endif
 
 #if defined(PNG_READ_gAMA_SUPPORTED)
-png_uint_32
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
 png_get_gAMA(png_structp png_ptr, png_infop info_ptr, double *file_gamma)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_gAMA &&
-      file_gamma != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
+      && file_gamma != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "gAMA");
       *file_gamma = (double)info_ptr->gamma;
@@ -108,12 +434,77 @@ png_get_gAMA(png_structp png_ptr, png_infop info_ptr, double *file_gamma)
    return (0);
 }
 #endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA_fixed(png_structp png_ptr, png_infop info_ptr,
+    png_fixed_point *int_file_gamma)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
+      && int_file_gamma != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "gAMA");
+      *int_file_gamma = info_ptr->int_gamma;
+      return (PNG_INFO_gAMA);
+   }
+   return (0);
+}
+#endif
+#endif
+
+#if defined(PNG_READ_sRGB_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sRGB(png_structp png_ptr, png_infop info_ptr, int *file_srgb_intent)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
+      && file_srgb_intent != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "sRGB");
+      *file_srgb_intent = (int)info_ptr->srgb_intent;
+      return (PNG_INFO_sRGB);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_READ_iCCP_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_iCCP(png_structp png_ptr, png_infop info_ptr,
+             png_charpp name, int *compression_type,
+             png_charpp profile, png_uint_32 *proflen)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
+      && name != NULL && profile != NULL && proflen != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "iCCP");
+      *name = info_ptr->iccp_name;
+      *profile = info_ptr->iccp_profile;
+      /* compression_type is a dummy so the API won't have to change
+         if we introduce multiple compression types later. */
+      *proflen = (int)info_ptr->iccp_proflen;
+      *compression_type = (int)info_ptr->iccp_compression;
+      return (PNG_INFO_iCCP);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_READ_sPLT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sPLT(png_structp png_ptr, png_infop info_ptr,
+             png_sPLT_tpp spalettes)
+{
+   if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
+     *spalettes = info_ptr->splt_palettes;
+   return ((png_uint_32)info_ptr->splt_palettes_num);
+}
+#endif
 
 #if defined(PNG_READ_hIST_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p *hist)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_hIST && hist != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
+      && hist != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "hIST");
       *hist = info_ptr->hist;
@@ -123,16 +514,19 @@ png_get_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p *hist)
 }
 #endif
 
-png_uint_32
+png_uint_32 PNGAPI
 png_get_IHDR(png_structp png_ptr, png_infop info_ptr,
    png_uint_32 *width, png_uint_32 *height, int *bit_depth,
    int *color_type, int *interlace_type, int *compression_type,
    int *filter_type)
-   
+
 {
-   if (info_ptr != NULL && width != NULL && height != NULL &&
+   if (png_ptr != NULL && info_ptr != NULL && width != NULL && height != NULL &&
       bit_depth != NULL && color_type != NULL)
    {
+      int pixel_depth, channels;
+      png_uint_32 rowbytes_per_pixel;
+
       png_debug1(1, "in %s retrieval function\n", "IHDR");
       *width = info_ptr->width;
       *height = info_ptr->height;
@@ -144,18 +538,35 @@ png_get_IHDR(png_structp png_ptr, png_infop info_ptr,
          *filter_type = info_ptr->filter_type;
       if (interlace_type != NULL)
          *interlace_type = info_ptr->interlace_type;
+
+      /* check for potential overflow of rowbytes */
+      if (*color_type == PNG_COLOR_TYPE_PALETTE)
+         channels = 1;
+      else if (*color_type & PNG_COLOR_MASK_COLOR)
+         channels = 3;
+      else
+         channels = 1;
+      if (*color_type & PNG_COLOR_MASK_ALPHA)
+         channels++;
+      pixel_depth = *bit_depth * channels;
+      rowbytes_per_pixel = (pixel_depth + 7) >> 3;
+      if ((*width > PNG_MAX_UINT/rowbytes_per_pixel))
+      {
+         png_warning(png_ptr,
+            "Width too large for libpng to process image data.");
+      }
       return (1);
    }
    return (0);
 }
 
 #if defined(PNG_READ_oFFs_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_oFFs(png_structp png_ptr, png_infop info_ptr,
-   png_uint_32 *offset_x, png_uint_32 *offset_y, int *unit_type)
+   png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_oFFs &&
-      offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
+      && offset_x != NULL && offset_y != NULL && unit_type != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "oFFs");
       *offset_x = info_ptr->x_offset;
@@ -168,13 +579,13 @@ png_get_oFFs(png_structp png_ptr, png_infop info_ptr,
 #endif
 
 #if defined(PNG_READ_pCAL_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_pCAL(png_structp png_ptr, png_infop info_ptr,
    png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
    png_charp *units, png_charpp *params)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_pCAL &&
-      purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
+      && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
       nparams != NULL && units != NULL && params != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "pCAL");
@@ -191,29 +602,79 @@ png_get_pCAL(png_structp png_ptr, png_infop info_ptr,
 }
 #endif
 
+#if defined(PNG_READ_sCAL_SUPPORTED) || defined(PNG_WRITE_sCAL_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL(png_structp png_ptr, png_infop info_ptr,
+             int *unit, double *width, double *height)
+{
+    if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL))
+    {
+        *unit = info_ptr->scal_unit;
+        *width = info_ptr->scal_pixel_width;
+        *height = info_ptr->scal_pixel_height;
+        return (PNG_INFO_sCAL);
+    }
+    return(0);
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL_s(png_structp png_ptr, png_infop info_ptr,
+             int *unit, png_charpp width, png_charpp height)
+{
+    if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL))
+    {
+        *unit = info_ptr->scal_unit;
+        *width = info_ptr->scal_s_width;
+        *height = info_ptr->scal_s_height;
+        return (PNG_INFO_sCAL);
+    }
+    return(0);
+}
+#endif
+#endif
+#endif
+
 #if defined(PNG_READ_pHYs_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_pHYs(png_structp png_ptr, png_infop info_ptr,
    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_pHYs &&
-      res_x != NULL && res_y != NULL && unit_type != NULL)
+   png_uint_32 retval = 0;
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_pHYs))
    {
       png_debug1(1, "in %s retrieval function\n", "pHYs");
-      *res_x = info_ptr->x_pixels_per_unit;
-      *res_y = info_ptr->y_pixels_per_unit;
-      *unit_type = (int)info_ptr->phys_unit_type;
-      return (PNG_INFO_pHYs);
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+      }
    }
-   return (0);
+   return (retval);
 }
 #endif
 
-png_uint_32
+png_uint_32 PNGAPI
 png_get_PLTE(png_structp png_ptr, png_infop info_ptr, png_colorp *palette,
    int *num_palette)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_PLTE && palette != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
+       && palette != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "PLTE");
       *palette = info_ptr->palette;
@@ -225,10 +686,11 @@ png_get_PLTE(png_structp png_ptr, png_infop info_ptr, png_colorp *palette,
 }
 
 #if defined(PNG_READ_sBIT_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_sBIT(png_structp png_ptr, png_infop info_ptr, png_color_8p *sig_bit)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_sBIT && sig_bit != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
+      && sig_bit != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "sBIT");
       *sig_bit = &(info_ptr->sig_bit);
@@ -238,30 +700,34 @@ png_get_sBIT(png_structp png_ptr, png_infop info_ptr, png_color_8p *sig_bit)
 }
 #endif
 
-#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_READ_zTXt_SUPPORTED)
-png_uint_32
+#if defined(PNG_READ_TEXT_SUPPORTED)
+png_uint_32 PNGAPI
 png_get_text(png_structp png_ptr, png_infop info_ptr, png_textp *text_ptr,
    int *num_text)
 {
-   if ((info_ptr != NULL) || (info_ptr->num_text > 0))
+   if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
    {
       png_debug1(1, "in %s retrieval function\n",
-         (png_ptr->chunk_name[0] == '\0' ? "text" : png_ptr->chunk_name));
+         (png_ptr->chunk_name[0] == '\0' ? "text"
+             : (png_const_charp)png_ptr->chunk_name));
       if (text_ptr != NULL)
          *text_ptr = info_ptr->text;
       if (num_text != NULL)
          *num_text = info_ptr->num_text;
-      return (info_ptr->num_text);
+      return ((png_uint_32)info_ptr->num_text);
    }
+   if (num_text != NULL)
+     *num_text = 0;
    return(0);
 }
 #endif
 
 #if defined(PNG_READ_tIME_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_tIME(png_structp png_ptr, png_infop info_ptr, png_timep *mod_time)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_tIME && mod_time != NULL)
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
+       && mod_time != NULL)
    {
       png_debug1(1, "in %s retrieval function\n", "tIME");
       *mod_time = &(info_ptr->mod_time);
@@ -272,29 +738,74 @@ png_get_tIME(png_structp png_ptr, png_infop info_ptr, png_timep *mod_time)
 #endif
 
 #if defined(PNG_READ_tRNS_SUPPORTED)
-png_uint_32
+png_uint_32 PNGAPI
 png_get_tRNS(png_structp png_ptr, png_infop info_ptr,
    png_bytep *trans, int *num_trans, png_color_16p *trans_values)
 {
-   if (info_ptr != NULL && info_ptr->valid & PNG_INFO_tRNS)
+   png_uint_32 retval = 0;
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
    {
       png_debug1(1, "in %s retrieval function\n", "tRNS");
-      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE && trans != NULL)
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
-          *trans = info_ptr->trans;
+          if (trans != NULL)
+          {
+             *trans = info_ptr->trans;
+             retval |= PNG_INFO_tRNS;
+          }
+          if (trans_values != NULL)
+             *trans_values = &(info_ptr->trans_values);
       }
-      else if (trans_values != NULL)
+      else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
       {
-         *trans_values = &(info_ptr->trans_values);
+          if (trans_values != NULL)
+          {
+             *trans_values = &(info_ptr->trans_values);
+             retval |= PNG_INFO_tRNS;
+          }
+          if(trans != NULL)
+             *trans = NULL;
       }
-      else
+      if(num_trans != NULL)
       {
-         return (0);
+         *num_trans = info_ptr->num_trans;
+         retval |= PNG_INFO_tRNS;
       }
-      *num_trans = info_ptr->num_trans;
-      return (PNG_INFO_tRNS);
    }
-   return (0);
+   return (retval);
 }
 #endif
 
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_unknown_chunks(png_structp png_ptr, png_infop info_ptr,
+             png_unknown_chunkpp unknowns)
+{
+   if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
+     *unknowns = info_ptr->unknown_chunks;
+   return ((png_uint_32)info_ptr->unknown_chunks_num);
+}
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+png_byte PNGAPI
+png_get_rgb_to_gray_status (png_structp png_ptr)
+{
+   return png_ptr->rgb_to_gray_status;
+}
+#endif
+
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+png_voidp PNGAPI
+png_get_user_chunk_ptr(png_structp png_ptr)
+{
+   return (png_ptr->user_chunk_ptr);
+}
+#endif
+
+
+png_uint_32 PNGAPI
+png_get_compression_buffer_size(png_structp png_ptr)
+{
+   return(png_ptr->zbuf_size);
+}

pngmem.c

@@ -1,15 +1,18 @@
 
 /* pngmem.c - stub functions for memory allocation
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-
-   This file provides a location for all memory allocation.  Users which
-   need special memory handling are expected to modify the code in this file
-   to meet their needs.  See the instructions at each function. */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ *
+ * This file provides a location for all memory allocation.  Users who
+ * need special memory handling are expected to supply replacement
+ * functions for png_malloc() and png_free(), and to use
+ * png_create_read_struct_2() and png_create_write_struct_2() to
+ * identify the replacement functions.
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
@@ -20,9 +23,18 @@
 
 /* Allocate memory for a png_struct.  The malloc and memset can be replaced
    by a single call to calloc() if this is thought to improve performance. */
-png_voidp
+png_voidp /* PRIVATE */
 png_create_struct(int type)
 {
+#ifdef PNG_USER_MEM_SUPPORTED
+   return (png_create_struct_2(type, NULL));
+}
+
+/* Alternate version of png_create_struct, for use with user-defined malloc. */
+png_voidp /* PRIVATE */
+png_create_struct_2(int type, png_malloc_ptr malloc_fn)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
    png_size_t size;
    png_voidp struct_ptr;
 
@@ -31,23 +43,50 @@ png_create_struct(int type)
    else if (type == PNG_STRUCT_PNG)
      size = sizeof(png_struct);
    else
-     return (png_voidp)NULL;
+     return ((png_voidp)NULL);
 
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(malloc_fn != NULL)
+   {
+      if ((struct_ptr = (*(malloc_fn))(NULL, size)) != NULL)
+         png_memset(struct_ptr, 0, size);
+         return (struct_ptr);
+   }
+#endif /* PNG_USER_MEM_SUPPORTED */
    if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
    {
       png_memset(struct_ptr, 0, size);
    }
-
    return (struct_ptr);
 }
 
 
 /* Free memory allocated by a png_create_struct() call */
-void
+void /* PRIVATE */
 png_destroy_struct(png_voidp struct_ptr)
 {
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_destroy_struct_2(struct_ptr, (png_free_ptr)NULL);
+}
+
+/* Free memory allocated by a png_create_struct() call */
+void /* PRIVATE */
+png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn)
+{
+#endif
    if (struct_ptr != NULL)
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if(free_fn != NULL)
+      {
+         png_struct dummy_struct;
+         png_structp png_ptr = &dummy_struct;
+         (*(free_fn))(png_ptr, struct_ptr);
+         return;
+      }
+#endif /* PNG_USER_MEM_SUPPORTED */
       farfree (struct_ptr);
+   }
 }
 
 /* Allocate memory.  For reasonable files, size should never exceed
@@ -57,7 +96,7 @@ png_destroy_struct(png_voidp struct_ptr)
  * have the ability to do that.
  *
  * Borland seems to have a problem in DOS mode for exactly 64K.
- * It gives you a segment with an offset of 8 (perhaps to store it's
+ * It gives you a segment with an offset of 8 (perhaps to store its
  * memory stuff).  zlib doesn't like this at all, so we have to
  * detect and deal with it.  This code should not be needed in
  * Windows or OS/2 modes, and only in 16 bit mode.  This code has
@@ -69,19 +108,34 @@ png_destroy_struct(png_voidp struct_ptr)
  * result, we would be truncating potentially larger memory requests
  * (which should cause a fatal error) and introducing major problems.
  */
-png_voidp
+png_voidp PNGAPI
 png_malloc(png_structp png_ptr, png_uint_32 size)
 {
+#ifndef PNG_USER_MEM_SUPPORTED
    png_voidp ret;
+#endif
    if (png_ptr == NULL || size == 0)
-      return ((voidp)NULL);
+      return ((png_voidp)NULL);
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(png_ptr->malloc_fn != NULL)
+       return ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
+   else
+       return png_malloc_default(png_ptr, size);
+}
+
+png_voidp PNGAPI
+png_malloc_default(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ret;
+#endif /* PNG_USER_MEM_SUPPORTED */
 
 #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
       png_error(png_ptr, "Cannot Allocate > 64K");
 #endif
 
-   if (size == (png_uint_32)(65536L))
+   if (size == (png_uint_32)65536L)
    {
       if (png_ptr->offset_table == NULL)
       {
@@ -96,11 +150,14 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
             png_byte huge * hptr;
 
             if (ret != NULL)
+            {
                farfree(ret);
-            ret = NULL;
+               ret = NULL;
+            }
 
-            num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
-            if (num_blocks < 1)
+            if(png_ptr->zlib_window_bits > 14)
+               num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
+            else
                num_blocks = 1;
             if (png_ptr->zlib_mem_level >= 7)
                num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
@@ -113,7 +170,7 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
 
             if (table == NULL)
             {
-               png_error(png_ptr, "Out of Memory");
+               png_error(png_ptr, "Out Of Memory."); /* Note "O" and "M" */
             }
 
             if ((png_size_t)table & 0xfff0)
@@ -127,19 +184,19 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
 
             if (png_ptr->offset_table_ptr == NULL)
             {
-               png_error(png_ptr, "Out of memory");
+               png_error(png_ptr, "Out Of memory.");
             }
 
             hptr = (png_byte huge *)table;
             if ((png_size_t)hptr & 0xf)
             {
                hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
-               hptr += 16L;
+               hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
             }
             for (i = 0; i < num_blocks; i++)
             {
                png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
-               hptr += 65536L;
+               hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
             }
 
             png_ptr->offset_table_number = num_blocks;
@@ -149,7 +206,7 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
       }
 
       if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
-         png_error(png_ptr, "Out of Memory");
+         png_error(png_ptr, "Out of Memory.");
 
       ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
    }
@@ -158,21 +215,35 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
 
    if (ret == NULL)
    {
-      png_error(png_ptr, "Out of Memory");
+      png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
    }
 
-   return ret;
+   return (ret);
 }
 
 /* free a pointer allocated by png_malloc().  In the default
    configuration, png_ptr is not used, but is passed in case it
    is needed.  If ptr is NULL, return without taking any action. */
-void
+void PNGAPI
 png_free(png_structp png_ptr, png_voidp ptr)
 {
    if (png_ptr == NULL || ptr == NULL)
       return;
 
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr->free_fn != NULL)
+   {
+      (*(png_ptr->free_fn))(png_ptr, ptr);
+      return;
+   }
+   else png_free_default(png_ptr, ptr);
+}
+
+void PNGAPI
+png_free_default(png_structp png_ptr, png_voidp ptr)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+
    if (png_ptr->offset_table != NULL)
    {
       int i;
@@ -196,7 +267,9 @@ png_free(png_structp png_ptr, png_voidp ptr)
    }
 
    if (ptr != NULL)
+   {
       farfree(ptr);
+   }
 }
 
 #else /* Not the Borland DOS special memory handler */
@@ -204,9 +277,20 @@ png_free(png_structp png_ptr, png_voidp ptr)
 /* Allocate memory for a png_struct or a png_info.  The malloc and
    memset can be replaced by a single call to calloc() if this is thought
    to improve performance noticably.*/
-png_voidp
+png_voidp /* PRIVATE */
 png_create_struct(int type)
 {
+#ifdef PNG_USER_MEM_SUPPORTED
+   return (png_create_struct_2(type, NULL));
+}
+
+/* Allocate memory for a png_struct or a png_info.  The malloc and
+   memset can be replaced by a single call to calloc() if this is thought
+   to improve performance noticably.*/
+png_voidp /* PRIVATE */
+png_create_struct_2(int type, png_malloc_ptr malloc_fn)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
    png_size_t size;
    png_voidp struct_ptr;
 
@@ -215,7 +299,16 @@ png_create_struct(int type)
    else if (type == PNG_STRUCT_PNG)
       size = sizeof(png_struct);
    else
-      return (png_voidp)NULL;
+      return ((png_voidp)NULL);
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(malloc_fn != NULL)
+   {
+      if ((struct_ptr = (*(malloc_fn))(NULL, size)) != NULL)
+         png_memset(struct_ptr, 0, size);
+      return (struct_ptr);
+   }
+#endif /* PNG_USER_MEM_SUPPORTED */
 
 #if defined(__TURBOC__) && !defined(__FLAT__)
    if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
@@ -235,10 +328,29 @@ png_create_struct(int type)
 
 
 /* Free memory allocated by a png_create_struct() call */
-void
+void /* PRIVATE */
 png_destroy_struct(png_voidp struct_ptr)
 {
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_destroy_struct_2(struct_ptr, (png_free_ptr)NULL);
+}
+
+/* Free memory allocated by a png_create_struct() call */
+void /* PRIVATE */
+png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
    if (struct_ptr != NULL)
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if(free_fn != NULL)
+      {
+         png_struct dummy_struct;
+         png_structp png_ptr = &dummy_struct;
+         (*(free_fn))(png_ptr, struct_ptr);
+         return;
+      }
+#endif /* PNG_USER_MEM_SUPPORTED */
 #if defined(__TURBOC__) && !defined(__FLAT__)
       farfree(struct_ptr);
 #else
@@ -248,6 +360,7 @@ png_destroy_struct(png_voidp struct_ptr)
       free(struct_ptr);
 # endif
 #endif
+   }
 }
 
 
@@ -257,12 +370,26 @@ png_destroy_struct(png_voidp struct_ptr)
    need to allocate exactly 64K, so whatever you call here must
    have the ability to do that. */
 
-png_voidp
+png_voidp PNGAPI
 png_malloc(png_structp png_ptr, png_uint_32 size)
 {
+#ifndef PNG_USER_MEM_SUPPORTED
    png_voidp ret;
+#endif
    if (png_ptr == NULL || size == 0)
-      return (NULL);
+      return ((png_voidp)NULL);
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(png_ptr->malloc_fn != NULL)
+       return ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
+   else
+       return (png_malloc_default(png_ptr, size));
+}
+png_voidp /* PRIVATE */
+png_malloc_default(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ret;
+#endif /* PNG_USER_MEM_SUPPORTED */
 
 #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
@@ -270,12 +397,12 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
 #endif
 
 #if defined(__TURBOC__) && !defined(__FLAT__)
-   ret = farmalloc((png_size_t)size);
+   ret = farmalloc(size);
 #else
 # if defined(_MSC_VER) && defined(MAXSEG_64K)
    ret = halloc(size, 1);
 # else
-   ret = malloc(size);
+   ret = malloc((size_t)size);
 # endif
 #endif
 
@@ -284,18 +411,33 @@ png_malloc(png_structp png_ptr, png_uint_32 size)
       png_error(png_ptr, "Out of Memory");
    }
 
-   return ret;
+   return (ret);
 }
 
-/* Free a pointer allocated by png_malloc().  In the default
-  configuration, png_ptr is not used, but is passed in case it
-  is needed.  If ptr is NULL, return without taking any action. */
-void
+/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
+   without taking any action. */
+void PNGAPI
 png_free(png_structp png_ptr, png_voidp ptr)
 {
    if (png_ptr == NULL || ptr == NULL)
       return;
 
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr->free_fn != NULL)
+   {
+      (*(png_ptr->free_fn))(png_ptr, ptr);
+      return;
+   }
+   else png_free_default(png_ptr, ptr);
+}
+void /* PRIVATE */
+png_free_default(png_structp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+
+#endif /* PNG_USER_MEM_SUPPORTED */
+
 #if defined(__TURBOC__) && !defined(__FLAT__)
    farfree(ptr);
 #else
@@ -309,3 +451,53 @@ png_free(png_structp png_ptr, png_voidp ptr)
 
 #endif /* Not Borland DOS special memory handler */
 
+png_voidp /* PRIVATE */
+png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
+   png_uint_32 length)
+{
+   png_size_t size;
+
+   size = (png_size_t)length;
+   if ((png_uint_32)size != length)
+      png_error(png_ptr,"Overflow in png_memcpy_check.");
+
+   return(png_memcpy (s1, s2, size));
+}
+
+png_voidp /* PRIVATE */
+png_memset_check (png_structp png_ptr, png_voidp s1, int value,
+   png_uint_32 length)
+{
+   png_size_t size;
+
+   size = (png_size_t)length;
+   if ((png_uint_32)size != length)
+      png_error(png_ptr,"Overflow in png_memset_check.");
+
+   return (png_memset (s1, value, size));
+
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* This function is called when the application wants to use another method
+ * of allocating and freeing memory.
+ */
+void PNGAPI
+png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
+  malloc_fn, png_free_ptr free_fn)
+{
+   png_ptr->mem_ptr = mem_ptr;
+   png_ptr->malloc_fn = malloc_fn;
+   png_ptr->free_fn = free_fn;
+}
+
+/* This function returns a pointer to the mem_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_mem_ptr(png_structp png_ptr)
+{
+   return ((png_voidp)png_ptr->mem_ptr);
+}
+#endif /* PNG_USER_MEM_SUPPORTED */

pngpread.c

@@ -1,19 +1,30 @@
 
 /* pngpread.c - read a png file in push mode
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-   */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
 
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 
-void
+/* push model modes */
+#define PNG_READ_SIG_MODE   0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE  2
+#define PNG_SKIP_MODE       3
+#define PNG_READ_tEXt_MODE  4
+#define PNG_READ_zTXt_MODE  5
+#define PNG_READ_DONE_MODE  6
+#define PNG_READ_iTXt_MODE  7
+#define PNG_ERROR_MODE      8
+
+void PNGAPI
 png_process_data(png_structp png_ptr, png_infop info_ptr,
    png_bytep buffer, png_size_t buffer_size)
 {
@@ -28,7 +39,7 @@ png_process_data(png_structp png_ptr, png_infop info_ptr,
 /* What we do with the incoming data depends on what we were previously
  * doing before we ran out of data...
  */
-void
+void /* PRIVATE */
 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
 {
    switch (png_ptr->process_mode)
@@ -61,6 +72,13 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
          png_push_read_zTXt(png_ptr, info_ptr);
          break;
       }
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      case PNG_READ_iTXt_MODE:
+      {
+         png_push_read_iTXt(png_ptr, info_ptr);
+         break;
+      }
 #endif
       case PNG_SKIP_MODE:
       {
@@ -77,10 +95,11 @@ png_process_some_data(png_structp png_ptr, png_infop info_ptr)
 
 /* Read any remaining signature bytes from the stream and compare them with
  * the correct PNG signature.  It is possible that this routine is called
- * with bytes already read from the signature, whether because they have been
- * checked by the calling application, or from multiple calls to this routine.
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
  */
-void
+void /* PRIVATE */
 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
 {
    png_size_t num_checked = png_ptr->sig_bytes,
@@ -91,9 +110,9 @@ png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
       num_to_check = png_ptr->buffer_size;
    }
 
-   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), 
+   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
       num_to_check);
-   png_ptr->sig_bytes += num_to_check;
+   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);
 
    if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
    {
@@ -112,15 +131,73 @@ png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
    }
 }
 
-void
+void /* PRIVATE */
 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 {
+#ifdef PNG_USE_LOCAL_ARRAYS
+      PNG_IHDR;
+      PNG_IDAT;
+      PNG_IEND;
+      PNG_PLTE;
+#if defined(PNG_READ_bKGD_SUPPORTED)
+      PNG_bKGD;
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+      PNG_cHRM;
+#endif
+#if defined(PNG_READ_gAMA_SUPPORTED)
+      PNG_gAMA;
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+      PNG_hIST;
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+      PNG_iCCP;
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      PNG_iTXt;
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+      PNG_oFFs;
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+      PNG_pCAL;
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+      PNG_pHYs;
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+      PNG_sBIT;
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+      PNG_sCAL;
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      PNG_sRGB;
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+      PNG_sPLT;
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      PNG_tEXt;
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+      PNG_tIME;
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+      PNG_tRNS;
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      PNG_zTXt;
+#endif
+#endif /* PNG_USE_LOCAL_ARRAYS */
    /* First we make sure we have enough data for the 4 byte chunk name
-      and the 4 byte chunk length before proceeding with decoding the
-      chunk data.  To fully decode each of these chunks, we also make
-      sure we have enough data in the buffer for the 4 byte CRC at the
-      end of every chunk (except IDAT, which is handled separately). */
-   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
+    * and the 4 byte chunk length before proceeding with decoding the
+    * chunk data.  To fully decode each of these chunks, we also make
+    * sure we have enough data in the buffer for the 4 byte CRC at the
+    * end of every chunk (except IDAT, which is handled separately).
+    */
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_length[4];
 
@@ -134,7 +211,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       png_ptr->push_length = png_get_uint_32(chunk_length);
       png_reset_crc(png_ptr);
       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
-      png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
    }
 
    if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
@@ -157,11 +234,12 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 
       png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
    }
-   else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+   else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
    {
       /* If we reach an IDAT chunk, this means we have read all of the
-         header chunks, and we can start reading the image (or if this
-         is called after the image has been read - we have an error). */
+       * header chunks, and we can start reading the image (or if this
+       * is called after the image has been read - we have an error).
+       */
       if (png_ptr->mode & PNG_HAVE_IDAT)
       {
          if (png_ptr->push_length == 0)
@@ -227,6 +305,42 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
    }
 #endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
    {
@@ -299,6 +413,18 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
       png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
    }
 #endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
 #if defined(PNG_READ_tIME_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
    {
@@ -322,23 +448,29 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
    {
       png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
+   {
+      png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
 #endif
    else
    {
       png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
    }
 
-   png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
+   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 }
 
-void
+void /* PRIVATE */
 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
 {
    png_ptr->process_mode = PNG_SKIP_MODE;
    png_ptr->skip_length = skip;
 }
 
-void
+void /* PRIVATE */
 png_push_crc_finish(png_structp png_ptr)
 {
    if (png_ptr->skip_length && png_ptr->save_buffer_size)
@@ -386,7 +518,7 @@ png_push_crc_finish(png_structp png_ptr)
    }
 }
 
-void
+void /* PRIVATE */
 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 {
    png_bytep ptr;
@@ -424,20 +556,20 @@ png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
    }
 }
 
-void
+void /* PRIVATE */
 png_push_save_buffer(png_structp png_ptr)
 {
    if (png_ptr->save_buffer_size)
    {
       if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
       {
-         png_size_t i;
+         png_size_t i,istop;
          png_bytep sp;
          png_bytep dp;
 
+         istop = png_ptr->save_buffer_size;
          for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
-            i < png_ptr->save_buffer_size;
-            i++, sp++, dp++)
+            i < istop; i++, sp++, dp++)
          {
             *dp = *sp;
          }
@@ -451,7 +583,8 @@ png_push_save_buffer(png_structp png_ptr)
 
       new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
       old_buffer = png_ptr->save_buffer;
-      png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr, new_max);
+      png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
+         (png_uint_32)new_max);
       png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
       png_free(png_ptr, old_buffer);
       png_ptr->save_buffer_max = new_max;
@@ -467,7 +600,7 @@ png_push_save_buffer(png_structp png_ptr)
    png_ptr->buffer_size = 0;
 }
 
-void
+void /* PRIVATE */
 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
    png_size_t buffer_length)
 {
@@ -477,10 +610,13 @@ png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
    png_ptr->current_buffer_ptr = png_ptr->current_buffer;
 }
 
-void
+void /* PRIVATE */
 png_push_read_IDAT(png_structp png_ptr)
 {
-   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_IDAT;
+#endif
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_length[4];
 
@@ -495,9 +631,9 @@ png_push_read_IDAT(png_structp png_ptr)
 
       png_reset_crc(png_ptr);
       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
-      png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 
-      if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+      if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
       {
          png_ptr->process_mode = PNG_READ_CHUNK_MODE;
          if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
@@ -512,7 +648,12 @@ png_push_read_IDAT(png_structp png_ptr)
       png_size_t save_size;
 
       if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
-         save_size = png_ptr->idat_size;
+      {
+         save_size = (png_size_t)png_ptr->idat_size;
+         /* check for overflow */
+         if((png_uint_32)save_size != png_ptr->idat_size)
+            png_error(png_ptr, "save_size overflowed in pngpread");
+      }
       else
          save_size = png_ptr->save_buffer_size;
 
@@ -529,7 +670,12 @@ png_push_read_IDAT(png_structp png_ptr)
       png_size_t save_size;
 
       if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
-         save_size = png_ptr->idat_size;
+      {
+         save_size = (png_size_t)png_ptr->idat_size;
+         /* check for overflow */
+         if((png_uint_32)save_size != png_ptr->idat_size)
+            png_error(png_ptr, "save_size overflowed in pngpread");
+      }
       else
          save_size = png_ptr->current_buffer_size;
 
@@ -550,11 +696,11 @@ png_push_read_IDAT(png_structp png_ptr)
       }
 
       png_crc_finish(png_ptr, 0);
-      png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
+      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
    }
 }
 
-void
+void /* PRIVATE */
 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
    png_size_t buffer_length)
 {
@@ -565,7 +711,7 @@ png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
 
    png_ptr->zstream.next_in = buffer;
    png_ptr->zstream.avail_in = (uInt)buffer_length;
-   while(1)
+   for(;;)
    {
       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
       if (ret == Z_STREAM_END)
@@ -596,7 +742,7 @@ png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
    }
 }
 
-void
+void /* PRIVATE */
 png_push_process_row(png_structp png_ptr)
 {
    png_ptr->row_info.color_type = png_ptr->color_type;
@@ -604,6 +750,7 @@ png_push_process_row(png_structp png_ptr)
    png_ptr->row_info.channels = png_ptr->channels;
    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
+
    png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
       (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
 
@@ -611,7 +758,8 @@ png_push_process_row(png_structp png_ptr)
       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
       (int)(png_ptr->row_buf[0]));
 
-   png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
+   png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
+      png_ptr->rowbytes + 1);
 
    if (png_ptr->transformations)
       png_do_read_transformations(png_ptr);
@@ -736,9 +884,35 @@ png_push_process_row(png_structp png_ptr)
    }
 }
 
-void
+void /* PRIVATE */
 png_read_push_finish_row(png_structp png_ptr)
 {
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   const int png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   const int png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* start of interlace block in the y direction */
+   const int png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* offset to next interlace block in the y direction */
+   const int png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+   /* Width of interlace block.  This is not currently used - if you need
+    * it, uncomment it here and in png.h
+   const int png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
+   */
+
+   /* Height of interlace block.  This is not currently used - if you need
+    * it, uncomment it here and in png.h
+   const int png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+   */
+#endif
+
    png_ptr->row_number++;
    if (png_ptr->row_number < png_ptr->num_rows)
       return;
@@ -746,60 +920,66 @@ png_read_push_finish_row(png_structp png_ptr)
    if (png_ptr->interlaced)
    {
       png_ptr->row_number = 0;
-      png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+      png_memset_check(png_ptr, png_ptr->prev_row, 0,
+         png_ptr->rowbytes + 1);
       do
       {
          png_ptr->pass++;
          if (png_ptr->pass >= 7)
             break;
+
          png_ptr->iwidth = (png_ptr->width +
             png_pass_inc[png_ptr->pass] - 1 -
             png_pass_start[png_ptr->pass]) /
             png_pass_inc[png_ptr->pass];
+
          png_ptr->irowbytes = ((png_ptr->iwidth *
             png_ptr->pixel_depth + 7) >> 3) + 1;
-         if (!(png_ptr->transformations & PNG_INTERLACE))
-         {
-            png_ptr->num_rows = (png_ptr->height +
-               png_pass_yinc[png_ptr->pass] - 1 -
-               png_pass_ystart[png_ptr->pass]) /
-               png_pass_yinc[png_ptr->pass];
-            if (!(png_ptr->num_rows))
-               continue;
-         }
+
          if (png_ptr->transformations & PNG_INTERLACE)
             break;
-      } while (png_ptr->iwidth == 0);
+
+         png_ptr->num_rows = (png_ptr->height +
+            png_pass_yinc[png_ptr->pass] - 1 -
+            png_pass_ystart[png_ptr->pass]) /
+            png_pass_yinc[png_ptr->pass];
+
+      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
    }
 }
 
 #if defined(PNG_READ_tEXt_SUPPORTED)
-void
+void /* PRIVATE */
 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
-   if (png_ptr->mode == PNG_BEFORE_IHDR || png_ptr->mode & PNG_HAVE_IEND)
-      png_error(png_ptr, "Out of place tEXt");
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
+      {
+         png_error(png_ptr, "Out of place tEXt");
+         /* to quiet some compiler warnings */
+         if(info_ptr == NULL) return;
+      }
 
 #ifdef PNG_MAX_MALLOC_64K
    png_ptr->skip_length = 0;  /* This may not be necessary */
 
-   if (length > 65535L)  /* We can't hold the entire string in memory */
+   if (length > (png_uint_32)65535L) /* Can't hold the entire string in memory */
    {
       png_warning(png_ptr, "tEXt chunk too large to fit in memory");
-      png_ptr->skip_length = length - 65535L;
-      length = 65535L;
+      png_ptr->skip_length = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
    }
 #endif
 
-   png_ptr->current_text = (png_charp)png_malloc(png_ptr, length+1);
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+         (png_uint_32)(length+1));
    png_ptr->current_text[length] = '\0';
    png_ptr->current_text_ptr = png_ptr->current_text;
-   png_ptr->current_text_size = length;
-   png_ptr->current_text_left = length;
+   png_ptr->current_text_size = (png_size_t)length;
+   png_ptr->current_text_left = (png_size_t)length;
    png_ptr->process_mode = PNG_READ_tEXt_MODE;
 }
 
-void
+void /* PRIVATE */
 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->buffer_size && png_ptr->current_text_left)
@@ -842,9 +1022,13 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
       if (text != key + png_ptr->current_text_size)
          text++;
 
-      text_ptr = (png_textp)png_malloc(png_ptr, sizeof(png_text));
+      text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
       text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
       text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+      text_ptr->lang = (char *)NULL;
+      text_ptr->lang_key = (char *)NULL;
+#endif
       text_ptr->text = text;
 
       png_set_text(png_ptr, info_ptr, text_ptr, 1);
@@ -855,18 +1039,22 @@ png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
 #endif
 
 #if defined(PNG_READ_zTXt_SUPPORTED)
-void
+void /* PRIVATE */
 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
-   if (png_ptr->mode == PNG_BEFORE_IHDR || png_ptr->mode & PNG_HAVE_IEND)
-      png_error(png_ptr, "Out of place zTXt");
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
+      {
+         png_error(png_ptr, "Out of place zTXt");
+         /* to quiet some compiler warnings */
+         if(info_ptr == NULL) return;
+      }
 
 #ifdef PNG_MAX_MALLOC_64K
    /* We can't handle zTXt chunks > 64K, since we don't have enough space
     * to be able to store the uncompressed data.  Actually, the threshold
     * is probably around 32K, but it isn't as definite as 64K is.
     */
-   if (length > 65535L)
+   if (length > (png_uint_32)65535L)
    {
       png_warning(png_ptr, "zTXt chunk too large to fit in memory");
       png_push_crc_skip(png_ptr, length);
@@ -874,15 +1062,16 @@ png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length
    }
 #endif
 
-   png_ptr->current_text = (png_charp)png_malloc(png_ptr, length+1);
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+       (png_uint_32)(length+1));
    png_ptr->current_text[length] = '\0';
    png_ptr->current_text_ptr = png_ptr->current_text;
-   png_ptr->current_text_size = length;
-   png_ptr->current_text_left = length;
+   png_ptr->current_text_size = (png_size_t)length;
+   png_ptr->current_text_left = (png_size_t)length;
    png_ptr->process_mode = PNG_READ_zTXt_MODE;
 }
 
-void
+void /* PRIVATE */
 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->buffer_size && png_ptr->current_text_left)
@@ -940,7 +1129,7 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
       png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
          (text - key));
       png_ptr->zstream.next_out = png_ptr->zbuf;
-      png_ptr->zstream.avail_out = png_ptr->zbuf_size;
+      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 
       key_size = text - key;
       text_size = 0;
@@ -963,8 +1152,8 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
             if (text == NULL)
             {
                text = (png_charp)png_malloc(png_ptr,
-                  png_ptr->zbuf_size - png_ptr->zstream.avail_out +
-                     key_size + 1);
+                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out +
+                     key_size + 1));
                png_memcpy(text + key_size, png_ptr->zbuf,
                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
                png_memcpy(text, key, key_size);
@@ -977,8 +1166,9 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
                png_charp tmp;
 
                tmp = text;
-               text = png_malloc(png_ptr, text_size +
-                  png_ptr->zbuf_size - png_ptr->zstream.avail_out + 1);
+               text = (png_charp)png_malloc(png_ptr, text_size +
+                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
+                   + 1));
                png_memcpy(text, tmp, text_size);
                png_free(png_ptr, tmp);
                png_memcpy(text + text_size, png_ptr->zbuf,
@@ -1014,11 +1204,14 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
       png_free(png_ptr, key);
       key = text;
       text += key_size;
-      text_size -= key_size;
 
-      text_ptr = (png_textp)png_malloc(png_ptr, sizeof(png_text));
+      text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
       text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
       text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+      text_ptr->lang = (char *)NULL;
+      text_ptr->lang_key = (char *)NULL;
+#endif
       text_ptr->text = text;
 
       png_set_text(png_ptr, info_ptr, text_ptr, 1);
@@ -1028,43 +1221,197 @@ png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
 }
 #endif
 
+#if defined(PNG_READ_iTXt_SUPPORTED)
+void /* PRIVATE */
+png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
+      {
+         png_error(png_ptr, "Out of place iTXt");
+         /* to quiet some compiler warnings */
+         if(info_ptr == NULL) return;
+      }
+
+#ifdef PNG_MAX_MALLOC_64K
+   png_ptr->skip_length = 0;  /* This may not be necessary */
+
+   if (length > (png_uint_32)65535L) /* Can't hold the entire string in memory */
+   {
+      png_warning(png_ptr, "iTXt chunk too large to fit in memory");
+      png_ptr->skip_length = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+         (png_uint_32)(length+1));
+   png_ptr->current_text[length] = '\0';
+   png_ptr->current_text_ptr = png_ptr->current_text;
+   png_ptr->current_text_size = (png_size_t)length;
+   png_ptr->current_text_left = (png_size_t)length;
+   png_ptr->process_mode = PNG_READ_iTXt_MODE;
+}
+
+void /* PRIVATE */
+png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
+{
+
+   if (png_ptr->buffer_size && png_ptr->current_text_left)
+   {
+      png_size_t text_size;
+
+      if (png_ptr->buffer_size < png_ptr->current_text_left)
+         text_size = png_ptr->buffer_size;
+      else
+         text_size = png_ptr->current_text_left;
+      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
+      png_ptr->current_text_left -= text_size;
+      png_ptr->current_text_ptr += text_size;
+   }
+   if (!(png_ptr->current_text_left))
+   {
+      png_textp text_ptr;
+      png_charp key;
+      int comp_flag;
+      png_charp lang;
+      png_charp lang_key;
+      png_charp text;
+
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_crc_finish(png_ptr);
+
+#if defined(PNG_MAX_MALLOC_64K)
+      if (png_ptr->skip_length)
+         return;
+#endif
+
+      key = png_ptr->current_text;
+      png_ptr->current_text = 0;
+
+      for (lang = key; *lang; lang++)
+         /* empty loop */ ;
+
+      if (lang != key + png_ptr->current_text_size)
+         lang++;
+
+      comp_flag = *lang++;
+      lang++;     /* skip comp_type, always zero */
+
+      for (lang_key = lang; *lang_key; lang_key++)
+         /* empty loop */ ;
+      lang_key++;        /* skip NUL separator */
+
+      for (text = lang_key; *text; text++)
+         /* empty loop */ ;
+
+      if (text != key + png_ptr->current_text_size)
+         text++;
+
+      text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
+      text_ptr->compression = comp_flag + 2;
+      text_ptr->key = key;
+      text_ptr->lang = lang;
+      text_ptr->lang_key = lang_key;
+      text_ptr->text = text;
+      text_ptr->text_length = 0;
+      text_ptr->itxt_length = png_strlen(text);
+
+      png_set_text(png_ptr, info_ptr, text_ptr, 1);
+
+      png_free(png_ptr, text_ptr);
+   }
+}
+#endif
+
 /* This function is called when we haven't found a handler for this
-   chunk.  In the future we will have code here which can handle
-   user-defined callback functions for unknown chunks before they are
-   ignored or cause an error.  If there isn't a problem with the
-   chunk itself (ie a bad chunk name or a critical chunk), the chunk
-   is (currently) silently ignored. */
-void
+ * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
+ * name or a critical chunk), the chunk is (currently) silently ignored.
+ */
+void /* PRIVATE */
 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
+   png_uint_32 skip=0;
    png_check_chunk_name(png_ptr, png_ptr->chunk_name);
 
    if (!(png_ptr->chunk_name[0] & 0x20))
    {
-      char msg[40];
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+      if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+           HANDLE_CHUNK_ALWAYS
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+           && png_ptr->read_user_chunk_fn == (png_user_chunk_ptr)NULL
+#endif
+         )
+#endif
+         png_chunk_error(png_ptr, "unknown critical chunk");
 
-      sprintf(msg, "Unknown critical chunk %s", png_ptr->chunk_name);
-      png_error(png_ptr, msg);
+      /* to quiet compiler warnings about unused info_ptr */
+      if (info_ptr == NULL)
+         return;
    }
 
-   png_push_crc_skip(png_ptr, length);
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+   if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
+   {
+       png_unknown_chunk chunk;
+
+#ifdef PNG_MAX_MALLOC_64K
+       if (length > (png_uint_32)65535L)
+       {
+           png_warning(png_ptr, "unknown chunk too large to fit in memory");
+           skip = length - (png_uint_32)65535L;
+           length = (png_uint_32)65535L;
+       }
+#endif
+
+       strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
+       chunk.data = (png_bytep)png_malloc(png_ptr, length);
+       png_crc_read(png_ptr, chunk.data, length);
+       chunk.size = length;
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+       if(png_ptr->read_user_chunk_fn != (png_user_chunk_ptr)NULL)
+       {
+          /* callback to user unknown chunk handler */
+          if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
+          {
+             if (!(png_ptr->chunk_name[0] & 0x20))
+                if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+                     HANDLE_CHUNK_ALWAYS)
+                   png_chunk_error(png_ptr, "unknown critical chunk");
+          }
+             png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
+       }
+       else
+#endif
+          png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
+       png_free(png_ptr, chunk.data);
+   }
+   else
+#endif
+      skip=length;
+   png_push_crc_skip(png_ptr, skip);
 }
 
-void
+void /* PRIVATE */
 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->info_fn != NULL)
       (*(png_ptr->info_fn))(png_ptr, info_ptr);
 }
 
-void
+void /* PRIVATE */
 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr->end_fn != NULL)
       (*(png_ptr->end_fn))(png_ptr, info_ptr);
 }
 
-void
+void /* PRIVATE */
 png_push_have_row(png_structp png_ptr, png_bytep row)
 {
    if (png_ptr->row_fn != NULL)
@@ -1072,15 +1419,18 @@ png_push_have_row(png_structp png_ptr, png_bytep row)
          (int)png_ptr->pass);
 }
 
-void
+void PNGAPI
 png_progressive_combine_row (png_structp png_ptr,
    png_bytep old_row, png_bytep new_row)
 {
-   if (new_row != NULL)
+#ifdef PNG_USE_LOCAL_ARRAYS
+   const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
+#endif
+   if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
       png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
 }
 
-void
+void PNGAPI
 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
    png_progressive_end_ptr end_fn)
@@ -1092,7 +1442,7 @@ png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
    png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
 }
 
-png_voidp
+png_voidp PNGAPI
 png_get_progressive_ptr(png_structp png_ptr)
 {
    return png_ptr->io_ptr;

pngrio.c

@@ -1,18 +1,19 @@
 
 /* pngrio.c - functions for data input
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-
-   This file provides a location for all input.  Users which need
-   special handling are expected to write a function which has the same
-   arguments as this, and perform a similar function, but possibly has
-   a different input method.  Note that you shouldn't change this
-   function, but rather write a replacement function and then make
-   libpng use it at run time with png_set_read_fn(...) */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ *
+ * This file provides a location for all input.  Users who need
+ * special handling are expected to write a function that has the same
+ * arguments as this and performs a similar function, but that possibly
+ * has a different input method.  Note that you shouldn't change this
+ * function, but rather write a replacement function and then make
+ * libpng use it at run time with png_set_read_fn(...).
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
@@ -22,7 +23,7 @@
    with very small lengths, so you should implement some kind of simple
    buffering if you are using unbuffered reads.  This should never be asked
    to read more then 64K on a 16 bit machine. */
-void
+void /* PRIVATE */
 png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_debug1(4,"reading %d bytes\n", length);
@@ -32,12 +33,13 @@ png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
       png_error(png_ptr, "Call to NULL read function");
 }
 
-/* This is the function which does the actual reading of data.  If you are
+#if !defined(PNG_NO_STDIO)
+/* This is the function that does the actual reading of data.  If you are
    not reading from a standard C stream, you should create a replacement
    read_data function and use it at run time with png_set_read_fn(), rather
    than changing the library. */
 #ifndef USE_FAR_KEYWORD
-static void
+static void /* PRIVATE */
 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_size_t check;
@@ -58,11 +60,11 @@ png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
    can't handle far buffers in the medium and small models, we have to copy
    the data.
 */
- 
+
 #define NEAR_BUF_SIZE 1024
 #define MIN(a,b) (a <= b ? a : b)
- 
-static void
+
+static void /* PRIVATE */
 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    int check;
@@ -96,12 +98,13 @@ png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
       }
       while (remaining != 0);
    }
-   if (check != length)
+   if ((png_uint_32)check != (png_uint_32)length)
    {
       png_error(png_ptr, "read Error");
    }
 }
 #endif
+#endif
 
 /* This function allows the application to supply a new input function
    for libpng if standard C streams aren't being used.
@@ -110,28 +113,39 @@ png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
    png_ptr      - pointer to a png input data structure
    io_ptr       - pointer to user supplied structure containing info about
                   the input functions.  May be NULL.
-   read_data_fn - pointer to a new input function which takes as it's
+   read_data_fn - pointer to a new input function that takes as its
                   arguments a pointer to a png_struct, a pointer to
                   a location where input data can be stored, and a 32-bit
-                  unsigned int which is the number of bytes to be read.
+                  unsigned int that is the number of bytes to be read.
                   To exit and output any fatal error messages the new write
                   function should call png_error(png_ptr, "Error msg"). */
-void
+void PNGAPI
 png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
    png_rw_ptr read_data_fn)
 {
    png_ptr->io_ptr = io_ptr;
 
+#if !defined(PNG_NO_STDIO)
    if (read_data_fn != NULL)
       png_ptr->read_data_fn = read_data_fn;
    else
       png_ptr->read_data_fn = png_default_read_data;
+#else
+   png_ptr->read_data_fn = read_data_fn;
+#endif
 
    /* It is an error to write to a read device */
-   png_ptr->write_data_fn = NULL;
+   if (png_ptr->write_data_fn != NULL)
+   {
+      png_ptr->write_data_fn = NULL;
+      png_warning(png_ptr,
+         "It's an error to set both read_data_fn and write_data_fn in the ");
+      png_warning(png_ptr,
+         "same structure.  Resetting write_data_fn to NULL.");
+   }
 
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
    png_ptr->output_flush_fn = NULL;
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+#endif
 }
 

pngset.c

@@ -1,22 +1,27 @@
 
 /* pngset.c - storage of image information into info struct
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-   */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ *
+ * The functions here are used during reads to store data from the file
+ * into the info struct, and during writes to store application data
+ * into the info struct for writing into the file.  This abstracts the
+ * info struct and allows us to change the structure in the future.
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
 
-#if defined(PNG_READ_bKGD_SUPPORTED) || defined(PNG_WRITE_bKGD_SUPPORTED)
-void
+#if defined(PNG_bKGD_SUPPORTED)
+void PNGAPI
 png_set_bKGD(png_structp png_ptr, png_infop info_ptr, png_color_16p background)
 {
    png_debug1(1, "in %s storage function\n", "bKGD");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    png_memcpy(&(info_ptr->background), background, sizeof(png_color_16));
@@ -24,14 +29,15 @@ png_set_bKGD(png_structp png_ptr, png_infop info_ptr, png_color_16p background)
 }
 #endif
 
-#if defined(PNG_READ_cHRM_SUPPORTED) || defined(PNG_WRITE_cHRM_SUPPORTED)
-void
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
 png_set_cHRM(png_structp png_ptr, png_infop info_ptr,
    double white_x, double white_y, double red_x, double red_y,
    double green_x, double green_y, double blue_x, double blue_y)
 {
    png_debug1(1, "in %s storage function\n", "cHRM");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->x_white = (float)white_x;
@@ -42,29 +48,93 @@ png_set_cHRM(png_structp png_ptr, png_infop info_ptr,
    info_ptr->y_green = (float)green_y;
    info_ptr->x_blue  = (float)blue_x;
    info_ptr->y_blue  = (float)blue_y;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   info_ptr->int_x_white = (png_fixed_point)(white_x*100000.+0.5);
+   info_ptr->int_y_white = (png_fixed_point)(white_y*100000.+0.5);
+   info_ptr->int_x_red   = (png_fixed_point)(red_x*100000.+0.5);
+   info_ptr->int_y_red   = (png_fixed_point)(red_y*100000.+0.5);
+   info_ptr->int_x_green = (png_fixed_point)(green_x*100000.+0.5);
+   info_ptr->int_y_green = (png_fixed_point)(green_y*100000.+0.5);
+   info_ptr->int_x_blue  = (png_fixed_point)(blue_x*100000.+0.5);
+   info_ptr->int_y_blue  = (png_fixed_point)(blue_y*100000.+0.5);
+#endif
    info_ptr->valid |= PNG_INFO_cHRM;
 }
 #endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
+   png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+   png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+   png_fixed_point blue_x, png_fixed_point blue_y)
+{
+   png_debug1(1, "in %s storage function\n", "cHRM");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
 
-#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_WRITE_gAMA_SUPPORTED)
-void
+   info_ptr->int_x_white = white_x;
+   info_ptr->int_y_white = white_y;
+   info_ptr->int_x_red   = red_x;
+   info_ptr->int_y_red   = red_y;
+   info_ptr->int_x_green = green_x;
+   info_ptr->int_y_green = green_y;
+   info_ptr->int_x_blue  = blue_x;
+   info_ptr->int_y_blue  = blue_y;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   info_ptr->x_white = (float)(white_x/100000.);
+   info_ptr->y_white = (float)(white_y/100000.);
+   info_ptr->x_red   = (float)(red_x/100000.);
+   info_ptr->y_red   = (float)(red_y/100000.);
+   info_ptr->x_green = (float)(green_x/100000.);
+   info_ptr->y_green = (float)(green_y/100000.);
+   info_ptr->x_blue  = (float)(blue_x/100000.);
+   info_ptr->y_blue  = (float)(blue_y/100000.);
+#endif
+   info_ptr->valid |= PNG_INFO_cHRM;
+}
+#endif
+#endif
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
 png_set_gAMA(png_structp png_ptr, png_infop info_ptr, double file_gamma)
 {
    png_debug1(1, "in %s storage function\n", "gAMA");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->gamma = (float)file_gamma;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   info_ptr->int_gamma = (int)(file_gamma*100000.+.5);
+#endif
    info_ptr->valid |= PNG_INFO_gAMA;
 }
 #endif
+#endif
+void PNGAPI
+png_set_gAMA_fixed(png_structp png_ptr, png_infop info_ptr, png_fixed_point
+   int_gamma)
+{
+   png_debug1(1, "in %s storage function\n", "gAMA");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
 
-#if defined(PNG_READ_hIST_SUPPORTED) || defined(PNG_WRITE_hIST_SUPPORTED)
-void
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   info_ptr->gamma = (float)(int_gamma/100000.);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   info_ptr->int_gamma = int_gamma;
+#endif
+   info_ptr->valid |= PNG_INFO_gAMA;
+}
+
+#if defined(PNG_hIST_SUPPORTED)
+void PNGAPI
 png_set_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p hist)
 {
    png_debug1(1, "in %s storage function\n", "hIST");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->hist = hist;
@@ -72,14 +142,15 @@ png_set_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p hist)
 }
 #endif
 
-void
+void PNGAPI
 png_set_IHDR(png_structp png_ptr, png_infop info_ptr,
    png_uint_32 width, png_uint_32 height, int bit_depth,
    int color_type, int interlace_type, int compression_type,
    int filter_type)
 {
+   int rowbytes_per_pixel;
    png_debug1(1, "in %s storage function\n", "IHDR");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->width = width;
@@ -98,16 +169,26 @@ png_set_IHDR(png_structp png_ptr, png_infop info_ptr,
    if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
       info_ptr->channels++;
    info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
-   info_ptr->rowbytes = ((info_ptr->width * info_ptr->pixel_depth + 7) >> 3);
+
+   /* check for overflow */
+   rowbytes_per_pixel = (info_ptr->pixel_depth + 7) >> 3;
+   if (( width > PNG_MAX_UINT/rowbytes_per_pixel))
+   {
+      png_warning(png_ptr,
+         "Width too large to process image data; rowbytes will overflow.");
+      info_ptr->rowbytes = (png_size_t)0;
+   }
+   else
+      info_ptr->rowbytes = (info_ptr->width * info_ptr->pixel_depth + 7) >> 3;
 }
 
-#if defined(PNG_READ_oFFs_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
-void
+#if defined(PNG_oFFs_SUPPORTED)
+void PNGAPI
 png_set_oFFs(png_structp png_ptr, png_infop info_ptr,
-   png_uint_32 offset_x, png_uint_32 offset_y, int unit_type)
+   png_int_32 offset_x, png_int_32 offset_y, int unit_type)
 {
    png_debug1(1, "in %s storage function\n", "oFFs");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->x_offset = offset_x;
@@ -117,23 +198,23 @@ png_set_oFFs(png_structp png_ptr, png_infop info_ptr,
 }
 #endif
 
-#if defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED)
-void
+#if defined(PNG_pCAL_SUPPORTED)
+void PNGAPI
 png_set_pCAL(png_structp png_ptr, png_infop info_ptr,
    png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
    png_charp units, png_charpp params)
 {
-   png_size_t length;
+   png_uint_32 length;
    int i;
 
    png_debug1(1, "in %s storage function\n", "pCAL");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    length = png_strlen(purpose) + 1;
    png_debug1(3, "allocating purpose for info (%d bytes)\n", length);
    info_ptr->pcal_purpose = (png_charp)png_malloc(png_ptr, length);
-   png_memcpy(info_ptr->pcal_purpose, purpose, length);
+   png_memcpy(info_ptr->pcal_purpose, purpose, (png_size_t)length);
 
    png_debug(3, "storing X0, X1, type, and nparams in info\n");
    info_ptr->pcal_X0 = X0;
@@ -144,10 +225,10 @@ png_set_pCAL(png_structp png_ptr, png_infop info_ptr,
    length = png_strlen(units) + 1;
    png_debug1(3, "allocating units for info (%d bytes)\n", length);
    info_ptr->pcal_units = (png_charp)png_malloc(png_ptr, length);
-   png_memcpy(info_ptr->pcal_units, units, length);
+   png_memcpy(info_ptr->pcal_units, units, (png_size_t)length);
 
    info_ptr->pcal_params = (png_charpp)png_malloc(png_ptr,
-      (nparams + 1) * sizeof(png_charp));
+      (png_uint_32)((nparams + 1) * sizeof(png_charp)));
    info_ptr->pcal_params[nparams] = NULL;
 
    for (i = 0; i < nparams; i++)
@@ -155,20 +236,72 @@ png_set_pCAL(png_structp png_ptr, png_infop info_ptr,
       length = png_strlen(params[i]) + 1;
       png_debug2(3, "allocating parameter %d for info (%d bytes)\n", i, length);
       info_ptr->pcal_params[i] = (png_charp)png_malloc(png_ptr, length);
-      png_memcpy(info_ptr->pcal_params[i], params[i], length);
+      png_memcpy(info_ptr->pcal_params[i], params[i], (png_size_t)length);
    }
 
    info_ptr->valid |= PNG_INFO_pCAL;
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_PCAL;
+#endif
 }
 #endif
 
-#if defined(PNG_READ_pHYs_SUPPORTED) || defined(PNG_WRITE_pHYs_SUPPORTED)
-void
+#if defined(PNG_READ_sCAL_SUPPORTED) || defined(PNG_WRITE_sCAL_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL(png_structp png_ptr, png_infop info_ptr,
+             int unit, double width, double height)
+{
+   png_debug1(1, "in %s storage function\n", "sCAL");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->scal_unit = (png_byte)unit;
+   info_ptr->scal_pixel_width = width;
+   info_ptr->scal_pixel_height = height;
+
+   info_ptr->valid |= PNG_INFO_sCAL;
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL_s(png_structp png_ptr, png_infop info_ptr,
+             int unit, png_charp swidth, png_charp sheight)
+{
+   png_uint_32 length;
+
+   png_debug1(1, "in %s storage function\n", "sCAL");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->scal_unit = (png_byte)unit;
+
+   length = png_strlen(swidth) + 1;
+   png_debug1(3, "allocating unit for info (%d bytes)\n", length);
+   info_ptr->scal_s_width = (png_charp)png_malloc(png_ptr, length);
+   png_memcpy(info_ptr->scal_s_width, swidth, (png_size_t)length);
+
+   length = png_strlen(sheight) + 1;
+   png_debug1(3, "allocating unit for info (%d bytes)\n", length);
+   info_ptr->scal_s_width = (png_charp)png_malloc(png_ptr, length);
+   png_memcpy(info_ptr->scal_s_height, sheight, (png_size_t)length);
+
+   info_ptr->valid |= PNG_INFO_sCAL;
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_SCAL;
+#endif
+}
+#endif
+#endif
+#endif
+
+#if defined(PNG_pHYs_SUPPORTED)
+void PNGAPI
 png_set_pHYs(png_structp png_ptr, png_infop info_ptr,
    png_uint_32 res_x, png_uint_32 res_y, int unit_type)
 {
    png_debug1(1, "in %s storage function\n", "pHYs");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->x_pixels_per_unit = res_x;
@@ -178,26 +311,28 @@ png_set_pHYs(png_structp png_ptr, png_infop info_ptr,
 }
 #endif
 
-void
+void PNGAPI
 png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
    png_colorp palette, int num_palette)
 {
+
    png_debug1(1, "in %s storage function\n", "PLTE");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    info_ptr->palette = palette;
+
    info_ptr->num_palette = (png_uint_16)num_palette;
    info_ptr->valid |= PNG_INFO_PLTE;
 }
 
-#if defined(PNG_READ_sBIT_SUPPORTED) || defined(PNG_WRITE_sBIT_SUPPORTED)
-void
+#if defined(PNG_sBIT_SUPPORTED)
+void PNGAPI
 png_set_sBIT(png_structp png_ptr, png_infop info_ptr,
    png_color_8p sig_bit)
 {
    png_debug1(1, "in %s storage function\n", "sBIT");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    png_memcpy(&(info_ptr->sig_bit), sig_bit, sizeof (png_color_8));
@@ -205,18 +340,133 @@ png_set_sBIT(png_structp png_ptr, png_infop info_ptr,
 }
 #endif
 
-#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED) || \
-    defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
-void
+#if defined(PNG_sRGB_SUPPORTED)
+void PNGAPI
+png_set_sRGB(png_structp png_ptr, png_infop info_ptr, int intent)
+{
+   png_debug1(1, "in %s storage function\n", "sRGB");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->srgb_intent = (png_byte)intent;
+   info_ptr->valid |= PNG_INFO_sRGB;
+}
+
+void PNGAPI
+png_set_sRGB_gAMA_and_cHRM(png_structp png_ptr, png_infop info_ptr,
+   int intent)
+{
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float file_gamma;
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_fixed_point int_file_gamma;
+#endif
+#endif
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
+      int_green_y, int_blue_x, int_blue_y;
+#endif
+#endif
+   png_debug1(1, "in %s storage function\n", "sRGB_gAMA_and_cHRM");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_set_sRGB(png_ptr, info_ptr, intent);
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   file_gamma = (float).45455;
+   png_set_gAMA(png_ptr, info_ptr, file_gamma);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   int_file_gamma = 45455L;
+   png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+#endif
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   int_white_x = 31270L;
+   int_white_y = 32900L;
+   int_red_x   = 64000L;
+   int_red_y   = 33000L;
+   int_green_x = 30000L;
+   int_green_y = 60000L;
+   int_blue_x  = 15000L;
+   int_blue_y  =  6000L;
+
+   png_set_cHRM_fixed(png_ptr, info_ptr,
+      int_white_x, int_white_y, int_red_x, int_red_y, int_green_x, int_green_y,
+      int_blue_x, int_blue_y);
+#endif
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   white_x = (float).3127;
+   white_y = (float).3290;
+   red_x   = (float).64;
+   red_y   = (float).33;
+   green_x = (float).30;
+   green_y = (float).60;
+   blue_x  = (float).15;
+   blue_y  = (float).06;
+
+   png_set_cHRM(png_ptr, info_ptr,
+      white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
+#endif
+#endif
+}
+#endif
+
+
+#if defined(PNG_iCCP_SUPPORTED)
+void PNGAPI
+png_set_iCCP(png_structp png_ptr, png_infop info_ptr,
+             png_charp name, int compression_type,
+             png_charp profile, png_uint_32 proflen)
+{
+   png_charp new_iccp_name;
+   png_charp new_iccp_profile;
+
+   png_debug1(1, "in %s storage function\n", "iCCP");
+   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
+      return;
+
+   new_iccp_name = png_malloc(png_ptr, png_strlen(name)+1);
+   strcpy(new_iccp_name, name);
+   new_iccp_profile = png_malloc(png_ptr, proflen);
+   png_memcpy(new_iccp_profile, profile, (png_size_t)proflen);
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
+
+   info_ptr->iccp_proflen = proflen;
+   info_ptr->iccp_name = new_iccp_name;
+   info_ptr->iccp_profile = new_iccp_profile;
+   /* Compression is always zero but is here so the API and info structure
+    * does not have to change if we introduce multiple compression types */
+   info_ptr->iccp_compression = (png_byte)compression_type;
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_ICCP;
+#endif
+   info_ptr->valid |= PNG_INFO_iCCP;
+}
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED)
+void PNGAPI
 png_set_text(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
    int num_text)
 {
    int i;
 
    png_debug1(1, "in %s storage function\n", (png_ptr->chunk_name[0] == '\0' ?
-      "text" : png_ptr->chunk_name));
+      "text" : (png_const_charp)png_ptr->chunk_name));
 
-   if (info_ptr == NULL || num_text == 0)
+   if (png_ptr == NULL || info_ptr == NULL || num_text == 0)
       return;
 
    /* Make sure we have enough space in the "text" array in info_struct
@@ -233,8 +483,9 @@ png_set_text(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
          info_ptr->max_text = info_ptr->num_text + num_text + 8;
          old_text = info_ptr->text;
          info_ptr->text = (png_textp)png_malloc(png_ptr,
-            info_ptr->max_text * sizeof (png_text));
-         png_memcpy(info_ptr->text, old_text, old_max * sizeof(png_text));
+            (png_uint_32)(info_ptr->max_text * sizeof (png_text)));
+         png_memcpy(info_ptr->text, old_text, (png_size_t)(old_max *
+            sizeof(png_text)));
          png_free(png_ptr, old_text);
       }
       else
@@ -242,43 +493,127 @@ png_set_text(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
          info_ptr->max_text = num_text + 8;
          info_ptr->num_text = 0;
          info_ptr->text = (png_textp)png_malloc(png_ptr,
-            info_ptr->max_text * sizeof (png_text));
+            (png_uint_32)(info_ptr->max_text * sizeof (png_text)));
+#ifdef PNG_FREE_ME_SUPPORTED
+         info_ptr->free_me |= PNG_FREE_TEXT;
+#endif
       }
       png_debug1(3, "allocated %d entries for info_ptr->text\n",
          info_ptr->max_text);
    }
-
    for (i = 0; i < num_text; i++)
    {
+      png_size_t text_length,key_len;
+      png_size_t lang_len,lang_key_len;
       png_textp textp = &(info_ptr->text[info_ptr->num_text]);
 
-      if (text_ptr[i].text == NULL)
-         text_ptr[i].text = "";
+      if (text_ptr[i].key == (png_charp)NULL)
+          continue;
 
-      if (text_ptr[i].text[0] == '\0')
+      key_len = png_strlen(text_ptr[i].key);
+
+      if(text_ptr[i].compression <= 0)
       {
-         textp->text_length = 0;
-         textp->compression = PNG_TEXT_COMPRESSION_NONE;
+        lang_len = 0;
+        lang_key_len = 0;
+      }
+      else
+#ifdef PNG_iTXt_SUPPORTED
+      {
+        /* set iTXt data */
+        if (text_ptr[i].key != (png_charp)NULL)
+          lang_len = png_strlen(text_ptr[i].lang);
+        else
+          lang_len = 0;
+        if (text_ptr[i].lang_key != (png_charp)NULL)
+          lang_key_len = png_strlen(text_ptr[i].lang_key);
+        else
+          lang_key_len = 0;
+      }
+#else
+      {
+        png_warning(png_ptr, "iTXt chunk not supported.");
+        continue;
+      }
+#endif
+
+      if (text_ptr[i].text == (png_charp)NULL || text_ptr[i].text[0] == '\0')
+      {
+         text_length = 0;
+#ifdef PNG_iTXt_SUPPORTED
+         if(text_ptr[i].compression > 0)
+            textp->compression = PNG_ITXT_COMPRESSION_NONE;
+         else
+#endif
+            textp->compression = PNG_TEXT_COMPRESSION_NONE;
       }
       else
       {
-         textp->text_length = png_strlen(text_ptr[i].text);
+         text_length = png_strlen(text_ptr[i].text);
          textp->compression = text_ptr[i].compression;
       }
-      textp->text = text_ptr[i].text;
-      textp->key = text_ptr[i].key;
+
+      textp->key = (png_charp)png_malloc(png_ptr,
+         (png_uint_32)(key_len + text_length + lang_len + lang_key_len + 4));
+      png_debug2(2, "Allocated %d bytes at %x in png_set_text\n",
+         key_len + lang_len + lang_key_len + text_length + 4, textp->key);
+
+      png_memcpy(textp->key, text_ptr[i].key,
+         (png_size_t)(key_len));
+      *(textp->key+key_len) = '\0';
+#ifdef PNG_iTXt_SUPPORTED
+      if (text_ptr[i].compression > 0)
+      {
+         textp->lang=textp->key + key_len + 1;
+         png_memcpy(textp->lang, text_ptr[i].lang, lang_len);
+         *(textp->lang+lang_len) = '\0';
+         textp->lang_key=textp->lang + lang_len + 1;
+         png_memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
+         *(textp->lang_key+lang_key_len) = '\0';
+         textp->text=textp->lang_key + lang_key_len + 1;
+      }
+      else
+#endif
+      {
+#ifdef PNG_iTXt_SUPPORTED
+         textp->lang=(png_charp)NULL;
+         textp->lang_key=(png_charp)NULL;
+#endif
+         textp->text=textp->key + key_len + 1;
+      }
+      if(text_length)
+         png_memcpy(textp->text, text_ptr[i].text,
+            (png_size_t)(text_length));
+      *(textp->text+text_length) = '\0';
+
+#ifdef PNG_iTXt_SUPPORTED
+      if(textp->compression > 0)
+      {
+         textp->text_length = 0;
+         textp->itxt_length = text_length;
+      }
+      else
+#endif
+      {
+         textp->text_length = text_length;
+#ifdef PNG_iTXt_SUPPORTED
+         textp->itxt_length = 0;
+#endif
+      }
+      info_ptr->text[info_ptr->num_text]= *textp;
       info_ptr->num_text++;
       png_debug1(3, "transferred text chunk %d\n", info_ptr->num_text);
    }
 }
 #endif
 
-#if defined(PNG_READ_tIME_SUPPORTED) || defined(PNG_WRITE_tIME_SUPPORTED)
-void
+#if defined(PNG_tIME_SUPPORTED)
+void PNGAPI
 png_set_tIME(png_structp png_ptr, png_infop info_ptr, png_timep mod_time)
 {
    png_debug1(1, "in %s storage function\n", "tIME");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL ||
+       (png_ptr->mode & PNG_WROTE_tIME))
       return;
 
    png_memcpy(&(info_ptr->mod_time), mod_time, sizeof (png_time));
@@ -286,27 +621,205 @@ png_set_tIME(png_structp png_ptr, png_infop info_ptr, png_timep mod_time)
 }
 #endif
 
-#if defined(PNG_READ_tRNS_SUPPORTED) || defined(PNG_WRITE_tRNS_SUPPORTED)
-void
+#if defined(PNG_tRNS_SUPPORTED)
+void PNGAPI
 png_set_tRNS(png_structp png_ptr, png_infop info_ptr,
    png_bytep trans, int num_trans, png_color_16p trans_values)
 {
    png_debug1(1, "in %s storage function\n", "tRNS");
-   if (info_ptr == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
 
    if (trans != NULL)
-   {
       info_ptr->trans = trans;
-   }
 
    if (trans_values != NULL)
    {
       png_memcpy(&(info_ptr->trans_values), trans_values,
          sizeof(png_color_16));
+      if (num_trans == 0)
+        num_trans = 1;
    }
    info_ptr->num_trans = (png_uint_16)num_trans;
    info_ptr->valid |= PNG_INFO_tRNS;
 }
 #endif
 
+#if defined(PNG_sPLT_SUPPORTED)
+void PNGAPI
+png_set_sPLT(png_structp png_ptr,
+             png_infop info_ptr, png_sPLT_tp entries, int nentries)
+{
+    png_sPLT_tp np;
+    int i;
+
+    np = (png_sPLT_tp)png_malloc(png_ptr,
+        (info_ptr->splt_palettes_num + nentries) * sizeof(png_sPLT_t));
+
+    png_memcpy(np, info_ptr->splt_palettes,
+           info_ptr->splt_palettes_num * sizeof(png_sPLT_t));
+    png_free(png_ptr, info_ptr->splt_palettes);
+
+    for (i = 0; i < nentries; i++)
+    {
+        png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
+        png_sPLT_tp from = entries + i;
+
+        to->name = (png_charp)png_malloc(png_ptr,
+                                        png_strlen(from->name) + 1);
+        png_strcpy(to->name, from->name);
+        to->entries = (png_sPLT_entryp)png_malloc(png_ptr,
+                                 from->nentries * sizeof(png_sPLT_t));
+        png_memcpy(to->entries, from->entries,
+               from->nentries * sizeof(png_sPLT_t));
+        to->nentries = from->nentries;
+        to->depth = from->depth;
+    }
+
+    info_ptr->splt_palettes = np;
+    info_ptr->splt_palettes_num += nentries;
+    info_ptr->valid |= PNG_INFO_sPLT;
+#ifdef PNG_FREE_ME_SUPPORTED
+    info_ptr->free_me |= PNG_FREE_SPLT;
+#endif
+}
+#endif /* PNG_sPLT_SUPPORTED */
+
+#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
+void PNGAPI
+png_set_unknown_chunks(png_structp png_ptr,
+   png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns)
+{
+    png_unknown_chunkp np;
+    int i;
+
+    if (png_ptr == NULL || info_ptr == NULL || num_unknowns == 0)
+        return;
+
+    np = (png_unknown_chunkp)png_malloc(png_ptr,
+        (info_ptr->unknown_chunks_num + num_unknowns) *
+        sizeof(png_unknown_chunk));
+
+    png_memcpy(np, info_ptr->unknown_chunks,
+           info_ptr->unknown_chunks_num * sizeof(png_unknown_chunk));
+    png_free(png_ptr, info_ptr->unknown_chunks);
+
+    for (i = 0; i < num_unknowns; i++)
+    {
+        png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
+        png_unknown_chunkp from = unknowns + i;
+
+        png_strcpy((png_charp)to->name, (png_charp)from->name);
+        to->data = (png_bytep)png_malloc(png_ptr, from->size);
+        png_memcpy(to->data, from->data, from->size);
+        to->size = from->size;
+
+        /* note our location in the read or write sequence */
+        to->location = (png_byte)(png_ptr->mode & 0xff);
+    }
+
+    info_ptr->unknown_chunks = np;
+    info_ptr->unknown_chunks_num += num_unknowns;
+#ifdef PNG_FREE_ME_SUPPORTED
+    info_ptr->free_me |= PNG_FREE_UNKN;
+#endif
+}
+void PNGAPI
+png_set_unknown_chunk_location(png_structp png_ptr, png_infop info_ptr,
+   int chunk, int location)
+{
+   if(png_ptr != NULL && info_ptr != NULL && chunk >= 0 && chunk < 
+         (int)info_ptr->unknown_chunks_num)
+      info_ptr->unknown_chunks[chunk].location = (png_byte)location;
+}
+#endif
+
+#if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
+    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
+void PNGAPI
+png_permit_empty_plte (png_structp png_ptr, int empty_plte_permitted)
+{
+   png_debug1(1, "in png_permit_empty_plte\n", "");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->empty_plte_permitted=(png_byte)empty_plte_permitted;
+}
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+void PNGAPI
+png_set_keep_unknown_chunks(png_structp png_ptr, int keep, png_bytep
+   chunk_list, int num_chunks)
+{
+    png_bytep new_list, p;
+    int i, old_num_chunks;
+    if (num_chunks == 0)
+    {
+      if(keep == HANDLE_CHUNK_ALWAYS || keep == HANDLE_CHUNK_IF_SAFE)
+        png_ptr->flags |= PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
+      else
+        png_ptr->flags &= ~PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
+
+      if(keep == HANDLE_CHUNK_ALWAYS)
+        png_ptr->flags |= PNG_FLAG_KEEP_UNSAFE_CHUNKS;
+      else
+        png_ptr->flags &= ~PNG_FLAG_KEEP_UNSAFE_CHUNKS;
+      return;
+    }
+    if (chunk_list == NULL)
+      return;
+    old_num_chunks=png_ptr->num_chunk_list;
+    new_list=png_malloc(png_ptr,5*(num_chunks+old_num_chunks));
+    if(png_ptr->chunk_list != (png_bytep)NULL)
+    {
+       png_memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
+       png_free(png_ptr, png_ptr->chunk_list);
+    }
+    png_memcpy(new_list+5*old_num_chunks, chunk_list, 5*num_chunks);
+    for (p=new_list+5*old_num_chunks+4, i=0; i<num_chunks; i++, p+=5)
+       *p=(png_byte)keep;
+    png_ptr->num_chunk_list=old_num_chunks+num_chunks;
+    png_ptr->chunk_list=new_list;
+#ifdef PNG_FREE_ME_SUPPORTED
+    png_ptr->free_me |= PNG_FREE_LIST;
+#endif
+}
+#endif
+
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+void PNGAPI
+png_set_read_user_chunk_fn(png_structp png_ptr, png_voidp user_chunk_ptr,
+   png_user_chunk_ptr read_user_chunk_fn)
+{
+   png_debug(1, "in png_set_read_user_chunk_fn\n");
+   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
+   png_ptr->user_chunk_ptr = user_chunk_ptr;
+}
+#endif
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+void PNGAPI
+png_set_rows(png_structp png_ptr, png_infop info_ptr, png_bytepp row_pointers)
+{
+   png_debug1(1, "in %s storage function\n", "rows");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if(info_ptr->row_pointers != row_pointers)
+   {
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+      info_ptr->row_pointers = row_pointers;
+   }
+}
+#endif
+
+void PNGAPI
+png_set_compression_buffer_size(png_structp png_ptr, png_uint_32 size)
+{
+    if(png_ptr->zbuf)
+       png_free(png_ptr, png_ptr->zbuf);
+    png_ptr->zbuf_size = (png_size_t)size;
+    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr, size);
+    png_ptr->zstream.next_out = png_ptr->zbuf;
+    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+}

pngtrans.c

@@ -1,19 +1,19 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-   */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-/* turn on bgr to rgb mapping */
-void
+/* turn on BGR-to-RGB mapping */
+void PNGAPI
 png_set_bgr(png_structp png_ptr)
 {
    png_debug(1, "in png_set_bgr\n");
@@ -23,7 +23,7 @@ png_set_bgr(png_structp png_ptr)
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
 /* turn on 16 bit byte swapping */
-void
+void PNGAPI
 png_set_swap(png_structp png_ptr)
 {
    png_debug(1, "in png_set_swap\n");
@@ -34,7 +34,7 @@ png_set_swap(png_structp png_ptr)
 
 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
 /* turn on pixel packing */
-void
+void PNGAPI
 png_set_packing(png_structp png_ptr)
 {
    png_debug(1, "in png_set_packing\n");
@@ -48,7 +48,7 @@ png_set_packing(png_structp png_ptr)
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
 /* turn on packed pixel swapping */
-void
+void PNGAPI
 png_set_packswap(png_structp png_ptr)
 {
    png_debug(1, "in png_set_packswap\n");
@@ -58,7 +58,7 @@ png_set_packswap(png_structp png_ptr)
 #endif
 
 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
-void
+void PNGAPI
 png_set_shift(png_structp png_ptr, png_color_8p true_bits)
 {
    png_debug(1, "in png_set_shift\n");
@@ -67,28 +67,29 @@ png_set_shift(png_structp png_ptr, png_color_8p true_bits)
 }
 #endif
 
-#if defined(PNG_READ_INTERLACING_SUPPORTED) || defined(PNG_WRITE_INTERLACING_SUPPORTED)
-int
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+int PNGAPI
 png_set_interlace_handling(png_structp png_ptr)
 {
    png_debug(1, "in png_set_interlace handling\n");
    if (png_ptr->interlaced)
    {
       png_ptr->transformations |= PNG_INTERLACE;
-      return 7;
+      return (7);
    }
 
-   return 1;
+   return (1);
 }
 #endif
 
 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
 /* Add a filler byte on read, or remove a filler or alpha byte on write.
  * The filler type has changed in v0.95 to allow future 2-byte fillers
- * for 48-bit input data, as well as avoiding problems with some compilers
- * which don't like bytes as parameters.
+ * for 48-bit input data, as well as to avoid problems with some compilers
+ * that don't like bytes as parameters.
  */
-void
+void PNGAPI
 png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
 {
    png_debug(1, "in png_set_filler\n");
@@ -99,17 +100,29 @@ png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
    else
       png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
 
-   /* This should probably go in the "do_filler" routine */
-   if (png_ptr->color_type == PNG_COLOR_TYPE_RGB && png_ptr->bit_depth == 8)
+   /* This should probably go in the "do_filler" routine.
+    * I attempted to do that in libpng-1.0.1a but that caused problems
+    * so I restored it in libpng-1.0.2a
+   */
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
    {
       png_ptr->usr_channels = 4;
    }
+
+   /* Also I added this in libpng-1.0.2a (what happens when we expand
+    * a less-than-8-bit grayscale to GA? */
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth >= 8)
+   {
+      png_ptr->usr_channels = 2;
+   }
 }
 #endif
 
 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
     defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
-void
+void PNGAPI
 png_set_swap_alpha(png_structp png_ptr)
 {
    png_debug(1, "in png_set_swap_alpha\n");
@@ -117,16 +130,26 @@ png_set_swap_alpha(png_structp png_ptr)
 }
 #endif
 
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_invert_alpha(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_invert_alpha\n");
+   png_ptr->transformations |= PNG_INVERT_ALPHA;
+}
+#endif
+
 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
-void
+void PNGAPI
 png_set_invert_mono(png_structp png_ptr)
 {
    png_debug(1, "in png_set_invert_mono\n");
    png_ptr->transformations |= PNG_INVERT_MONO;
 }
 
-/* invert monocrome grayscale data */
-void
+/* invert monochrome grayscale data */
+void /* PRIVATE */
 png_do_invert(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_invert\n");
@@ -136,12 +159,14 @@ png_do_invert(png_row_infop row_info, png_bytep row)
 #endif
        row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
-      png_bytep rp;
+      png_bytep rp = row;
       png_uint_32 i;
+      png_uint_32 istop = row_info->rowbytes;
 
-      for (i = 0, rp = row; i < row_info->rowbytes; i++, rp++)
+      for (i = 0; i < istop; i++)
       {
          *rp = (png_byte)(~(*rp));
+         rp++;
       }
    }
 }
@@ -149,7 +174,7 @@ png_do_invert(png_row_infop row_info, png_bytep row)
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
 /* swaps byte order on 16 bit depth images */
-void
+void /* PRIVATE */
 png_do_swap(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_swap\n");
@@ -159,15 +184,13 @@ png_do_swap(png_row_infop row_info, png_bytep row)
 #endif
        row_info->bit_depth == 16)
    {
-      png_bytep rp;
-      png_byte t;
+      png_bytep rp = row;
       png_uint_32 i;
+      png_uint_32 istop= row_info->width * row_info->channels;
 
-      for (i = 0, rp = row;
-         i < row_info->width * row_info->channels;
-         i++, rp += 2)
+      for (i = 0; i < istop; i++, rp += 2)
       {
-         t = *rp;
+         png_byte t = *rp;
          *rp = *(rp + 1);
          *(rp + 1) = t;
       }
@@ -282,13 +305,13 @@ static png_byte fourbppswaptable[256] = {
 };
 
 /* swaps pixel packing order within bytes */
-void
+void /* PRIVATE */
 png_do_packswap(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_packswap\n");
    if (
 #if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL
+       row != NULL && row_info != NULL &&
 #endif
        row_info->bit_depth < 8)
    {
@@ -314,7 +337,7 @@ png_do_packswap(png_row_infop row_info, png_bytep row)
 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
 /* remove filler or alpha byte(s) */
-void
+void /* PRIVATE */
 png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
 {
    png_debug(1, "in png_do_strip_filler\n");
@@ -326,6 +349,11 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
       if (row_info->color_type == PNG_COLOR_TYPE_RGB ||
           row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
 */
+      png_bytep sp=row;
+      png_bytep dp=row;
+      png_uint_32 row_width=row_info->width;
+      png_uint_32 i;
+
       if (row_info->channels == 4)
       {
          if (row_info->bit_depth == 8)
@@ -333,10 +361,8 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             /* This converts from RGBX or RGBA to RGB */
             if (flags & PNG_FLAG_FILLER_AFTER)
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
-               for (i = 1, sp = row + 4, dp = row + 3; i < row_info->width; i++)
+               dp+=3; sp+=4;
+               for (i = 1; i < row_width; i++)
                {
                   *dp++ = *sp++;
                   *dp++ = *sp++;
@@ -347,10 +373,7 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             /* This converts from XRGB or ARGB to RGB */
             else
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
-               for (i = 0, sp = row, dp = row; i < row_info->width; i++)
+               for (i = 0; i < row_width; i++)
                {
                   sp++;
                   *dp++ = *sp++;
@@ -359,17 +382,15 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
                }
             }
             row_info->pixel_depth = 24;
-            row_info->rowbytes = row_info->width * 3;
+            row_info->rowbytes = row_width * 3;
          }
          else /* if (row_info->bit_depth == 16) */
          {
             if (flags & PNG_FLAG_FILLER_AFTER)
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
                /* This converts from RRGGBBXX or RRGGBBAA to RRGGBB */
-               for (i = 1, sp = row + 8, dp = row + 6; i < row_info->width; i++)
+               sp += 8; dp += 6;
+               for (i = 1; i < row_width; i++)
                {
                   /* This could be (although memcpy is probably slower):
                   png_memcpy(dp, sp, 6);
@@ -387,17 +408,15 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             }
             else
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
                /* This converts from XXRRGGBB or AARRGGBB to RRGGBB */
-               for (i = 0, sp = row + 2, dp = row; i < row_info->width; i++)
+               for (i = 0; i < row_width; i++)
                {
                   /* This could be (although memcpy is probably slower):
                   png_memcpy(dp, sp, 6);
                   sp += 8;
                   dp += 6;
                   */
+                  sp+=2;
                   *dp++ = *sp++;
                   *dp++ = *sp++;
                   *dp++ = *sp++;
@@ -407,9 +426,10 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
                }
             }
             row_info->pixel_depth = 48;
-            row_info->rowbytes = row_info->width * 6;
+            row_info->rowbytes = row_width * 6;
          }
          row_info->channels = 3;
+         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
       }
 /*
       else if (row_info->color_type == PNG_COLOR_TYPE_GRAY ||
@@ -422,10 +442,7 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             /* This converts from GX or GA to G */
             if (flags & PNG_FLAG_FILLER_AFTER)
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
-               for (i = 1, sp = row + 2, dp = row + 1; i < row_info->width; i++)
+               for (i = 0; i < row_width; i++)
                {
                   *dp++ = *sp++;
                   sp++;
@@ -434,27 +451,22 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             /* This converts from XG or AG to G */
             else
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
-               for (i = 0, sp = row, dp = row; i < row_info->width; i++)
+               for (i = 0; i < row_width; i++)
                {
                   sp++;
                   *dp++ = *sp++;
                }
             }
             row_info->pixel_depth = 8;
-            row_info->rowbytes = row_info->width;
+            row_info->rowbytes = row_width;
          }
          else /* if (row_info->bit_depth == 16) */
          {
             if (flags & PNG_FLAG_FILLER_AFTER)
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
                /* This converts from GGXX or GGAA to GG */
-               for (i = 1, sp = row + 4, dp = row + 2; i < row_info->width; i++)
+               sp += 4; dp += 2;
+               for (i = 1; i < row_width; i++)
                {
                   *dp++ = *sp++;
                   *dp++ = *sp++;
@@ -463,11 +475,8 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
             }
             else
             {
-               png_bytep sp, dp;
-               png_uint_32 i;
-
                /* This converts from XXGG or AAGG to GG */
-               for (i = 0, sp = row, dp = row; i < row_info->width; i++)
+               for (i = 0; i < row_width; i++)
                {
                   sp += 2;
                   *dp++ = *sp++;
@@ -475,9 +484,10 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
                }
             }
             row_info->pixel_depth = 16;
-            row_info->rowbytes = row_info->width * 2;
+            row_info->rowbytes = row_width * 2;
          }
          row_info->channels = 1;
+         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
       }
    }
 }
@@ -485,7 +495,7 @@ png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
 /* swaps red and blue bytes within a pixel */
-void
+void /* PRIVATE */
 png_do_bgr(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_bgr\n");
@@ -495,17 +505,17 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 #endif
        (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
+      png_uint_32 row_width = row_info->width;
       if (row_info->bit_depth == 8)
       {
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
          {
             png_bytep rp;
-            png_byte save;
             png_uint_32 i;
 
-            for (i = 0, rp = row; i < row_info->width; i++, rp += 3)
+            for (i = 0, rp = row; i < row_width; i++, rp += 3)
             {
-               save = *rp;
+               png_byte save = *rp;
                *rp = *(rp + 2);
                *(rp + 2) = save;
             }
@@ -513,12 +523,11 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
          {
             png_bytep rp;
-            png_byte save;
             png_uint_32 i;
 
-            for (i = 0, rp = row; i < row_info->width; i++, rp += 4)
+            for (i = 0, rp = row; i < row_width; i++, rp += 4)
             {
-               save = *rp;
+               png_byte save = *rp;
                *rp = *(rp + 2);
                *(rp + 2) = save;
             }
@@ -529,33 +538,31 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
          {
             png_bytep rp;
-            png_byte save[2];
             png_uint_32 i;
 
-            for (i = 0, rp = row; i < row_info->width; i++, rp += 6)
+            for (i = 0, rp = row; i < row_width; i++, rp += 6)
             {
-               save[0] = *rp;
-               save[1] = *(rp + 1);
+               png_byte save = *rp;
                *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
                *(rp + 1) = *(rp + 5);
-               *(rp + 4) = save[0];
-               *(rp + 5) = save[1];
+               *(rp + 5) = save;
             }
          }
          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
          {
             png_bytep rp;
-            png_byte save[2];
             png_uint_32 i;
 
-            for (i = 0, rp = row; i < row_info->width; i++, rp += 8)
+            for (i = 0, rp = row; i < row_width; i++, rp += 8)
             {
-               save[0] = *rp;
-               save[1] = *(rp + 1);
+               png_byte save = *rp;
                *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
                *(rp + 1) = *(rp + 5);
-               *(rp + 4) = save[0];
-               *(rp + 5) = save[1];
+               *(rp + 5) = save;
             }
          }
       }
@@ -563,3 +570,39 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
 }
 #endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
 
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+void PNGAPI
+png_set_user_transform_info(png_structp png_ptr, png_voidp
+   user_transform_ptr, int user_transform_depth, int user_transform_channels)
+{
+   png_debug(1, "in png_set_user_transform_info\n");
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   png_ptr->user_transform_ptr = user_transform_ptr;
+   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
+   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+#else
+   if(user_transform_ptr || user_transform_depth || user_transform_channels)
+      png_warning(png_ptr,
+        "This version of libpng does not support user transform info");
+#endif
+}
+#endif
+
+/* This function returns a pointer to the user_transform_ptr associated with
+ * the user transform functions.  The application should free any memory
+ * associated with this pointer before png_write_destroy and png_read_destroy
+ * are called.
+ */
+png_voidp PNGAPI
+png_get_user_transform_ptr(png_structp png_ptr)
+{
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   return ((png_voidp)png_ptr->user_transform_ptr);
+#else
+   if(png_ptr)
+     return (NULL);
+   return (NULL);
+#endif
+}

pngwio.c

@@ -1,18 +1,19 @@
 
 /* pngwio.c - functions for data output
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-
-   This file provides a location for all output.  Users which need
-   special handling are expected to write functions which have the same
-   arguments as these, and perform similar functions, but possibly use
-   different output methods.  Note that you shouldn't change these
-   functions, but rather write replacement functions and then change
-   them at run time with png_set_write_fn(...) */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ *
+ * This file provides a location for all output.  Users who need
+ * special handling are expected to write functions that have the same
+ * arguments as these and perform similar functions, but that possibly
+ * use different output methods.  Note that you shouldn't change these
+ * functions, but rather write replacement functions and then change
+ * them at run time with png_set_write_fn(...).
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
@@ -21,9 +22,9 @@
    writes to a file pointer.  Note that this routine sometimes gets called
    with very small lengths, so you should implement some kind of simple
    buffering if you are using unbuffered writes.  This should never be asked
-   to write more then 64K on a 16 bit machine.  */
+   to write more than 64K on a 16 bit machine.  */
 
-void
+void /* PRIVATE */
 png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    if (png_ptr->write_data_fn != NULL )
@@ -32,12 +33,13 @@ png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
       png_error(png_ptr, "Call to NULL write function");
 }
 
-/* This is the function which does the actual writing of data.  If you are
+#if !defined(PNG_NO_STDIO)
+/* This is the function that does the actual writing of data.  If you are
    not writing to a standard C stream, you should create a replacement
    write_data function and use it at run time with png_set_write_fn(), rather
    than changing the library. */
 #ifndef USE_FAR_KEYWORD
-static void
+static void /* PRIVATE */
 png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_uint_32 check;
@@ -57,7 +59,7 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 #define NEAR_BUF_SIZE 1024
 #define MIN(a,b) (a <= b ? a : b)
 
-static void
+static void /* PRIVATE */
 png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_uint_32 check;
@@ -97,20 +99,22 @@ png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
    }
 }
 
+#endif
 #endif
 
 /* This function is called to output any data pending writing (normally
    to disk).  After png_flush is called, there should be no data pending
    writing in any buffers. */
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
-void
+void /* PRIVATE */
 png_flush(png_structp png_ptr)
 {
    if (png_ptr->output_flush_fn != NULL)
       (*(png_ptr->output_flush_fn))(png_ptr);
 }
 
-static void
+#if !defined(PNG_NO_STDIO)
+static void /* PRIVATE */
 png_default_flush(png_structp png_ptr)
 {
    FILE *io_ptr;
@@ -119,6 +123,7 @@ png_default_flush(png_structp png_ptr)
       fflush(io_ptr);
 }
 #endif
+#endif
 
 /* This function allows the application to supply new output functions for
    libpng if standard C streams aren't being used.
@@ -127,13 +132,13 @@ png_default_flush(png_structp png_ptr)
    png_ptr       - pointer to a png output data structure
    io_ptr        - pointer to user supplied structure containing info about
                    the output functions.  May be NULL.
-   write_data_fn - pointer to a new output function which takes as its
+   write_data_fn - pointer to a new output function that takes as its
                    arguments a pointer to a png_struct, a pointer to
-                   data to be written, and a 32-bit unsigned int which is
+                   data to be written, and a 32-bit unsigned int that is
                    the number of bytes to be written.  The new write
                    function should call png_error(png_ptr, "Error msg")
                    to exit and output any fatal error messages.
-   flush_data_fn - pointer to a new flush function which takes as its
+   flush_data_fn - pointer to a new flush function that takes as its
                    arguments a pointer to a png_struct.  After a call to
                    the flush function, there should be no data in any buffers
                    or pending transmission.  If the output method doesn't do
@@ -142,33 +147,48 @@ png_default_flush(png_structp png_ptr)
                    PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
                    time, output_flush_fn will be ignored, although it must be
                    supplied for compatibility. */
-void
+void PNGAPI
 png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
 {
    png_ptr->io_ptr = io_ptr;
 
+#if !defined(PNG_NO_STDIO)
    if (write_data_fn != NULL)
       png_ptr->write_data_fn = write_data_fn;
    else
       png_ptr->write_data_fn = png_default_write_data;
+#else
+   png_ptr->write_data_fn = write_data_fn;
+#endif
 
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
+#if !defined(PNG_NO_STDIO)
    if (output_flush_fn != NULL)
       png_ptr->output_flush_fn = output_flush_fn;
    else
       png_ptr->output_flush_fn = png_default_flush;
+#else
+   png_ptr->output_flush_fn = output_flush_fn;
+#endif
 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
 
    /* It is an error to read while writing a png file */
-   png_ptr->read_data_fn = NULL;
+   if (png_ptr->read_data_fn != NULL)
+   {
+      png_ptr->read_data_fn = NULL;
+      png_warning(png_ptr,
+         "Attempted to set both read_data_fn and write_data_fn in");
+      png_warning(png_ptr,
+         "the same structure.  Resetting read_data_fn to NULL.");
+   }
 }
 
-#if defined(USE_FAR_KEYWORD) 
-#if defined(_MSC_VER)   
-void *far_to_near(png_structp png_ptr,png_voidp ptr, int check)
+#if defined(USE_FAR_KEYWORD)
+#if defined(_MSC_VER)
+void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
 {
-   void *near_ptr;   
+   void *near_ptr;
    void FAR *far_ptr;
    FP_OFF(near_ptr) = FP_OFF(ptr);
    far_ptr = (void FAR *)near_ptr;
@@ -178,9 +198,9 @@ void *far_to_near(png_structp png_ptr,png_voidp ptr, int check)
    return(near_ptr);
 }
 #  else
-void *far_to_near(png_structp png_ptr,png_voidp ptr, int check)
+void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
 {
-   void *near_ptr;   
+   void *near_ptr;
    void FAR *far_ptr;
    near_ptr = (void FAR *)ptr;
    far_ptr = (void FAR *)near_ptr;

pngwtran.c

@@ -1,40 +1,67 @@
 
 /* pngwtran.c - transforms the data in a row for PNG writers
-
-   libpng 1.0 beta 6 - version 0.96
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   Copyright (c) 1996, 1997 Andreas Dilger
-   May 12, 1997
-   */
+ *
+ * libpng 1.0.7beta12 - May 12, 2000
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
+ */
 
 #define PNG_INTERNAL
 #include "png.h"
 
-/* transform the data according to the users wishes.  The order of
-   transformations is significant. */
-void
+/* Transform the data according to the user's wishes.  The order of
+ * transformations is significant.
+ */
+void /* PRIVATE */
 png_do_write_transformations(png_structp png_ptr)
 {
    png_debug(1, "in png_do_write_transformations\n");
+
+   if (png_ptr == NULL)
+      return;
+
+#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+      if(png_ptr->write_user_transform_fn != NULL)
+        (*(png_ptr->write_user_transform_fn)) /* user write transform function */
+          (png_ptr,                    /* png_ptr */
+           &(png_ptr->row_info),       /* row_info:     */
+             /*  png_uint_32 width;          width of row */
+             /*  png_uint_32 rowbytes;       number of bytes in row */
+             /*  png_byte color_type;        color type of pixels */
+             /*  png_byte bit_depth;         bit depth of samples */
+             /*  png_byte channels;          number of channels (1-4) */
+             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
+           png_ptr->row_buf + 1);      /* start of pixel data for row */
+#endif
 #if defined(PNG_WRITE_FILLER_SUPPORTED)
    if (png_ptr->transformations & PNG_FILLER)
       png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
          png_ptr->flags);
 #endif
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
 #if defined(PNG_WRITE_PACK_SUPPORTED)
    if (png_ptr->transformations & PNG_PACK)
       png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->bit_depth);
 #endif
+#if defined(PNG_WRITE_SWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
    if (png_ptr->transformations & PNG_SHIFT)
       png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif
-#if defined(PNG_WRITE_SWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+      png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
    if (png_ptr->transformations & PNG_SWAP_ALPHA)
@@ -51,10 +78,11 @@ png_do_write_transformations(png_structp png_ptr)
 }
 
 #if defined(PNG_WRITE_PACK_SUPPORTED)
-/* pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
-   row_info bit depth should be 8 (one pixel per byte).  The channels
-   should be 1 (this only happens on grayscale and paletted images) */
-void
+/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
+ * row_info bit depth should be 8 (one pixel per byte).  The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+void /* PRIVATE */
 png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
 {
    png_debug(1, "in png_do_pack\n");
@@ -71,12 +99,14 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
             png_bytep sp, dp;
             int mask, v;
             png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
 
             sp = row;
             dp = row;
             mask = 0x80;
             v = 0;
-            for (i = 0; i < row_info->width; i++)
+
+            for (i = 0; i < row_width; i++)
             {
                if (*sp != 0)
                   v |= mask;
@@ -100,16 +130,17 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
             png_bytep sp, dp;
             int shift, v;
             png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
 
             sp = row;
             dp = row;
             shift = 6;
             v = 0;
-            for (i = 0; i < row_info->width; i++)
+            for (i = 0; i < row_width; i++)
             {
                png_byte value;
 
-               value = (png_byte)(*sp & 0x3);
+               value = (png_byte)(*sp & 0x03);
                v |= (value << shift);
                if (shift == 0)
                {
@@ -131,16 +162,17 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
             png_bytep sp, dp;
             int shift, v;
             png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
 
             sp = row;
             dp = row;
             shift = 4;
             v = 0;
-            for (i = 0; i < row_info->width; i++)
+            for (i = 0; i < row_width; i++)
             {
                png_byte value;
 
-               value = (png_byte)(*sp & 0xf);
+               value = (png_byte)(*sp & 0x0f);
                v |= (value << shift);
 
                if (shift == 0)
@@ -169,13 +201,14 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
 #endif
 
 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
-/* shift pixel values to take advantage of whole range.  Pass the
-   true number of bits in bit_depth.  The row should be packed
-   according to row_info->bit_depth.  Thus, if you had a row of
-   bit depth 4, but the pixels only had values from 0 to 7, you
-   would pass 3 as bit_depth, and this routine would translate the
-   data to 0 to 15. */
-void
+/* Shift pixel values to take advantage of whole range.  Pass the
+ * true number of bits in bit_depth.  The row should be packed
+ * according to row_info->bit_depth.  Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+void /* PRIVATE */
 png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
 {
    png_debug(1, "in png_do_shift\n");
@@ -187,9 +220,8 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
       row_info->color_type != PNG_COLOR_TYPE_PALETTE)
    {
       int shift_start[4], shift_dec[4];
-      png_uint_32 channels;
+      int channels = 0;
 
-      channels = 0;
       if (row_info->color_type & PNG_COLOR_MASK_COLOR)
       {
          shift_start[channels] = row_info->bit_depth - bit_depth->red;
@@ -215,12 +247,13 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
          channels++;
       }
 
-      /* with low row dephts, could only be grayscale, so one channel */
+      /* with low row depths, could only be grayscale, so one channel */
       if (row_info->bit_depth < 8)
       {
-         png_bytep bp;
+         png_bytep bp = row;
          png_uint_32 i;
          png_byte mask;
+         png_uint_32 row_bytes = row_info->rowbytes;
 
          if (bit_depth->gray == 1 && row_info->bit_depth == 2)
             mask = 0x55;
@@ -229,7 +262,7 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
          else
             mask = 0xff;
 
-         for (bp = row, i = 0; i < row_info->rowbytes; i++, bp++)
+         for (i = 0; i < row_bytes; i++, bp++)
          {
             png_uint_16 v;
             int j;
@@ -247,27 +280,25 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
       }
       else if (row_info->bit_depth == 8)
       {
-         png_bytep bp;
+         png_bytep bp = row;
          png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
 
-         for (bp = row, i = 0; i < row_info->width; i++)
+         for (i = 0; i < istop; i++, bp++)
          {
-            int c;
 
-            for (c = 0; c < channels; c++, bp++)
+            png_uint_16 v;
+            int j;
+            int c = (int)(i%channels);
+
+            v = *bp;
+            *bp = 0;
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
             {
-               png_uint_16 v;
-               int j;
-
-               v = *bp;
-               *bp = 0;
-               for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
-               {
-                  if (j > 0)
-                     *bp |= (png_byte)((v << j) & 0xff);
-                  else
-                     *bp |= (png_byte)((v >> (-j)) & 0xff);
-               }
+               if (j > 0)
+                  *bp |= (png_byte)((v << j) & 0xff);
+               else
+                  *bp |= (png_byte)((v >> (-j)) & 0xff);
             }
          }
       }
@@ -275,28 +306,25 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
       {
          png_bytep bp;
          png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
 
-         for (bp = row, i = 0; i < row_info->width * row_info->channels; i++)
+         for (bp = row, i = 0; i < istop; i++)
          {
-            int c;
+            int c = (int)(i%channels);
+            png_uint_16 value, v;
+            int j;
 
-            for (c = 0; c < channels; c++, bp += 2)
+            v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
+            value = 0;
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
             {
-               png_uint_16 value, v;
-               int j;
-
-               v = ((png_uint_16)(*bp) << 8) + *(bp + 1);
-               value = 0;
-               for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
-               {
-                  if (j > 0)
-                     value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
-                  else
-                     value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
-               }
-               *bp = (png_byte)(value >> 8);
-               *(bp + 1) = (png_byte)(value & 0xff);
+               if (j > 0)
+                  value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
+               else
+                  value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
             }
+            *bp++ = (png_byte)(value >> 8);
+            *bp++ = (png_byte)(value & 0xff);
          }
       }
    }
@@ -304,7 +332,7 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
 #endif
 
 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
-void
+void /* PRIVATE */
 png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_write_swap_alpha\n");
@@ -318,12 +346,11 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
          if (row_info->bit_depth == 8)
          {
             png_bytep sp, dp;
-            png_byte save;
             png_uint_32 i;
-
-            for (i = 0, sp = dp = row; i < row_info->width; i++)
+            png_uint_32 row_width = row_info->width;
+            for (i = 0, sp = dp = row; i < row_width; i++)
             {
-               save = *(sp++);
+               png_byte save = *(sp++);
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
@@ -334,11 +361,12 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
          else
          {
             png_bytep sp, dp;
-            png_byte save[2];
             png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
 
-            for (i = 0, sp = dp = row; i < row_info->width; i++)
+            for (i = 0, sp = dp = row; i < row_width; i++)
             {
+               png_byte save[2];
                save[0] = *(sp++);
                save[1] = *(sp++);
                *(dp++) = *(sp++);
@@ -358,12 +386,12 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
          if (row_info->bit_depth == 8)
          {
             png_bytep sp, dp;
-            png_byte save;
             png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
 
-            for (i = 0, sp = dp = row; i < row_info->width; i++)
+            for (i = 0, sp = dp = row; i < row_width; i++)
             {
-               save = *(sp++);
+               png_byte save = *(sp++);
                *(dp++) = *(sp++);
                *(dp++) = save;
             }
@@ -372,11 +400,12 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
          else
          {
             png_bytep sp, dp;
-            png_byte save[2];
             png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
 
-            for (i = 0, sp = dp = row; i < row_info->width; i++)
+            for (i = 0, sp = dp = row; i < row_width; i++)
             {
+               png_byte save[2];
                save[0] = *(sp++);
                save[1] = *(sp++);
                *(dp++) = *(sp++);
@@ -390,3 +419,82 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
 }
 #endif
 
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_invert_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         /* This inverts the alpha channel in RGBA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+         /* This inverts the alpha channel in RRGGBBAA */
+         else
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         /* This inverts the alpha channel in GA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+         /* This inverts the alpha channel in GGAA */
+         else
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+      }
+   }
+}
+#endif

scripts/SCOPTIONS.ppc

@@ -0,0 +1,7 @@
+OPTIMIZE
+OPTPEEP
+OPTTIME
+OPTSCHED
+AUTOREGISTER
+PARMS=REGISTERS
+INCLUDEDIR=hlp:ppc/include

scripts/libpng.icc

@@ -0,0 +1,43 @@
+// Project file for libpng (static)
+// IBM VisualAge/C++ version 4.0 or later
+// Copyright (C) 2000 Cosmin Truta
+// Notes:
+//   All modules are compiled in C mode
+//   Tested with IBM VAC++ 4.0 under Win32
+//   Expected to work with IBM VAC++ 4.0 or later under OS/2 and Win32
+//   Can be easily adapted for IBM VAC++ 4.0 or later under AIX
+// For conditions of distribution and use, see copyright notice in png.h
+
+option incl(searchpath, "../zlib"), opt(level, "2"),
+ link(libsearchpath, "../zlib")
+{
+   target type(lib) "libpng.lib"
+   {
+      source type(c) "png.c"
+      source type(c) "pngerror.c"
+      source type(c) "pngget.c"
+      source type(c) "pngmem.c"
+      source type(c) "pngpread.c"
+      source type(c) "pngread.c"
+      source type(c) "pngrio.c"
+      source type(c) "pngrtran.c"
+      source type(c) "pngrutil.c"
+      source type(c) "pngset.c"
+      source type(c) "pngtrans.c"
+      source type(c) "pngwio.c"
+      source type(c) "pngwrite.c"
+      source type(c) "pngwtran.c"
+      source type(c) "pngwutil.c"
+   }
+}
+
+option incl(searchpath, "../zlib"), opt(level, "2"),
+ link(libsearchpath, "../zlib")
+{
+   target type(exe) "pngtest.exe"
+   {
+      source type(c) "pngtest.c"
+      source type(lib) "libpng.lib"
+      source type(lib) "zlib.lib"
+   }
+}

scripts/makefile.acorn

@@ -0,0 +1,51 @@
+# Project:   libpng
+
+
+# Toolflags:
+CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah 
+C++flags = -c -depend !Depend -IC: -throwback
+Linkflags = -aif -c++ -o $@
+ObjAsmflags = -throwback -NoCache -depend !Depend
+CMHGflags = 
+LibFileflags = -c -l -o $@ 
+Squeezeflags = -o $@
+
+
+# Final targets:
+@.libpng-lib:   @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
+	@.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngrtran \
+	@.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil 
+	LibFile $(LibFileflags) @.o.png @.o.pngerror @.o.pngrio @.o.pngrtran \
+	@.o.pngmem @.o.pngpread @.o.pngset @.o.pngget @.o.pngread @.o.pngwio \
+	@.o.pngrutil @.o.pngtrans  @.o.pngwrite @.o.pngwtran @.o.pngwutil 
+@.mm-libpng-lib:   @.mm.png @.mm.pngerror @.mm.pngrio @.mm.pngwio @.mm.pngmem \
+	@.mm.pngpread @.mm.pngset @.mm.pngget @.mm.pngread @.mm.pngrtran \
+	@.mm.pngrutil @.mm.pngtrans @.mm.pngwrite @.mm.pngwtran @.mm.pngwutil 
+	LibFile $(LibFileflags) @.mm.png @.mm.pngerror @.mm.pngrio \
+	@.mm.pngwio @.mm.pngmem @.mm.pngpread @.mm.pngset @.mm.pngget \
+	@.mm.pngread @.mm.pngrtran @.mm.pngrutil @.mm.pngtrans @.mm.pngwrite \
+	@.mm.pngwtran @.mm.pngwutil 
+
+
+# User-editable dependencies:
+# (C) Copyright 1997 Tom Tanner
+Test: @.pngtest 
+	<Prefix$Dir>.pngtest
+	@remove <Prefix$Dir>.pngtest
+
+#It would be nice if you could stop "make" listing from here on!
+@.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib 
+	Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib 
+
+.SUFFIXES: .o .mm .c
+
+.c.mm:
+	MemCheck.CC cc $(ccflags) -o $@ LibPng:$<
+.c.o:
+	cc $(ccflags) -o $@ $<
+
+
+# Static dependencies:
+
+
+# Dynamic dependencies:

scripts/makefile.amiga

@@ -8,7 +8,7 @@ CC=sc
 # WARNING: a bug in V6.51 causes bad code with OPTGO
 #          So use V6.55 or set NOOPTGO!!!!!!!!!
 CFLAGS= NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
-        OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 DEFINE=PNG_INTERNAL
+	OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 DEFINE=PNG_INTERNAL
 #linker flags
 LDFLAGS= SD ND BATCH
 #link libs

scripts/makefile.atari

@@ -9,6 +9,7 @@ LBR = png.lib
 LDFLAGS=-lpng -lz -lm
 
 # where make install puts libpng.a and png.h
+prefix=/usr/local
 
 OBJS = $(LBR)(png.o) $(LBR)(pngset.o) $(LBR)(pngget.o) $(LBR)(pngrutil.o)\
 	$(LBR)(pngtrans.o) $(LBR)(pngwutil.o)\
@@ -28,4 +29,5 @@ install: libpng.a
 	-@mkdir $(prefix)/lib
 	cp png.h $(prefix)/include
 	cp pngconf.h $(prefix)/include
-	chmod 644 $(prefix)/include/p
+	chmod 644 $(prefix)/include/png.h
+	chmod 644 $(prefix)/include/pngconf.h

scripts/makefile.bc32

@@ -0,0 +1,151 @@
+# Makefile for libpng
+# 32-bit Borland C++ (Note: All modules are compiled in C mode)
+# To build the library, do:
+#       "make -fmakefile.bc32"
+#
+# ---------- 32-bit Borland C++ ----------
+
+### Absolutely necessary for this makefile to work
+.AUTODEPEND
+
+## Where zlib.h, zconf.h and zlib.lib are
+ZLIB_DIR=..\zlib
+
+
+## Compiler, linker and lib stuff
+CC=bcc32
+LD=bcc32
+LIB=tlib
+
+#TARGET_CPU=6
+# 3 = 386, 4 = 486, 5 = Pentium etc.
+!ifndef TARGET_CPU
+TARGET_CPU=5
+!endif
+
+# Use this if you don't want Borland's fancy exception handling
+NOEHLIB=noeh32.lib
+
+!ifdef DEBUG
+CDEBUG=-v
+LDEBUG=-v
+!else
+CDEBUG=
+LDEBUG=
+!endif
+
+# STACKOFLOW=1
+!ifdef STACKOFLOW
+CDEBUG=$(CDEBUG) -N
+LDEBUG=$(LDEBUG) -N
+!endif
+
+# -X- turn on dependency generation in the object file
+# -w  set all warnings on
+# -O2 optimize for speed
+# -Z  global optimization
+CFLAGS=-O2 -Z -X- -w -I$(ZLIB_DIR) -$(TARGET_CPU) $(CDEBUG)
+
+# -M  generate map file
+LDFLAGS=-M -L$(ZLIB_DIR) $(LDEBUG)
+
+
+## Variables
+OBJS = \
+	png.obj \
+	pngerror.obj \
+	pngget.obj \
+	pngmem.obj \
+	pngpread.obj \
+	pngread.obj \
+	pngrio.obj \
+	pngrtran.obj \
+	pngrutil.obj \
+	pngset.obj \
+	pngtrans.obj \
+	pngwio.obj \
+	pngwrite.obj \
+	pngwtran.obj \
+	pngwutil.obj
+
+LIBOBJS = \
+	+png.obj \
+	+pngerror.obj \
+	+pngget.obj \
+	+pngmem.obj \
+	+pngpread.obj \
+	+pngread.obj \
+	+pngrio.obj \
+	+pngrtran.obj \
+	+pngrutil.obj \
+	+pngset.obj \
+	+pngtrans.obj \
+	+pngwio.obj \
+	+pngwrite.obj \
+	+pngwtran.obj \
+	+pngwutil.obj
+
+LIBNAME=libpng.lib
+
+
+## Implicit rules
+# Braces let make "batch" calls to the compiler,
+# 2 calls instead of 12; space is important.
+.c.obj:
+	$(CC) $(CFLAGS) -c {$*.c }
+
+.c.exe:
+	$(CC) $(CFLAGS) $(LDFLAGS) $*.c $(LIBNAME) zlib.lib $(NOEHLIB)
+
+.obj.exe:
+	$(LD) $(LDFLAGS) $*.obj $(LIBNAME) zlib.lib $(NOEHLIB)
+
+
+## Major targets
+all: libpng pngtest
+
+libpng: $(LIBNAME)
+
+pngtest: pngtest.exe
+
+test: pngtest.exe
+	pngtest
+
+
+## Minor Targets
+
+png.obj: png.c
+pngerror.obj: pngerror.c
+pngget.obj: pngget.c
+pngmem.obj: pngmem.c
+pngpread.obj: pngpread.c
+pngread.obj: pngread.c
+pngrio.obj: pngrio.c
+pngrtran.obj: pngrtran.c
+pngrutil.obj: pngrutil.c
+pngset.obj: pngset.c
+pngtrans.obj: pngtrans.c
+pngwio.obj: pngwio.c
+pngwrite.obj: pngwrite.c
+pngwtran.obj: pngwtran.c
+pngwutil.obj: pngwutil.c
+
+
+$(LIBNAME): $(OBJS)
+	-del $(LIBNAME)
+	$(LIB) $(LIBNAME) @&&|
+$(LIBOBJS), libpng
+|
+
+
+# Clean up anything else you want
+clean:
+	-del *.obj
+	-del *.exe
+	-del *.lib
+	-del *.lst
+	-del *.map
+	-del *.tds
+
+
+# End of makefile for libpng

scripts/makefile.bd32

@@ -0,0 +1,76 @@
+# Makefile for png32bd.dll
+# ------------- 32-bit Borland C++ -------------
+
+# This makefile expects to find zlib.h and zlib32bd.lib in the
+# $(ZLIBDIR) directory.
+
+# The object files here are compiled with the "stdcall" calling convention.
+# This DLL requires zlib32bd.lib to be compiled in the same way.
+
+# Note that png32bd.dll exports the zlib functions adler32, crc32 and
+# the deflate... and inflate... functions. It does not export the
+# compress and uncompress functions, nor any of the gz... functions,
+# since libpng does not call them.
+
+.AUTODEPEND
+
+ZLIBDIR=..\zlib
+ZLIB=zlib32bd.lib
+PNGDLL=png32bd.dll
+PNGLIB=png32bd.lib
+
+CC=bcc32
+CFLAGS= -ps -O2 -N- -k- -d -r- -w-par -w-aus -I$(ZLIBDIR) \
+  -DPNG_NO_GLOBAL_ARRAYS #-DPNG_DEBUG=5
+#LINK=tlink32
+#LINK=ilink32
+LINK=bcc32
+#LINKFLAGS= -Tpd -aa -c
+LINKFLAGS= -WDE
+IMPLIB=implib
+
+# Use this if you don't want Borland's fancy exception handling
+NOEHLIB=noeh32.lib
+
+.c.obj:
+	$(CC) -c $(CFLAGS) $<
+
+.c.exe:
+	$(CC) $(CFLAGS) $< $(PNGLIB) $(NOEHLIB)
+
+
+OBJ1=png.obj pngerror.obj pngget.obj pngmem.obj pngpread.obj
+OBJ2=pngread.obj pngrio.obj pngrtran.obj pngrutil.obj pngset.obj
+OBJ3=pngtrans.obj pngwio.obj pngwrite.obj pngwtran.obj pngwutil.obj
+
+all: $(PNGDLL)
+
+test: pngtest.exe
+	pngtest
+
+
+$(PNGDLL): $(OBJ1) $(OBJ2) $(OBJ3) $(ZLIBDIR)\$(ZLIB)
+	$(LINK) @&&|
+$(LINKFLAGS)
+-e$(PNGDLL)
+$(OBJ1)
+$(OBJ2)
+$(OBJ3)
+$(ZLIBDIR)\$(ZLIB)
+$(NOEHLIB)
+|
+	$(IMPLIB) -c $(@R).lib $@
+
+
+# Clean up anything else you want
+clean:
+	-del *.obj
+	-del *.dll
+	-del *.exe
+	-del *.lib
+	-del *.lst
+	-del *.map
+	-del *.tds
+
+
+# End of makefile for png32bd.dll

scripts/makefile.beos

@@ -0,0 +1,104 @@
+# makefile for libpng on BeOS x86 ELF with gcc
+# modified from makefile.linux by Sander Stoks
+# Copyright (C) 1996, 1997 Andreas Dilger
+# Copyright (C) 1999 Greg Roelofs
+# For conditions of distribution and use, see copyright notice in png.h
+
+CC=gcc
+
+# Where the zlib library and include files are located
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+ALIGN=
+# For i386:
+# ALIGN=-malign-loops=2 -malign-functions=2
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes #-Wconversion
+
+# On BeOS, -O1 is actually better than -O3.  This is a known bug but it's
+# still here in R4.5
+CFLAGS=-I$(ZLIBINC) -Wall -O1 -funroll-loops \
+	$(ALIGN) # $(WARNMORE) -g -DPNG_DEBUG=5
+# LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz -lm
+LDFLAGS=-L. -Wl,-soname=libpng.so.$(PNGMAJ) -L$(ZLIBLIB) -lz -lm
+
+RANLIB=ranlib
+#RANLIB=echo
+
+# read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
+# have to change it.
+PNGMAJ = 2
+PNGMIN = 1.0.7beta12
+PNGVER = $(PNGMAJ).$(PNGMIN)
+
+# where make install puts libpng.a, libpng.so*, and png.h
+prefix=/usr/local
+INCPATH=$(prefix)/include
+LIBPATH=$(prefix)/lib
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+OBJSDLL = $(OBJS)
+
+.SUFFIXES:      .c .o
+
+all: libpng.a libpng.so pngtest
+
+libpng.a: $(OBJS)
+	ar rc $@ $(OBJS)
+	$(RANLIB) $@
+
+libpng.so: libpng.so.$(PNGMAJ)
+	ln -sf libpng.so.$(PNGMAJ) libpng.so
+	cp libpng.so* /boot/home/config/lib
+
+libpng.so.$(PNGMAJ): libpng.so.$(PNGVER)
+	ln -sf libpng.so.$(PNGVER) libpng.so.$(PNGMAJ)
+
+libpng.so.$(PNGVER): $(OBJSDLL)
+	$(CC) -L$(ZLIBLIB) -lz -nostart -Wl,-soname,libpng.so.$(PNGMAJ) -o
+libpng.so.$(PNGVER) \
+	 $(OBJSDLL)
+
+pngtest: pngtest.o libpng.so
+	$(CC) -L$(ZLIBLIB) -lz -lpng -o pngtest pngtest.o
+
+test: pngtest
+	./pngtest
+
+install: libpng.a libpng.so.$(PNGVER)
+	-@mkdir $(INCPATH) $(LIBPATH)
+	cp png.h pngconf.h $(INCPATH)
+	chmod 644 $(INCPATH)/png.h $(INCPATH)/pngconf.h
+	cp libpng.a libpng.so.$(PNGVER) $(LIBPATH)
+	chmod 755 $(LIBPATH)/libpng.so.$(PNGVER)
+	-@/bin/rm -f $(LIBPATH)/libpng.so.$(PNGMAJ) $(LIBPATH)/libpng.so
+	(cd $(LIBPATH); ln -sf libpng.so.$(PNGVER) libpng.so.$(PNGMAJ); \
+	 ln -sf libpng.so.$(PNGMAJ) libpng.so)
+
+clean:
+	/bin/rm -f *.o libpng.a libpng.so* pngtest pngout.png
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o png.pic.o: png.h pngconf.h
+pngerror.o pngerror.pic.o: png.h pngconf.h
+pngrio.o pngrio.pic.o: png.h pngconf.h
+pngwio.o pngwio.pic.o: png.h pngconf.h
+pngmem.o pngmem.pic.o: png.h pngconf.h
+pngset.o pngset.pic.o: png.h pngconf.h
+pngget.o pngget.pic.o: png.h pngconf.h
+pngread.o pngread.pic.o: png.h pngconf.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h
+pngpread.o pngpread.pic.o: png.h pngconf.h
+pngtest.o: png.h pngconf.h

scripts/makefile.bor

@@ -1,39 +1,38 @@
 # Makefile for libpng
-# Borland C++ 4.5 (Note: All modules are compiled in C mode)
-# Will work with C++ 4.02 also
-# To build the library, do: 
-#       "make -fmakefile.bor -DMODEL=m"
+# 16-bit Borland C++ (Note: All modules are compiled in C mode)
+# To build the library, do:
+#       "make -fmakefile.bor -DMODEL=c"
 # or:   "make -fmakefile.bor -DMODEL=l"
 #
-# ------------- Borland C++ 4.5 -------------
+# ------------ Borland C++ ------------
 
 ### Absolutely necessary for this makefile to work
 .AUTODEPEND
 
-## Useful user options
+## Where zlib.h, zconf.h and zlib_MODEL.lib are
+ZLIB_DIR=..\zlib
 
-# Usually defined in builtins.mak or the environment
-# Currently unused.
-!ifndef BCROOT
-BCROOT=N:\BC45
-!endif
 
-# Where zlib.h and zconf.h and zlib.lib are
-ZLIB_PATH=..\zlib
+## Compiler, linker and lib stuff
+CC=bcc
+LD=bcc
+LIB=tlib
 
 !ifndef MODEL
 MODEL=l
 !endif
 
+MODEL_ARG=-m$(MODEL)
+
 #TARGET_CPU=3
 # 2 = 286, 3 = 386, etc.
 !ifndef TARGET_CPU
 TARGET_CPU=2
 !endif
 
-
-# Use this if you don't want Borland's fancy exception handling.
-NOEHLIB=noeh$(MODEL).lib
+# Use this if you don't want Borland's fancy exception handling
+# (for Borland C++ 4.0 or later)
+#NOEHLIB=noeh$(MODEL).lib
 
 !ifdef DEBUG
 CDEBUG=-v
@@ -49,59 +48,50 @@ CDEBUG=$(CDEBUG) -N
 LDEBUG=$(LDEBUG) -N
 !endif
 
-
-## Compiler, linker, and lib stuff
-CC=bcc
-LD=bcc
-LIB=tlib
-
-MODELARG=-m$(MODEL)
-
-# -X- turns on dependency generation in the object file
-# -w  sets all warnings on
+# -X- turn on dependency generation in the object file
+# -w  set all warnings on
 # -O2 optimize for speed
 # -Z  global optimization
-CFLAGS=-O2 -Z -X- -w -I$(ZLIB_PATH) -$(TARGET_CPU) $(MODELARG) $(CDEBUG)
+CFLAGS=-O2 -Z -X- -w -I$(ZLIB_DIR) -$(TARGET_CPU) $(MODEL_ARG) $(CDEBUG)
 
 # -M  generate map file
-LDFLAGS=-M $(LDEBUG)
+LDFLAGS=-M -L$(ZLIB_DIR) $(MODEL_ARG) $(LDEBUG)
 
-O=obj
 
-## variables
+## Variables
 OBJS = \
- png.$(O) \
- pngerror.$(O) \
- pngmem.$(O) \
- pngpread.$(O) \
- pngset.$(O) \
- pngget.$(O) \
- pngread.$(O) \
- pngrio.$(O) \
- pngrtran.$(O) \
- pngrutil.$(O) \
- pngtrans.$(O) \
- pngwrite.$(O) \
- pngwtran.$(O) \
- pngwio.$(O) \
- pngwutil.$(O)
+	png.obj \
+	pngerror.obj \
+	pngget.obj \
+	pngmem.obj \
+	pngpread.obj \
+	pngread.obj \
+	pngrio.obj \
+	pngrtran.obj \
+	pngrutil.obj \
+	pngset.obj \
+	pngtrans.obj \
+	pngwio.obj \
+	pngwrite.obj \
+	pngwtran.obj \
+	pngwutil.obj
 
 LIBOBJS = \
- +png.$(O) \
- +pngerror.$(O) \
- +pngmem.$(O) \
- +pngpread.$(O) \
- +pngread.$(O) \
- +pngset.$(O) \
- +pngget.$(O) \
- +pngrio.$(O) \
- +pngrtran.$(O) \
- +pngrutil.$(O) \
- +pngtrans.$(O) \
- +pngwrite.$(O) \
- +pngwtran.$(O) \
- +pngwio.$(O)
- +pngwutil.$(O)
+	+png.obj \
+	+pngerror.obj \
+	+pngget.obj \
+	+pngmem.obj \
+	+pngpread.obj \
+	+pngread.obj \
+	+pngrio.obj \
+	+pngrtran.obj \
+	+pngrutil.obj \
+	+pngset.obj \
+	+pngtrans.obj \
+	+pngwio.obj \
+	+pngwrite.obj \
+	+pngwtran.obj \
+	+pngwutil.obj
 
 LIBNAME=libpng$(MODEL).lib
 
@@ -113,32 +103,34 @@ LIBNAME=libpng$(MODEL).lib
 	$(CC) $(CFLAGS) -c {$*.c }
 
 .c.exe:
-	$(CC) $(CFLAGS) $(LDFLAGS) $*.c
+	$(CC) $(CFLAGS) $(LDFLAGS) $*.c $(LIBNAME) zlib_$(MODEL).lib $(NOEHLIB)
 
 
 ## Major targets
+all: libpng pngtest
+
 libpng: $(LIBNAME)
 
 pngtest: pngtest$(MODEL).exe
 
-test:
+test: pngtest$(MODEL).exe
 	pngtest$(MODEL)
 
 
 ## Minor Targets
 
 png.obj: png.c
-pngset.obj: pngset.c
+pngerror.obj: pngerror.c
 pngget.obj: pngget.c
-pngread.obj: pngread.c
+pngmem.obj: pngmem.c
 pngpread.obj: pngpread.c
+pngread.obj: pngread.c
+pngrio.obj: pngrio.c
 pngrtran.obj: pngrtran.c
 pngrutil.obj: pngrutil.c
-pngerror.obj: pngerror.c
-pngmem.obj: pngmem.c
-pngrio.obj: pngrio.c
-pngwio.obj: pngwio.c
+pngset.obj: pngset.c
 pngtrans.obj: pngtrans.c
+pngwio.obj: pngwio.c
 pngwrite.obj: pngwrite.c
 pngwtran.obj: pngwtran.c
 pngwutil.obj: pngwutil.c
@@ -146,7 +138,7 @@ pngwutil.obj: pngwutil.c
 
 $(LIBNAME): $(OBJS)
 	-del $(LIBNAME)
-        $(LIB) $(LIBNAME) @&&|
+	$(LIB) $(LIBNAME) @&&|
 $(LIBOBJS), libpng$(MODEL)
 |
 
@@ -155,14 +147,16 @@ pngtest$(MODEL).obj: pngtest.c
 	$(CC) $(CFLAGS) -opngtest$(MODEL) -c pngtest.c
 
 pngtest$(MODEL).exe: pngtest$(MODEL).obj
-	$(CC) $(MODELARG) $(LDFLAGS) -L$(ZLIB_PATH) pngtest$(MODEL).obj $(LIBNAME) zlib$(MODEL).lib $(NOEHLIB)
+	$(LD) $(LDFLAGS) pngtest$(MODEL).obj $(LIBNAME) zlib_$(MODEL).lib $(NOEHLIB)
 
 
 # Clean up anything else you want
 clean:
 	-del *.obj
+	-del *.exe
 	-del *.lib
 	-del *.lst
+	-del *.map
 
 
 # End of makefile for libpng

scripts/makefile.dec

@@ -0,0 +1,89 @@
+# makefile for libpng on DEC Alpha Unix
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# For conditions of distribution and use, see copyright notice in png.h
+
+# where make install puts libpng.a and png.h
+prefix=/usr/local
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+# read libpng.txt or png.h to see why PNGMAJ is 2.  You should not
+# have to change it.
+PNGMAJ = 2
+PNGMIN = 1.0.7beta12
+PNGVER = $(PNGMAJ).$(PNGMIN)
+
+CC=cc
+CFLAGS=-std -w1 -I$(ZLIBINC) -O # -g -DPNG_DEBUG=1
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+#RANLIB=echo
+RANLIB=ranlib
+
+
+OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
+	pngwtran.o pngmem.o pngerror.o pngpread.o
+
+all: libpng.so libpng.a pngtest
+
+libpng.a: $(OBJS)
+	ar rc $@  $(OBJS)
+	$(RANLIB) $@
+
+libpng.so: libpng.so.$(PNGMAJ)
+	ln -f -s libpng.so.$(PNGMAJ) libpng.so
+
+libpng.so.$(PNGMAJ): libpng.so.$(PNGVER)
+	ln -f -s libpng.so.$(PNGVER) libpng.so.$(PNGMAJ)
+
+libpng.so.$(PNGVER): $(OBJS)
+	$(CC) -shared -o $@ $(OBJS) -L$(ZLIBLIB) -lz -lm
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install: libpng.a libpng.so.$(PNGVER)
+	-@mkdir $(prefix)/include
+	-@mkdir $(prefix)/lib
+	cp png.h $(prefix)/include
+	cp pngconf.h $(prefix)/include
+	chmod 644 $(prefix)/include/png.h
+	chmod 644 $(prefix)/include/pngconf.h
+	cp libpng.a $(prefix)/lib
+	cp libpng.so.$(PNGVER) $(prefix)/lib
+	chmod 644 $(prefix)/lib/libpng.a
+	chmod 644 $(prefix)/lib/libpng.so.$(PNGVER)
+	-@/bin/rm -f $(LIBPATH)/libpng.so.$(PNGMAJ) $(LIBPATH)/libpng.so
+	(cd $(LIBPATH); ln -f -s libpng.so.$(PNGVER) libpng.so.$(PNGMAJ); \
+	 ln -f -s libpng.so.$(PNGMAJ) libpng.so)
+
+clean:
+	rm -f *.o libpng.a pngtest pngout.png libpng.so*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o: png.h pngconf.h
+pngerror.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
+pngmem.o: png.h pngconf.h
+pngset.o: png.h pngconf.h
+pngget.o: png.h pngconf.h
+pngread.o: png.h pngconf.h
+pngrtran.o: png.h pngconf.h
+pngrutil.o: png.h pngconf.h
+pngtest.o: png.h pngconf.h
+pngtrans.o: png.h pngconf.h
+pngwrite.o: png.h pngconf.h
+pngwtran.o: png.h pngconf.h
+pngwutil.o: png.h pngconf.h
+pngpread.o: png.h pngconf.h
+

scripts/makefile.dj2

@@ -2,16 +2,16 @@
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
 # For conditions of distribution and use, see copyright notice in png.h
 
+# where make install puts libpng.a and png.h
+#prefix=/usr/local
+prefix=.
+
 CC=gcc
 CFLAGS=-I../zlib -O
 LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
 
 RANLIB=ranlib
 
-# where make install puts libpng.a and png.h
-#prefix=/usr/local
-prefix=.
-
 OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
 	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o pngwtran.o \
 	pngmem.o pngerror.o pngpread.o
@@ -23,7 +23,7 @@ libpng.a: $(OBJS)
 	$(RANLIB) $@
 
 pngtest: pngtest.o libpng.a
-	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
 	coff2exe pngtest
 
 test: pngtest

scripts/makefile.gcc

@@ -0,0 +1,66 @@
+# makefile for libpng using gcc (generic, static library)
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+# Copyright (C) 2000 Cosmin Truta
+# For conditions of distribution and use, see copyright notice in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR = ar rcs
+RANLIB = ranlib
+RM = rm -f
+
+CDEBUG = -g -DPNG_DEBUG=5
+LDDEBUG =
+CRELEASE = -O2
+LDRELEASE = -s
+CFLAGS = -I$(ZLIBINC) -Wall $(CRELEASE)
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng -lz -lm $(LDRELEASE)
+
+# File extensions
+O=.o
+A=.a
+E=
+
+# Variables
+OBJS = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
+	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
+	pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+
+# Targets
+all: libpng$(A) pngtest$(E)
+
+libpng$(A): $(OBJS)
+	$(AR) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(E)
+	./pngtest$(E)
+
+pngtest$(E): pngtest$(O) libpng$(A)
+	$(LD) -o $@ pngtest$(O) $(LDFLAGS)
+
+clean:
+	$(RM) *$(O) libpng$(A) pngtest$(E) pngout.png
+
+png$(O): png.h pngconf.h
+pngerror$(O): png.h pngconf.h
+pngget$(O): png.h pngconf.h
+pngmem$(O): png.h pngconf.h
+pngpread$(O): png.h pngconf.h
+pngread$(O): png.h pngconf.h
+pngrio$(O): png.h pngconf.h
+pngrtran$(O): png.h pngconf.h
+pngrutil$(O): png.h pngconf.h
+pngset$(O): png.h pngconf.h
+pngtest$(O): png.h pngconf.h
+pngtrans$(O): png.h pngconf.h
+pngwio$(O): png.h pngconf.h
+pngwrite$(O): png.h pngconf.h
+pngwtran$(O): png.h pngconf.h
+pngwutil$(O): png.h pngconf.h
+