Imported from libpng-0.90.tar

CHANGES

@@ -0,0 +1,122 @@
+pngchange.txt - changes for libpng
+
+version 0.2
+   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
+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
+version 0.5
+   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()
+version 0.7
+   cleaned up lots of bugs
+   finished dithering and other stuff
+   added test program
+   changed name from pnglib to libpng
+version 0.71
+   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
+version 0.81
+   incorporated Tim Wegner's medium model code (thanks, Tim)
+version 0.85
+   added more medium model code (almost everythings 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
+   fixed bugs
+   improved documentation
+version 0.87
+   fixed medium model bugs
+   fixed other bugs introduced in 0.85 and 0.86
+   added some minor documentation
+version 0.88
+   fixed progressive bugs
+   replaced tabs with spaces
+   cleaned up documentation
+   added callbacks for read/write and warning/error functions
+version 0.89 
+   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
+   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