[libpng17] Imported from libpng-1.7.0beta24.tar

instead of png_chunk_report(), which by default issues a warning
rather than an error, leading to later reading from a NULL pointer
(png_ptr->palette) in png_do_expand_palette().

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.7.0beta23 - November 24, 2013
+Libpng 1.7.0beta24 - December 15, 2013
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -9,19 +9,19 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   1.7.0beta23.tar.xz (LZMA-compressed, recommended)
-   1.7.0beta23.tar.gz
+   1.7.0beta24.tar.xz (LZMA-compressed, recommended)
+   1.7.0beta24.tar.gz
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp170b23.7z  (LZMA-compressed, recommended)
-   lp170b23.zip
+   lp170b24.7z  (LZMA-compressed, recommended)
+   lp170b24.zip
 
 Other information:
 
-   1.7.0beta23-README.txt
-   1.7.0beta23-LICENSE.txt
+   1.7.0beta24-README.txt
+   1.7.0beta24-LICENSE.txt
    Gnupg/*.asc (PGP armored detached signatures)
 
 Changes since the last public release (1.6.0):
@@ -425,12 +425,41 @@ Version 1.7.0beta23 [November 24, 2013]
   Moved prototype for png_handle_unknown() in pngpriv.h outside of
     the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
   Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
+  Conditionally compile some unused functions reported by -Wall in
+    pngminim.
   Fixed 'minimal' builds. Various obviously useful minimal configurations
-    don't build because of missing contrib/libtests test programs and overly
-    complex dependencies in scripts/pnglibconf.dfa. This change adds
-    contrib/conftest/*.dfa files that can be used in automatic build
+    don't build because of missing contrib/libtests test programs and
+    overly complex dependencies in scripts/pnglibconf.dfa. This change
+    adds contrib/conftest/*.dfa files that can be used in automatic build
     scripts to ensure that these configurations continue to build.
   Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
+  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
+    This reverts to the previous 'static' implementation and works round
+    the 'unused static function' warning by using PNG_UNUSED().
+
+Version 1.7.0beta24 [December 15, 2013]
+  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
+    by clang scan-build.
+  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
+    to '"%s" m' to improve portability among compilers.
+  Changed png_free_default() to free() in pngtest.c
+  Tidied up pngfix inits and fixed pngtest no-write builds.
+  Bookkeeping: Moved functions around (no changes). Moved transform
+    function definitions before the place where they are called so that
+    they can be masde static. Move the intrapixel functions and the
+    grayscale palette builder out of the png?tran.c files. The latter
+    isn't a transform function and is no longer used internally, and the
+    former MNG specific functions are better placed in pngread/pngwrite.c
+  Made transform implementation functions static. This makes the internal
+    functions called by png_do_{read|write}_transformations static. On an
+    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
+    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
+    maintenance by removing the declarations from pngpriv.h and allowing
+    easier changes to the internal interfaces.
+  Handle zero-length PLTE chunk or NULL palette with png_error()
+    instead of png_chunk_report(), which by default issues a warning
+    rather than an error, leading to later reading from a NULL pointer
+    (png_ptr->palette) in png_do_expand_palette().
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -4714,12 +4714,41 @@ Version 1.7.0beta23 [November 24, 2013]
   Moved prototype for png_handle_unknown() in pngpriv.h outside of
     the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
   Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
+  Conditionally compile some unused functions reported by -Wall in
+    pngminim.
   Fixed 'minimal' builds. Various obviously useful minimal configurations
-    don't build because of missing contrib/libtests test programs and overly
-    complex dependencies in scripts/pnglibconf.dfa. This change adds
-    contrib/conftest/*.dfa files that can be used in automatic build
+    don't build because of missing contrib/libtests test programs and
+    overly complex dependencies in scripts/pnglibconf.dfa. This change
+    adds contrib/conftest/*.dfa files that can be used in automatic build
     scripts to ensure that these configurations continue to build.
   Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
+  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
+    This reverts to the previous 'static' implementation and works round
+    the 'unused static function' warning by using PNG_UNUSED().
+
+Version 1.7.0beta24 [December 15, 2013]
+  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
+    by clang scan-build.
+  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
+    to '"%s" m' to improve portability among compilers.
+  Changed png_free_default() to free() in pngtest.c
+  Tidied up pngfix inits and fixed pngtest no-write builds.
+  Bookkeeping: Moved functions around (no changes). Moved transform
+    function definitions before the place where they are called so that
+    they can be masde static. Move the intrapixel functions and the
+    grayscale palette builder out of the png?tran.c files. The latter
+    isn't a transform function and is no longer used internally, and the
+    former MNG specific functions are better placed in pngread/pngwrite.c
+  Made transform implementation functions static. This makes the internal
+    functions called by png_do_{read|write}_transformations static. On an
+    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
+    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
+    maintenance by removing the declarations from pngpriv.h and allowing
+    easier changes to the internal interfaces.
+  Handle zero-length PLTE chunk or NULL palette with png_error()
+    instead of png_chunk_report(), which by default issues a warning
+    rather than an error, leading to later reading from a NULL pointer
+    (png_ptr->palette) in png_do_expand_palette().
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CMakeLists.txt

@@ -252,7 +252,7 @@ endif(NOT WIN32 OR CYGWIN OR MINGW)
 # SET UP LINKS
 if(PNG_SHARED)
   set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 17.${PNGLIB_RELEASE}.1.7.0beta23
+#   VERSION 17.${PNGLIB_RELEASE}.1.7.0beta24
     VERSION 17.${PNGLIB_RELEASE}.0
     SOVERSION 17
     CLEAN_DIRECT_OUTPUT 1)

LICENSE

@@ -10,7 +10,7 @@ this sentence.
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.7.0beta23, November 24, 2013, are
+libpng versions 1.2.6, August 15, 2004, through 1.7.0beta24, December 15, 2013, are
 Copyright (c) 2004, 2006-2013 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -108,4 +108,4 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-November 24, 2013
+December 15, 2013

README

@@ -1,4 +1,4 @@
-README for libpng version 1.7.0beta23 - November 24, 2013 (shared library 17.0)
+README for libpng version 1.7.0beta24 - December 15, 2013 (shared library 17.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.

configure.ac

@@ -18,7 +18,7 @@ AC_PREREQ([2.68])
 
 dnl Version number stuff here:
 
-AC_INIT([libpng],[1.7.0beta23],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.7.0beta24],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts])
 
 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -39,7 +39,7 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake
 
-PNGLIB_VERSION=1.7.0beta23
+PNGLIB_VERSION=1.7.0beta24
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=7
 PNGLIB_RELEASE=0

contrib/tools/pngfix.c

@@ -1575,7 +1575,7 @@ chunk_end(struct chunk **chunk_var)
 }
 
 static void
-chunk_init(struct chunk *chunk, struct file *file)
+chunk_init(struct chunk * const chunk, struct file * const file)
    /* When a chunk is initialized the file length/type/pos are copied into the
     * corresponding chunk fields and the new chunk is registered in the file
     * structure.  There can only be one chunk at a time.
@@ -1784,7 +1784,7 @@ IDAT_end(struct IDAT **idat_var)
 }
 
 static void
-IDAT_init(struct IDAT *idat, struct file *file)
+IDAT_init(struct IDAT * const idat, struct file * const file)
    /* When the chunk is png_IDAT instantiate an IDAT control structure in place
     * of a chunk control structure.  The IDAT will instantiate a chunk control
     * structure using the file alloc routine.
@@ -3545,22 +3545,14 @@ allocate(struct file *file, int allocate_idat)
 
    if (allocate_idat)
    {
-      struct IDAT *idat;
-
       assert(file->idat == NULL);
-      idat = &control->idat;
-      IDAT_init(idat, file);
-      file->idat = idat;
+      IDAT_init(&control->idat, file);
    }
 
    else /* chunk */
    {
-      struct chunk *chunk;
-
       assert(file->chunk == NULL);
-      chunk = &control->chunk;
-      chunk_init(chunk, file);
-      file->chunk = chunk;
+      chunk_init(&control->chunk, file);
    }
 }
 

libpng-manual.txt

@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.7.0beta23 - November 24, 2013
+ libpng version 1.7.0beta24 - December 15, 2013
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.7.0beta23 - November 24, 2013
+ libpng versions 0.97, January 1998, through 1.7.0beta24 - December 15, 2013
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
 
@@ -3117,6 +3117,19 @@ Here is an example of writing two private chunks, prVt and miNE:
     /* Needed because miNE is not safe-to-copy */
     png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
        (png_bytep) "miNE", 1);
+    # if PNG_LIBPNG_VER < 10600
+      /* Deal with unknown chunk location bug in 1.5.x and earlier */
+      png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+      png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+    # endif
+    # if PNG_LIBPNG_VER < 10500
+      /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+       * one before IDAT and another after IDAT, so don't use it; only use
+       * PNG_HAVE_IHDR location.  This call resets the location previously
+       * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+       */
+      png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+    # endif
     #endif
 
 The high-level write interface
@@ -4608,11 +4621,11 @@ XI.  Changes to Libpng from version 1.4.x to 1.5.x
 From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
 function) incorrectly returned a value of type png_uint_32.
 
-Checking for invalid palette index on read or write was added at libpng
-1.5.10.  When an invalid index is found, libpng issues a benign error.
-This is enabled by default because this condition is an error according
-to the PNG specification, Clause 11.3.2, but the error can be ignored in
-each png_ptr with
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
 
    png_set_check_for_invalid_index(png_ptr, allowed);
 
@@ -5037,18 +5050,19 @@ The machine-generated configure files are no longer included in branches
 libpng16 and later of the GIT repository.  They continue to be included
 in the tarball releases, however.
 
-Libpng-1.6.0 and later use the CMF bytes at the beginning of the IDAT stream
-to set the size of the sliding window for reading instead of using the default
-32-kbyte sliding window size.  It was discovered that there are hundreds of PNG
-files in the wild that have incorrect CMF bytes that cause libpng to now issue
-a "too far back" error and reject the file.  Libpng-1.6.3 provides a way to
-revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size.  It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+libpng to issue a "too far back" error and reject the file.  Libpng-1.6.3 and
+later calculate their own safe CMF from the image dimensions, provide a way
+to revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
 32-kbyte sliding window), by using
 
     png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
         PNG_OPTION_ON);
 
-and provides a tool (contrib/tools/pngfix) for optimizing the CMF bytes
+and provide a tool (contrib/tools/pngfix) for optimizing the CMF bytes
 correctly.
 
 Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
@@ -5234,7 +5248,8 @@ left parenthesis that follows it:
        y[i] = a(x) + (int)b;
 
 We prefer #ifdef and #ifndef to #if defined() and #if !defined()
-when there is only one macro being tested.
+when there is only one macro being tested.  We always use parentheses
+with "defined".
 
 We prefer to express integers that are used as bit masks in hex format,
 with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
@@ -5250,13 +5265,13 @@ Other rules can be inferred by inspecting the libpng source.
 
 XVII. Y2K Compliance in libpng
 
-November 24, 2013
+December 15, 2013
 
 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 1.7.0beta23 are Y2K compliant.  It is my belief that earlier
+upward through 1.7.0beta24 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has two year fields.  One is a 2-byte unsigned integer

libpng.3

@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "November 24, 2013"
+.TH LIBPNG 3 "December 15, 2013"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta23
+libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta24
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -494,7 +494,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.7.0beta23 - November 24, 2013
+ libpng version 1.7.0beta24 - December 15, 2013
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -505,7 +505,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.7.0beta23 - November 24, 2013
+ libpng versions 0.97, January 1998, through 1.7.0beta24 - December 15, 2013
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
 
@@ -3611,6 +3611,19 @@ Here is an example of writing two private chunks, prVt and miNE:
     /* Needed because miNE is not safe-to-copy */
     png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
        (png_bytep) "miNE", 1);
+    # if PNG_LIBPNG_VER < 10600
+      /* Deal with unknown chunk location bug in 1.5.x and earlier */
+      png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+      png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+    # endif
+    # if PNG_LIBPNG_VER < 10500
+      /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+       * one before IDAT and another after IDAT, so don't use it; only use
+       * PNG_HAVE_IHDR location.  This call resets the location previously
+       * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+       */
+      png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+    # endif
     #endif
 
 .SS The high-level write interface
@@ -5103,11 +5116,11 @@ We removed the trailing '.' from the warning and error messages.
 From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
 function) incorrectly returned a value of type png_uint_32.
 
-Checking for invalid palette index on read or write was added at libpng
-1.5.10.  When an invalid index is found, libpng issues a benign error.
-This is enabled by default because this condition is an error according
-to the PNG specification, Clause 11.3.2, but the error can be ignored in
-each png_ptr with
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
 
    png_set_check_for_invalid_index(png_ptr, allowed);
 
@@ -5532,18 +5545,19 @@ The machine-generated configure files are no longer included in branches
 libpng16 and later of the GIT repository.  They continue to be included
 in the tarball releases, however.
 
-Libpng-1.6.0 and later use the CMF bytes at the beginning of the IDAT stream
-to set the size of the sliding window for reading instead of using the default
-32-kbyte sliding window size.  It was discovered that there are hundreds of PNG
-files in the wild that have incorrect CMF bytes that cause libpng to now issue
-a "too far back" error and reject the file.  Libpng-1.6.3 provides a way to
-revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size.  It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+libpng to issue a "too far back" error and reject the file.  Libpng-1.6.3 and
+later calculate their own safe CMF from the image dimensions, provide a way
+to revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a
 32-kbyte sliding window), by using
 
     png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
         PNG_OPTION_ON);
 
-and provides a tool (contrib/tools/pngfix) for optimizing the CMF bytes
+and provide a tool (contrib/tools/pngfix) for optimizing the CMF bytes
 correctly.
 
 Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
@@ -5729,7 +5743,8 @@ left parenthesis that follows it:
        y[i] = a(x) + (int)b;
 
 We prefer #ifdef and #ifndef to #if defined() and #if !defined()
-when there is only one macro being tested.
+when there is only one macro being tested.  We always use parentheses
+with "defined".
 
 We prefer to express integers that are used as bit masks in hex format,
 with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
@@ -5745,13 +5760,13 @@ Other rules can be inferred by inspecting the libpng source.
 
 .SH XVII. Y2K Compliance in libpng
 
-November 24, 2013
+December 15, 2013
 
 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 1.7.0beta23 are Y2K compliant.  It is my belief that earlier
+upward through 1.7.0beta24 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -5958,7 +5973,7 @@ the first widely used release:
  1.5.7               15    10507  15.so.15.7[.0]
  1.6.0beta01-37      16    10600  16.so.16.0[.0]
  1.7.0alpha01-10     17    10700  17.so.17.0[.0]
- 1.7.0beta01-23      17    10700  17.so.17.0[.0]
+ 1.7.0beta01-24      17    10700  17.so.17.0[.0]
 
 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -6015,7 +6030,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.7.0beta23 - November 24, 2013:
+Libpng version 1.7.0beta24 - December 15, 2013:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -6038,7 +6053,7 @@ this sentence.
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.7.0beta23, November 24, 2013, are
+libpng versions 1.2.6, August 15, 2004, through 1.7.0beta24, December 15, 2013, are
 Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -6137,7 +6152,7 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-November 24, 2013
+December 15, 2013
 
 .\" end of man page
 

libpngpf.3

@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "November 24, 2013"
+.TH LIBPNGPF 3 "December 15, 2013"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta23
+libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta24
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"

png.5

@@ -1,4 +1,4 @@
-.TH PNG 5 "November 24, 2013"
+.TH PNG 5 "December 15, 2013"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION

png.c

@@ -14,7 +14,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_7_0beta23 Your_png_h_is_not_version_1_7_0beta23;
+typedef png_libpng_version_1_7_0beta24 Your_png_h_is_not_version_1_7_0beta24;
 
 /* 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
@@ -201,6 +201,7 @@ png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
          pos = png_safecat(m, (sizeof m), pos, user_png_ver);
          pos = png_safecat(m, (sizeof m), pos, " but running with ");
          pos = png_safecat(m, (sizeof m), pos, png_libpng_ver);
+         PNG_UNUSED(pos)
 
          png_warning(png_ptr, m);
 #endif
@@ -695,13 +696,13 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.7.0beta23 - November 24, 2013" PNG_STRING_NEWLINE \
+     "libpng version 1.7.0beta24 - December 15, 2013" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2013 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.7.0beta23 - November 24, 2013\
+      return "libpng version 1.7.0beta24 - December 15, 2013\
       Copyright (c) 1998-2013 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -748,6 +749,63 @@ png_get_header_version(png_const_structrp png_ptr)
 #endif
 }
 
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+/* NOTE: this routine is not used internally! */
+/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
+ * large of png_color.  This lets grayscale images be treated as
+ * paletted.  Most useful for gamma correction and simplification
+ * of code.  This API is not used internally.
+ */
+void PNGAPI
+png_build_grayscale_palette(int bit_depth, png_colorp palette)
+{
+   int num_palette;
+   int color_inc;
+   int i;
+   int v;
+
+   png_debug(1, "in png_do_build_grayscale_palette");
+
+   if (palette == NULL)
+      return;
+
+   switch (bit_depth)
+   {
+      case 1:
+         num_palette = 2;
+         color_inc = 0xff;
+         break;
+
+      case 2:
+         num_palette = 4;
+         color_inc = 0x55;
+         break;
+
+      case 4:
+         num_palette = 16;
+         color_inc = 0x11;
+         break;
+
+      case 8:
+         num_palette = 256;
+         color_inc = 1;
+         break;
+
+      default:
+         num_palette = 0;
+         color_inc = 0;
+         break;
+   }
+
+   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
+   {
+      palette[i].red = (png_byte)v;
+      palette[i].green = (png_byte)v;
+      palette[i].blue = (png_byte)v;
+   }
+}
+#endif
+
 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 int PNGAPI
 png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
@@ -1634,6 +1692,7 @@ png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
 #  endif
    /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
    pos = png_safecat(message, (sizeof message), pos, reason);
+   PNG_UNUSED(pos)
 
    /* This is recoverable, but make it unconditionally an app_error on write to
     * avoid writing invalid ICC profiles into PNG files.  (I.e.  we handle them

png.h

@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.7.0beta23 - November 24, 2013
+ * libpng version 1.7.0beta24 - December 15, 2013
  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -11,7 +11,7 @@
  * Authors and maintainers:
  *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.7.0beta23 - November 24, 2013: Glenn
+ *   libpng versions 0.97, January 1998, through 1.7.0beta24 - December 15, 2013: Glenn
  *   See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -168,7 +168,7 @@
  *    1.5.7                   15    10507  15.so.15.7[.0]
  *    1.6.0beta01-37          16    10600  16.so.16.0[.0]
  *    1.7.0alpha01-10         17    10700  17.so.17.0[.0]
- *    1.7.0beta01-23          17    10700  17.so.17.0[.0]
+ *    1.7.0beta01-24          17    10700  17.so.17.0[.0]
  *
  *   Henceforth the source version will match the shared-library major
  *   and minor numbers; the shared-library major version number will be
@@ -200,7 +200,7 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.7.0beta23, November 24, 2013, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.7.0beta24, December 15, 2013, are
  * Copyright (c) 2004, 2006-2013 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -312,13 +312,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    November 24, 2013
+ *    December 15, 2013
  *
  *    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 1.7.0beta23 are Y2K compliant.  It is my belief that
+ *    upward through 1.7.0beta24 are Y2K compliant.  It is my belief that
  *    earlier versions were also Y2K compliant.
  *
  *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -378,9 +378,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.7.0beta23"
+#define PNG_LIBPNG_VER_STRING "1.7.0beta24"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.7.0beta23 - November 24, 2013\n"
+     " libpng version 1.7.0beta24 - December 15, 2013\n"
 
 #define PNG_LIBPNG_VER_SONUM   17
 #define PNG_LIBPNG_VER_DLLNUM  17
@@ -394,7 +394,7 @@
  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
  */
 
-#define PNG_LIBPNG_VER_BUILD  23
+#define PNG_LIBPNG_VER_BUILD  24
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -640,7 +640,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_7_0beta23;
+typedef char* png_libpng_version_1_7_0beta24;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *

pngconf.h

@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.7.0beta23 - November 24, 2013
+ * libpng version 1.7.0beta24 - December 15, 2013
  *
  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

pngdebug.h

@@ -1,11 +1,11 @@
 
 /* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
  *
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.5.18 [(PENDING RELEASE)]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -25,7 +25,7 @@
  *   (actually ((void)0)).
  *
  *   level: level of detail of message, starting at 0.  A level 'n'
- *          message is preceded by 'n' tab characters (not implemented
+ *          message is preceded by 'n' 3-space indentations (not implemented
  *          on Microsoft compilers unless PNG_DEBUG_FILE is also
  *          defined, to allow debug DLL compilation with no standard IO).
  *   message: a printf(3) style text string.  A trailing '\n' is added
@@ -77,32 +77,29 @@
 #      endif /* PNG_DEBUG_FILE */
 
 #      if (PNG_DEBUG > 1)
-/* Note: ["%s"m PNG_STRING_NEWLINE] probably does not work on
- * non-ISO compilers
- */
 #        ifdef __STDC__
 #          ifndef png_debug
 #            define png_debug(l,m) \
        do { \
        int num_tabs=l; \
-       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : "")))); \
        } while (0)
 #          endif
 #          ifndef png_debug1
 #            define png_debug1(l,m,p1) \
        do { \
        int num_tabs=l; \
-       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1); \
        } while (0)
 #          endif
 #          ifndef png_debug2
 #            define png_debug2(l,m,p1,p2) \
        do { \
        int num_tabs=l; \
-       fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
-         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1,p2);\
        } while (0)
 #          endif
 #        else /* __STDC __ */

pngpriv.h

@@ -1147,32 +1147,7 @@ PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
     png_inforp info_ptr),PNG_EMPTY);
 #endif
 
-/* These are the functions that do the transformations */
-#ifdef PNG_READ_FILLER_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_read_filler,(png_row_infop row_info,
-    png_bytep row, png_uint_32 filler, png_uint_32 flags),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_read_swap_alpha,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_write_swap_alpha,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_read_invert_alpha,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_write_invert_alpha,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
+/* Shared transform functions, defined in pngtran.c */
 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
 PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
@@ -1192,96 +1167,16 @@ PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
     png_bytep row),PNG_EMPTY);
 #endif
 
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-PNG_INTERNAL_FUNCTION(int,png_do_rgb_to_gray,(png_structrp png_ptr,
-    png_row_infop row_info, png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_gray_to_rgb,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_PACK_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_unpack,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_unshift,(png_row_infop row_info,
-    png_bytep row, png_const_color_8p sig_bits),PNG_EMPTY);
-#endif
-
 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
 PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
     png_bytep row),PNG_EMPTY);
 #endif
 
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_scale_16_to_8,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_chop,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_quantize,(png_row_infop row_info,
-    png_bytep row, png_const_bytep palette_lookup,
-    png_const_bytep quantize_lookup),PNG_EMPTY);
-
-#  ifdef PNG_CORRECT_PALETTE_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_correct_palette,(png_structrp png_ptr,
-    png_colorp palette, int num_palette),PNG_EMPTY);
-#  endif
-#endif
-
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
 PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
     png_bytep row),PNG_EMPTY);
 #endif
 
-#ifdef PNG_WRITE_PACK_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_pack,(png_row_infop row_info,
-   png_bytep row, png_uint_32 bit_depth),PNG_EMPTY);
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_shift,(png_row_infop row_info,
-    png_bytep row, png_const_color_8p bit_depth),PNG_EMPTY);
-#endif
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-PNG_INTERNAL_FUNCTION(void,png_do_compose,(png_row_infop row_info,
-    png_bytep row, png_structrp png_ptr),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_gamma,(png_row_infop row_info,
-    png_bytep row, png_structrp png_ptr),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_encode_alpha,(png_row_infop row_info,
-   png_bytep row, png_structrp png_ptr),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_expand_palette,(png_row_infop row_info,
-    png_bytep row, png_const_colorp palette, png_const_bytep trans,
-    int num_trans),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_do_expand,(png_row_infop row_info,
-    png_bytep row, png_const_color_16p trans_color),PNG_EMPTY);
-#endif
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_expand_16,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
 /* The following decodes the appropriate chunks, and does error correction,
  * then calls the appropriate callback for the chunk if it is valid.
  */
@@ -1468,13 +1363,6 @@ PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
 
 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
 
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-PNG_INTERNAL_FUNCTION(void,png_do_read_intrapixel,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_do_write_intrapixel,(png_row_infop row_info,
-    png_bytep row),PNG_EMPTY);
-#endif
-
 /* Added at libpng version 1.6.0 */
 #ifdef PNG_GAMMA_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,

pngread.c

@@ -305,6 +305,72 @@ png_start_read_image(png_structrp png_ptr)
 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 
 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing,
+ * NOTE: this is apparently only supported in the 'sequential' reader.
+ */
+static void
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_intrapixel");
+
+   if (
+       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
+            *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (s0 + s1 + 65536) & 0xffff;
+            png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
+            *(rp    ) = (png_byte)((red >> 8) & 0xff);
+            *(rp + 1) = (png_byte)(red & 0xff);
+            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp + 5) = (png_byte)(blue & 0xff);
+         }
+      }
+   }
+}
+#endif /* PNG_MNG_FEATURES_SUPPORTED */
+
 void PNGAPI
 png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
 {
@@ -489,7 +555,6 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
    }
 #endif
 
-
 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
    if (png_ptr->transformations)
       png_do_read_transformations(png_ptr, &row_info);
@@ -2811,7 +2876,6 @@ png_image_read_and_map(png_voidp argument)
          break;
 
       default:
-         passes = 0;
          png_error(png_ptr, "unknown interlace type");
    }
 
@@ -3130,7 +3194,6 @@ png_image_read_composite(png_voidp argument)
          break;
 
       default:
-         passes = 0;
          png_error(png_ptr, "unknown interlace type");
    }
 
@@ -3279,7 +3342,6 @@ png_image_read_background(png_voidp argument)
          break;
 
       default:
-         passes = 0;
          png_error(png_ptr, "unknown interlace type");
    }
 

pngrtran.c

@@ -1839,6 +1839,9 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
 
          info_ptr->bit_depth = 8;
          info_ptr->num_trans = 0;
+
+         if (png_ptr->palette == NULL)
+            png_error (png_ptr, "Palette is NULL in indexed image");
       }
       else
       {
@@ -2017,303 +2020,6 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
 #endif
 }
 
-/* Transform the row.  The order of transformations is significant,
- * and is very touchy.  If you add a transformation, take care to
- * decide how it fits in with the other transformations here.
- */
-void /* PRIVATE */
-png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
-{
-   png_debug(1, "in png_do_read_transformations");
-
-   if (png_ptr->row_buf == NULL)
-   {
-      /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
-       * error is incredibly rare and incredibly easy to debug without this
-       * information.
-       */
-      png_error(png_ptr, "NULL row buffer");
-   }
-
-   /* The following is debugging; prior to 1.5.4 the code was never compiled in;
-    * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
-    * PNG_WARN_UNINITIALIZED_ROW removed.  In 1.6 the new flag is set only for
-    * all transformations, however in practice the ROW_INIT always gets done on
-    * demand, if necessary.
-    */
-   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
-      !(png_ptr->flags & PNG_FLAG_ROW_INIT))
-   {
-      /* Application has failed to call either png_read_start_image() or
-       * png_read_update_info() after setting transforms that expand pixels.
-       * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
-       */
-      png_error(png_ptr, "Uninitialized row");
-   }
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-   if (png_ptr->transformations & PNG_EXPAND)
-   {
-      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         png_do_expand_palette(row_info, png_ptr->row_buf + 1,
-             png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
-      }
-
-      else
-      {
-         if (png_ptr->num_trans &&
-             (png_ptr->transformations & PNG_EXPAND_tRNS))
-            png_do_expand(row_info, png_ptr->row_buf + 1,
-                &(png_ptr->trans_color));
-
-         else
-            png_do_expand(row_info, png_ptr->row_buf + 1,
-                NULL);
-      }
-   }
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      !(png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
-      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         0 /* at_start == false, because SWAP_ALPHA happens later */);
-#endif
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
-   {
-      int rgb_error =
-          png_do_rgb_to_gray(png_ptr, row_info,
-              png_ptr->row_buf + 1);
-
-      if (rgb_error)
-      {
-         png_ptr->rgb_to_gray_status=1;
-         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
-             PNG_RGB_TO_GRAY_WARN)
-            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
-
-         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
-             PNG_RGB_TO_GRAY_ERR)
-            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
-      }
-   }
-#endif
-
-/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
- *
- *   In most cases, the "simple transparency" should be done prior to doing
- *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
- *   pixel is transparent.  You would also need to make sure that the
- *   transparency information is upgraded to RGB.
- *
- *   To summarize, the current flow is:
- *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
- *                                   with background "in place" if transparent,
- *                                   convert to RGB if necessary
- *   - Gray + alpha -> composite with gray background and remove alpha bytes,
- *                                   convert to RGB if necessary
- *
- *   To support RGB backgrounds for gray images we need:
- *   - Gray + simple transparency -> convert to RGB + simple transparency,
- *                                   compare 3 or 6 bytes and composite with
- *                                   background "in place" if transparent
- *                                   (3x compare/pixel compared to doing
- *                                   composite with gray bkgrnd)
- *   - Gray + alpha -> convert to RGB + alpha, composite with background and
- *                                   remove alpha bytes (3x float
- *                                   operations/pixel compared with composite
- *                                   on gray background)
- *
- *  Greg's change will do this.  The reason it wasn't done before is for
- *  performance, as this increases the per-pixel operations.  If we would check
- *  in advance if the background was gray or RGB, and position the gray-to-RGB
- *  transform appropriately, then it would save a lot of work/time.
- */
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   /* If gray -> RGB, do so now only if background is non-gray; else do later
-    * for performance reasons
-    */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       !(png_ptr->flags & PNG_FLAG_BACKGROUND_IS_GRAY))
-      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
-#endif
-
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-   if (png_ptr->transformations & PNG_COMPOSE)
-      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
-   if ((png_ptr->transformations & PNG_GAMMA) &&
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-      /* Because RGB_TO_GRAY does the gamma transform. */
-      !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
-   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
-      /* Because PNG_COMPOSE does the gamma transform if there is something to
-       * do (if there is an alpha channel or transparency.)
-       */
-       !((png_ptr->transformations & PNG_COMPOSE) &&
-       ((png_ptr->num_trans != 0) ||
-       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
-#endif
-      /* Because png_init_read_transformations transforms the palette, unless
-       * RGB_TO_GRAY will do the transform.
-       */
-       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
-      png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
-      (png_ptr->transformations & PNG_COMPOSE) &&
-      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
-      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
-      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         0 /* at_start == false, because SWAP_ALPHA happens later */);
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
-   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
-      (row_info->color_type & PNG_COLOR_MASK_ALPHA))
-      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
-#endif
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-   if (png_ptr->transformations & PNG_SCALE_16_TO_8)
-      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-   /* There is no harm in doing both of these because only one has any effect,
-    * by putting the 'scale' option first if the app asks for scale (either by
-    * calling the API or in a TRANSFORM flag) this is what happens.
-    */
-   if (png_ptr->transformations & PNG_16_TO_8)
-      png_do_chop(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_QUANTIZE_SUPPORTED
-   if (png_ptr->transformations & PNG_QUANTIZE)
-   {
-      png_do_quantize(row_info, png_ptr->row_buf + 1,
-          png_ptr->palette_lookup, png_ptr->quantize_index);
-
-      if (row_info->rowbytes == 0)
-         png_error(png_ptr, "png_do_quantize returned rowbytes=0");
-   }
-#endif /* PNG_READ_QUANTIZE_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-   /* Do the expansion now, after all the arithmetic has been done.  Notice
-    * that previous transformations can handle the PNG_EXPAND_16 flag if this
-    * is efficient (particularly true in the case of gamma correction, where
-    * better accuracy results faster!)
-    */
-   if (png_ptr->transformations & PNG_EXPAND_16)
-      png_do_expand_16(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-   /* NOTE: moved here in 1.5.4 (from much later in this list.) */
-   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
-       (png_ptr->flags & PNG_FLAG_BACKGROUND_IS_GRAY))
-      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_do_invert(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
-      png_do_unshift(row_info, png_ptr->row_buf + 1,
-          &(png_ptr->shift));
-#endif
-
-#ifdef PNG_READ_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
-      png_do_unpack(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
-   /* Added at libpng-1.5.10 */
-   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
-       png_ptr->num_palette_max >= 0)
-      png_do_check_palette_indexes(png_ptr, row_info);
-#endif
-
-#ifdef PNG_READ_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
-      png_do_bgr(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
-      png_do_packswap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
-      png_do_read_filler(row_info, png_ptr->row_buf + 1,
-          (png_uint_32)png_ptr->filler, png_ptr->flags);
-#endif
-
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
-      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
-      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-#ifdef PNG_READ_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_do_swap(row_info, png_ptr->row_buf + 1);
-#endif
-#endif
-
-#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
-   if (png_ptr->transformations & PNG_USER_TRANSFORM)
-    {
-      if (png_ptr->read_user_transform_fn != NULL)
-         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
-             (png_ptr,     /* png_ptr */
-             row_info,     /* row_info: */
-                /*  png_uint_32 width;       width of row */
-                /*  png_size_t 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 */
-#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
-      if (png_ptr->user_transform_depth)
-         row_info->bit_depth = png_ptr->user_transform_depth;
-
-      if (png_ptr->user_transform_channels)
-         row_info->channels = png_ptr->user_transform_channels;
-#endif
-      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
-          row_info->channels);
-
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
-   }
-#endif
-}
-
 #ifdef PNG_READ_PACK_SUPPORTED
 /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
  * without changing the actual values.  Thus, if you had a row with
@@ -2321,7 +2027,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
  * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
  * png_do_shift() after this.
  */
-void /* PRIVATE */
+static void
 png_do_unpack(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_unpack");
@@ -2419,7 +2125,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
  * a row of bit depth 8, but only 5 are significant, this will shift
  * the values back to 0 through 31.
  */
-void /* PRIVATE */
+static void
 png_do_unshift(png_row_infop row_info, png_bytep row,
     png_const_color_8p sig_bits)
 {
@@ -2558,7 +2264,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
 
 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
 /* Scale rows of bit depth 16 down to 8 accurately */
-void /* PRIVATE */
+static void
 png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_scale_16_to_8");
@@ -2616,7 +2322,7 @@ png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
 #endif
 
 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
-void /* PRIVATE */
+static void
 /* Simply discard the low byte.  This was the default behavior prior
  * to libpng-1.5.4.
  */
@@ -2644,7 +2350,7 @@ png_do_chop(png_row_infop row_info, png_bytep row)
 #endif
 
 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
-void /* PRIVATE */
+static void
 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_read_swap_alpha");
@@ -2741,7 +2447,7 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 #endif
 
 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
-void /* PRIVATE */
+static void
 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 {
    png_uint_32 row_width;
@@ -2843,7 +2549,7 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 
 #ifdef PNG_READ_FILLER_SUPPORTED
 /* Add filler channel if we have RGB color */
-void /* PRIVATE */
+static void
 png_do_read_filler(png_row_infop row_info, png_bytep row,
     png_uint_32 filler, png_uint_32 flags)
 {
@@ -3030,7 +2736,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 
 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
 /* Expand grayscale files to RGB, with or without alpha */
-void /* PRIVATE */
+static void
 png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
 {
    png_uint_32 i;
@@ -3169,7 +2875,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
  *  calculated to make the sum 32768.  This will result in different rounding
  *  to that used above.
  */
-int /* PRIVATE */
+static int
 png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
 
 {
@@ -3358,73 +3064,14 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
    return rgb_error;
 }
 #endif
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
 
-#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
-/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
- * large of png_color.  This lets grayscale images be treated as
- * paletted.  Most useful for gamma correction and simplification
- * of code.  This API is not used internally.
- */
-void PNGAPI
-png_build_grayscale_palette(int bit_depth, png_colorp palette)
-{
-   int num_palette;
-   int color_inc;
-   int i;
-   int v;
-
-   png_debug(1, "in png_do_build_grayscale_palette");
-
-   if (palette == NULL)
-      return;
-
-   switch (bit_depth)
-   {
-      case 1:
-         num_palette = 2;
-         color_inc = 0xff;
-         break;
-
-      case 2:
-         num_palette = 4;
-         color_inc = 0x55;
-         break;
-
-      case 4:
-         num_palette = 16;
-         color_inc = 0x11;
-         break;
-
-      case 8:
-         num_palette = 256;
-         color_inc = 1;
-         break;
-
-      default:
-         num_palette = 0;
-         color_inc = 0;
-         break;
-   }
-
-   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
-   {
-      palette[i].red = (png_byte)v;
-      palette[i].green = (png_byte)v;
-      palette[i].blue = (png_byte)v;
-   }
-}
-#endif
-
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
 /* Replace any alpha or transparency with the supplied background color.
  * "background" is already in the screen gamma, while "background_1" is
  * at a gamma of 1.0.  Paletted files have already been taken care of.
  */
-void /* PRIVATE */
+static void
 png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
 {
    png_const_bytep gamma_table = png_ptr->gamma_table;
@@ -4186,7 +3833,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
  * is 16, use gamma_16_table and gamma_shift.  Build these with
  * build_gamma_table().
  */
-void /* PRIVATE */
+static void
 png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
 {
    png_const_bytep gamma_table = png_ptr->gamma_table;
@@ -4366,7 +4013,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
  * linear.)  Called only with color types that have an alpha channel.  Needs the
  * from_1 tables.
  */
-void /* PRIVATE */
+static void
 png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
 {
    png_uint_32 row_width = row_info->width;
@@ -4434,7 +4081,7 @@ png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
 /* Expands a palette row to an RGB or RGBA row depending
  * upon whether you supply trans and num_trans.
  */
-void /* PRIVATE */
+static void
 png_do_expand_palette(png_row_infop row_info, png_bytep row,
    png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
 {
@@ -4587,7 +4234,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
 /* If the bit depth < 8, it is expanded to 8.  Also, if the already
  * expanded transparency value is supplied, an alpha channel is built.
  */
-void /* PRIVATE */
+static void
 png_do_expand(png_row_infop row_info, png_bytep row,
     png_const_color_16p trans_color)
 {
@@ -4817,7 +4464,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
 /* If the bit depth is 8 and the color type is not a palette type expand the
  * whole row to 16 bits.  Has no effect otherwise.
  */
-void /* PRIVATE */
+static void
 png_do_expand_16(png_row_infop row_info, png_bytep row)
 {
    if (row_info->bit_depth == 8 &&
@@ -4845,7 +4492,7 @@ png_do_expand_16(png_row_infop row_info, png_bytep row)
 #endif
 
 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-void /* PRIVATE */
+static void
 png_do_quantize(png_row_infop row_info, png_bytep row,
     png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
 {
@@ -4937,69 +4584,302 @@ png_do_quantize(png_row_infop row_info, png_bytep row,
    }
 }
 #endif /* PNG_READ_QUANTIZE_SUPPORTED */
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
 
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-/* Undoes intrapixel differencing  */
+/* Transform the row.  The order of transformations is significant,
+ * and is very touchy.  If you add a transformation, take care to
+ * decide how it fits in with the other transformations here.
+ */
 void /* PRIVATE */
-png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
 {
-   png_debug(1, "in png_do_read_intrapixel");
+   png_debug(1, "in png_do_read_transformations");
 
-   if (
-       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   if (png_ptr->row_buf == NULL)
    {
-      int bytes_per_pixel;
-      png_uint_32 row_width = row_info->width;
+      /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
+       * error is incredibly rare and incredibly easy to debug without this
+       * information.
+       */
+      png_error(png_ptr, "NULL row buffer");
+   }
 
-      if (row_info->bit_depth == 8)
+   /* The following is debugging; prior to 1.5.4 the code was never compiled in;
+    * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
+    * PNG_WARN_UNINITIALIZED_ROW removed.  In 1.6 the new flag is set only for
+    * all transformations, however in practice the ROW_INIT always gets done on
+    * demand, if necessary.
+    */
+   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
+      !(png_ptr->flags & PNG_FLAG_ROW_INIT))
+   {
+      /* Application has failed to call either png_read_start_image() or
+       * png_read_update_info() after setting transforms that expand pixels.
+       * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
+       */
+      png_error(png_ptr, "Uninitialized row");
+   }
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if (png_ptr->transformations & PNG_EXPAND)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
       {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 3;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 4;
-
-         else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
-            *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
-         }
+         png_do_expand_palette(row_info, png_ptr->row_buf + 1,
+             png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
       }
-      else if (row_info->bit_depth == 16)
+
+      else
       {
-         png_bytep rp;
-         png_uint_32 i;
-
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 6;
-
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 8;
+         if (png_ptr->num_trans &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS))
+            png_do_expand(row_info, png_ptr->row_buf + 1,
+                &(png_ptr->trans_color));
 
          else
-            return;
-
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
-            png_uint_32 red  = (s0 + s1 + 65536) & 0xffff;
-            png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
-            *(rp    ) = (png_byte)((red >> 8) & 0xff);
-            *(rp + 1) = (png_byte)(red & 0xff);
-            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
-            *(rp + 5) = (png_byte)(blue & 0xff);
-         }
+            png_do_expand(row_info, png_ptr->row_buf + 1,
+                NULL);
       }
    }
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
+      !(png_ptr->transformations & PNG_COMPOSE) &&
+      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+         0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   {
+      int rgb_error =
+          png_do_rgb_to_gray(png_ptr, row_info,
+              png_ptr->row_buf + 1);
+
+      if (rgb_error)
+      {
+         png_ptr->rgb_to_gray_status=1;
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_WARN)
+            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_ERR)
+            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+      }
+   }
+#endif
+
+/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
+ *
+ *   In most cases, the "simple transparency" should be done prior to doing
+ *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
+ *   pixel is transparent.  You would also need to make sure that the
+ *   transparency information is upgraded to RGB.
+ *
+ *   To summarize, the current flow is:
+ *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+ *                                   with background "in place" if transparent,
+ *                                   convert to RGB if necessary
+ *   - Gray + alpha -> composite with gray background and remove alpha bytes,
+ *                                   convert to RGB if necessary
+ *
+ *   To support RGB backgrounds for gray images we need:
+ *   - Gray + simple transparency -> convert to RGB + simple transparency,
+ *                                   compare 3 or 6 bytes and composite with
+ *                                   background "in place" if transparent
+ *                                   (3x compare/pixel compared to doing
+ *                                   composite with gray bkgrnd)
+ *   - Gray + alpha -> convert to RGB + alpha, composite with background and
+ *                                   remove alpha bytes (3x float
+ *                                   operations/pixel compared with composite
+ *                                   on gray background)
+ *
+ *  Greg's change will do this.  The reason it wasn't done before is for
+ *  performance, as this increases the per-pixel operations.  If we would check
+ *  in advance if the background was gray or RGB, and position the gray-to-RGB
+ *  transform appropriately, then it would save a lot of work/time.
+ */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* If gray -> RGB, do so now only if background is non-gray; else do later
+    * for performance reasons
+    */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+       !(png_ptr->flags & PNG_FLAG_BACKGROUND_IS_GRAY))
+      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   if (png_ptr->transformations & PNG_COMPOSE)
+      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   if ((png_ptr->transformations & PNG_GAMMA) &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+      /* Because RGB_TO_GRAY does the gamma transform. */
+      !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+      /* Because PNG_COMPOSE does the gamma transform if there is something to
+       * do (if there is an alpha channel or transparency.)
+       */
+       !((png_ptr->transformations & PNG_COMPOSE) &&
+       ((png_ptr->num_trans != 0) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+#endif
+      /* Because png_init_read_transformations transforms the palette, unless
+       * RGB_TO_GRAY will do the transform.
+       */
+       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+      png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
+      (png_ptr->transformations & PNG_COMPOSE) &&
+      (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+      row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+         0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
+      (row_info->color_type & PNG_COLOR_MASK_ALPHA))
+      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+   /* There is no harm in doing both of these because only one has any effect,
+    * by putting the 'scale' option first if the app asks for scale (either by
+    * calling the API or in a TRANSFORM flag) this is what happens.
+    */
+   if (png_ptr->transformations & PNG_16_TO_8)
+      png_do_chop(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if (png_ptr->transformations & PNG_QUANTIZE)
+   {
+      png_do_quantize(row_info, png_ptr->row_buf + 1,
+          png_ptr->palette_lookup, png_ptr->quantize_index);
+
+      if (row_info->rowbytes == 0)
+         png_error(png_ptr, "png_do_quantize returned rowbytes=0");
+   }
+#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   /* Do the expansion now, after all the arithmetic has been done.  Notice
+    * that previous transformations can handle the PNG_EXPAND_16 flag if this
+    * is efficient (particularly true in the case of gamma correction, where
+    * better accuracy results faster!)
+    */
+   if (png_ptr->transformations & PNG_EXPAND_16)
+      png_do_expand_16(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* NOTE: moved here in 1.5.4 (from much later in this list.) */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+       (png_ptr->flags & PNG_FLAG_BACKGROUND_IS_GRAY))
+      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_SUPPORTED
+   if (png_ptr->transformations & PNG_INVERT_MONO)
+      png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   if (png_ptr->transformations & PNG_SHIFT)
+      png_do_unshift(row_info, png_ptr->row_buf + 1,
+          &(png_ptr->shift));
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+   if (png_ptr->transformations & PNG_PACK)
+      png_do_unpack(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Added at libpng-1.5.10 */
+   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= 0)
+      png_do_check_palette_indexes(png_ptr, row_info);
+#endif
+
+#ifdef PNG_READ_BGR_SUPPORTED
+   if (png_ptr->transformations & PNG_BGR)
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   if (png_ptr->transformations & PNG_FILLER)
+      png_do_read_filler(row_info, png_ptr->row_buf + 1,
+          (png_uint_32)png_ptr->filler, png_ptr->flags);
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+#ifdef PNG_READ_SWAP_SUPPORTED
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_do_swap(row_info, png_ptr->row_buf + 1);
+#endif
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+    {
+      if (png_ptr->read_user_transform_fn != NULL)
+         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
+             (png_ptr,     /* png_ptr */
+             row_info,     /* row_info: */
+                /*  png_uint_32 width;       width of row */
+                /*  png_size_t 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 */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+      if (png_ptr->user_transform_depth)
+         row_info->bit_depth = png_ptr->user_transform_depth;
+
+      if (png_ptr->user_transform_channels)
+         row_info->channels = png_ptr->user_transform_channels;
+#endif
+      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
+          row_info->channels);
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
+   }
+#endif
 }
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
 #endif /* PNG_READ_SUPPORTED */

pngrutil.c

@@ -3794,7 +3794,6 @@ png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
       /* Calculate the current pixel in a, and move the previous row pixel to c
        * for the next time round the loop
        */
-      c = b;
       a += *row;
       *row++ = (png_byte)a;
    }

pngset.c

@@ -528,7 +528,7 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
 #        endif
       ))
    {
-      png_chunk_report(png_ptr, "Invalid palette", PNG_CHUNK_ERROR);
+      png_error(png_ptr, "Invalid palette");
       return;
    }
 

pngtest.c

@@ -569,7 +569,8 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
             /* We must free the list element too, but first kill
                the memory that is to be freed. */
             memset(ptr, 0x55, pinfo->size);
-            png_free_default(png_ptr, pinfo);
+            if (pinfo)
+               free(pinfo);
             pinfo = NULL;
             break;
          }
@@ -588,7 +589,8 @@ png_debug_free(png_structp png_ptr, png_voidp ptr)
    if (verbose)
       printf("Freeing %p\n", ptr);
 
-   png_free_default(png_ptr, ptr);
+   if (ptr)
+      free(ptr);
    ptr = NULL;
 }
 #endif /* PNG_USER_MEM_SUPPORTED && PNG_DEBUG */
@@ -1574,14 +1576,12 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
 
 #ifdef PNG_WRITE_SUPPORTED /* else nothing was written */
    {
-      int wrote_question = 0;
-
       for (;;)
       {
+         static int wrote_question = 0;
          png_size_t num_in, num_out;
          char inbuf[256], outbuf[256];
 
-
          num_in = fread(inbuf, 1, sizeof inbuf, fpin);
          num_out = fread(outbuf, 1, sizeof outbuf, fpout);
 
@@ -1966,4 +1966,4 @@ main(void)
 #endif
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_7_0beta23 Your_png_h_is_not_version_1_7_0beta23;
+typedef png_libpng_version_1_7_0beta24 Your_png_h_is_not_version_1_7_0beta24;

pngwrite.c

@@ -613,6 +613,71 @@ png_write_image(png_structrp png_ptr, png_bytepp image)
    }
 }
 
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Performs intrapixel differencing  */
+static void
+png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_intrapixel");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp)     = (png_byte)((*rp       - *(rp + 1)) & 0xff);
+            *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
+         }
+      }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
+            *(rp    ) = (png_byte)((red >> 8) & 0xff);
+            *(rp + 1) = (png_byte)(red & 0xff);
+            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp + 5) = (png_byte)(blue & 0xff);
+         }
+      }
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
+   }
+}
+#endif /* PNG_MNG_FEATURES_SUPPORTED */
+
 /* Called by user to write a row of image data */
 void PNGAPI
 png_write_row(png_structrp png_ptr, png_const_bytep row)

pngwtran.c

@@ -14,90 +14,14 @@
 #include "pngpriv.h"
 
 #ifdef PNG_WRITE_SUPPORTED
-
 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
-/* Transform the data according to the user's wishes.  The order of
- * transformations is significant.
- */
-void /* PRIVATE */
-png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
-{
-   png_debug(1, "in png_do_write_transformations");
-
-   if (png_ptr == NULL)
-      return;
-
-#ifdef 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 */
-             row_info,  /* row_info: */
-                /*  png_uint_32 width;       width of row */
-                /*  png_size_t 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
-
-#ifdef PNG_WRITE_FILLER_SUPPORTED
-   if (png_ptr->transformations & PNG_FILLER)
-      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
-         !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
-#endif
-
-#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_PACKSWAP)
-      png_do_packswap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_PACK_SUPPORTED
-   if (png_ptr->transformations & PNG_PACK)
-      png_do_pack(row_info, png_ptr->row_buf + 1,
-          (png_uint_32)png_ptr->bit_depth);
-#endif
-
-#ifdef PNG_WRITE_SWAP_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_do_swap(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_SHIFT_SUPPORTED
-   if (png_ptr->transformations & PNG_SHIFT)
-      png_do_shift(row_info, png_ptr->row_buf + 1,
-          &(png_ptr->shift));
-#endif
-
-#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_SWAP_ALPHA)
-      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_ALPHA)
-      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_BGR_SUPPORTED
-   if (png_ptr->transformations & PNG_BGR)
-      png_do_bgr(row_info, png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_WRITE_INVERT_SUPPORTED
-   if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_do_invert(row_info, png_ptr->row_buf + 1);
-#endif
-}
 
 #ifdef 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 /* PRIVATE */
+static void
 png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
 {
    png_debug(1, "in png_do_pack");
@@ -242,7 +166,7 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
  * would pass 3 as bit_depth, and this routine would translate the
  * data to 0 to 15.
  */
-void /* PRIVATE */
+static void
 png_do_shift(png_row_infop row_info, png_bytep row,
     png_const_color_8p bit_depth)
 {
@@ -381,7 +305,7 @@ png_do_shift(png_row_infop row_info, png_bytep row,
 #endif
 
 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
-void /* PRIVATE */
+static void
 png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_write_swap_alpha");
@@ -475,7 +399,7 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
 #endif
 
 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
-void /* PRIVATE */
+static void
 png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
 {
    png_debug(1, "in png_do_write_invert_alpha");
@@ -568,70 +492,81 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
    }
 }
 #endif
-#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
 
-#ifdef PNG_MNG_FEATURES_SUPPORTED
-/* Undoes intrapixel differencing  */
+/* Transform the data according to the user's wishes.  The order of
+ * transformations is significant.
+ */
 void /* PRIVATE */
-png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
+png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
 {
-   png_debug(1, "in png_do_write_intrapixel");
+   png_debug(1, "in png_do_write_transformations");
 
-   if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
-   {
-      int bytes_per_pixel;
-      png_uint_32 row_width = row_info->width;
-      if (row_info->bit_depth == 8)
-      {
-         png_bytep rp;
-         png_uint_32 i;
+   if (png_ptr == NULL)
+      return;
 
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 3;
+#ifdef 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 */
+             row_info,  /* row_info: */
+                /*  png_uint_32 width;       width of row */
+                /*  png_size_t 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
 
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 4;
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+   if (png_ptr->transformations & PNG_FILLER)
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+         !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
+#endif
 
-         else
-            return;
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
 
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            *(rp)     = (png_byte)((*rp       - *(rp + 1)) & 0xff);
-            *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
-         }
-      }
+#ifdef PNG_WRITE_PACK_SUPPORTED
+   if (png_ptr->transformations & PNG_PACK)
+      png_do_pack(row_info, png_ptr->row_buf + 1,
+          (png_uint_32)png_ptr->bit_depth);
+#endif
 
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-      else if (row_info->bit_depth == 16)
-      {
-         png_bytep rp;
-         png_uint_32 i;
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_do_swap(row_info, png_ptr->row_buf + 1);
+#endif
 
-         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
-            bytes_per_pixel = 6;
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+   if (png_ptr->transformations & PNG_SHIFT)
+      png_do_shift(row_info, png_ptr->row_buf + 1,
+          &(png_ptr->shift));
+#endif
 
-         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-            bytes_per_pixel = 8;
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
 
-         else
-            return;
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
 
-         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
-         {
-            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
-            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
-            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
-            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
-            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
-            *(rp    ) = (png_byte)((red >> 8) & 0xff);
-            *(rp + 1) = (png_byte)(red & 0xff);
-            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
-            *(rp + 5) = (png_byte)(blue & 0xff);
-         }
-      }
-#endif /* PNG_WRITE_16BIT_SUPPORTED */
-   }
+#ifdef PNG_WRITE_BGR_SUPPORTED
+   if (png_ptr->transformations & PNG_BGR)
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+   if (png_ptr->transformations & PNG_INVERT_MONO)
+      png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
 }
-#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
 #endif /* PNG_WRITE_SUPPORTED */

projects/vstudio/readme.txt

@@ -1,7 +1,7 @@
 
 VisualStudio instructions
 
-libpng version 1.7.0beta23 - November 24, 2013
+libpng version 1.7.0beta24 - December 15, 2013
 
 Copyright (c) 1998-2010 Glenn Randers-Pehrson
 

projects/vstudio/zlib.props

@@ -2,7 +2,7 @@
 <!--
  * zlib.props - location of zlib source
  *
- * libpng version 1.7.0beta23 - November 24, 2013
+ * libpng version 1.7.0beta24 - December 15, 2013
  *
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  *

scripts/README.txt

@@ -1,9 +1,9 @@
 
-Makefiles for  libpng version 1.7.0beta23 - November 24, 2013
+Makefiles for  libpng version 1.7.0beta24 - December 15, 2013
 
 pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng17.so.17.1.7.0beta23)
+                       (gcc, creates libpng17.so.17.1.7.0beta24)
  makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
  makefile.knr      =>  Archaic UNIX Makefile that converts files with
                        ansi2knr (Requires ansi2knr.c from
@@ -20,7 +20,7 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.dec      =>  DEC Alpha UNIX makefile
  makefile.dj2      =>  DJGPP 2 makefile
  makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       (gcc, creates libpng17.so.17.1.7.0beta23)
+                       (gcc, creates libpng17.so.17.1.7.0beta24)
  makefile.freebsd  =>  FreeBSD makefile
  makefile.gcc      =>  Generic gcc makefile
  makefile.hpgcc    =>  HPUX makefile using gcc
@@ -35,12 +35,12 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
  makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
  makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng17.so.17.1.7.0beta23)
+                       creates libpng17.so.17.1.7.0beta24)
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
  makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng17.so.17.1.7.0beta23)
+                       creates libpng17.so.17.1.7.0beta24)
  makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng17.so.17.1.7.0beta23)
+                       creates libpng17.so.17.1.7.0beta24)
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
  makefile.sunos    =>  Sun makefile
  makefile.32sunu   =>  Sun Ultra 32-bit makefile

scripts/def.dfn

@@ -21,7 +21,7 @@ PNG_DFN "OS2 DESCRIPTION "PNG image compression library""
 PNG_DFN "OS2 CODE PRELOAD MOVEABLE DISCARDABLE"
 PNG_DFN ""
 PNG_DFN "EXPORTS"
-PNG_DFN ";Version 1.7.0beta23"
+PNG_DFN ";Version 1.7.0beta24"
 
 #define PNG_EXPORTA(ordinal, type, name, args, attributes)\
         PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"

scripts/libpng-config-head.in

@@ -11,7 +11,7 @@
 
 # Modeled after libxml-config.
 
-version=1.7.0beta23
+version=1.7.0beta24
 prefix=""
 libdir=""
 libs=""

scripts/libpng.pc.in

@@ -5,6 +5,6 @@ includedir=@includedir@/libpng17
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.7.0beta23
+Version: 1.7.0beta24
 Libs: -L${libdir} -lpng17
 Cflags: -I${includedir}

scripts/makefile.ne12bsd

@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include/libpng17
 
 LIB=	png17
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.7.0beta23
+SHLIB_MINOR=	1.7.0beta24
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c

scripts/makefile.netbsd

@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include
 
 LIB=	png
 SHLIB_MAJOR=	17
-SHLIB_MINOR=	1.7.0beta23
+SHLIB_MINOR=	1.7.0beta24
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c

scripts/makefile.openbsd

@@ -11,7 +11,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat
 
 SHLIB_MAJOR=	17
-SHLIB_MINOR=	1.7.0beta23
+SHLIB_MINOR=	1.7.0beta24
 
 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \

scripts/pnglibconf.dfa

@@ -506,6 +506,7 @@ option INCH_CONVERSIONS
 = INCH_CONVERSIONS INCH_CONVERSIONS
 
 # API to build a grayscale palette
+# NOTE: this is not used internally by libpng at present.
 
 option BUILD_GRAYSCALE_PALETTE
 

scripts/pnglibconf.h.prebuilt

@@ -1,8 +1,8 @@
-/* libpng 1.7.0beta23 STANDARD API DEFINITION */
+/* libpng 1.7.0beta24 STANDARD API DEFINITION */
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng version 1.7.0beta23 - November 24, 2013 */
+/* Libpng version 1.7.0beta24 - December 15, 2013 */
 
 /* Copyright (c) 1998-2013 Glenn Randers-Pehrson */
 

scripts/symbols.def

@@ -1,4 +1,4 @@
-;Version 1.7.0beta23
+;Version 1.7.0beta24
 ;--------------------------------------------------------------
 ; LIBPNG symbol list as a Win32 DEF file
 ; Contains all the symbols that can be exported from libpng