+Version 1.5.1 [February 3, 2011]
+ No changes.
+
+Version 1.5.2beta01 [February 13, 2011]
+ More -Wshadow fixes for older gcc compilers. Older gcc versions apparently
+ check formal parameters names in function declarations (as well as
+ definitions) to see if they match a name in the global namespace.
+ Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
+ old VisualC++ preprocessor.
+ Turned on interlace handling in png_read_png().
+ Fixed gcc pendantic warnings.
+ Handle longjmp in Cygwin.
+ Fixed png_get_current_row_number() in the interlaced case.
+ Cleaned up ALPHA flags and transformations.
+ Implemented expansion to 16 bits.
+
+Version 1.5.2beta02 [February 19, 2011]
+ Fixed mistake in the descriptions of user read_transform and write_transform
+ function prototypes in the manual. The row_info struct is png_row_infop.
+ Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
+ Corrected png_get_current_row_number documentation
+ Fixed the read/write row callback documentation.
+ This documents the current behavior, where the callback is called after
+ every row with information pertaining to the next row.
+
+Version 1.5.2beta03 [March 3, 2011]
+ Fixed scripts/makefile.vcwin32
+ Updated contrib/pngsuite/README to add the word "modify".
+ Define PNG_ALLOCATED to blank when _MSC_VER<1300.
+
+Version 1.5.2rc01 [March 19, 2011]
+ Define remaining attributes to blank when MSC_VER<1300.
+ ifdef out mask arrays in pngread.c when interlacing is not supported.
+
+Version 1.5.2rc02 [March 22, 2011]
+ Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
+ and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
+ from the makefiles.
+ Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
+ to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
+
+Version 1.5.2rc03 [March 24, 2011]
+ Don't include standard header files in png.h while building the symbol table,
+ to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
+
+Version 1.5.2 [March 31, 2011]
+ No changes.
+
+Version 1.5.3beta01 [April 1, 2011]
+ Re-initialize the zlib compressor before compressing non-IDAT chunks.
+ Added API functions (png_set_text_compression_level() and four others) to
+ set parameters for zlib compression of non-IDAT chunks.
+
+Version 1.5.3beta02 [April 3, 2011]
+ Updated scripts/symbols.def with new API functions.
+ Only compile the new zlib re-initializing code when text or iCCP is
+ supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
+ Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
+ Optimize the zlib CMF byte in non-IDAT compressed chunks
+
+Version 1.5.3beta03 [April 16, 2011]
+ Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
+ snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
+ than __STDC__ (John Bowler).
+ Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
+ the compiler that a user supplied callback (the error handler) does not
+ return, yet there is no guarantee in practice that the application code
+ will correctly implement the error handler because the compiler only
+ issues a warning if there is a mistake (John Bowler).
+ Removed the no-longer-used PNG_DEPSTRUCT macro.
+ Updated the zlib version to 1.2.5 in the VStudio project.
+ Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
+ pngwutil.c (John Bowler).
+ Fixed bug with stripping the filler or alpha channel when writing, that
+ was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+ Updated pngtest.png with the new zlib CMF optimization.
+ Cleaned up conditional compilation code and of background/gamma handling
+ Internal changes only except a new option to avoid compiling the
+ png_build_grayscale_palette API (which is not used at all internally.)
+ The main change is to move the transform tests (READ_TRANSFORMS,
+ WRITE_TRANSFORMS) up one level to the caller of the APIs. This avoids
+ calls to spurious functions if all transforms are disabled and slightly
+ simplifies those functions. Pngvalid modified to handle this.
+ A minor change is to stop the strip_16 and expand_16 interfaces from
+ disabling each other; this allows the future alpha premultiplication
+ code to use 16-bit intermediate values while still producing 8-bit output.
+ png_do_background and png_do_gamma have been simplified to take a single
+ pointer to the png_struct rather than pointers to every item required
+ from the png_struct. This makes no practical difference to the internal
+ code.
+ A serious bug in the pngvalid internal routine 'standard_display_init' has
+ been fixed - this failed to initialize the red channel and accidentally
+ initialized the alpha channel twice.
+ Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+ avoid a possible clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+ Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
+ correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
+ pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
+ Removed png_snprintf and added formatted warning messages. This change adds
+ internal APIs to allow png_warning messages to have parameters without
+ requiring the host OS to implement snprintf. As a side effect the
+ dependency of the tIME-supporting RFC1132 code on stdio is removed and
+ PNG_NO_WARNINGS does actually work now.
+ Pass "" instead of '\0' to png_default_error() in png_err(). This mistake
+ was introduced in libpng-1.2.20beta01. This fixes CVE-2011-2691.
+ Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+ optimization configureable.
+ IDAT compression failed if preceded by a compressed text chunk (bug
+ introduced in libpng-1.5.3beta01-02). This was because the attempt to
+ reset the zlib stream in png_write_IDAT happened after the first IDAT
+ chunk had been deflated - much too late. In this change internal
+ functions were added to claim/release the z_stream and, hopefully, make
+ the code more robust. Also deflateEnd checking is added - previously
+ libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+ Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+ Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+ Added expand_16 support to the high level interface.
+ Added named value and 'flag' gamma support to png_set_gamma. Made a minor
+ change from the previous (unreleased) ABI/API to hide the exact value used
+ for Macs - it's not a good idea to embed this in the ABI!
+ Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+ from pngpriv.h to png.h because they must be visible to applications
+ that call png_set_unknown_chunks().
+ Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+ before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+ Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+ Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+ The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+ parameters are supplied by the caller), while in the absence of cHRM
+ sRGB/Rec 709 values are still used. This introduced a divide-by-zero
+ bug in png_handle_cHRM().
+ The bKGD chunk no longer overwrites the background value set by
+ png_set_background(), allowing the latter to be used before the file
+ header is read. It never performed any useful function to override
+ the default anyway.
+ Added memory overwrite and palette image checks to pngvalid.c
+ Previously palette image code was poorly checked. Since the transformation
+ code has a special palette path in most cases this was a severe weakness.
+ Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+ expanding an indexed image, always expand to RGBA if transparency is
+ present.
+
+Version 1.5.3beta09 [May 17, 2011]
+ Reversed earlier 1.5.3 change of transformation order; move png_expand_16
+ back where it was. The change doesn't work because it requires 16-bit
+ gamma tables when the code only generates 8-bit ones. This fails
+ silently; the libpng code just doesn't do any gamma correction. Moving
+ the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
+ these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+
+ png_set_background() and png_expand_16() did not work together correctly.
+ This problem is present in 1.5.2; if png_set_background is called with
+ need_expand false and the matching 16 bit color libpng erroneously just
+ treats it as an 8-bit color because of where png_do_expand_16 is in the
+ transform list. This simple fix reduces the supplied colour to 8-bits,
+ so it gets smashed, but this is better than the current behavior.
+ Added tests for expand16, more fixes for palette image tests to pngvalid.
+ Corrects the code for palette image tests and disables attempts to
+ validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+ No changes.