Libpng 1.5.3beta10 - May 20, 2011

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.

Files available for download:

Source files with LF line endings (for Unix/Linux) and with a
"configure" script

   1.5.3beta10.tar.xz (LZMA-compressed, recommended)
   1.5.3beta10.tar.gz
   1.5.3beta10.tar.bz2

Source files with CRLF line endings (for Windows), without the
"configure" script

   lp153b10.7z  (LZMA-compressed, recommended)
   lp153b10.zip

Other information:

   1.5.3beta10-README.txt
   1.5.3beta10-LICENSE.txt

Changes since the last public release (1.5.2):

Version 1.5.3beta01 [April 1, 2011]
  Re-initialize the zlib compressor before compressing non-IDAT chunks.
  Added API functions 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 clash with the png_jmpbuf macro on some platforms.

Version 1.5.3beta05 [May 6, 2011]
  Added appropriate feature test macros 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.  _ISOC99_SOURCE is
    defined in pngpriv.h to obtain the ISO C99 snprintf definition, when
    available.
  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.
  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.
  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

Version 1.5.3beta09 [May 17, 2011]
 Reversed earlier 1.5.3 change of transformation order; move png_expand_16 back.
   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.

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