[png-mng-implement] libpng-1.6.0beta28 is available

[Glenn Randers-P. <gl...@gm...>]

libpng-1.6.0beta28 is available from
ftp://ftp.simplesystems.org
and from
http://libpng.sf.net

Version 1.6.0beta28 [August 29, 2012]
  Unknown handling fixes and clean up. This adds more correct option
    control of the unknown handling, corrects the pre-existing bug where
    the per-chunk 'keep' setting is ignored and makes it possible to skip
    IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
    There is a new test program, test-unknown.c, which is a work in progress
    (not currently part of the test suite).  Comments in the header files now
    explain how the unknown handling works.
  Allow fine grain control of unknown chunk APIs. This change allows
    png_set_keep_unknown_chunks() to be turned off if not required and causes
    both read and write to behave appropriately (on read this is only possible
    if the user callback is used to handle unknown chunks).  The change
    also removes the support for storing unknown chunks in the info_struct
    if the only unknown handling enabled is via the callback, allowing libpng
    to be configured with callback reading and none of the unnecessary code.
  Corrected fix for unknown handling in pngtest. This reinstates the
    libpng handling of unknown chunks other than vpAg and sTER (including
    unsafe-to-copy chunks which were dropped before) and eliminates the
    repositioning of vpAg and sTER in pngtest.png by changing pngtest.png
    (so the chunks are where libpng would put them).
  Added "tunknown" test and corrected a logic error in png_handle_unknown()
    when SAVE support is absent.  Moved the shell test scripts for
    contrib/libtests from the libpng top directory to contrib/libtests.
    png_handle_unknown() must always read or skip the chunk, if
    SAVE_UNKNOWN_CHUNKS is turned off *and* the application does not set
    a user callback an unknown chunk will not be read, leading to a read
    error, which was revealed by the "tunknown" test.
  Cleaned up and corrected ICC profile handling.
    contrib/libtests/makepng: corrected 'rgb' and 'gray' cases.  profile_error
    messages could be truncated; made a correct buffer size calculation and
    adjusted pngerror.c appropriately. png_icc_check_* checking improved;
    changed the functions to receive the correct color type of the PNG on read
    or write and check that it matches the color space of the profile (despite
    what the comments said before, there is danger in assuming the app will
    cope correctly with an RGB profile on a grayscale image and, since it
    violates the PNG spec, allowing it is certain to produce inconsistent
    app behavior and might even cause app crashes.) Check that profiles
    contain the tags needed to process the PNG (tags all required by the ICC
    spec). Removed unused PNG_STATIC from pngpriv.h.

Glenn