Libpng 1.6.1 - March 28, 2013

This is a public release of libpng, intended for use in production codes.

Files available for download:

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

   libpng-1.6.1.tar.xz (LZMA-compressed, recommended)
   libpng-1.6.1.tar.gz

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

   lpng161.7z  (LZMA-compressed, recommended)
   lpng161.zip

Other information:

   libpng-1.6.1-README.txt
   libpng-1.6.1-LICENSE.txt

Changes since the last public release (1.6.0):

  Made symbol prefixing work with the ARM neon optimizations. Also allow
    pngpriv.h to be included for preprocessor definitions only, so it can
    be used in non-C/C++ files. Back ported from libpng 1.7.
  Made sRGB check numbers consistent.
  Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
  Removed cc -E workround, corrected png_get_palette_max API Tested on
    SUN OS cc 5.9, which demonstrates the tokenization problem previously
    avoided by using /lib/cpp.  Since all .dfn output is now protected in
    double quotes unless it is to be macro substituted the fix should
    work everywhere.
  Enabled parallel tests - back ported from libpng-1.7.
  scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
  Fixed a race condition in the creation of the build 'scripts' directory
    while building with a parallel make.
  Use approved/supported Android method to check for NEON, use Linux/POSIX
    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
    library calls (ported from libpng15).
  Use parentheses more consistently in "#if defined(MACRO)" tests.
  Folded long lines.
  Reenabled code to allow zero length PLTE chunks for MNG.
  Fixed ALIGNED_MEMORY support.
  Allow run-time ARM NEON checking to be disabled. A new configure option:
    --enable-arm-neon=always will stop the run-time checks. New checks
    within arm/arm_init.c will cause the code not to be compiled unless
    __ARM_NEON__ is set. This should make it fail safe (if someone asks
    for it on then the build will fail if it can't be done.)
  Updated the INSTALL document.
  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
    with CRLF line endings.
  Avoid a possible memory leak in contrib/gregbook/readpng.c
  Better documentation of unknown handling API interactions.
  Corrected Android builds and corrected libpng.vers with symbol
    prefixing This adds an API to set optimization options externally,
    providing an alternative and general solution for the non-portable
    run-time tests used by the ARM Neon code.  It also makes those tests
    compile and link on Android.
  The order of settings vs options in pnglibconf.h is reversed to allow
    settings to depend on options and options can now set (or override) the
    defaults for settings.
  Corrected simplified API default gamma for color-mapped output, added
    a flag to change default. In 1.6.0 when the simplified API was used
    to produce color-mapped output from an input image with no gamma
    information the gamma assumed for the input could be different from
    that assumed for non-color-mapped output.  In particular 16-bit depth
    input files were assumed to be sRGB encoded, whereas in the 'direct'
    case they were assumed to have linear data.  This was an error.  The
    fix makes the simplified API treat all input files the same way and
    adds a new flag to the png_image::flags member to allow the
    application/user to specify that 16-bit files contain sRGB data
    rather than the default linear.
  Fixed bugs in the pngpixel and makepng test programs.
  Fixed CMakelists.txt to allow building a single variant of the library
    (Claudio Bley):
  Introduced a PNG_LIB_TARGETS variable that lists all activated library
    targets.  It is an error if this variable ends up empty, ie. you have
    to build at least one library variant.
  Made the *_COPY targets only depend on library targets actually being build.
  Use PNG_LIB_TARGETS to unify a code path.
  Changed the CREATE_SYMLINK macro to expect the full path to a file as the
    first argument. When symlinking the filename component of that path is
    determined and used as the link target.
  Use copy_if_different in the CREATE_SYMLINK macro.
  Eliminated two warnings from the Intel C compiler. The warnings are
    technically valid, although a reasonable treatment of division would
    show it to be incorrect.

Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
https://lists.sourceforge.net/lists/listinfo/png-mng-implement
to subscribe)
or to glennrp at users.sourceforge.net

Glenn R-P