ANNOUNCE - third_party/libpng - Git at Google


 Libpng 1.7.0alpha03 - December 19, 2012

 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

    1.7.0alpha03.tar.xz (LZMA-compressed, recommended)
    1.7.0alpha03.tar.gz
    1.7.0alpha03.tar.bz2

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

    lp170a03.7z  (LZMA-compressed, recommended)
    lp170a03.zip

 Other information:

    1.7.0alpha03-README.txt
    1.7.0alpha03-LICENSE.txt

 Changes since the last public release (1.6.0):

 Version 1.7.0alpha01 [December 15, 2012]
   Started 1.7.0 branch from libpng-1.6.0beta33.
   Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
     changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
     corrected compose and grayscale operations.  The arithmetic errors have
     three sources all of which are fixed in this commit:
     1) 8-bit linear calculations produce massive errors for lower intensity
        values.
     2) The old 16-bit "16 to 8" gamma table code erroneously wrote the lowest
        output value into a table entry which corresponded to multiple output
        values (so where the value written should have been the closest to the
        transformed input value.)
     3) In a number of cases the code to access the 16-bit table did not round;
        it did a simple shift, which was wrong and made the side effects of (2)
        even worse.
   The new gamma code does not have the 16-to-8 problem at the cost of slightly
     more calculations and the algorithm used to minimize the number of
     calculations has been extended to all the 16-bit tables; it has advantages
     for any significant gamma correction.
   Rearranged png_struct, remove unused members, change png_set_filter handling
     png_struct members rearranged - partly to reorder to avoid packing, partly
     to put frequently accessed members at the start and partly to make
     the grouping more clear. png_set_filter code has been rewritten and the
     code shared with png_write_start_row moved to a common function.  Comments
     in png.h have been made more clear. Minor fixes to
     contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
     more error detection in png_set_tRNS.
   Cleaned up USER_LIMITS feature, removing members from png_struct when not
     required.
   Rearranged ARM-NEON optimizations to isolate the machine specific code to
     the hardware subdirectory, and add comments to pngrutil.c so that
     implementors of other optimizations will know what to do.
   Fixed cases of unquoted DESTDIR in Makefile.am.
   Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.12.5.

 Version 1.7.0alpha02 [December 17, 2012]
   Removed functions that were deprecated in libpng-1.6.0:
     png_reset_zstream(), png_info_init_3(), and png_data_freer() and its
     associated flags.
   Removed some duplicated lines from contrib/tools/scale.c and png.c.
   Changed some instances of png_warning() to png_app_error().
   Updated some left over "1.6.0beta32" in code sources.
   Fixed a "png_structp" prototype (should be png_structrp) in arm_init.c
   Updated the version-number hack in pngvalid.c

 Version 1.7.0alpha03 [December 19, 2012]
   Cleaned up and enhanced the configure option; libpng now correctly
     links and tests against zlib with a prefix; tests have been clarified; and
     irrelevant or obsolete things (as defined by the autotools man page) have
     been removed.
   Documented new PNG_ABORT behavior in the manual and commentary in pngerror.c
   Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
   Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs;
     some of these use floating point arithmetic so they need to be disabled if
     floating point arithmetic is switched off.  This is a quiet API change -
     previously it appeared that the APIs were supported if fixed point
     arithmetic was used internally, however they required certain APIs (floor,
     modf, frexp, atof) that are part of C floating point support. Changed
     png_fixed and the gamma code specific version of the same to avoid floor(),
     which may be a library function (not an intrinsic). Removed unused #if 0
     code.
   Disassembled the version number in scripts/options.awk (necessary for
     building on SunOs).

   ===========================================================================
                        NOTICE November 17, 2012:
      The location of the git repository at SourceForge has changed.
                Visit http://libpng.sf.net/ for details.
   ===========================================================================

 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

	Libpng 1.7.0alpha03 - December 19, 2012

	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

	1.7.0alpha03.tar.xz (LZMA-compressed, recommended)
	1.7.0alpha03.tar.gz
	1.7.0alpha03.tar.bz2

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

	lp170a03.7z (LZMA-compressed, recommended)
	lp170a03.zip

	Other information:

	1.7.0alpha03-README.txt
	1.7.0alpha03-LICENSE.txt

	Changes since the last public release (1.6.0):

	Version 1.7.0alpha01 [December 15, 2012]
	Started 1.7.0 branch from libpng-1.6.0beta33.
	Made 8-bit compose and rgb_to_grayscale accuracy improvements. These
	changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
	corrected compose and grayscale operations. The arithmetic errors have
	three sources all of which are fixed in this commit:
	1) 8-bit linear calculations produce massive errors for lower intensity
	values.
	2) The old 16-bit "16 to 8" gamma table code erroneously wrote the lowest
	output value into a table entry which corresponded to multiple output
	values (so where the value written should have been the closest to the
	transformed input value.)
	3) In a number of cases the code to access the 16-bit table did not round;
	it did a simple shift, which was wrong and made the side effects of (2)
	even worse.
	The new gamma code does not have the 16-to-8 problem at the cost of slightly
	more calculations and the algorithm used to minimize the number of
	calculations has been extended to all the 16-bit tables; it has advantages
	for any significant gamma correction.
	Rearranged png_struct, remove unused members, change png_set_filter handling
	png_struct members rearranged - partly to reorder to avoid packing, partly
	to put frequently accessed members at the start and partly to make
	the grouping more clear. png_set_filter code has been rewritten and the
	code shared with png_write_start_row moved to a common function. Comments
	in png.h have been made more clear. Minor fixes to
	contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
	more error detection in png_set_tRNS.
	Cleaned up USER_LIMITS feature, removing members from png_struct when not
	required.
	Rearranged ARM-NEON optimizations to isolate the machine specific code to
	the hardware subdirectory, and add comments to pngrutil.c so that
	implementors of other optimizations will know what to do.
	Fixed cases of unquoted DESTDIR in Makefile.am.
	Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.12.5.

	Version 1.7.0alpha02 [December 17, 2012]
	Removed functions that were deprecated in libpng-1.6.0:
	png_reset_zstream(), png_info_init_3(), and png_data_freer() and its
	associated flags.
	Removed some duplicated lines from contrib/tools/scale.c and png.c.
	Changed some instances of png_warning() to png_app_error().
	Updated some left over "1.6.0beta32" in code sources.
	Fixed a "png_structp" prototype (should be png_structrp) in arm_init.c
	Updated the version-number hack in pngvalid.c

	Version 1.7.0alpha03 [December 19, 2012]
	Cleaned up and enhanced the configure option; libpng now correctly
	links and tests against zlib with a prefix; tests have been clarified; and
	irrelevant or obsolete things (as defined by the autotools man page) have
	been removed.
	Documented new PNG_ABORT behavior in the manual and commentary in pngerror.c
	Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
	Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs;
	some of these use floating point arithmetic so they need to be disabled if
	floating point arithmetic is switched off. This is a quiet API change -
	previously it appeared that the APIs were supported if fixed point
	arithmetic was used internally, however they required certain APIs (floor,
	modf, frexp, atof) that are part of C floating point support. Changed
	png_fixed and the gamma code specific version of the same to avoid floor(),
	which may be a library function (not an intrinsic). Removed unused #if 0
	code.
	Disassembled the version number in scripts/options.awk (necessary for
	building on SunOs).

	===========================================================================
	NOTICE November 17, 2012:
	The location of the git repository at SourceForge has changed.
	Visit http://libpng.sf.net/ for details.
	===========================================================================

	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