aa725a375c
The API is extremely inaccurate for sRGB conversions because it uses an 8-bit intermediate linear value and it does not use the sRGB transform, so it suffers from the known instability in gamma transforms for values close to 0 (see Poynton). The net result is that the calculation has a maximum error of 14.99/255; 0.5/255^(1/2.2). pngstest now uses 15 for the permitted 8-bit error. This may still not be enough because of arithmetic error.
199 lines
10 KiB
Plaintext
199 lines
10 KiB
Plaintext
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Libpng 1.6.0beta11 - February 4, 2012
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This is not intended to be a public release. It will be replaced
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within a few weeks by a public version or by another test version.
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Files available for download:
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Source files with LF line endings (for Unix/Linux) and with a
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"configure" script
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1.6.0beta11.tar.xz (LZMA-compressed, recommended)
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1.6.0beta11.tar.gz
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1.6.0beta11.tar.bz2
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Source files with CRLF line endings (for Windows), without the
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"configure" script
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lp160b11.7z (LZMA-compressed, recommended)
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lp160b11.zip
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Other information:
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1.6.0beta11-README.txt
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1.6.0beta11-LICENSE.txt
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Changes since the last public release (1.5.7):
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Version 1.6.0beta01 [December 15, 2011]
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Removed machine-generated configure files from the GIT repository (they will
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continue to appear in the tarball distributions).
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Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
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but later deleted from libpng-1.5.7beta05.
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Added example programs for the new 'simplified' API.
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Added ANSI-C (C90) headers and require them, and take advantage of the
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change. Also fixed some of the projects/* and contrib/* files that needed
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updates for libpng16 and the move of pngvalid.c.
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With this change the required ANSI-C header files are assumed to exist: the
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implementation must provide float.h, limits.h, stdarg.h and stddef.h and
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libpng relies on limits.h and stddef.h existing and behaving as defined
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(the other two required headers aren't used). Non-ANSI systems that don't
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have stddef.h or limits.h will have to provide an appropriate fake
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containing the relevant types and #defines.
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The use of FAR/far has been eliminated and the definition of png_alloc_size_t
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is now controlled by a flag so that 'small size_t' systems can select it
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if necessary. Libpng 1.6 may not currently work on such systems -- it
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seems likely that it will ask 'malloc' for more than 65535 bytes with any
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image that has a sufficiently large row size (rather than simply failing
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to read such images).
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New tools directory containing tools used to generate libpng code.
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Fixed race conditions in parallel make builds. With higher degrees of
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parallelism during 'make' the use of the same temporary file names such
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as 'dfn*' can result in a race where a temporary file from one arm of the
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build is deleted or overwritten in another arm. This changes the
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temporary files for suffix rules to always use $* and ensures that the
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non-suffix rules use unique file names.
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Version 1.6.0beta02 [December 21, 2011]
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Correct configure builds where build and source directories are separate.
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The include path of 'config.h' was erroneously made relative in pngvalid.c
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in libpng 1.5.7.
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Version 1.6.0beta03 [December 22, 2011]
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Start-up code size improvements, error handler flexibility. These changes
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alter how the tricky allocation of the initial png_struct and png_info
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structures are handled. png_info is now handled in pretty much the same
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way as everything else, except that the allocations handle NULL return
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silently. png_struct is changed in a similar way on allocation and on
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deallocation a 'safety' error handler is put in place (which should never
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be required). The error handler itself is changed to permit mismatches
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in the application and libpng error buffer size; however, this means a
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silent change to the API to return the jmp_buf if the size doesn't match
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the size from the libpng compilation; libpng now allocates the memory and
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this may fail. Overall these changes result in slight code size
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reductions; however, this is a reduction in code that is always executed
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so is particularly valuable. Overall on a 64-bit system the libpng DLL
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decreases in code size by 1733 bytes. pngerror.o increases in size by
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about 465 bytes because of the new functionality.
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Version 1.6.0beta04 [December 30, 2011]
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Regenerated configure scripts with automake-1.11.2
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Eliminated png_info_destroy(). It is now used only in png.c and only calls
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one other internal function and memset().
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Enabled png_get_sCAL_fixed() if floating point APIs are enabled. Previously
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it was disabled whenever internal fixed point arithmetic was selected,
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which meant it didn't exist even on systems where FP was available but not
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preferred.
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Added pngvalid.c compile time checks for const APIs.
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Implemented 'restrict' for png_info and png_struct. Because of the way
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libpng works both png_info and png_struct are always accessed via a
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single pointer. This means adding C99 'restrict' to the pointer gives
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the compiler some opportunity to optimize the code. This change allows
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that.
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Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
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location in configure.ac (Gilles Espinasse).
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Changed png_memcpy to C assignment where appropriate. Changed all those
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uses of png_memcpy that were doing a simple assignment to assignments
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(all those cases where the thing being copied is a non-array C L-value).
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Added some error checking to png_set_*() routines.
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Removed the reference to the non-exported function png_memcpy() from
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example.c.
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Fixed the Visual C 64-bit build - it requires jmp_buf to be aligned, but
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it had become misaligned.
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Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32
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and unsigned long are of different sizes.
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Version 1.6.0beta05 [January 15, 2012]
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Updated manual with description of the simplified API (copied from png.h)
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Fix bug in pngerror.c: some long warnings were being improperly truncated
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(CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
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Version 1.6.0beta06 [January 24, 2012]
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Added palette support to the simplified APIs. This commit
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changes some of the macro definitions in png.h, app code
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may need corresponding changes.
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Increased the formatted warning buffer to 192 bytes.
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Added color-map support to simplified API. This is an initial version for
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review; the documentation has not yet been updated.
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Fixed Min/GW uninstall to remove libpng.dll.a
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Version 1.6.0beta07 [January 28, 2012]
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Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived)
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compiler issues slightly different warnings from those issued by the
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current vesions of GCC. This eliminates those warnings by
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adding/removing casts and small code rewrites.
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Updated configure.ac from autoupdate: added --enable-werror option.
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Also some layout regularization and removal of introduced tab characters
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(replaced with 3-character indentation). Obsolete macros identified by
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autoupdate have been removed; the replacements are all in 2.59 so
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the pre-req hasn't been changed. --enable-werror checks for support
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for -Werror (or the given argument) in the compiler. This mimics the
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gcc configure option by allowing -Werror to be turned on safely; without
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the option the tests written in configure itself fail compilation because
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they cause compiler warnings.
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Rewrote autogen.sh to run autoreconf instead of running tools one-by-one.
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Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt and
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set CMAKE_LIBRARY_OUTPUT_DIRECTORY to "lib" on all platforms (C. Yapp).
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Freeze libtool files in the 'scripts' directory. This version of autogen.sh
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attempts to dissuade people from running it when it is not, or should not,
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be necessary. In fact, autogen.sh does not work when run in a libpng
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directory extracted from atar distribution anymore. You must run it in
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a GIT clone instead.
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Added two images to contrib/pngsuite (1-bit and 2-bit transparent grayscale),
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and renamed three whose names were inconsistent with those in
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pngsuite/README.txt.
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Version 1.6.0beta08 [February 1, 2012]
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Fixed Image::colormap misalignment in pngstest.c
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Check libtool/libtoolize version number (2.4.2) in configure.ac
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Divide test-pngstest.sh into separate pngstest runs for basic and
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transparent images.
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Moved automake options to AM_INIT_AUTOMAKE in configure.ac
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Added color-tests, silent-rules (Not yet implemented in Makefile.am) and
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version checking to configure.ac
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Improved pngstest speed by not doing redundant tests and add const to
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the background parameter of png_image_finish_read. The --background
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option is now done automagically only when required, so that commandline
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option no longer exists.
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Cleaned up pngpriv.h to consistently declare all functions and data.
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Also eliminated PNG_CONST_DATA, which is apparently not needed but we
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can't be sure until it is gone.
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Added symbol prefixing that allows all the libpng external symbols
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to be prefixed (suggested by Reuben Hawkins).
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Updated "ftbb*.png" list in the owatcom and vstudio projects.
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Fixed 'prefix' builds on clean systems. The generation of pngprefix.h
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should not require itself.
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Updated INSTALL to explain that autogen.sh must be run in a GIT clone,
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not in a libpng directory extracted from a tar distribution.
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Version 1.6.0beta09 [February 1, 2011]
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Reverted the prebuilt configure files to libpng-1.6.0beta05 condition.
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Version 1.6.0beta10 [February 3, 2012]
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Added Z_SOLO for zlib-1.2.6+ and correct pngstest tests
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Updated list of test images in CMakeLists.txt
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Updated the prebuilt configure files to current condition.
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Revised INSTALL information about autogen.sh; it works in tar distributions.
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Version 1.6.0beta11 [February 4, 2012]
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Fix character count in pngstest command in projects/owatcom/pngstest.tgt
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Revised test-pngstest.sh to report PASS/FAIL for each image.
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Updated documentation about the simplified API.
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Corrected estimate of error in libpng png_set_rgb_to_gray API. The API is
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extremely inaccurate for sRGB conversions because it uses an 8-bit
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intermediate linear value and it does not use the sRGB transform, so it
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suffers from the known instability in gamma transforms for values close
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to 0 (see Poynton). The net result is that the calculation has a maximum
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error of 14.99/255; 0.5/255^(1/2.2). pngstest now uses 15 for the
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permitted 8-bit error. This may still not be enough because of arithmetic
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error.
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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(subscription required; visit
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https://lists.sourceforge.net/lists/listinfo/png-mng-implement
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to subscribe)
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or to glennrp at users.sourceforge.net
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Glenn R-P
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