Libpng 1.7.0beta17 - August 22, 2013 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 1.7.0beta17.tar.xz (LZMA-compressed, recommended) 1.7.0beta17.tar.gz Source files with CRLF line endings (for Windows), without the "configure" script lp170b17.7z (LZMA-compressed, recommended) lp170b17.zip Other information: 1.7.0beta17-README.txt 1.7.0beta17-LICENSE.txt Gnupg/*.asc (PGP armored detached signatures) 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). Version 1.7.0alpha04 [December 23, 2012] Added scripts/makefile.msys contributed by Christopher M. Wheeler Made default Zlib compression settings be configurable. This adds #defines to pnglibconf.h to control the defaults. Fixed Windows build issues, enabled ARM compilation. Various warnings issued by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old GCCs.) ARM support is enabled by default in zlib.props (unsupported by Microsoft) and ARM compilation is made possible by deleting the check for x86. The test programs cannot be run because they are not signed. Version 1.7.0alpha05 [December 24, 2012] Discontinued distributing libpng-1.x.x.tar.bz2. Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar. Version 1.7.0alpha06 [January 1, 2013] Fixed 'make distcheck' on SUN OS - libpng.so was not being removed Version 1.7.0alpha07 [January 10, 2013] Fixed conceivable but difficult to repro overflow. Also added two test programs to generate and test a PNG which should have the problem. Version 1.7.0alpha08 [January 17, 2013] Corrected previous attempt at overflow detection in png_set_unknown_chunks(). Version 1.7.0alpha09 [January 21, 2013] Pulled changes to multi-chunk handling from libpng-1.6.0beta40. Version 1.7.0alpha10 [February 5, 2013] Make 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. Added png_get_palette_max() function. Changed png_size_t to size_t throughout headers, make sRGB check numbers consistent. Fixed ARM support (Mans Rullgard). Removed stray out-of-order #endif and #ifdef (Mans Rullgard). Ported libpng 1.5 options.awk/dfn file handling to 1.7, fixed one bug. Rebuilt Makefile.in, configure, etc., with autoconf-2.69 and automake-1.13. Minor fixes to assembler changes, verified with a dummy .S file 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. Version 1.7.0beta01 [February 15, 2013] Enable parallel tests and rearrange TESTS order to take advantage of the massive speed improvements use a make capable of parallel builds on a multi-CPU machine and pass the right arguments to make (-j10000 for GNU make) to get the build to run in parallel. Fixed previous support for Z_PREFIX in configure builds, corrected sCAL APIs; some of these use floating point arithmetic so 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. Fixed make distcheck to skip over the test result files. They were being included because the whole of the 'tests' directory is included, fixed to just include the actual test files and tests/pngstest. Also reverted the previous erroneous change to remove the ${srcdir} from the front of contrib, scripts, projects and added an explanation of what is going on to Makefile.am Fixed missing dependency in --prefix builds. The intermediate internal 'prefix.h' file can only be generated correctly after pnglibconf.h, however the dependency was not in Makefile.am. The symptoms are unpredictable depending on the order make chooses to build pngprefix.h and pnglibconf.h, often the error goes unnoticed because there is a system pnglibconf.h to use instead. Accept "," as a separator in pnglibconf.dfa and allow for continuation lines. This adds to the syntax of "option" and "chunk" lines, allowing the elements to be separated by a "," at the end of an element and interpreting a "," at end of line as a continuation - so the following line is read. The new syntax is optional and solely provided for readability. Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly. Version 1.7.0beta02 [February 18, 2013] 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. Version 1.7.0beta03 [February 22, 2013] 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. Version 1.7.0beta04 [February 27, 2013] 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. Version 1.7.0beta05 [March 5, 2013] Avoid a possible memory leak in contrib/gregbook/readpng.c Changed user chunk callback API to respect global and per chunk defaults. Previously a return of 0 from a user chunk callback would result in the chunk being saved (if this was safe, even if the chunk was unsafe-to-copy); this change respects the defaults set by the application, so unknown chunks can be discarded by default and known-safe ones preserved. 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. Version 1.7.0beta06 [March 13, 2013] 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. Version 1.7.0beta07 [April 14, 2013] Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling. Fixed incorrect warning of excess deflate data. End condition - the warning would be produced if the end of the deflate stream wasn't read in the last row. The warning is harmless. Corrected the test on user transform changes on read. It was in the png_set of the transform function, but that doesn't matter unless the transform function changes the rowbuf size, and that is only valid if transform_info is called. Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c (Flavio Medeiros). Corrected length written to uncompressed iTXt chunks (Samuli Suominen). Version 1.7.0beta08 [April 18, 2013] Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length written by libpng-1.6.0 and 1.6.1. Disallow storing sRGB information when the sRGB is not supported. Version 1.7.0beta09 [April 24, 2013] Exposed PNG chunk types in png.h Modified png_uint_32 macros/code to make as few assumptions as possible Revised stack marking in arm/filter_neon.S and configure.ac Ensure that NEON filter stuff is completely disabled when switched 'off'. Previously the ARM NEON specific files were still built if the option was switched 'off' as opposed to being explicitly disabled. Version 1.7.0beta10 [April 24, 2013] Attempt to fix the PNG_ARM_NEON configuration mess. Version 1.7.0beta11 [April 26, 2013] Test for 'arm*', not just 'arm' in the host_cpu configure variable. Version 1.7.0beta12 [April 30, 2013] Added png_app_warning for out-of-range unknown chunk index in png_set_unknown_chunk_location(). Expanded manual paragraph about writing private chunks. Avoid dereferencing NULL pointer possibly returned from png_create_write_struct() (Andrew Church). Version 1.7.0beta13 [May 12, 2013] Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the right zlib header files. Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile Updated contrib/pngminus/pnm2png.c (Paul Stewart): Check for EOF Ignore "#" delimited comments in input file to pnm2png.c. Fixed whitespace handling Added a call to png_set_packing() Initialize dimension values so if sscanf fails at least we have known invalid values. Calculate our own zlib windowBits when decoding rather than trusting the CMF bytes in the PNG datastream. Added an option to force maximum window size for inflating, which was the behavior of libpng15 and earlier. Added png-fix-itxt and png-fix-too-far-back to the built programs and removed warnings from the source code and timepng that are revealed as a result. Detect wrong libpng versions linked to png-fix-too-far-back, which currently only works with libpng versions that can be made to reliably fail when the deflate data contains an out-of-window reference. This means only 1.6 and later. Attempt to detect configuration issues with png-fix-too-far-back, which requires both the correct libpng and the correct zlib to function correctly. Check ZLIB_VERNUM for mismatches, enclose #error in quotes Added information in the documentation about problems with and fixes for the bad CRC and bad iTXt chunk situations. Version 1.7.0beta14 [June 8, 2013] Removed a redundant test in png_set_IHDR(). Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt) Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt Enclose the prototypes for the simplified write API in #ifdef STDIO/#endif Make ARM NEON support work at compile time (not just configure time). This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when using a compiler that compiles for multiple architectures at one time. Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from pnglibconf.h, allowing more of the decisions to be made internally (pngpriv.h) during the compile. Without this, symbol prefixing is broken under certain circumstances on ARM platforms. Now only the API parts of the optimizations ('check' vs 'api') are exposed in the public header files except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the decision about whether or not to use the optimizations. Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage. Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test on __ARM_NEON__ from configure time to compile time. This breaks symbol prefixing because the definition of the special png_init_filter_functions call was hidden at configure time if the relevant compiler arguments are passed in CFLAGS as opposed to CC. This change attempts to avoid all the confusion that would result by declaring the init function even when it is not used, so that it will always get prefixed. Version 1.7.0beta15 [June 18, 2013] Revised libpng.3 so that "doclifter" can process it. Version 1.7.0beta16 [July 5, 2013] Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18 as parameters for png_set_gamma(). These have been available since libpng-1.5.4. Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it to check all compressed chunks known to libpng. Updated documentation to show default behavior of benign errors correctly. Added perfect hash code generation for lists of PNG chunks. This is a work in progress; checked in for use in pngfix.c Ported ARM no-read patch from libpng16. Ported pngfix.c patches from libpng16. Version 1.7.0beta17 [August 22, 2013] Revised manual about changes in iTXt chunk handling made in libpng-1.6.0. Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings may be erroneously issued by code-checking applications. Added information about png_set_options() to the manual. Delay calling png_init_filter_functions() until a row with nonzero filter is found. 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