Libpng 1.5.4 - July 7, 2011
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-1.5.4.tar.xz (LZMA-compressed, recommended)
libpng-1.5.4.tar.gz
libpng-1.5.4.tar.bz2
Source files with CRLF line endings (for Windows), without the
"configure" script
lpng154.7z (LZMA-compressed, recommended)
lpng154.zip
Other information:
libpng-1.5.4-README.txt
libpng-1.5.4-LICENSE.txt
Changes since the last public release (1.5.2):
Re-initialize the zlib compressor before compressing non-IDAT chunks.
Added API functions to set parameters for zlib compression of non-IDAT
chunks.
Updated scripts/symbols.def with new API functions.
Only compile the new zlib re-initializing code when text or iCCP is
supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
Improved the optimization of the zlib CMF byte (see libpng-1.2.6).
Optimize the zlib CMF byte in non-IDAT compressed chunks
Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
than __STDC__ (John Bowler).
Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
the compiler that a user supplied callback (the error handler) does not
return, yet there is no guarantee in practice that the application code
will correctly implement the error handler because the compiler only
issues a warning if there is a mistake (John Bowler).
Removed the no-longer-used PNG_DEPSTRUCT macro.
Updated the zlib version to 1.2.5 in the VStudio project.
Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
pngwutil.c (John Bowler).
Fixed bug with stripping the filler or alpha channel when writing, that
was introduced in libpng-1.5.2 (bug report by Andrew Church).
Updated pngtest.png with the new zlib CMF optimization.
Cleaned up conditional compilation code and of background/gamma handling
Internal changes only except a new option to avoid compiling the
png_build_grayscale_palette API (which is not used at all internally.)
The main change is to move the transform tests (READ_TRANSFORMS,
WRITE_TRANSFORMS) up one level to the caller of the APIs. This avoids
calls to spurious functions if all transforms are disabled and slightly
simplifies those functions. Pngvalid modified to handle this.
A minor change is to stop the strip_16 and expand_16 interfaces from
disabling each other; this allows the future alpha premultiplication
code to use 16-bit intermediate values while still producing 8-bit output.
png_do_background and png_do_gamma have been simplified to take a single
pointer to the png_struct rather than pointers to every item required
from the png_struct. This makes no practical difference to the internal
code.
A serious bug in the pngvalid internal routine 'standard_display_init' has
been fixed - this failed to initialize the red channel and accidentally
initialized the alpha channel twice.
Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
avoid a clash with the png_jmpbuf macro on some platforms.
Added appropriate feature test macros to ensure libpng sees the correct API
_POSIX_SOURCE is defined in pngpriv.h, pngtest.c and pngvalid.c to ensure
that POSIX conformant systems disable non-POSIX APIs. _ISOC99_SOURCE is
defined in pngpriv.h to obtain the ISO C99 snprintf definition, when
available.
Removed png_snprintf and added formatted warning messages. This change adds
internal APIs to allow png_warning messages to have parameters without
requiring the host OS to implement snprintf. As a side effect the
dependency of the tIME-supporting RFC1132 code on stdio is removed and
PNG_NO_WARNINGS does actually work now.
Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
optimization configureable.
Internal functions were added to claim/release the z_stream and, hopefully,
make the code more robust. Also deflateEnd checking is added - previously
libpng would ignore an error at the end of the stream.
Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
Implemented premultiplied alpha support: png_set_alpha_mode API
Added expand_16 support to the high level interface.
Added named value and 'flag' gamma support to png_set_gamma. Made a minor
change from the previous (unreleased) ABI/API to hide the exact value used
for Macs - it's not a good idea to embed this in the ABI!
Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
from pngpriv.h to png.h because they must be visible to applications
that call png_set_unknown_chunks().
Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
before IDAT.
Improved "pngvalid --speed" to exclude more of pngvalid from the time.
Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
parameters are supplied by the caller), while in the absence of cHRM
sRGB/Rec 709 values are still used.
The bKGD chunk no longer overwrites the background value set by
png_set_background(), allowing the latter to be used before the file
header is read. It never performed any useful function to override
the default anyway.
Added memory overwrite and palette image checks to pngvalid.c
Previously palette image code was poorly checked. Since the transformation
code has a special palette path in most cases this was a severe weakness.
Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
expanding an indexed image, always expand to RGBA if transparency is
present.
Reversed earlier 1.5.3 change of transformation order; move png_expand_16
back where it was. The change doesn't work because it requires 16-bit
gamma tables when the code only generates 8-bit ones. This fails
silently; the libpng code just doesn't do any gamma correction. Moving
the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
these are clearly better than none!
png_set_background() and png_expand_16() did not work together correctly.
This problem is present in 1.5.2; if png_set_background is called with
need_expand false and the matching 16 bit color libpng erroneously just
treats it as an 8-bit color because of where png_do_expand_16 is in the
transform list. This simple fix reduces the supplied colour to 8-bits,
so it gets smashed, but this is better than the current behavior.
Added tests for expand16, more fixes for palette image tests to pngvalid.
Corrects the code for palette image tests and disables attempts to
validate palette colors.
Fixed uninitialized memory read in png_format_buffer() (Bug report by
Frank Busse, related to CVE-2004-0421).
Fixed png_handle_sCAL which is broken in 1.5; added sCAL to pngtest.png
Revised documentation about png_set_user_limits() to say that it also affects
png writing.
Revised handling of png_set_user_limits() so that it can increase the
limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
reduce it.
Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
wrong (high by one) 25% of the time. Dividing by 257 with rounding is
wrong in 128 out of 65536 cases. Getting the right answer all the time
without division is easy.
Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
Added projects/owatcom, an IDE project for OpenWatcom to replace
scripts/makefile.watcom. This project works with OpenWatcom 1.9. The
IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
The project is configurable, unlike the Visual Studio project, so long
as the developer has an awk.
Changed png_set_gAMA to limit the gamma value range so that the inverse
of the stored value cannot overflow the fixed point representation,
and changed other things OpenWatcom warns about.
Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
pngvalid to build when ALPHA_MODE is not supported, which is required if
it is to build on libpng 1.4.
Removed string/memory macros that are no longer used and are not
necessarily fully supportable, particularly png_strncpy and png_snprintf.
Added log option to pngvalid.c and attempted to improve gamma messages.
People found the presence of a beta release following an rc release
to be confusing; therefore we bump the version to libpng-1.5.4beta01
and there will be no libpng-1.5.3 release.
Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
outside of an unknown-chunk block in png.h because they are also
needed for other uses.
Added png_set_scale_16() API, to match inaccurate results from previous
libpng versions, configurable with PNG_READ_SCALE_16_TO_8_SUPPORTED.
Fixed a problem in png_do_expand_palette() exposed by optimization in
1.5.3beta06
Also removed a spurious and confusing "trans" member ("trans") from png_info.
The palette expand optimization prevented expansion to an intermediate RGBA
form if tRNS was present but alpha was marked to be stripped; this exposed
a check for tRNS in png_do_expand_palette() which is inconsistent with the
code elsewhere in libpng.
Added PNG_TRANSFORM_SCALE_16 to the high-level read transforms.
If PNG_READ_16_TO_8_ACCURATE_SCALE is not enabled, png_set_scale_16()
and png_do_scale_16_to_8() aren't built.
Revised contrib/visupng, gregbook, and pngminim to demonstrate scale_16_to_8
Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
The ACCURATE scale macro is no longer defined in libpng-1.5 - call the
png_scale_16_to_8 API. Made sure that PNG_READ_16_TO_8 is still defined
if the png_strip_16_to_8 API is present. png_check_fp_number now
maintains some state so that positive, negative and zero values are
identified. sCAL uses these to be strictly spec conformant.
Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
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*/ }
#endif
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