2016-01-03 00:48:18 +00:00
|
|
|
README for libpng version 1.2.57beta01 - January 3, 2016 (shared library 12.0)
|
1998-03-07 12:06:55 +00:00
|
|
|
See the note about version numbers near the top of png.h
|
1997-05-16 07:46:07 +00:00
|
|
|
|
1998-03-07 12:06:55 +00:00
|
|
|
See INSTALL for instructions on how to install libpng.
|
1998-01-08 02:54:20 +00:00
|
|
|
|
2015-11-26 06:01:58 +00:00
|
|
|
Libpng comes in several distribution formats. Get libpng-*.tar.gz or
|
|
|
|
|
libpng-*.tar.xz if you want UNIX-style line
|
2008-04-02 17:27:58 +00:00
|
|
|
endings in the text files, or lpng*.7z or lpng*.zip if you want DOS-style
|
2008-06-25 17:40:22 +00:00
|
|
|
line endings. You can get UNIX-style line endings from the *.zip file
|
|
|
|
|
by using "unzip -a" but there seems to be no simple way to recover
|
2009-11-27 21:48:31 +00:00
|
|
|
UNIX-style line endings from the *.7z file. The *.tar.xz file is
|
2008-06-25 17:40:22 +00:00
|
|
|
recommended for *NIX users instead.
|
2000-02-05 05:40:16 +00:00
|
|
|
|
1999-10-14 12:43:10 +00:00
|
|
|
Version 0.89 was the first official release of libpng. Don't let the
|
|
|
|
|
fact that it's the first release fool you. The libpng library has been in
|
|
|
|
|
extensive use and testing since mid-1995. By late 1997 it had
|
|
|
|
|
finally gotten to the stage where there hadn't been significant
|
1998-01-01 13:13:13 +00:00
|
|
|
changes to the API in some time, and people have a bad feeling about
|
1999-10-14 12:43:10 +00:00
|
|
|
libraries with versions < 1.0. Version 1.0.0 was released in
|
|
|
|
|
March 1998.
|
1998-01-01 13:13:13 +00:00
|
|
|
|
1997-05-16 07:46:07 +00:00
|
|
|
****
|
|
|
|
|
Note that some of the changes to the png_info structure render this
|
|
|
|
|
version of the library binary incompatible with libpng-0.89 or
|
|
|
|
|
earlier versions if you are using a shared library. The type of the
|
|
|
|
|
"filler" parameter for png_set_filler() has changed from png_byte to
|
1998-01-08 02:54:20 +00:00
|
|
|
png_uint_32, which will affect shared-library applications that use
|
1997-05-16 07:46:07 +00:00
|
|
|
this function.
|
|
|
|
|
|
|
|
|
|
To avoid problems with changes to the internals of png_info_struct,
|
|
|
|
|
new APIs have been made available in 0.95 to avoid direct application
|
|
|
|
|
access to info_ptr. These functions are the png_set_<chunk> and
|
|
|
|
|
png_get_<chunk> functions. These functions should be used when
|
|
|
|
|
accessing/storing the info_struct data, rather than manipulating it
|
|
|
|
|
directly, to avoid such problems in the future.
|
1998-01-01 13:13:13 +00:00
|
|
|
|
|
|
|
|
It is important to note that the APIs do not make current programs
|
1998-01-08 02:54:20 +00:00
|
|
|
that access the info struct directly incompatible with the new
|
1998-01-01 13:13:13 +00:00
|
|
|
library. However, it is strongly suggested that new programs use
|
1999-10-14 12:43:10 +00:00
|
|
|
the new APIs (as shown in example.c and pngtest.c), and older programs
|
|
|
|
|
be converted to the new format, to facilitate upgrades in the future.
|
1997-05-16 07:46:07 +00:00
|
|
|
****
|
|
|
|
|
|
|
|
|
|
Additions since 0.90 include the ability to compile libpng as a
|
|
|
|
|
Windows DLL, and new APIs for accessing data in the info struct.
|
|
|
|
|
Experimental functions include the ability to set weighting and cost
|
|
|
|
|
factors for row filter selection, direct reads of integers from buffers
|
|
|
|
|
on big-endian processors that support misaligned data access, faster
|
|
|
|
|
methods of doing alpha composition, and more accurate 16->8 bit color
|
|
|
|
|
conversion.
|
|
|
|
|
|
|
|
|
|
The additions since 0.89 include the ability to read from a PNG stream
|
|
|
|
|
which has had some (or all) of the signature bytes read by the calling
|
|
|
|
|
application. This also allows the reading of embedded PNG streams that
|
|
|
|
|
do not have the PNG file signature. As well, it is now possible to set
|
|
|
|
|
the library action on the detection of chunk CRC errors. It is possible
|
|
|
|
|
to set different actions based on whether the CRC error occurred in a
|
|
|
|
|
critical or an ancillary chunk.
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
The changes made to the library, and bugs fixed are based on discussions
|
2009-11-27 21:48:31 +00:00
|
|
|
on the png-mng-implement mailing list and not on material submitted
|
|
|
|
|
privately to Guy, Andreas, or Glenn. They will forward any good
|
|
|
|
|
suggestions to the list.
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
For a detailed description on using libpng, read libpng.txt. For
|
1997-05-16 07:46:07 +00:00
|
|
|
examples of libpng in a program, see example.c and pngtest.c. For usage
|
|
|
|
|
information and restrictions (what little they are) on libpng, see
|
|
|
|
|
png.h. For a description on using zlib (the compression library used by
|
|
|
|
|
libpng) and zlib's restrictions, see zlib.h
|
1997-01-17 07:34:35 +00:00
|
|
|
|
1997-05-16 07:46:07 +00:00
|
|
|
I have included a general makefile, as well as several machine and
|
|
|
|
|
compiler specific ones, but you may have to modify one for your own needs.
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
You should use zlib 1.0.4 or later to run this, but it MAY work with
|
|
|
|
|
versions as old as zlib 0.95. Even so, there are bugs in older zlib
|
|
|
|
|
versions which can cause the output of invalid compression streams for
|
|
|
|
|
some images. You will definitely need zlib 1.0.4 or later if you are
|
|
|
|
|
taking advantage of the MS-DOS "far" structure allocation for the small
|
|
|
|
|
and medium memory models. You should also note that zlib is a
|
|
|
|
|
compression library that is useful for more things than just PNG files.
|
|
|
|
|
You can use zlib as a drop-in replacement for fread() and fwrite() if
|
|
|
|
|
you are so inclined.
|
|
|
|
|
|
2008-02-01 03:27:55 +00:00
|
|
|
zlib should be available at the same place that libpng is, or at
|
2008-02-06 16:32:29 +00:00
|
|
|
ftp://ftp.simplesystems.org/pub/png/src/
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
You may also want a copy of the PNG specification. It is available
|
2004-08-26 03:00:45 +00:00
|
|
|
as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find
|
2008-02-01 03:27:55 +00:00
|
|
|
these at http://www.libpng.org/pub/png/pngdocs.html
|
1997-01-17 07:34:35 +00:00
|
|
|
|
2004-08-26 03:00:45 +00:00
|
|
|
This code is currently being archived at libpng.sf.net in the
|
|
|
|
|
[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
|
1997-01-17 07:34:35 +00:00
|
|
|
at GO GRAPHSUP. If you can't find it in any of those places,
|
|
|
|
|
e-mail me, and I'll help you find it.
|
|
|
|
|
|
2014-11-06 14:22:13 +00:00
|
|
|
I am not a lawyer, but I believe that the Export Control Classification
|
|
|
|
|
Number (ECCN) for libpng is EAR99, which means not subject to export
|
|
|
|
|
controls or International Traffic in Arms Regulations (ITAR) because it
|
|
|
|
|
is open source, publicly available software, that does not contain any
|
|
|
|
|
encryption software. See the EAR, paragraphs 734.3(b)(3) and 734.7(b).
|
|
|
|
|
|
1997-01-17 07:34:35 +00:00
|
|
|
If you have any code changes, requests, problems, etc., please e-mail
|
|
|
|
|
them to me. Also, I'd appreciate any make files or project files,
|
|
|
|
|
and any modifications you needed to make to get libpng to compile,
|
|
|
|
|
along with a #define variable to tell what compiler/system you are on.
|
|
|
|
|
If you needed to add transformations to libpng, or wish libpng would
|
|
|
|
|
provide the image in a different way, drop me a note (and code, if
|
|
|
|
|
possible), so I can consider supporting the transformation.
|
|
|
|
|
Finally, if you get any warning messages when compiling libpng
|
|
|
|
|
(note: not zlib), and they are easy to fix, I'd appreciate the
|
|
|
|
|
fix. Please mention "libpng" somewhere in the subject line. Thanks.
|
|
|
|
|
|
|
|
|
|
This release was created and will be supported by myself (of course
|
2009-11-27 21:48:31 +00:00
|
|
|
based in a large way on Guy's and Andreas' earlier work), and the PNG
|
|
|
|
|
development group.
|
1997-01-17 07:34:35 +00:00
|
|
|
|
2006-02-21 04:09:05 +00:00
|
|
|
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
|
1997-01-17 07:34:35 +00:00
|
|
|
|
1998-01-17 04:06:18 +00:00
|
|
|
You can't reach Guy, the original libpng author, at the addresses
|
2009-11-27 21:48:31 +00:00
|
|
|
given in previous versions of this document. He and Andreas will
|
|
|
|
|
read mail addressed to the png-mng-implement list, however.
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
Please do not send general questions about PNG. Send them to
|
2007-11-02 11:47:49 +00:00
|
|
|
the (png-mng-misc at lists.sourceforge.net, subscription required, visit
|
2009-11-27 21:48:31 +00:00
|
|
|
https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
|
|
|
|
|
subscribe). On the other hand, please do not send libpng questions to
|
|
|
|
|
that address, send them to me or to the png-mng-implement list. I'll
|
1997-01-17 07:34:35 +00:00
|
|
|
get them in the end anyway. If you have a question about something
|
|
|
|
|
in the PNG specification that is related to using libpng, send it
|
|
|
|
|
to me. Send me any questions that start with "I was using libpng,
|
|
|
|
|
and ...". If in doubt, send questions to me. I'll bounce them
|
|
|
|
|
to others, if necessary.
|
|
|
|
|
|
|
|
|
|
Please do not send suggestions on how to change PNG. We have
|
2015-10-23 11:34:11 +00:00
|
|
|
been discussing PNG for twenty years now, and it is official and
|
1997-01-17 07:34:35 +00:00
|
|
|
finished. If you have suggestions for libpng, however, I'll
|
2004-08-26 03:00:45 +00:00
|
|
|
gladly listen. Even if your suggestion is not used immediately,
|
|
|
|
|
it may be used later.
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
Files in this distribution:
|
|
|
|
|
|
2000-03-21 11:13:06 +00:00
|
|
|
ANNOUNCE => Announcement of this version, with recent changes
|
1997-05-16 07:46:07 +00:00
|
|
|
CHANGES => Description of changes between libpng versions
|
2000-03-21 11:13:06 +00:00
|
|
|
KNOWNBUG => List of known bugs and deficiencies
|
|
|
|
|
LICENSE => License to use and redistribute libpng
|
1997-01-17 07:34:35 +00:00
|
|
|
README => This file
|
|
|
|
|
TODO => Things not implemented in the current library
|
2000-03-21 11:13:06 +00:00
|
|
|
Y2KINFO => Statement of Y2K compliance
|
1997-01-17 07:34:35 +00:00
|
|
|
example.c => Example code for using libpng functions
|
2007-10-08 15:47:56 +00:00
|
|
|
libpng-*-*-diff.txt => Diff from previous release
|
2000-03-21 11:13:06 +00:00
|
|
|
libpng.3 => manual page for libpng (includes libpng.txt)
|
1997-01-17 07:34:35 +00:00
|
|
|
libpng.txt => Description of libpng and its functions
|
1998-02-28 13:00:24 +00:00
|
|
|
libpngpf.3 => manual page for libpng's private functions
|
|
|
|
|
png.5 => manual page for the PNG format
|
1997-01-17 07:34:35 +00:00
|
|
|
png.c => Basic interface functions common to library
|
|
|
|
|
png.h => Library function and interface declarations
|
|
|
|
|
pngconf.h => System specific library configuration
|
|
|
|
|
pngerror.c => Error/warning message I/O functions
|
1998-02-28 13:00:24 +00:00
|
|
|
pngget.c => Functions for retrieving info from struct
|
1997-01-17 07:34:35 +00:00
|
|
|
pngmem.c => Memory handling functions
|
2000-07-14 13:15:12 +00:00
|
|
|
pngbar.png => PNG logo, 88x31
|
|
|
|
|
pngnow.png => PNG logo, 98x31
|
1997-01-17 07:34:35 +00:00
|
|
|
pngpread.c => Progressive reading functions
|
|
|
|
|
pngread.c => Read data/helper high-level functions
|
|
|
|
|
pngrio.c => Lowest-level data read I/O functions
|
|
|
|
|
pngrtran.c => Read data transformation functions
|
|
|
|
|
pngrutil.c => Read data utility functions
|
1997-05-16 07:46:07 +00:00
|
|
|
pngset.c => Functions for storing data into the info_struct
|
1997-01-17 07:34:35 +00:00
|
|
|
pngtest.c => Library test program
|
|
|
|
|
pngtest.png => Library test sample image
|
|
|
|
|
pngtrans.c => Common data transformation functions
|
|
|
|
|
pngwio.c => Lowest-level write I/O functions
|
|
|
|
|
pngwrite.c => High-level write functions
|
|
|
|
|
pngwtran.c => Write data transformations
|
|
|
|
|
pngwutil.c => Write utility functions
|
1999-10-14 12:43:10 +00:00
|
|
|
contrib => Contributions
|
|
|
|
|
gregbook => source code for PNG reading and writing, from
|
|
|
|
|
Greg Roelofs' "PNG: The Definitive Guide",
|
|
|
|
|
O'Reilly, 1999
|
2013-06-04 02:08:59 +00:00
|
|
|
pngminim => Minimal pnm2pngm and png2pnmm programs
|
1999-10-23 13:39:18 +00:00
|
|
|
pngminus => Simple pnm2png and png2pnm programs
|
|
|
|
|
pngsuite => Test images
|
2000-06-24 02:38:16 +00:00
|
|
|
visupng => Contains a MSVC workspace for VisualPng
|
2009-11-27 21:48:31 +00:00
|
|
|
projects => Contains project files and workspaces for
|
|
|
|
|
building a DLL
|
2001-05-07 19:52:45 +00:00
|
|
|
beos => Contains a Beos workspace for building libpng
|
2009-11-27 21:48:31 +00:00
|
|
|
c5builder => Contains a Borland workspace for building
|
|
|
|
|
libpng and zlib
|
2013-06-04 02:08:59 +00:00
|
|
|
MacOSX => Contains a MacOSX workspace for building libpng
|
2009-11-27 21:48:31 +00:00
|
|
|
netware.txt => Contains instructions for downloading a set
|
|
|
|
|
of project files for building libpng and
|
|
|
|
|
zlib on Netware.
|
|
|
|
|
visualc6 => Contains a Microsoft Visual C++ (MSVC)
|
|
|
|
|
workspace for building libpng and zlib
|
2013-06-04 02:08:59 +00:00
|
|
|
visualc71 => Contains a Microsoft Visual C++ (MSVC)
|
|
|
|
|
workspace for building libpng and zlib
|
2009-11-27 21:48:31 +00:00
|
|
|
wince.txt => Contains instructions for downloading a
|
|
|
|
|
Microsoft Visual C++ (Windows CD Toolkit)
|
|
|
|
|
workspace for building libpng and zlib on
|
|
|
|
|
WindowsCE
|
|
|
|
|
xcode => Contains xcode project files
|
1998-03-07 12:06:55 +00:00
|
|
|
scripts => Directory containing scripts for building libpng:
|
1999-09-18 15:54:36 +00:00
|
|
|
descrip.mms => VMS makefile for MMS or MMK
|
2009-11-27 21:48:31 +00:00
|
|
|
makefile.std => Generic UNIX makefile (cc, creates static
|
|
|
|
|
libpng.a)
|
|
|
|
|
makefile.elf => Linux/ELF gcc makefile symbol versioning,
|
2016-01-03 00:48:18 +00:00
|
|
|
creates libpng12.so.0.1.2.57beta01)
|
2009-11-27 21:48:31 +00:00
|
|
|
makefile.linux => Linux/ELF makefile (gcc, creates
|
2016-01-03 00:48:18 +00:00
|
|
|
libpng12.so.0.1.2.57beta01)
|
2009-11-27 21:48:31 +00:00
|
|
|
makefile.gcmmx => Linux/ELF makefile (gcc, creates
|
2016-01-03 00:48:18 +00:00
|
|
|
libpng12.so.0.1.2.57beta01, previously
|
2009-11-27 21:48:31 +00:00
|
|
|
used assembler code tuned for Intel MMX
|
|
|
|
|
platform)
|
|
|
|
|
makefile.gcc => Generic makefile (gcc, creates static
|
|
|
|
|
libpng.a)
|
|
|
|
|
makefile.knr => Archaic UNIX Makefile that converts files
|
|
|
|
|
with ansi2knr (Requires ansi2knr.c from
|
1999-09-18 15:54:36 +00:00
|
|
|
ftp://ftp.cs.wisc.edu/ghost)
|
2000-11-23 17:51:42 +00:00
|
|
|
makefile.aix => AIX makefile
|
2000-11-10 18:26:19 +00:00
|
|
|
makefile.cygwin => Cygwin/gcc makefile
|
2001-11-07 13:10:08 +00:00
|
|
|
makefile.darwin => Darwin makefile
|
1999-09-18 15:54:36 +00:00
|
|
|
makefile.dec => DEC Alpha UNIX makefile
|
2002-04-27 15:11:25 +00:00
|
|
|
makefile.freebsd => FreeBSD makefile
|
2001-05-07 19:52:45 +00:00
|
|
|
makefile.hpgcc => HPUX makefile using gcc
|
1999-09-18 15:54:36 +00:00
|
|
|
makefile.hpux => HPUX (10.20 and 11.00) makefile
|
2004-09-12 02:19:54 +00:00
|
|
|
makefile.hp64 => HPUX (10.20 and 11.00) makefile, 64 bit
|
2009-11-27 21:48:31 +00:00
|
|
|
makefile.ibmc => IBM C/C++ version 3.x for Win32 and OS/2
|
|
|
|
|
(static)
|
2000-05-16 11:17:36 +00:00
|
|
|
makefile.intel => Intel C/C++ version 4.0 and later
|
2000-04-02 03:10:05 +00:00
|
|
|
libpng.icc => Project file, IBM VisualAge/C++ 4.0 or later
|
2009-11-27 21:48:31 +00:00
|
|
|
makefile.netbsd => NetBSD/cc makefile, makes libpng.so.
|
|
|
|
|
makefile.ne12bsd => NetBSD/cc makefile, makes libpng12.so
|
2002-03-07 04:08:00 +00:00
|
|
|
makefile.openbsd => OpenBSD makefile
|
2000-03-21 11:13:06 +00:00
|
|
|
makefile.sgi => Silicon Graphics IRIX (cc, creates static lib)
|
2004-08-26 03:00:45 +00:00
|
|
|
makefile.sggcc => Silicon Graphics
|
2016-01-03 00:48:18 +00:00
|
|
|
(gcc, creates libpng12.so.0.1.2.57beta01)
|
1999-09-18 15:54:36 +00:00
|
|
|
makefile.sunos => Sun makefile
|
|
|
|
|
makefile.solaris => Solaris 2.X makefile
|
2016-01-03 00:48:18 +00:00
|
|
|
(gcc, creates libpng12.so.0.1.2.57beta01)
|
2001-11-07 13:10:08 +00:00
|
|
|
makefile.so9 => Solaris 9 makefile
|
2016-01-03 00:48:18 +00:00
|
|
|
(gcc, creates libpng12.so.0.1.2.57beta01)
|
2002-03-07 04:08:00 +00:00
|
|
|
makefile.32sunu => Sun Ultra 32-bit makefile
|
|
|
|
|
makefile.64sunu => Sun Ultra 64-bit makefile
|
1999-09-18 15:54:36 +00:00
|
|
|
makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc
|
|
|
|
|
makefile.mips => MIPS makefile
|
|
|
|
|
makefile.acorn => Acorn makefile
|
|
|
|
|
makefile.amiga => Amiga makefile
|
|
|
|
|
smakefile.ppc => AMIGA smakefile for SAS C V6.58/7.00 PPC
|
|
|
|
|
compiler (Requires SCOPTIONS, copied from
|
|
|
|
|
scripts/SCOPTIONS.ppc)
|
|
|
|
|
makefile.atari => Atari makefile
|
|
|
|
|
makefile.beos => BEOS makefile for X86
|
2000-03-21 11:13:06 +00:00
|
|
|
makefile.bor => Borland makefile (uses bcc)
|
|
|
|
|
makefile.bc32 => 32-bit Borland C++ (all modules compiled in C mode)
|
|
|
|
|
makefile.tc3 => Turbo C 3.0 makefile
|
1999-09-18 15:54:36 +00:00
|
|
|
makefile.dj2 => DJGPP 2 makefile
|
|
|
|
|
makefile.msc => Microsoft C makefile
|
2004-08-26 03:00:45 +00:00
|
|
|
makefile.vcawin32=> makefile for Microsoft Visual C++ 5.0 and
|
2009-11-27 21:48:31 +00:00
|
|
|
later (previously used assembler code tuned
|
|
|
|
|
for Intel MMX platform)
|
1999-10-01 19:22:25 +00:00
|
|
|
makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and
|
|
|
|
|
later (does not use assembler code)
|
1999-09-18 15:54:36 +00:00
|
|
|
makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def)
|
|
|
|
|
pngos2.def => OS/2 module definition file used by makefile.os2
|
|
|
|
|
makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model
|
|
|
|
|
makevms.com => VMS build script
|
|
|
|
|
SCOPTIONS.ppc => Used with smakefile.ppc
|
1997-01-17 07:34:35 +00:00
|
|
|
|
|
|
|
|
Good luck, and happy coding.
|
|
|
|
|
|
2010-01-01 16:43:19 +00:00
|
|
|
-Glenn Randers-Pehrson (current maintainer, since 1998)
|
2004-11-24 13:50:16 +00:00
|
|
|
Internet: glennrp at users.sourceforge.net
|
1998-01-17 04:06:18 +00:00
|
|
|
|
2004-08-26 03:00:45 +00:00
|
|
|
-Andreas Eric Dilger (former maintainer, 1996-1997)
|
2004-11-24 13:50:16 +00:00
|
|
|
Internet: adilger at enel.ucalgary.ca
|
2008-02-01 03:27:55 +00:00
|
|
|
Web: http://members.shaw.ca/adilger/
|
1997-01-17 07:34:35 +00:00
|
|
|
|
2004-08-26 03:00:45 +00:00
|
|
|
-Guy Eric Schalnat (original author and former maintainer, 1995-1996)
|
1998-01-17 04:06:18 +00:00
|
|
|
(formerly of Group 42, Inc)
|
2004-11-24 13:50:16 +00:00
|
|
|
Internet: gschal at infinet.com
|
