author | Dremov Kirill (Nokia-D-MSW/Tampere) <kirill.dremov@nokia.com> |
Wed, 18 Aug 2010 10:37:55 +0300 | |
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README for libpng version 1.4.0 - January 3, 2010 (shared library 14.0) |
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See the note about version numbers near the top of png.h |
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See INSTALL for instructions on how to install libpng. |
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Libpng comes in several distribution formats. Get libpng-*.tar.gz, |
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libpng-*.tar.xz or libpng-*.tar.bz2 if you want UNIX-style line endings |
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in the text files, or lpng*.zip if you want DOS-style line endings. |
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Version 0.89 was the first official release of libpng. Don't let the |
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fact that it's the first release fool you. The libpng library has been in |
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extensive use and testing since mid-1995. By late 1997 it had |
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finally gotten to the stage where there hadn't been significant |
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changes to the API in some time, and people have a bad feeling about |
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libraries with versions < 1.0. Version 1.0.0 was released in |
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March 1998. |
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**** |
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Note that some of the changes to the png_info structure render this |
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version of the library binary incompatible with libpng-0.89 or |
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earlier versions if you are using a shared library. The type of the |
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"filler" parameter for png_set_filler() has changed from png_byte to |
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png_uint_32, which will affect shared-library applications that use |
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this function. |
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To avoid problems with changes to the internals of png_info_struct, |
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new APIs have been made available in 0.95 to avoid direct application |
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access to info_ptr. These functions are the png_set_<chunk> and |
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png_get_<chunk> functions. These functions should be used when |
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accessing/storing the info_struct data, rather than manipulating it |
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directly, to avoid such problems in the future. |
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It is important to note that the APIs do not make current programs |
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that access the info struct directly incompatible with the new |
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library. However, it is strongly suggested that new programs use |
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the new APIs (as shown in example.c and pngtest.c), and older programs |
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be converted to the new format, to facilitate upgrades in the future. |
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**** |
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Additions since 0.90 include the ability to compile libpng as a |
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Windows DLL, and new APIs for accessing data in the info struct. |
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Experimental functions include the ability to set weighting and cost |
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factors for row filter selection, direct reads of integers from buffers |
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on big-endian processors that support misaligned data access, faster |
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methods of doing alpha composition, and more accurate 16->8 bit color |
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conversion. |
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The additions since 0.89 include the ability to read from a PNG stream |
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which has had some (or all) of the signature bytes read by the calling |
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application. This also allows the reading of embedded PNG streams that |
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do not have the PNG file signature. As well, it is now possible to set |
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the library action on the detection of chunk CRC errors. It is possible |
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to set different actions based on whether the CRC error occurred in a |
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critical or an ancillary chunk. |
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The changes made to the library, and bugs fixed are based on discussions |
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on the PNG-implement mailing list and not on material submitted |
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privately to Guy, Andreas, or Glenn. They will forward any good |
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suggestions to the list. |
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For a detailed description on using libpng, read libpng.txt. For |
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examples of libpng in a program, see example.c and pngtest.c. For usage |
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information and restrictions (what little they are) on libpng, see |
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png.h. For a description on using zlib (the compression library used by |
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libpng) and zlib's restrictions, see zlib.h |
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I have included a general makefile, as well as several machine and |
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compiler specific ones, but you may have to modify one for your own needs. |
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You should use zlib 1.0.4 or later to run this, but it MAY work with |
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versions as old as zlib 0.95. Even so, there are bugs in older zlib |
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versions which can cause the output of invalid compression streams for |
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some images. You will definitely need zlib 1.0.4 or later if you are |
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taking advantage of the MS-DOS "far" structure allocation for the small |
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and medium memory models. You should also note that zlib is a |
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compression library that is useful for more things than just PNG files. |
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You can use zlib as a drop-in replacement for fread() and fwrite() if |
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you are so inclined. |
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zlib should be available at the same place that libpng is, or at. |
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ftp://ftp.info-zip.org/pub/infozip/zlib |
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You may also want a copy of the PNG specification. It is available |
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as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find |
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these at http://www.libpng.org/pub/png/documents/ |
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This code is currently being archived at libpng.sf.net in the |
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[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT) |
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at GO GRAPHSUP. If you can't find it in any of those places, |
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e-mail me, and I'll help you find it. |
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If you have any code changes, requests, problems, etc., please e-mail |
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them to me. Also, I'd appreciate any make files or project files, |
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and any modifications you needed to make to get libpng to compile, |
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along with a #define variable to tell what compiler/system you are on. |
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If you needed to add transformations to libpng, or wish libpng would |
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provide the image in a different way, drop me a note (and code, if |
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possible), so I can consider supporting the transformation. |
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Finally, if you get any warning messages when compiling libpng |
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(note: not zlib), and they are easy to fix, I'd appreciate the |
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fix. Please mention "libpng" somewhere in the subject line. Thanks. |
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This release was created and will be supported by myself (of course |
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based in a large way on Guy's and Andreas' earlier work), and the PNG |
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development group. |
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Send comments/corrections/commendations to png-mng-implement at |
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lists.sourceforge.net (subscription required; visit |
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https://lists.sourceforge.net/lists/listinfo/png-mng-implement |
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to subscribe) or to glennrp at users.sourceforge.net |
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You can't reach Guy, the original libpng author, at the addresses |
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given in previous versions of this document. He and Andreas will |
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read mail addressed to the png-implement list, however. |
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Please do not send general questions about PNG. Send them to |
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the (png-list at ccrc.wustl.edu, subscription required, write to |
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majordomo at ccrc.wustl.edu with "subscribe png-list" in your message). |
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On the other hand, |
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please do not send libpng questions to that address, send them to me |
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or to the png-implement list. I'll |
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get them in the end anyway. If you have a question about something |
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in the PNG specification that is related to using libpng, send it |
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to me. Send me any questions that start with "I was using libpng, |
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and ...". If in doubt, send questions to me. I'll bounce them |
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to others, if necessary. |
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Please do not send suggestions on how to change PNG. We have |
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been discussing PNG for nine years now, and it is official and |
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finished. If you have suggestions for libpng, however, I'll |
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gladly listen. Even if your suggestion is not used immediately, |
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it may be used later. |
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Files in this distribution: |
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ANNOUNCE => Announcement of this version, with recent changes |
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CHANGES => Description of changes between libpng versions |
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KNOWNBUG => List of known bugs and deficiencies |
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LICENSE => License to use and redistribute libpng |
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README => This file |
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TODO => Things not implemented in the current library |
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Y2KINFO => Statement of Y2K compliance |
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example.c => Example code for using libpng functions |
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libpng.3 => manual page for libpng (includes libpng.txt) |
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libpng.txt => Description of libpng and its functions |
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libpngpf.3 => manual page for libpng's private functions |
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png.5 => manual page for the PNG format |
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png.c => Basic interface functions common to library |
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png.h => Library function and interface declarations |
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pngconf.h => System specific library configuration |
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pngerror.c => Error/warning message I/O functions |
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pngget.c => Functions for retrieving info from struct |
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pngmem.c => Memory handling functions |
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pngbar.png => PNG logo, 88x31 |
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pngnow.png => PNG logo, 98x31 |
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pngpread.c => Progressive reading functions |
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pngread.c => Read data/helper high-level functions |
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pngrio.c => Lowest-level data read I/O functions |
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pngrtran.c => Read data transformation functions |
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pngrutil.c => Read data utility functions |
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pngset.c => Functions for storing data into the info_struct |
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pngtest.c => Library test program |
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pngtest.png => Library test sample image |
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pngtrans.c => Common data transformation functions |
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pngwio.c => Lowest-level write I/O functions |
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pngwrite.c => High-level write functions |
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pngwtran.c => Write data transformations |
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pngwutil.c => Write utility functions |
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contrib => Contributions |
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gregbook => source code for PNG reading and writing, from |
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Greg Roelofs' "PNG: The Definitive Guide", |
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O'Reilly, 1999 |
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msvctest => Builds and runs pngtest using a MSVC workspace |
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pngminus => Simple pnm2png and png2pnm programs |
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pngsuite => Test images |
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visupng => Contains a MSVC workspace for VisualPng |
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projects => Contains project files and workspaces for |
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building a DLL |
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c5builder => Contains a Borland workspace for building |
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libpng and zlib |
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visualc6 => Contains a Microsoft Visual C++ (MSVC) |
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workspace for building libpng and zlib |
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scripts => Directory containing scripts for building libpng: |
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descrip.mms => VMS makefile for MMS or MMK |
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makefile.std => Generic UNIX makefile (cc, creates static |
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libpng.a) |
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makefile.elf => Linux/ELF makefile symbol versioning, |
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gcc, creates libpng14.so.14.1.4.0) |
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makefile.linux => Linux/ELF makefile |
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(gcc, creates libpng14.so.14.1.4.0) |
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makefile.gcc => Generic makefile (gcc, creates static libpng.a) |
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makefile.knr => Archaic UNIX Makefile that converts files with |
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ansi2knr (Requires ansi2knr.c from |
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ftp://ftp.cs.wisc.edu/ghost) |
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makefile.aix => AIX makefile |
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makefile.cygwin => Cygwin/gcc makefile |
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makefile.darwin => Darwin makefile |
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makefile.dec => DEC Alpha UNIX makefile |
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makefile.freebsd => FreeBSD makefile |
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makefile.hpgcc => HPUX makefile using gcc |
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makefile.hpux => HPUX (10.20 and 11.00) makefile |
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makefile.hp64 => HPUX (10.20 and 11.00) makefile, 64 bit |
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makefile.ibmc => IBM C/C++ version 3.x for Win32 and OS/2 (static) |
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makefile.intel => Intel C/C++ version 4.0 and later |
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makefile.mingw => Mingw/gcc makefile |
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makefile.netbsd => NetBSD/cc makefile, makes libpng.so. |
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makefile.ne14bsd => NetBSD/cc makefile, makes |
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libpng14.so |
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makefile.openbsd => OpenBSD makefile |
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makefile.sgi => Silicon Graphics IRIX (cc, creates static lib) |
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makefile.sggcc => Silicon Graphics |
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(gcc, creates libpng14.so.14.1.4.0) |
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makefile.sunos => Sun makefile |
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makefile.solaris => Solaris 2.X makefile |
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(gcc, creates libpng14.so.14.1.4.0) |
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makefile.so9 => Solaris 9 makefile |
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(gcc, creates libpng14.so.14.1.4.0) |
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makefile.32sunu => Sun Ultra 32-bit makefile |
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makefile.64sunu => Sun Ultra 64-bit makefile |
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makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc |
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makefile.mips => MIPS makefile |
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makefile.acorn => Acorn makefile |
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makefile.amiga => Amiga makefile |
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smakefile.ppc => AMIGA smakefile for SAS C V6.58/7.00 PPC |
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compiler (Requires SCOPTIONS, copied from |
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scripts/SCOPTIONS.ppc) |
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makefile.atari => Atari makefile |
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makefile.beos => BEOS makefile for X86 |
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makefile.bor => Borland makefile (uses bcc) |
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makefile.bc32 => 32-bit Borland C++ (all modules compiled in C mode) |
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makefile.tc3 => Turbo C 3.0 makefile |
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makefile.dj2 => DJGPP 2 makefile |
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makefile.msc => Microsoft C makefile |
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makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and |
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later (does not use assembler code) |
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makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def) |
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png32ce.def => module definition for makefile.cegccg |
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pngos2.def => OS/2 module definition file used by |
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makefile.os2 |
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pngwin.def => module definition file used by |
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makefile.cygwin and makefile.mingw |
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makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model |
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makevms.com => VMS build script |
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SCOPTIONS.ppc => Used with smakefile.ppc |
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Good luck, and happy coding. |
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-Glenn Randers-Pehrson (current maintainer, since 1998) |
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Internet: glennrp at users.sourceforge.net |
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251 |
-Andreas Eric Dilger (former maintainer, 1996-1997) |
|
252 |
Internet: adilger at enel.ucalgary.ca |
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Dremov Kirill (Nokia-D-MSW/Tampere) <kirill.dremov@nokia.com>
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Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/ |
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-Guy Eric Schalnat (original author and former maintainer, 1995-1996) |
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(formerly of Group 42, Inc) |
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Internet: gschal at infinet.com |