Glenn Randers-Pehrson | 074af5e | 1999-11-28 23:32:18 -0600 | [diff] [blame^] | 1 | README for libpng 1.0.5d - November 29, 1999 (shared library 2.1) |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 2 | See the note about version numbers near the top of png.h |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 3 | |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 4 | See INSTALL for instructions on how to install libpng. |
Glenn Randers-Pehrson | 2687fcc | 1998-01-07 20:54:20 -0600 | [diff] [blame] | 5 | |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 6 | Version 0.89 was the first official release of libpng. Don't let the |
| 7 | fact that it's the first release fool you. The libpng library has been in |
| 8 | extensive use and testing since mid-1995. By late 1997 it had |
| 9 | finally gotten to the stage where there hadn't been significant |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 10 | changes to the API in some time, and people have a bad feeling about |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 11 | libraries with versions < 1.0. Version 1.0.0 was released in |
| 12 | March 1998. |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 13 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 14 | **** |
| 15 | Note that some of the changes to the png_info structure render this |
| 16 | version of the library binary incompatible with libpng-0.89 or |
| 17 | earlier versions if you are using a shared library. The type of the |
| 18 | "filler" parameter for png_set_filler() has changed from png_byte to |
Glenn Randers-Pehrson | 2687fcc | 1998-01-07 20:54:20 -0600 | [diff] [blame] | 19 | png_uint_32, which will affect shared-library applications that use |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 20 | this function. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 21 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 22 | To avoid problems with changes to the internals of png_info_struct, |
| 23 | new APIs have been made available in 0.95 to avoid direct application |
| 24 | access to info_ptr. These functions are the png_set_<chunk> and |
| 25 | png_get_<chunk> functions. These functions should be used when |
| 26 | accessing/storing the info_struct data, rather than manipulating it |
| 27 | directly, to avoid such problems in the future. |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 28 | |
| 29 | It is important to note that the APIs do not make current programs |
Glenn Randers-Pehrson | 2687fcc | 1998-01-07 20:54:20 -0600 | [diff] [blame] | 30 | that access the info struct directly incompatible with the new |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 31 | library. However, it is strongly suggested that new programs use |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 32 | the new APIs (as shown in example.c and pngtest.c), and older programs |
| 33 | be converted to the new format, to facilitate upgrades in the future. |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 34 | **** |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 35 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 36 | Additions since 0.90 include the ability to compile libpng as a |
| 37 | Windows DLL, and new APIs for accessing data in the info struct. |
| 38 | Experimental functions include the ability to set weighting and cost |
| 39 | factors for row filter selection, direct reads of integers from buffers |
| 40 | on big-endian processors that support misaligned data access, faster |
| 41 | methods of doing alpha composition, and more accurate 16->8 bit color |
| 42 | conversion. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 43 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 44 | The additions since 0.89 include the ability to read from a PNG stream |
| 45 | which has had some (or all) of the signature bytes read by the calling |
| 46 | application. This also allows the reading of embedded PNG streams that |
| 47 | do not have the PNG file signature. As well, it is now possible to set |
| 48 | the library action on the detection of chunk CRC errors. It is possible |
| 49 | to set different actions based on whether the CRC error occurred in a |
| 50 | critical or an ancillary chunk. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 51 | |
| 52 | The changes made to the library, and bugs fixed are based on discussions |
Glenn Randers-Pehrson | 4393a9a | 1999-09-17 12:27:26 -0500 | [diff] [blame] | 53 | on the PNG implementation mailing list <png-implement@ccrc.wustl.edu> |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 54 | and not on material submitted privately to Guy, Andreas, or Glenn. They will |
| 55 | forward any good suggestions to the list. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 56 | |
| 57 | For a detailed description on using libpng, read libpng.txt. For |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 58 | examples of libpng in a program, see example.c and pngtest.c. For usage |
| 59 | information and restrictions (what little they are) on libpng, see |
| 60 | png.h. For a description on using zlib (the compression library used by |
| 61 | libpng) and zlib's restrictions, see zlib.h |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 62 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 63 | I have included a general makefile, as well as several machine and |
| 64 | compiler specific ones, but you may have to modify one for your own needs. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 65 | |
| 66 | You should use zlib 1.0.4 or later to run this, but it MAY work with |
| 67 | versions as old as zlib 0.95. Even so, there are bugs in older zlib |
| 68 | versions which can cause the output of invalid compression streams for |
| 69 | some images. You will definitely need zlib 1.0.4 or later if you are |
| 70 | taking advantage of the MS-DOS "far" structure allocation for the small |
| 71 | and medium memory models. You should also note that zlib is a |
| 72 | compression library that is useful for more things than just PNG files. |
| 73 | You can use zlib as a drop-in replacement for fread() and fwrite() if |
| 74 | you are so inclined. |
| 75 | |
| 76 | zlib should be available at the same place that libpng is. |
| 77 | If not, it should be at ftp.uu.net in /graphics/png |
| 78 | Eventually, it will be at ftp.uu.net in /pub/archiving/zip/zlib |
| 79 | |
| 80 | You may also want a copy of the PNG specification. It is available |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 81 | as an RFC and a W3C Recommendation. Failing |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 82 | these resources you can try ftp.uu.net in the /graphics/png directory. |
| 83 | |
| 84 | This code is currently being archived at ftp.uu.net in the |
| 85 | /graphics/png directory, and on CompuServe, Lib 20 (PNG SUPPORT) |
| 86 | at GO GRAPHSUP. If you can't find it in any of those places, |
| 87 | e-mail me, and I'll help you find it. |
| 88 | |
| 89 | If you have any code changes, requests, problems, etc., please e-mail |
| 90 | them to me. Also, I'd appreciate any make files or project files, |
| 91 | and any modifications you needed to make to get libpng to compile, |
| 92 | along with a #define variable to tell what compiler/system you are on. |
| 93 | If you needed to add transformations to libpng, or wish libpng would |
| 94 | provide the image in a different way, drop me a note (and code, if |
| 95 | possible), so I can consider supporting the transformation. |
| 96 | Finally, if you get any warning messages when compiling libpng |
| 97 | (note: not zlib), and they are easy to fix, I'd appreciate the |
| 98 | fix. Please mention "libpng" somewhere in the subject line. Thanks. |
| 99 | |
| 100 | This release was created and will be supported by myself (of course |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 101 | based in a large way on Guy's and Andreas' earlier work), and the PNG group. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 102 | |
Glenn Randers-Pehrson | 4393a9a | 1999-09-17 12:27:26 -0500 | [diff] [blame] | 103 | randeg@alum.rpi.edu |
| 104 | png-implement@ccrc.wustl.edu |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 105 | |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 106 | You can't reach Guy, the original libpng author, at the addresses |
Glenn Randers-Pehrson | 46f61e2 | 1998-01-30 21:45:12 -0600 | [diff] [blame] | 107 | given in previous versions of this document. He and Andreas will read mail |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 108 | addressed to the png-implement list, however. |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 109 | |
| 110 | Please do not send general questions about PNG. Send them to |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 111 | the address in the specification (png-group@w3.org). At the same |
| 112 | time, please do not send libpng questions to that address, send them to me |
Glenn Randers-Pehrson | 4393a9a | 1999-09-17 12:27:26 -0500 | [diff] [blame] | 113 | or to png-implement@ccrc.wustl.edu. I'll |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 114 | get them in the end anyway. If you have a question about something |
| 115 | in the PNG specification that is related to using libpng, send it |
| 116 | to me. Send me any questions that start with "I was using libpng, |
| 117 | and ...". If in doubt, send questions to me. I'll bounce them |
| 118 | to others, if necessary. |
| 119 | |
| 120 | Please do not send suggestions on how to change PNG. We have |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 121 | been discussing PNG for three years now, and it is official and |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 122 | finished. If you have suggestions for libpng, however, I'll |
| 123 | gladly listen. Even if your suggestion is not used for version |
| 124 | 1.0, it may be used later. |
| 125 | |
| 126 | Files in this distribution: |
| 127 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 128 | CHANGES => Description of changes between libpng versions |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 129 | README => This file |
| 130 | TODO => Things not implemented in the current library |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 131 | build.bat => MS-DOS batch file for Borland compiler |
| 132 | descrip.mms => VMS project file |
| 133 | example.c => Example code for using libpng functions |
Glenn Randers-Pehrson | cbe52d8 | 1998-02-28 07:00:24 -0600 | [diff] [blame] | 134 | libpng.3 => manual page for libpng |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 135 | libpng.txt => Description of libpng and its functions |
Glenn Randers-Pehrson | cbe52d8 | 1998-02-28 07:00:24 -0600 | [diff] [blame] | 136 | libpngpf.3 => manual page for libpng's private functions |
Glenn Randers-Pehrson | cbe52d8 | 1998-02-28 07:00:24 -0600 | [diff] [blame] | 137 | png.5 => manual page for the PNG format |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 138 | png.c => Basic interface functions common to library |
| 139 | png.h => Library function and interface declarations |
| 140 | pngconf.h => System specific library configuration |
| 141 | pngerror.c => Error/warning message I/O functions |
Glenn Randers-Pehrson | cbe52d8 | 1998-02-28 07:00:24 -0600 | [diff] [blame] | 142 | pngget.c => Functions for retrieving info from struct |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 143 | pngmem.c => Memory handling functions |
| 144 | pngpread.c => Progressive reading functions |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 145 | pngread.c => Read data/helper high-level functions |
| 146 | pngrio.c => Lowest-level data read I/O functions |
| 147 | pngrtran.c => Read data transformation functions |
| 148 | pngrutil.c => Read data utility functions |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 149 | pngset.c => Functions for storing data into the info_struct |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 150 | pngtest.c => Library test program |
| 151 | pngtest.png => Library test sample image |
| 152 | pngtrans.c => Common data transformation functions |
| 153 | pngwio.c => Lowest-level write I/O functions |
| 154 | pngwrite.c => High-level write functions |
| 155 | pngwtran.c => Write data transformations |
| 156 | pngwutil.c => Write utility functions |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 157 | contrib => Contributions |
| 158 | gregbook => source code for PNG reading and writing, from |
| 159 | Greg Roelofs' "PNG: The Definitive Guide", |
| 160 | O'Reilly, 1999 |
Glenn Randers-Pehrson | 6d8f3b0 | 1999-10-23 08:39:18 -0500 | [diff] [blame] | 161 | pngminus => Simple pnm2png and png2pnm programs |
| 162 | pngsuite => Test images |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 163 | scripts => Directory containing scripts for building libpng: |
Glenn Randers-Pehrson | f8b008c | 1999-09-18 10:54:36 -0500 | [diff] [blame] | 164 | descrip.mms => VMS makefile for MMS or MMK |
| 165 | makefile.std => Generic UNIX makefile |
| 166 | makefile.knr => Archaic UNIX Makefile that converts files with |
| 167 | ansi2knr (Requires ansi2knr.c from |
| 168 | ftp://ftp.cs.wisc.edu/ghost) |
| 169 | makefile.dec => DEC Alpha UNIX makefile |
| 170 | makefile.hpux => HPUX (10.20 and 11.00) makefile |
| 171 | makefile.sgi => Silicon Graphics IRIX makefile |
| 172 | makefile.sunos => Sun makefile |
| 173 | makefile.solaris => Solaris 2.X makefile |
Glenn Randers-Pehrson | 074af5e | 1999-11-28 23:32:18 -0600 | [diff] [blame^] | 174 | (gcc, creates libpng.so.2.1.0.5d) |
Glenn Randers-Pehrson | f8b008c | 1999-09-18 10:54:36 -0500 | [diff] [blame] | 175 | makefile.linux => Linux/ELF makefile |
Glenn Randers-Pehrson | 074af5e | 1999-11-28 23:32:18 -0600 | [diff] [blame^] | 176 | (gcc, creates libpng.so.2.1.0.5d) |
Glenn Randers-Pehrson | f8b008c | 1999-09-18 10:54:36 -0500 | [diff] [blame] | 177 | makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc |
| 178 | makefile.mips => MIPS makefile |
| 179 | makefile.acorn => Acorn makefile |
| 180 | makefile.amiga => Amiga makefile |
| 181 | smakefile.ppc => AMIGA smakefile for SAS C V6.58/7.00 PPC |
| 182 | compiler (Requires SCOPTIONS, copied from |
| 183 | scripts/SCOPTIONS.ppc) |
| 184 | makefile.atari => Atari makefile |
| 185 | makefile.beos => BEOS makefile for X86 |
| 186 | makefile.borland => Borland makefile |
| 187 | build.bat => MS-DOS batch file for Borland compiler |
| 188 | makefile.dj2 => DJGPP 2 makefile |
| 189 | makefile.msc => Microsoft C makefile |
Glenn Randers-Pehrson | bcfd15d | 1999-10-01 14:22:25 -0500 | [diff] [blame] | 190 | makefile.vcawin32 => makefile for Microsoft Visual C++ 5.0 and |
| 191 | later (uses assembler code) |
| 192 | makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and |
| 193 | later (does not use assembler code) |
Glenn Randers-Pehrson | f8b008c | 1999-09-18 10:54:36 -0500 | [diff] [blame] | 194 | makefile.turboc3 => Turbo C 3.0 makefile |
| 195 | makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def) |
| 196 | pngos2.def => OS/2 module definition file used by makefile.os2 |
| 197 | makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model |
| 198 | makevms.com => VMS build script |
| 199 | pngdll.mak => To make a png32bd.dll with Borland C++ 4.5 |
| 200 | pngdef.pas => Defines for a png32bd.dll with Borland C++ 4.5 |
| 201 | SCOPTIONS.ppc => Used with smakefile.ppc |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 202 | |
| 203 | Good luck, and happy coding. |
| 204 | |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 205 | -Glenn Randers-Pehrson |
Glenn Randers-Pehrson | 4393a9a | 1999-09-17 12:27:26 -0500 | [diff] [blame] | 206 | Internet: randeg@alum.rpi.edu |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 207 | Web: http://www.rpi.edu/~randeg/index.html |
| 208 | |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 209 | -Andreas Eric Dilger |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 210 | Internet: adilger@enel.ucalgary.ca |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 211 | Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/ |
Andreas Dilger | 02ad0ef | 1997-01-17 01:34:35 -0600 | [diff] [blame] | 212 | |
| 213 | -Guy Eric Schalnat |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 214 | (formerly of Group 42, Inc) |
Glenn Randers-Pehrson | cbe52d8 | 1998-02-28 07:00:24 -0600 | [diff] [blame] | 215 | Internet: gschal@infinet.com |