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1 README for libpng version 1.2.45 - July 7, 2011 (shared library 12.0) | 1 README for libpng version 1.6.3 - July 18, 2013 (shared library 16.0) |
2 See the note about version numbers near the top of png.h | 2 See the note about version numbers near the top of png.h |
3 | 3 |
4 See INSTALL for instructions on how to install libpng. | 4 See INSTALL for instructions on how to install libpng. |
5 | 5 |
6 Libpng comes in several distribution formats. Get libpng-*.tar.gz, | 6 Libpng comes in several distribution formats. Get libpng-*.tar.gz or |
7 libpng-*.tar.xz, or libpng-*.tar.bz2 if you want UNIX-style line | 7 libpng-*.tar.xz or if you want UNIX-style line endings in the text files, |
8 endings in the text files, or lpng*.7z or lpng*.zip if you want DOS-style | 8 or lpng*.7z or lpng*.zip if you want DOS-style line endings. |
9 line endings. You can get UNIX-style line endings from the *.zip file | |
10 by using "unzip -a" but there seems to be no simple way to recover | |
11 UNIX-style line endings from the *.7z file. The *.tar.xz file is | |
12 recommended for *NIX users instead. | |
13 | 9 |
14 Version 0.89 was the first official release of libpng. Don't let the | 10 Version 0.89 was the first official release of libpng. Don't let the |
15 fact that it's the first release fool you. The libpng library has been in | 11 fact that it's the first release fool you. The libpng library has been in |
16 extensive use and testing since mid-1995. By late 1997 it had | 12 extensive use and testing since mid-1995. By late 1997 it had |
17 finally gotten to the stage where there hadn't been significant | 13 finally gotten to the stage where there hadn't been significant |
18 changes to the API in some time, and people have a bad feeling about | 14 changes to the API in some time, and people have a bad feeling about |
19 libraries with versions < 1.0. Version 1.0.0 was released in | 15 libraries with versions < 1.0. Version 1.0.0 was released in |
20 March 1998. | 16 March 1998. |
21 | 17 |
22 **** | 18 **** |
(...skipping 28 matching lines...) Expand all Loading... |
51 | 47 |
52 The additions since 0.89 include the ability to read from a PNG stream | 48 The additions since 0.89 include the ability to read from a PNG stream |
53 which has had some (or all) of the signature bytes read by the calling | 49 which has had some (or all) of the signature bytes read by the calling |
54 application. This also allows the reading of embedded PNG streams that | 50 application. This also allows the reading of embedded PNG streams that |
55 do not have the PNG file signature. As well, it is now possible to set | 51 do not have the PNG file signature. As well, it is now possible to set |
56 the library action on the detection of chunk CRC errors. It is possible | 52 the library action on the detection of chunk CRC errors. It is possible |
57 to set different actions based on whether the CRC error occurred in a | 53 to set different actions based on whether the CRC error occurred in a |
58 critical or an ancillary chunk. | 54 critical or an ancillary chunk. |
59 | 55 |
60 The changes made to the library, and bugs fixed are based on discussions | 56 The changes made to the library, and bugs fixed are based on discussions |
61 on the png-mng-implement mailing list and not on material submitted | 57 on the PNG-implement mailing list and not on material submitted |
62 privately to Guy, Andreas, or Glenn. They will forward any good | 58 privately to Guy, Andreas, or Glenn. They will forward any good |
63 suggestions to the list. | 59 suggestions to the list. |
64 | 60 |
65 For a detailed description on using libpng, read libpng.txt. For | 61 For a detailed description on using libpng, read libpng-manual.txt. For |
66 examples of libpng in a program, see example.c and pngtest.c. For usage | 62 examples of libpng in a program, see example.c and pngtest.c. For usage |
67 information and restrictions (what little they are) on libpng, see | 63 information and restrictions (what little they are) on libpng, see |
68 png.h. For a description on using zlib (the compression library used by | 64 png.h. For a description on using zlib (the compression library used by |
69 libpng) and zlib's restrictions, see zlib.h | 65 libpng) and zlib's restrictions, see zlib.h |
70 | 66 |
71 I have included a general makefile, as well as several machine and | 67 I have included a general makefile, as well as several machine and |
72 compiler specific ones, but you may have to modify one for your own needs. | 68 compiler specific ones, but you may have to modify one for your own needs. |
73 | 69 |
74 You should use zlib 1.0.4 or later to run this, but it MAY work with | 70 You should use zlib 1.0.4 or later to run this, but it MAY work with |
75 versions as old as zlib 0.95. Even so, there are bugs in older zlib | 71 versions as old as zlib 0.95. Even so, there are bugs in older zlib |
76 versions which can cause the output of invalid compression streams for | 72 versions which can cause the output of invalid compression streams for |
77 some images. You will definitely need zlib 1.0.4 or later if you are | 73 some images. You will definitely need zlib 1.0.4 or later if you are |
78 taking advantage of the MS-DOS "far" structure allocation for the small | 74 taking advantage of the MS-DOS "far" structure allocation for the small |
79 and medium memory models. You should also note that zlib is a | 75 and medium memory models. You should also note that zlib is a |
80 compression library that is useful for more things than just PNG files. | 76 compression library that is useful for more things than just PNG files. |
81 You can use zlib as a drop-in replacement for fread() and fwrite() if | 77 You can use zlib as a drop-in replacement for fread() and fwrite() if |
82 you are so inclined. | 78 you are so inclined. |
83 | 79 |
84 zlib should be available at the same place that libpng is, or at | 80 zlib should be available at the same place that libpng is, or at zlib.net. |
85 ftp://ftp.simplesystems.org/pub/png/src/ | |
86 | 81 |
87 You may also want a copy of the PNG specification. It is available | 82 You may also want a copy of the PNG specification. It is available |
88 as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find | 83 as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find |
89 these at http://www.libpng.org/pub/png/pngdocs.html | 84 these at http://www.libpng.org/pub/png/documents/ |
90 | 85 |
91 This code is currently being archived at libpng.sf.net in the | 86 This code is currently being archived at libpng.sf.net in the |
92 [DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT) | 87 [DOWNLOAD] area, and at ftp://ftp.simplesystems.org. If you can't find it |
93 at GO GRAPHSUP. If you can't find it in any of those places, | 88 in any of those places, e-mail me, and I'll help you find it. |
94 e-mail me, and I'll help you find it. | |
95 | 89 |
96 If you have any code changes, requests, problems, etc., please e-mail | 90 If you have any code changes, requests, problems, etc., please e-mail |
97 them to me. Also, I'd appreciate any make files or project files, | 91 them to me. Also, I'd appreciate any make files or project files, |
98 and any modifications you needed to make to get libpng to compile, | 92 and any modifications you needed to make to get libpng to compile, |
99 along with a #define variable to tell what compiler/system you are on. | 93 along with a #define variable to tell what compiler/system you are on. |
100 If you needed to add transformations to libpng, or wish libpng would | 94 If you needed to add transformations to libpng, or wish libpng would |
101 provide the image in a different way, drop me a note (and code, if | 95 provide the image in a different way, drop me a note (and code, if |
102 possible), so I can consider supporting the transformation. | 96 possible), so I can consider supporting the transformation. |
103 Finally, if you get any warning messages when compiling libpng | 97 Finally, if you get any warning messages when compiling libpng |
104 (note: not zlib), and they are easy to fix, I'd appreciate the | 98 (note: not zlib), and they are easy to fix, I'd appreciate the |
105 fix. Please mention "libpng" somewhere in the subject line. Thanks. | 99 fix. Please mention "libpng" somewhere in the subject line. Thanks. |
106 | 100 |
107 This release was created and will be supported by myself (of course | 101 This release was created and will be supported by myself (of course |
108 based in a large way on Guy's and Andreas' earlier work), and the PNG | 102 based in a large way on Guy's and Andreas' earlier work), and the PNG |
109 development group. | 103 development group. |
110 | 104 |
111 Send comments/corrections/commendations to png-mng-implement at lists.sf.net | 105 Send comments/corrections/commendations to png-mng-implement at |
112 (subscription required; visit | 106 lists.sourceforge.net (subscription required; visit |
113 https://lists.sourceforge.net/lists/listinfo/png-mng-implement | 107 https://lists.sourceforge.net/lists/listinfo/png-mng-implement |
114 to subscribe) or to glennrp at users.sourceforge.net | 108 to subscribe) or to glennrp at users.sourceforge.net |
115 | 109 |
116 You can't reach Guy, the original libpng author, at the addresses | 110 You can't reach Guy, the original libpng author, at the addresses |
117 given in previous versions of this document. He and Andreas will | 111 given in previous versions of this document. He and Andreas will |
118 read mail addressed to the png-mng-implement list, however. | 112 read mail addressed to the png-implement list, however. |
119 | 113 |
120 Please do not send general questions about PNG. Send them to | 114 Please do not send general questions about PNG. Send them to |
121 the (png-mng-misc at lists.sourceforge.net, subscription required, visit | 115 png-mng-misc at lists.sf.net (subscription required; visit |
122 https://lists.sourceforge.net/lists/listinfo/png-mng-misc to | 116 https://lists.sourceforge.net/lists/listinfo/png-mng-misc to |
123 subscribe). On the other hand, please do not send libpng questions to | 117 subscribe). If you have a question about something |
124 that address, send them to me or to the png-mng-implement list. I'll | |
125 get them in the end anyway. If you have a question about something | |
126 in the PNG specification that is related to using libpng, send it | 118 in the PNG specification that is related to using libpng, send it |
127 to me. Send me any questions that start with "I was using libpng, | 119 to me. Send me any questions that start with "I was using libpng, |
128 and ...". If in doubt, send questions to me. I'll bounce them | 120 and ...". If in doubt, send questions to me. I'll bounce them |
129 to others, if necessary. | 121 to others, if necessary. |
130 | 122 |
131 Please do not send suggestions on how to change PNG. We have | 123 Please do not send suggestions on how to change PNG. We have |
132 been discussing PNG for twelve years now, and it is official and | 124 been discussing PNG for eighteen years now, and it is official and |
133 finished. If you have suggestions for libpng, however, I'll | 125 finished. If you have suggestions for libpng, however, I'll |
134 gladly listen. Even if your suggestion is not used immediately, | 126 gladly listen. Even if your suggestion is not used immediately, |
135 it may be used later. | 127 it may be used later. |
136 | 128 |
137 Files in this distribution: | 129 Files in this distribution: |
138 | 130 |
139 ANNOUNCE => Announcement of this version, with recent changes | 131 ANNOUNCE => Announcement of this version, with recent changes |
140 CHANGES => Description of changes between libpng versions | 132 CHANGES => Description of changes between libpng versions |
141 KNOWNBUG => List of known bugs and deficiencies | 133 KNOWNBUG => List of known bugs and deficiencies |
142 LICENSE => License to use and redistribute libpng | 134 LICENSE => License to use and redistribute libpng |
143 README => This file | 135 README => This file |
144 TODO => Things not implemented in the current library | 136 TODO => Things not implemented in the current library |
145 Y2KINFO => Statement of Y2K compliance | 137 Y2KINFO => Statement of Y2K compliance |
146 example.c => Example code for using libpng functions | 138 example.c => Example code for using libpng functions |
147 libpng-*-*-diff.txt => Diff from previous release | 139 libpng.3 => manual page for libpng (includes libpng-manual.txt) |
148 libpng.3 => manual page for libpng (includes libpng.txt) | 140 libpng-manual.txt => Description of libpng and its functions |
149 libpng.txt => Description of libpng and its functions | |
150 libpngpf.3 => manual page for libpng's private functions | 141 libpngpf.3 => manual page for libpng's private functions |
151 png.5 => manual page for the PNG format | 142 png.5 => manual page for the PNG format |
152 png.c => Basic interface functions common to library | 143 png.c => Basic interface functions common to library |
153 png.h => Library function and interface declarations | 144 png.h => Library function and interface declarations (public) |
154 pngconf.h => System specific library configuration | 145 pngpriv.h => Library function and interface declarations (private) |
| 146 pngconf.h => System specific library configuration (public) |
| 147 pngstruct.h => png_struct declaration (private) |
| 148 pnginfo.h => png_info struct declaration (private) |
| 149 pngdebug.h => debugging macros (private) |
155 pngerror.c => Error/warning message I/O functions | 150 pngerror.c => Error/warning message I/O functions |
156 pngget.c => Functions for retrieving info from struct | 151 pngget.c => Functions for retrieving info from struct |
157 pngmem.c => Memory handling functions | 152 pngmem.c => Memory handling functions |
158 pngbar.png => PNG logo, 88x31 | 153 pngbar.png => PNG logo, 88x31 |
159 pngnow.png => PNG logo, 98x31 | 154 pngnow.png => PNG logo, 98x31 |
160 pngpread.c => Progressive reading functions | 155 pngpread.c => Progressive reading functions |
161 pngread.c => Read data/helper high-level functions | 156 pngread.c => Read data/helper high-level functions |
162 pngrio.c => Lowest-level data read I/O functions | 157 pngrio.c => Lowest-level data read I/O functions |
163 pngrtran.c => Read data transformation functions | 158 pngrtran.c => Read data transformation functions |
164 pngrutil.c => Read data utility functions | 159 pngrutil.c => Read data utility functions |
165 pngset.c => Functions for storing data into the info_struct | 160 pngset.c => Functions for storing data into the info_struct |
166 pngtest.c => Library test program | 161 pngtest.c => Library test program |
167 pngtest.png => Library test sample image | 162 pngtest.png => Library test sample image |
168 pngtrans.c => Common data transformation functions | 163 pngtrans.c => Common data transformation functions |
169 pngwio.c => Lowest-level write I/O functions | 164 pngwio.c => Lowest-level write I/O functions |
170 pngwrite.c => High-level write functions | 165 pngwrite.c => High-level write functions |
171 pngwtran.c => Write data transformations | 166 pngwtran.c => Write data transformations |
172 pngwutil.c => Write utility functions | 167 pngwutil.c => Write utility functions |
| 168 arm => Contains optimized code for the ARM platform |
173 contrib => Contributions | 169 contrib => Contributions |
| 170 examples => Example programs |
174 gregbook => source code for PNG reading and writing, from | 171 gregbook => source code for PNG reading and writing, from |
175 Greg Roelofs' "PNG: The Definitive Guide", | 172 Greg Roelofs' "PNG: The Definitive Guide", |
176 O'Reilly, 1999 | 173 O'Reilly, 1999 |
177 msvctest => Builds and runs pngtest using a MSVC workspace | 174 libtests => Test programs |
178 pngminim => Simple pnm2pngm and png2pnmm programs | 175 pngminim => Minimal decoder, encoder, and progressive decoder |
179 pngminus => Simple pnm2png and png2pnm programs | 176 programs demonstrating use of pngusr.dfa |
180 pngsuite => Test images | 177 pngminus => Simple pnm2png and png2pnm programs |
| 178 pngsuite => Test images |
| 179 tools => Various tools |
181 visupng => Contains a MSVC workspace for VisualPng | 180 visupng => Contains a MSVC workspace for VisualPng |
182 projects => Contains project files and workspaces for | 181 projects => Contains project files and workspaces for |
183 building a DLL | 182 building a DLL |
184 beos => Contains a Beos workspace for building libpng | 183 owatcom => Contains a WATCOM project for building libpng |
185 c5builder => Contains a Borland workspace for building | 184 visualc71 => Contains a Microsoft Visual C++ (MSVC) |
186 libpng and zlib | |
187 netware.txt => Contains instructions for downloading a set | |
188 of project files for building libpng and | |
189 zlib on Netware. | |
190 visualc6 => Contains a Microsoft Visual C++ (MSVC) | |
191 workspace for building libpng and zlib | 185 workspace for building libpng and zlib |
192 wince.txt => Contains instructions for downloading a | 186 vstudio => Contains a Microsoft Visual C++ (MSVC) |
193 Microsoft Visual C++ (Windows CD Toolkit) | 187 workspace for building libpng and zlib |
194 workspace for building libpng and zlib on | |
195 WindowsCE | |
196 xcode => Contains xcode project files | |
197 scripts => Directory containing scripts for building libpng: | 188 scripts => Directory containing scripts for building libpng: |
198 descrip.mms => VMS makefile for MMS or MMK | 189 (see scripts/README.txt for the list of scripts) |
199 makefile.std => Generic UNIX makefile (cc, creates static | |
200 libpng.a) | |
201 makefile.elf => Linux/ELF gcc makefile symbol versioning, | |
202 creates libpng12.so.0.1.2.45) | |
203 makefile.linux => Linux/ELF makefile (gcc, creates | |
204 libpng12.so.0.1.2.45) | |
205 makefile.gcmmx => Linux/ELF makefile (gcc, creates | |
206 libpng12.so.0.1.2.45, previously | |
207 used assembler code tuned for Intel MMX | |
208 platform) | |
209 makefile.gcc => Generic makefile (gcc, creates static | |
210 libpng.a) | |
211 makefile.knr => Archaic UNIX Makefile that converts files | |
212 with ansi2knr (Requires ansi2knr.c from | |
213 ftp://ftp.cs.wisc.edu/ghost) | |
214 makefile.aix => AIX makefile | |
215 makefile.cygwin => Cygwin/gcc makefile | |
216 makefile.darwin => Darwin makefile | |
217 makefile.dec => DEC Alpha UNIX makefile | |
218 makefile.freebsd => FreeBSD makefile | |
219 makefile.hpgcc => HPUX makefile using gcc | |
220 makefile.hpux => HPUX (10.20 and 11.00) makefile | |
221 makefile.hp64 => HPUX (10.20 and 11.00) makefile, 64 bit | |
222 makefile.ibmc => IBM C/C++ version 3.x for Win32 and OS/2 | |
223 (static) | |
224 makefile.intel => Intel C/C++ version 4.0 and later | |
225 libpng.icc => Project file, IBM VisualAge/C++ 4.0 or later | |
226 makefile.netbsd => NetBSD/cc makefile, makes libpng.so. | |
227 makefile.ne12bsd => NetBSD/cc makefile, makes libpng12.so | |
228 makefile.openbsd => OpenBSD makefile | |
229 makefile.sgi => Silicon Graphics IRIX (cc, creates static lib) | |
230 makefile.sggcc => Silicon Graphics | |
231 (gcc, creates libpng12.so.0.1.2.45) | |
232 makefile.sunos => Sun makefile | |
233 makefile.solaris => Solaris 2.X makefile | |
234 (gcc, creates libpng12.so.0.1.2.45) | |
235 makefile.so9 => Solaris 9 makefile | |
236 (gcc, creates libpng12.so.0.1.2.45) | |
237 makefile.32sunu => Sun Ultra 32-bit makefile | |
238 makefile.64sunu => Sun Ultra 64-bit makefile | |
239 makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc | |
240 makefile.mips => MIPS makefile | |
241 makefile.acorn => Acorn makefile | |
242 makefile.amiga => Amiga makefile | |
243 smakefile.ppc => AMIGA smakefile for SAS C V6.58/7.00 PPC | |
244 compiler (Requires SCOPTIONS, copied from | |
245 scripts/SCOPTIONS.ppc) | |
246 makefile.atari => Atari makefile | |
247 makefile.beos => BEOS makefile for X86 | |
248 makefile.bor => Borland makefile (uses bcc) | |
249 makefile.bc32 => 32-bit Borland C++ (all modules compiled in C mode) | |
250 makefile.tc3 => Turbo C 3.0 makefile | |
251 makefile.dj2 => DJGPP 2 makefile | |
252 makefile.msc => Microsoft C makefile | |
253 makefile.vcawin32=> makefile for Microsoft Visual C++ 5.0 and | |
254 later (previously used assembler code tuned | |
255 for Intel MMX platform) | |
256 makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and | |
257 later (does not use assembler code) | |
258 makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def) | |
259 pngos2.def => OS/2 module definition file used by makefile.os2 | |
260 makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model | |
261 makevms.com => VMS build script | |
262 SCOPTIONS.ppc => Used with smakefile.ppc | |
263 | 190 |
264 Good luck, and happy coding. | 191 Good luck, and happy coding. |
265 | 192 |
266 -Glenn Randers-Pehrson (current maintainer, since 1998) | 193 -Glenn Randers-Pehrson (current maintainer, since 1998) |
267 Internet: glennrp at users.sourceforge.net | 194 Internet: glennrp at users.sourceforge.net |
268 | 195 |
269 -Andreas Eric Dilger (former maintainer, 1996-1997) | 196 -Andreas Eric Dilger (former maintainer, 1996-1997) |
270 Internet: adilger at enel.ucalgary.ca | 197 Internet: adilger at enel.ucalgary.ca |
271 Web: http://members.shaw.ca/adilger/ | 198 Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/ |
272 | 199 |
273 -Guy Eric Schalnat (original author and former maintainer, 1995-1996) | 200 -Guy Eric Schalnat (original author and former maintainer, 1995-1996) |
274 (formerly of Group 42, Inc) | 201 (formerly of Group 42, Inc) |
275 Internet: gschal at infinet.com | 202 Internet: gschal at infinet.com |
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