Update libjpeg from 6b to 8b.
[reactos.git] / rosapps / lib / libpng / docs / README
1 README for libpng version 1.2.24 - December 14, 2007 (shared library 12.0)
2 See the note about version numbers near the top of png.h
3
4 See INSTALL for instructions on how to install libpng.
5
6 Libpng comes in several distribution formats. Get libpng-*.tar.gz
7 or libpng-*.tar.bz2 if you want UNIX-style line endings in the text
8 files, or lpng*.zip if you want DOS-style line endings.
9
10 Version 0.89 was the first official release of libpng. Don't let the
11 fact that it's the first release fool you. The libpng library has been in
12 extensive use and testing since mid-1995. By late 1997 it had
13 finally gotten to the stage where there hadn't been significant
14 changes to the API in some time, and people have a bad feeling about
15 libraries with versions < 1.0. Version 1.0.0 was released in
16 March 1998.
17
18 ****
19 Note that some of the changes to the png_info structure render this
20 version of the library binary incompatible with libpng-0.89 or
21 earlier versions if you are using a shared library. The type of the
22 "filler" parameter for png_set_filler() has changed from png_byte to
23 png_uint_32, which will affect shared-library applications that use
24 this function.
25
26 To avoid problems with changes to the internals of png_info_struct,
27 new APIs have been made available in 0.95 to avoid direct application
28 access to info_ptr. These functions are the png_set_<chunk> and
29 png_get_<chunk> functions. These functions should be used when
30 accessing/storing the info_struct data, rather than manipulating it
31 directly, to avoid such problems in the future.
32
33 It is important to note that the APIs do not make current programs
34 that access the info struct directly incompatible with the new
35 library. However, it is strongly suggested that new programs use
36 the new APIs (as shown in example.c and pngtest.c), and older programs
37 be converted to the new format, to facilitate upgrades in the future.
38 ****
39
40 Additions since 0.90 include the ability to compile libpng as a
41 Windows DLL, and new APIs for accessing data in the info struct.
42 Experimental functions include the ability to set weighting and cost
43 factors for row filter selection, direct reads of integers from buffers
44 on big-endian processors that support misaligned data access, faster
45 methods of doing alpha composition, and more accurate 16->8 bit color
46 conversion.
47
48 The additions since 0.89 include the ability to read from a PNG stream
49 which has had some (or all) of the signature bytes read by the calling
50 application. This also allows the reading of embedded PNG streams that
51 do not have the PNG file signature. As well, it is now possible to set
52 the library action on the detection of chunk CRC errors. It is possible
53 to set different actions based on whether the CRC error occurred in a
54 critical or an ancillary chunk.
55
56 The changes made to the library, and bugs fixed are based on discussions
57 on the PNG-implement mailing list
58 and not on material submitted privately to Guy, Andreas, or Glenn. They will
59 forward any good suggestions to the list.
60
61 For a detailed description on using libpng, read libpng.txt. For
62 examples of libpng in a program, see example.c and pngtest.c. For usage
63 information and restrictions (what little they are) on libpng, see
64 png.h. For a description on using zlib (the compression library used by
65 libpng) and zlib's restrictions, see zlib.h
66
67 I have included a general makefile, as well as several machine and
68 compiler specific ones, but you may have to modify one for your own needs.
69
70 You should use zlib 1.0.4 or later to run this, but it MAY work with
71 versions as old as zlib 0.95. Even so, there are bugs in older zlib
72 versions which can cause the output of invalid compression streams for
73 some images. You will definitely need zlib 1.0.4 or later if you are
74 taking advantage of the MS-DOS "far" structure allocation for the small
75 and medium memory models. You should also note that zlib is a
76 compression library that is useful for more things than just PNG files.
77 You can use zlib as a drop-in replacement for fread() and fwrite() if
78 you are so inclined.
79
80 zlib should be available at the same place that libpng is, or at.
81 ftp://ftp.info-zip.org/pub/infozip/zlib
82
83 You may also want a copy of the PNG specification. It is available
84 as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find
85 these at http://www.libpng.org/pub/png/documents/
86
87 This code is currently being archived at libpng.sf.net in the
88 [DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
89 at GO GRAPHSUP. If you can't find it in any of those places,
90 e-mail me, and I'll help you find it.
91
92 If you have any code changes, requests, problems, etc., please e-mail
93 them to me. Also, I'd appreciate any make files or project files,
94 and any modifications you needed to make to get libpng to compile,
95 along with a #define variable to tell what compiler/system you are on.
96 If you needed to add transformations to libpng, or wish libpng would
97 provide the image in a different way, drop me a note (and code, if
98 possible), so I can consider supporting the transformation.
99 Finally, if you get any warning messages when compiling libpng
100 (note: not zlib), and they are easy to fix, I'd appreciate the
101 fix. Please mention "libpng" somewhere in the subject line. Thanks.
102
103 This release was created and will be supported by myself (of course
104 based in a large way on Guy's and Andreas' earlier work), and the PNG group.
105
106 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
107 (subscription required; visit
108 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
109 to subscribe) or to glennrp at users.sourceforge.net
110
111 You can't reach Guy, the original libpng author, at the addresses
112 given in previous versions of this document. He and Andreas will read mail
113 addressed to the png-implement list, however.
114
115 Please do not send general questions about PNG. Send them to
116 the (png-mng-misc at lists.sourceforge.net, subscription required, visit
117 https://lists.sourceforge.net/lists/listinfo/png-mng-implement to subscribe)
118 On the other hand,
119 please do not send libpng questions to that address, send them to me
120 or to the png-implement list. I'll
121 get them in the end anyway. If you have a question about something
122 in the PNG specification that is related to using libpng, send it
123 to me. Send me any questions that start with "I was using libpng,
124 and ...". If in doubt, send questions to me. I'll bounce them
125 to others, if necessary.
126
127 Please do not send suggestions on how to change PNG. We have
128 been discussing PNG for twelve years now, and it is official and
129 finished. If you have suggestions for libpng, however, I'll
130 gladly listen. Even if your suggestion is not used immediately,
131 it may be used later.
132
133 Files in this distribution:
134
135 ANNOUNCE => Announcement of this version, with recent changes
136 CHANGES => Description of changes between libpng versions
137 KNOWNBUG => List of known bugs and deficiencies
138 LICENSE => License to use and redistribute libpng
139 README => This file
140 TODO => Things not implemented in the current library
141 Y2KINFO => Statement of Y2K compliance
142 example.c => Example code for using libpng functions
143 libpng-*-*-diff.txt => Diff from previous release
144 libpng.3 => manual page for libpng (includes libpng.txt)
145 libpng.txt => Description of libpng and its functions
146 libpngpf.3 => manual page for libpng's private functions
147 png.5 => manual page for the PNG format
148 png.c => Basic interface functions common to library
149 png.h => Library function and interface declarations
150 pngconf.h => System specific library configuration
151 pngerror.c => Error/warning message I/O functions
152 pngget.c => Functions for retrieving info from struct
153 pngmem.c => Memory handling functions
154 pngbar.png => PNG logo, 88x31
155 pngnow.png => PNG logo, 98x31
156 pngpread.c => Progressive reading functions
157 pngread.c => Read data/helper high-level functions
158 pngrio.c => Lowest-level data read I/O functions
159 pngrtran.c => Read data transformation functions
160 pngrutil.c => Read data utility functions
161 pngset.c => Functions for storing data into the info_struct
162 pngtest.c => Library test program
163 pngtest.png => Library test sample image
164 pngtrans.c => Common data transformation functions
165 pngwio.c => Lowest-level write I/O functions
166 pngwrite.c => High-level write functions
167 pngwtran.c => Write data transformations
168 pngwutil.c => Write utility functions
169 contrib => Contributions
170 gregbook => source code for PNG reading and writing, from
171 Greg Roelofs' "PNG: The Definitive Guide",
172 O'Reilly, 1999
173 msvctest => Builds and runs pngtest using a MSVC workspace
174 pngminus => Simple pnm2png and png2pnm programs
175 pngsuite => Test images
176 visupng => Contains a MSVC workspace for VisualPng
177 projects => Contains project files and workspaces for building DLL
178 beos => Contains a Beos workspace for building libpng
179 c5builder => Contains a Borland workspace for building libpng
180 and zlib
181 visualc6 => Contains a Microsoft Visual C++ (MSVC) workspace
182 for building libpng and zlib
183 netware.txt => Contains instructions for downloading a set of
184 project files for building libpng and zlib on
185 Netware.
186 wince.txt => Contains instructions for downloading a Microsoft
187 Visual C++ (Windows CD Toolkit) workspace for
188 building libpng and zlib on WindowsCE
189 scripts => Directory containing scripts for building libpng:
190 descrip.mms => VMS makefile for MMS or MMK
191 makefile.std => Generic UNIX makefile (cc, creates static libpng.a)
192 makefile.elf => Linux/ELF makefile symbol versioning,
193 gcc, creates libpng12.so.0.1.2.24)
194 makefile.linux => Linux/ELF makefile
195 (gcc, creates libpng12.so.0.1.2.24)
196 makefile.gcmmx => Linux/ELF makefile
197 (gcc, creates libpng12.so.0.1.2.24,
198 uses assembler code tuned for Intel MMX platform)
199 makefile.gcc => Generic makefile (gcc, creates static libpng.a)
200 makefile.knr => Archaic UNIX Makefile that converts files with
201 ansi2knr (Requires ansi2knr.c from
202 ftp://ftp.cs.wisc.edu/ghost)
203 makefile.aix => AIX makefile
204 makefile.cygwin => Cygwin/gcc makefile
205 makefile.darwin => Darwin makefile
206 makefile.dec => DEC Alpha UNIX makefile
207 makefile.freebsd => FreeBSD makefile
208 makefile.hpgcc => HPUX makefile using gcc
209 makefile.hpux => HPUX (10.20 and 11.00) makefile
210 makefile.hp64 => HPUX (10.20 and 11.00) makefile, 64 bit
211 makefile.ibmc => IBM C/C++ version 3.x for Win32 and OS/2 (static)
212 makefile.intel => Intel C/C++ version 4.0 and later
213 libpng.icc => Project file, IBM VisualAge/C++ 4.0 or later
214 makefile.netbsd => NetBSD/cc makefile, PNGGCCRD, makes libpng.so.
215 makefile.ne12bsd => NetBSD/cc makefile, PNGGCCRD, makes libpng12.so
216 makefile.openbsd => OpenBSD makefile
217 makefile.sgi => Silicon Graphics IRIX (cc, creates static lib)
218 makefile.sggcc => Silicon Graphics
219 (gcc, creates libpng12.so.0.1.2.24)
220 makefile.sunos => Sun makefile
221 makefile.solaris => Solaris 2.X makefile
222 (gcc, creates libpng12.so.0.1.2.24)
223 makefile.so9 => Solaris 9 makefile
224 (gcc, creates libpng12.so.0.1.2.24)
225 makefile.32sunu => Sun Ultra 32-bit makefile
226 makefile.64sunu => Sun Ultra 64-bit makefile
227 makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc
228 makefile.mips => MIPS makefile
229 makefile.acorn => Acorn makefile
230 makefile.amiga => Amiga makefile
231 smakefile.ppc => AMIGA smakefile for SAS C V6.58/7.00 PPC
232 compiler (Requires SCOPTIONS, copied from
233 scripts/SCOPTIONS.ppc)
234 makefile.atari => Atari makefile
235 makefile.beos => BEOS makefile for X86
236 makefile.bor => Borland makefile (uses bcc)
237 makefile.bc32 => 32-bit Borland C++ (all modules compiled in C mode)
238 makefile.tc3 => Turbo C 3.0 makefile
239 makefile.dj2 => DJGPP 2 makefile
240 makefile.msc => Microsoft C makefile
241 makefile.vcawin32=> makefile for Microsoft Visual C++ 5.0 and
242 later (uses assembler code tuned for Intel MMX
243 platform)
244 makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and
245 later (does not use assembler code)
246 makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def)
247 pngos2.def => OS/2 module definition file used by makefile.os2
248 makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model
249 makevms.com => VMS build script
250 SCOPTIONS.ppc => Used with smakefile.ppc
251
252 Good luck, and happy coding.
253
254 -Glenn Randers-Pehrson (current maintainer)
255 Internet: glennrp at users.sourceforge.net
256
257 -Andreas Eric Dilger (former maintainer, 1996-1997)
258 Internet: adilger at enel.ucalgary.ca
259 Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/
260
261 -Guy Eric Schalnat (original author and former maintainer, 1995-1996)
262 (formerly of Group 42, Inc)
263 Internet: gschal at infinet.com