2 /* png.h - header file for PNG reference library
4 * libpng version 1.6.17, March 26, 2015
6 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
10 * This code is released under the libpng license (See LICENSE, below)
12 * Authors and maintainers:
13 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
14 * libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
15 * libpng versions 0.97, January 1998, through 1.6.17, March 26, 2015: Glenn
16 * See also "Contributing Authors", below.
18 * Note about libpng version numbers:
20 * Due to various miscommunications, unforeseen code incompatibilities
21 * and occasional factors outside the authors' control, version numbering
22 * on the library has not always been consistent and straightforward.
23 * The following table summarizes matters since version 0.89c, which was
24 * the first widely used release:
26 * source png.h png.h shared-lib
27 * version string int version
28 * ------- ------ ----- ----------
29 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
30 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
31 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
32 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
33 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
34 * 0.97c 0.97 97 2.0.97
37 * 0.99a-m 0.99 99 2.0.99
38 * 1.00 1.00 100 2.1.0 [100 should be 10000]
39 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
40 * 1.0.1 png.h string is 10001 2.1.0
41 * 1.0.1a-e identical to the 10002 from here on, the shared library
42 * 1.0.2 source version) 10002 is 2.V where V is the source code
43 * 1.0.2a-b 10003 version, except as noted.
48 * 1.0.5 (+ 2 patches) 10005
50 * 1.0.5e-r 10100 (not source compatible)
51 * 1.0.5s-v 10006 (not binary compatible)
52 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
53 * 1.0.6d-f 10007 (still binary incompatible)
55 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
57 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
58 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
59 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
60 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
61 * 1.0.7 1 10007 (still compatible)
62 * 1.0.8beta1-4 1 10008 2.1.0.8beta1-4
63 * 1.0.8rc1 1 10008 2.1.0.8rc1
64 * 1.0.8 1 10008 2.1.0.8
65 * 1.0.9beta1-6 1 10009 2.1.0.9beta1-6
66 * 1.0.9rc1 1 10009 2.1.0.9rc1
67 * 1.0.9beta7-10 1 10009 2.1.0.9beta7-10
68 * 1.0.9rc2 1 10009 2.1.0.9rc2
69 * 1.0.9 1 10009 2.1.0.9
70 * 1.0.10beta1 1 10010 2.1.0.10beta1
71 * 1.0.10rc1 1 10010 2.1.0.10rc1
72 * 1.0.10 1 10010 2.1.0.10
73 * 1.0.11beta1-3 1 10011 2.1.0.11beta1-3
74 * 1.0.11rc1 1 10011 2.1.0.11rc1
75 * 1.0.11 1 10011 2.1.0.11
76 * 1.0.12beta1-2 2 10012 2.1.0.12beta1-2
77 * 1.0.12rc1 2 10012 2.1.0.12rc1
78 * 1.0.12 2 10012 2.1.0.12
79 * 1.1.0a-f - 10100 2.1.1.0a-f (branch abandoned)
80 * 1.2.0beta1-2 2 10200 2.1.2.0beta1-2
81 * 1.2.0beta3-5 3 10200 3.1.2.0beta3-5
82 * 1.2.0rc1 3 10200 3.1.2.0rc1
83 * 1.2.0 3 10200 3.1.2.0
84 * 1.2.1beta1-4 3 10201 3.1.2.1beta1-4
85 * 1.2.1rc1-2 3 10201 3.1.2.1rc1-2
86 * 1.2.1 3 10201 3.1.2.1
87 * 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6
88 * 1.0.13beta1 10 10013 10.so.0.1.0.13beta1
89 * 1.0.13rc1 10 10013 10.so.0.1.0.13rc1
90 * 1.2.2rc1 12 10202 12.so.0.1.2.2rc1
91 * 1.0.13 10 10013 10.so.0.1.0.13
92 * 1.2.2 12 10202 12.so.0.1.2.2
93 * 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6
94 * 1.2.3 12 10203 12.so.0.1.2.3
95 * 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3
96 * 1.0.14rc1 13 10014 10.so.0.1.0.14rc1
97 * 1.2.4rc1 13 10204 12.so.0.1.2.4rc1
98 * 1.0.14 10 10014 10.so.0.1.0.14
99 * 1.2.4 13 10204 12.so.0.1.2.4
100 * 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2
101 * 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3
102 * 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3
103 * 1.0.15 10 10015 10.so.0.1.0.15
104 * 1.2.5 13 10205 12.so.0.1.2.5
105 * 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4
106 * 1.0.16 10 10016 10.so.0.1.0.16
107 * 1.2.6 13 10206 12.so.0.1.2.6
108 * 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2
109 * 1.0.17rc1 10 10017 12.so.0.1.0.17rc1
110 * 1.2.7rc1 13 10207 12.so.0.1.2.7rc1
111 * 1.0.17 10 10017 12.so.0.1.0.17
112 * 1.2.7 13 10207 12.so.0.1.2.7
113 * 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5
114 * 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5
115 * 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5
116 * 1.0.18 10 10018 12.so.0.1.0.18
117 * 1.2.8 13 10208 12.so.0.1.2.8
118 * 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3
119 * 1.2.9beta4-11 13 10209 12.so.0.9[.0]
120 * 1.2.9rc1 13 10209 12.so.0.9[.0]
121 * 1.2.9 13 10209 12.so.0.9[.0]
122 * 1.2.10beta1-7 13 10210 12.so.0.10[.0]
123 * 1.2.10rc1-2 13 10210 12.so.0.10[.0]
124 * 1.2.10 13 10210 12.so.0.10[.0]
125 * 1.4.0beta1-5 14 10400 14.so.0.0[.0]
126 * 1.2.11beta1-4 13 10211 12.so.0.11[.0]
127 * 1.4.0beta7-8 14 10400 14.so.0.0[.0]
128 * 1.2.11 13 10211 12.so.0.11[.0]
129 * 1.2.12 13 10212 12.so.0.12[.0]
130 * 1.4.0beta9-14 14 10400 14.so.0.0[.0]
131 * 1.2.13 13 10213 12.so.0.13[.0]
132 * 1.4.0beta15-36 14 10400 14.so.0.0[.0]
133 * 1.4.0beta37-87 14 10400 14.so.14.0[.0]
134 * 1.4.0rc01 14 10400 14.so.14.0[.0]
135 * 1.4.0beta88-109 14 10400 14.so.14.0[.0]
136 * 1.4.0rc02-08 14 10400 14.so.14.0[.0]
137 * 1.4.0 14 10400 14.so.14.0[.0]
138 * 1.4.1beta01-03 14 10401 14.so.14.1[.0]
139 * 1.4.1rc01 14 10401 14.so.14.1[.0]
140 * 1.4.1beta04-12 14 10401 14.so.14.1[.0]
141 * 1.4.1 14 10401 14.so.14.1[.0]
142 * 1.4.2 14 10402 14.so.14.2[.0]
143 * 1.4.3 14 10403 14.so.14.3[.0]
144 * 1.4.4 14 10404 14.so.14.4[.0]
145 * 1.5.0beta01-58 15 10500 15.so.15.0[.0]
146 * 1.5.0rc01-07 15 10500 15.so.15.0[.0]
147 * 1.5.0 15 10500 15.so.15.0[.0]
148 * 1.5.1beta01-11 15 10501 15.so.15.1[.0]
149 * 1.5.1rc01-02 15 10501 15.so.15.1[.0]
150 * 1.5.1 15 10501 15.so.15.1[.0]
151 * 1.5.2beta01-03 15 10502 15.so.15.2[.0]
152 * 1.5.2rc01-03 15 10502 15.so.15.2[.0]
153 * 1.5.2 15 10502 15.so.15.2[.0]
154 * 1.5.3beta01-10 15 10503 15.so.15.3[.0]
155 * 1.5.3rc01-02 15 10503 15.so.15.3[.0]
156 * 1.5.3beta11 15 10503 15.so.15.3[.0]
158 * 1.5.4beta01-08 15 10504 15.so.15.4[.0]
159 * 1.5.4rc01 15 10504 15.so.15.4[.0]
160 * 1.5.4 15 10504 15.so.15.4[.0]
161 * 1.5.5beta01-08 15 10505 15.so.15.5[.0]
162 * 1.5.5rc01 15 10505 15.so.15.5[.0]
163 * 1.5.5 15 10505 15.so.15.5[.0]
164 * 1.5.6beta01-07 15 10506 15.so.15.6[.0]
165 * 1.5.6rc01-03 15 10506 15.so.15.6[.0]
166 * 1.5.6 15 10506 15.so.15.6[.0]
167 * 1.5.7beta01-05 15 10507 15.so.15.7[.0]
168 * 1.5.7rc01-03 15 10507 15.so.15.7[.0]
169 * 1.5.7 15 10507 15.so.15.7[.0]
170 * 1.6.0beta01-40 16 10600 16.so.16.0[.0]
171 * 1.6.0rc01-08 16 10600 16.so.16.0[.0]
172 * 1.6.0 16 10600 16.so.16.0[.0]
173 * 1.6.1beta01-09 16 10601 16.so.16.1[.0]
174 * 1.6.1rc01 16 10601 16.so.16.1[.0]
175 * 1.6.1 16 10601 16.so.16.1[.0]
176 * 1.6.2beta01 16 10602 16.so.16.2[.0]
177 * 1.6.2rc01-06 16 10602 16.so.16.2[.0]
178 * 1.6.2 16 10602 16.so.16.2[.0]
179 * 1.6.3beta01-11 16 10603 16.so.16.3[.0]
180 * 1.6.3rc01 16 10603 16.so.16.3[.0]
181 * 1.6.3 16 10603 16.so.16.3[.0]
182 * 1.6.4beta01-02 16 10604 16.so.16.4[.0]
183 * 1.6.4rc01 16 10604 16.so.16.4[.0]
184 * 1.6.4 16 10604 16.so.16.4[.0]
185 * 1.6.5 16 10605 16.so.16.5[.0]
186 * 1.6.6 16 10606 16.so.16.6[.0]
187 * 1.6.7beta01-04 16 10607 16.so.16.7[.0]
188 * 1.6.7rc01-03 16 10607 16.so.16.7[.0]
189 * 1.6.7 16 10607 16.so.16.7[.0]
190 * 1.6.8beta01-02 16 10608 16.so.16.8[.0]
191 * 1.6.8rc01-02 16 10608 16.so.16.8[.0]
192 * 1.6.8 16 10608 16.so.16.8[.0]
193 * 1.6.9beta01-04 16 10609 16.so.16.9[.0]
194 * 1.6.9rc01-02 16 10609 16.so.16.9[.0]
195 * 1.6.9 16 10609 16.so.16.9[.0]
196 * 1.6.10beta01-03 16 10610 16.so.16.10[.0]
197 * 1.6.10rc01-03 16 10610 16.so.16.10[.0]
198 * 1.6.10 16 10610 16.so.16.10[.0]
199 * 1.6.11beta01-06 16 10611 16.so.16.11[.0]
200 * 1.6.11rc01-02 16 10611 16.so.16.11[.0]
201 * 1.6.11 16 10611 16.so.16.11[.0]
202 * 1.6.12rc01-03 16 10612 16.so.16.12[.0]
203 * 1.6.12 16 10612 16.so.16.12[.0]
204 * 1.6.13beta01-04 16 10613 16.so.16.13[.0]
205 * 1.6.13rc01-02 16 10613 16.so.16.13[.0]
206 * 1.6.13 16 10613 16.so.16.13[.0]
207 * 1.6.14beta01-07 16 10614 16.so.16.14[.0]
208 * 1.6.14rc01-02 16 10614 16.so.16.14[.0]
209 * 1.6.14 16 10614 16.so.16.14[.0]
210 * 1.6.15beta01-08 16 10615 16.so.16.15[.0]
211 * 1.6.15rc01-03 16 10615 16.so.16.15[.0]
212 * 1.6.15 16 10615 16.so.16.15[.0]
213 * 1.6.16beta01-03 16 10616 16.so.16.16[.0]
214 * 1.6.16rc01-02 16 10616 16.so.16.16[.0]
215 * 1.6.16 16 10616 16.so.16.16[.0]
216 * 1.6.17beta01-06 16 10617 16.so.16.17[.0]
217 * 1.6.17rc01-06 16 10617 16.so.16.17[.0]
218 * 1.6.17 16 10617 16.so.16.17[.0]
220 * Henceforth the source version will match the shared-library major
221 * and minor numbers; the shared-library major version number will be
222 * used for changes in backward compatibility, as it is intended. The
223 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
224 * for applications, is an unsigned integer of the form xyyzz corresponding
225 * to the source version x.y.z (leading zeros in y and z). Beta versions
226 * were given the previous public release number plus a letter, until
227 * version 1.0.6j; from then on they were given the upcoming public
228 * release number plus "betaNN" or "rcNN".
230 * Binary incompatibility exists only when applications make direct access
231 * to the info_ptr or png_ptr members through png.h, and the compiled
232 * application is loaded with a different version of the library.
234 * DLLNUM will change each time there are forward or backward changes
235 * in binary compatibility (e.g., when a new feature is added).
237 * See libpng-manual.txt or libpng.3 for more information. The PNG
238 * specification is available as a W3C Recommendation and as an ISO
239 * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
243 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
245 * If you modify libpng you may insert additional notices immediately following
248 * This code is released under the libpng license.
250 * libpng versions 1.2.6, August 15, 2004, through 1.6.17, March 26, 2015, are
251 * Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
252 * distributed according to the same disclaimer and license as libpng-1.2.5
253 * with the following individual added to the list of Contributing Authors:
257 * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
258 * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
259 * distributed according to the same disclaimer and license as libpng-1.0.6
260 * with the following individuals added to the list of Contributing Authors:
262 * Simon-Pierre Cadieux
266 * and with the following additions to the disclaimer:
268 * There is no warranty against interference with your enjoyment of the
269 * library or against infringement. There is no warranty that our
270 * efforts or the library will fulfill any of your particular purposes
271 * or needs. This library is provided with all faults, and the entire
272 * risk of satisfactory quality, performance, accuracy, and effort is with
275 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
276 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
277 * distributed according to the same disclaimer and license as libpng-0.96,
278 * with the following individuals added to the list of Contributing Authors:
281 * Glenn Randers-Pehrson
284 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
285 * Copyright (c) 1996, 1997 Andreas Dilger
286 * Distributed according to the same disclaimer and license as libpng-0.88,
287 * with the following individuals added to the list of Contributing Authors:
296 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
297 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
299 * For the purposes of this copyright and license, "Contributing Authors"
300 * is defined as the following set of individuals:
308 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
309 * and Group 42, Inc. disclaim all warranties, expressed or implied,
310 * including, without limitation, the warranties of merchantability and of
311 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
312 * assume no liability for direct, indirect, incidental, special, exemplary,
313 * or consequential damages, which may result from the use of the PNG
314 * Reference Library, even if advised of the possibility of such damage.
316 * Permission is hereby granted to use, copy, modify, and distribute this
317 * source code, or portions hereof, for any purpose, without fee, subject
318 * to the following restrictions:
320 * 1. The origin of this source code must not be misrepresented.
322 * 2. Altered versions must be plainly marked as such and must not
323 * be misrepresented as being the original source.
325 * 3. This Copyright notice may not be removed or altered from
326 * any source or altered source distribution.
328 * The Contributing Authors and Group 42, Inc. specifically permit, without
329 * fee, and encourage the use of this source code as a component to
330 * supporting the PNG file format in commercial products. If you use this
331 * source code in a product, acknowledgment is not required but would be
336 * A "png_get_copyright" function is available, for convenient use in "about"
337 * boxes and the like:
339 * printf("%s", png_get_copyright(NULL));
341 * Also, the PNG logo (in PNG format, of course) is supplied in the
342 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
346 * Libpng is OSI Certified Open Source Software. OSI Certified is a
347 * certification mark of the Open Source Initiative.
351 * The contributing authors would like to thank all those who helped
352 * with testing, bug fixes, and patience. This wouldn't have been
353 * possible without all of you.
355 * Thanks to Frank J. T. Wojcik for helping with the documentation.
359 * Y2K compliance in libpng:
360 * =========================
364 * Since the PNG Development group is an ad-hoc body, we can't make
365 * an official declaration.
367 * This is your unofficial assurance that libpng from version 0.71 and
368 * upward through 1.6.17 are Y2K compliant. It is my belief that
369 * earlier versions were also Y2K compliant.
371 * Libpng only has two year fields. One is a 2-byte unsigned integer
372 * that will hold years up to 65535. The other, which is deprecated,
373 * holds the date in text format, and will hold years up to 9999.
376 * "png_uint_16 year" in png_time_struct.
379 * "char time_buffer[29]" in png_struct. This is no longer used
380 * in libpng-1.6.x and will be removed from libpng-1.7.0.
382 * There are seven time-related functions:
383 * png.c: png_convert_to_rfc_1123_buffer() in png.c
384 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
385 * png_convert_to_rfc_1152() in error prior to libpng-0.98)
386 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
387 * png_convert_from_time_t() in pngwrite.c
388 * png_get_tIME() in pngget.c
389 * png_handle_tIME() in pngrutil.c, called in pngread.c
390 * png_set_tIME() in pngset.c
391 * png_write_tIME() in pngwutil.c, called in pngwrite.c
393 * All handle dates properly in a Y2K environment. The
394 * png_convert_from_time_t() function calls gmtime() to convert from system
395 * clock time, which returns (year - 1900), which we properly convert to
396 * the full 4-digit year. There is a possibility that libpng applications
397 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
398 * function, or that they are incorrectly passing only a 2-digit year
399 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
400 * but this is not under our control. The libpng documentation has always
401 * stated that it works with 4-digit years, and the APIs have been
402 * documented as such.
404 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
405 * integer to hold the year, and can hold years as large as 65535.
407 * zlib, upon which libpng depends, is also Y2K compliant. It contains
408 * no date-related code.
410 * Glenn Randers-Pehrson
412 * PNG Development Group
418 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
419 * describes how to use libpng, and the file example.c summarizes it
420 * with some code on which to build. This file is useful for looking
421 * at the actual function definitions and structure components. If that
422 * file has been stripped from your copy of libpng, you can find it at
423 * <http://www.libpng.org/pub/png/libpng-manual.txt>
425 * If you just need to read a PNG file and don't want to read the documentation
426 * skip to the end of this file and read the section entitled 'simplified API'.
429 /* Version information for png.h - this should match the version in png.c */
430 #define PNG_LIBPNG_VER_STRING "1.6.17"
431 #define PNG_HEADER_VERSION_STRING \
432 " libpng version 1.6.17 - March 26, 2015\n"
434 #define PNG_LIBPNG_VER_SONUM 16
435 #define PNG_LIBPNG_VER_DLLNUM 16
437 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
438 #define PNG_LIBPNG_VER_MAJOR 1
439 #define PNG_LIBPNG_VER_MINOR 6
440 #define PNG_LIBPNG_VER_RELEASE 17
442 /* This should match the numeric part of the final component of
443 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
446 #define PNG_LIBPNG_VER_BUILD 0
449 #define PNG_LIBPNG_BUILD_ALPHA 1
450 #define PNG_LIBPNG_BUILD_BETA 2
451 #define PNG_LIBPNG_BUILD_RC 3
452 #define PNG_LIBPNG_BUILD_STABLE 4
453 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
455 /* Release-Specific Flags */
456 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
457 PNG_LIBPNG_BUILD_STABLE only */
458 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
459 PNG_LIBPNG_BUILD_SPECIAL */
460 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
461 PNG_LIBPNG_BUILD_PRIVATE */
463 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
465 /* Careful here. At one time, Guy wanted to use 082, but that would be octal.
466 * We must not include leading zeros.
467 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
468 * version 1.0.0 was mis-numbered 100 instead of 10000). From
469 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
471 #define PNG_LIBPNG_VER 10617 /* 1.6.17 */
473 /* Library configuration: these options cannot be changed after
474 * the library has been built.
477 /* If pnglibconf.h is missing, you can
478 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
480 # include "pnglibconf.h"
483 #ifndef PNG_VERSION_INFO_ONLY
484 /* Machine specific configuration. */
485 # include "pngconf.h"
489 * Added at libpng-1.2.8
491 * Ref MSDN: Private as priority over Special
492 * VS_FF_PRIVATEBUILD File *was not* built using standard release
493 * procedures. If this value is given, the StringFileInfo block must
494 * contain a PrivateBuild string.
496 * VS_FF_SPECIALBUILD File *was* built by the original company using
497 * standard release procedures but is a variation of the standard
498 * file of the same version number. If this value is given, the
499 * StringFileInfo block must contain a SpecialBuild string.
502 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
503 # define PNG_LIBPNG_BUILD_TYPE \
504 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
506 # ifdef PNG_LIBPNG_SPECIALBUILD
507 # define PNG_LIBPNG_BUILD_TYPE \
508 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
510 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
514 #ifndef PNG_VERSION_INFO_ONLY
516 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
519 #endif /* __cplusplus */
521 /* Version information for C files, stored in png.c. This had better match
524 #define png_libpng_ver png_get_header_ver(NULL)
526 /* This file is arranged in several sections:
528 * 1. Any configuration options that can be specified by for the application
529 * code when it is built. (Build time configuration is in pnglibconf.h)
530 * 2. Type definitions (base types are defined in pngconf.h), structure
532 * 3. Exported library functions.
535 * The library source code has additional files (principally pngpriv.h) that
536 * allow configuration of the library.
538 /* Section 1: run time configuration
539 * See pnglibconf.h for build time configuration
541 * Run time configuration allows the application to choose between
542 * implementations of certain arithmetic APIs. The default is set
543 * at build time and recorded in pnglibconf.h, but it is safe to
544 * override these (and only these) settings. Note that this won't
545 * change what the library does, only application code, and the
546 * settings can (and probably should) be made on a per-file basis
547 * by setting the #defines before including png.h
549 * Use macros to read integers from PNG data or use the exported
551 * PNG_USE_READ_MACROS: use the macros (see below) Note that
552 * the macros evaluate their argument multiple times.
553 * PNG_NO_USE_READ_MACROS: call the relevant library function.
555 * Use the alternative algorithm for compositing alpha samples that
556 * does not use division?
557 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
559 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
561 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
563 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
564 * APIs to png_warning.
565 * Otherwise the calls are mapped to png_error.
568 /* Section 2: type definitions, including structures and compile time
570 * See pngconf.h for base types that vary by machine/system
573 /* This triggers a compiler error in png.c, if png.c and png.h
574 * do not agree upon the version number.
576 typedef char* png_libpng_version_1_6_17;
578 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
580 * png_struct is the cache of information used while reading or writing a single
581 * PNG file. One of these is always required, although the simplified API
582 * (below) hides the creation and destruction of it.
584 typedef struct png_struct_def png_struct;
585 typedef const png_struct * png_const_structp;
586 typedef png_struct * png_structp;
587 typedef png_struct * * png_structpp;
589 /* png_info contains information read from or to be written to a PNG file. One
590 * or more of these must exist while reading or creating a PNG file. The
591 * information is not used by libpng during read but is used to control what
592 * gets written when a PNG file is created. "png_get_" function calls read
593 * information during read and "png_set_" functions calls write information
594 * when creating a PNG.
595 * been moved into a separate header file that is not accessible to
596 * applications. Read libpng-manual.txt or libpng.3 for more info.
598 typedef struct png_info_def png_info;
599 typedef png_info * png_infop;
600 typedef const png_info * png_const_infop;
601 typedef png_info * * png_infopp;
603 /* Types with names ending 'p' are pointer types. The corresponding types with
604 * names ending 'rp' are identical pointer types except that the pointer is
605 * marked 'restrict', which means that it is the only pointer to the object
606 * passed to the function. Applications should not use the 'restrict' types;
607 * it is always valid to pass 'p' to a pointer with a function argument of the
608 * corresponding 'rp' type. Different compilers have different rules with
609 * regard to type matching in the presence of 'restrict'. For backward
610 * compatibility libpng callbacks never have 'restrict' in their parameters and,
611 * consequentially, writing portable application code is extremely difficult if
612 * an attempt is made to use 'restrict'.
614 typedef png_struct * PNG_RESTRICT png_structrp;
615 typedef const png_struct * PNG_RESTRICT png_const_structrp;
616 typedef png_info * PNG_RESTRICT png_inforp;
617 typedef const png_info * PNG_RESTRICT png_const_inforp;
619 /* Three color definitions. The order of the red, green, and blue, (and the
620 * exact size) is not important, although the size of the fields need to
621 * be png_byte or png_uint_16 (as defined below).
623 typedef struct png_color_struct
629 typedef png_color * png_colorp;
630 typedef const png_color * png_const_colorp;
631 typedef png_color * * png_colorpp;
633 typedef struct png_color_16_struct
635 png_byte index; /* used for palette files */
636 png_uint_16 red; /* for use in red green blue files */
639 png_uint_16 gray; /* for use in grayscale files */
641 typedef png_color_16 * png_color_16p;
642 typedef const png_color_16 * png_const_color_16p;
643 typedef png_color_16 * * png_color_16pp;
645 typedef struct png_color_8_struct
647 png_byte red; /* for use in red green blue files */
650 png_byte gray; /* for use in grayscale files */
651 png_byte alpha; /* for alpha channel files */
653 typedef png_color_8 * png_color_8p;
654 typedef const png_color_8 * png_const_color_8p;
655 typedef png_color_8 * * png_color_8pp;
658 * The following two structures are used for the in-core representation
661 typedef struct png_sPLT_entry_struct
667 png_uint_16 frequency;
669 typedef png_sPLT_entry * png_sPLT_entryp;
670 typedef const png_sPLT_entry * png_const_sPLT_entryp;
671 typedef png_sPLT_entry * * png_sPLT_entrypp;
673 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples
674 * occupy the LSB of their respective members, and the MSB of each member
675 * is zero-filled. The frequency member always occupies the full 16 bits.
678 typedef struct png_sPLT_struct
680 png_charp name; /* palette name */
681 png_byte depth; /* depth of palette samples */
682 png_sPLT_entryp entries; /* palette entries */
683 png_int_32 nentries; /* number of palette entries */
685 typedef png_sPLT_t * png_sPLT_tp;
686 typedef const png_sPLT_t * png_const_sPLT_tp;
687 typedef png_sPLT_t * * png_sPLT_tpp;
689 #ifdef PNG_TEXT_SUPPORTED
690 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
691 * and whether that contents is compressed or not. The "key" field
692 * points to a regular zero-terminated C string. The "text" fields can be a
693 * regular C string, an empty string, or a NULL pointer.
694 * However, the structure returned by png_get_text() will always contain
695 * the "text" field as a regular zero-terminated C string (possibly
696 * empty), never a NULL pointer, so it can be safely used in printf() and
697 * other string-handling functions. Note that the "itxt_length", "lang", and
698 * "lang_key" members of the structure only exist when the library is built
699 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
700 * default without iTXt support. Also note that when iTXt *is* supported,
701 * the "lang" and "lang_key" fields contain NULL pointers when the
702 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
703 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
704 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
705 * which is always 0 or 1, or its "compression method" which is always 0.
707 typedef struct png_text_struct
709 int compression; /* compression value:
714 png_charp key; /* keyword, 1-79 character description of "text" */
715 png_charp text; /* comment, may be an empty string (ie "")
717 png_size_t text_length; /* length of the text string */
718 png_size_t itxt_length; /* length of the itxt string */
719 png_charp lang; /* language code, 0-79 characters
721 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
722 chars or a NULL pointer */
724 typedef png_text * png_textp;
725 typedef const png_text * png_const_textp;
726 typedef png_text * * png_textpp;
729 /* Supported compression types for text in PNG files (tEXt, and zTXt).
730 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
731 #define PNG_TEXT_COMPRESSION_NONE_WR -3
732 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
733 #define PNG_TEXT_COMPRESSION_NONE -1
734 #define PNG_TEXT_COMPRESSION_zTXt 0
735 #define PNG_ITXT_COMPRESSION_NONE 1
736 #define PNG_ITXT_COMPRESSION_zTXt 2
737 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
739 /* png_time is a way to hold the time in an machine independent way.
740 * Two conversions are provided, both from time_t and struct tm. There
741 * is no portable way to convert to either of these structures, as far
742 * as I know. If you know of a portable way, send it to me. As a side
743 * note - PNG has always been Year 2000 compliant!
745 typedef struct png_time_struct
747 png_uint_16 year; /* full year, as in, 1995 */
748 png_byte month; /* month of year, 1 - 12 */
749 png_byte day; /* day of month, 1 - 31 */
750 png_byte hour; /* hour of day, 0 - 23 */
751 png_byte minute; /* minute of hour, 0 - 59 */
752 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
754 typedef png_time * png_timep;
755 typedef const png_time * png_const_timep;
756 typedef png_time * * png_timepp;
758 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
759 defined(PNG_USER_CHUNKS_SUPPORTED)
760 /* png_unknown_chunk is a structure to hold queued chunks for which there is
761 * no specific support. The idea is that we can use this to queue
762 * up private chunks for output even though the library doesn't actually
763 * know about their semantics.
765 * The data in the structure is set by libpng on read and used on write.
767 typedef struct png_unknown_chunk_t
769 png_byte name[5]; /* Textual chunk name with '\0' terminator */
770 png_byte *data; /* Data, should not be modified on read! */
773 /* On write 'location' must be set using the flag values listed below.
774 * Notice that on read it is set by libpng however the values stored have
775 * more bits set than are listed below. Always treat the value as a
776 * bitmask. On write set only one bit - setting multiple bits may cause the
777 * chunk to be written in multiple places.
779 png_byte location; /* mode of operation at read time */
783 typedef png_unknown_chunk * png_unknown_chunkp;
784 typedef const png_unknown_chunk * png_const_unknown_chunkp;
785 typedef png_unknown_chunk * * png_unknown_chunkpp;
788 /* Flag values for the unknown chunk location byte. */
789 #define PNG_HAVE_IHDR 0x01
790 #define PNG_HAVE_PLTE 0x02
791 #define PNG_AFTER_IDAT 0x08
793 /* Maximum positive integer used in PNG is (2^31)-1 */
794 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
795 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
796 #define PNG_SIZE_MAX ((png_size_t)(-1))
798 /* These are constants for fixed point values encoded in the
799 * PNG specification manner (x100000)
801 #define PNG_FP_1 100000
802 #define PNG_FP_HALF 50000
803 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
804 #define PNG_FP_MIN (-PNG_FP_MAX)
806 /* These describe the color_type field in png_info. */
807 /* color type masks */
808 #define PNG_COLOR_MASK_PALETTE 1
809 #define PNG_COLOR_MASK_COLOR 2
810 #define PNG_COLOR_MASK_ALPHA 4
812 /* color types. Note that not all combinations are legal */
813 #define PNG_COLOR_TYPE_GRAY 0
814 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
815 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
816 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
817 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
819 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
820 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
822 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
823 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
824 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
826 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
827 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
828 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
829 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
831 /* These are for the interlacing type. These values should NOT be changed. */
832 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
833 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
834 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
836 /* These are for the oFFs chunk. These values should NOT be changed. */
837 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
838 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
839 #define PNG_OFFSET_LAST 2 /* Not a valid value */
841 /* These are for the pCAL chunk. These values should NOT be changed. */
842 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
843 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
844 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
845 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
846 #define PNG_EQUATION_LAST 4 /* Not a valid value */
848 /* These are for the sCAL chunk. These values should NOT be changed. */
849 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
850 #define PNG_SCALE_METER 1 /* meters per pixel */
851 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
852 #define PNG_SCALE_LAST 3 /* Not a valid value */
854 /* These are for the pHYs chunk. These values should NOT be changed. */
855 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
856 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
857 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
859 /* These are for the sRGB chunk. These values should NOT be changed. */
860 #define PNG_sRGB_INTENT_PERCEPTUAL 0
861 #define PNG_sRGB_INTENT_RELATIVE 1
862 #define PNG_sRGB_INTENT_SATURATION 2
863 #define PNG_sRGB_INTENT_ABSOLUTE 3
864 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
866 /* This is for text chunks */
867 #define PNG_KEYWORD_MAX_LENGTH 79
869 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
870 #define PNG_MAX_PALETTE_LENGTH 256
872 /* These determine if an ancillary chunk's data has been successfully read
873 * from the PNG header, or if the application has filled in the corresponding
874 * data in the info_struct to be written into the output file. The values
875 * of the PNG_INFO_<chunk> defines should NOT be changed.
877 #define PNG_INFO_gAMA 0x0001
878 #define PNG_INFO_sBIT 0x0002
879 #define PNG_INFO_cHRM 0x0004
880 #define PNG_INFO_PLTE 0x0008
881 #define PNG_INFO_tRNS 0x0010
882 #define PNG_INFO_bKGD 0x0020
883 #define PNG_INFO_hIST 0x0040
884 #define PNG_INFO_pHYs 0x0080
885 #define PNG_INFO_oFFs 0x0100
886 #define PNG_INFO_tIME 0x0200
887 #define PNG_INFO_pCAL 0x0400
888 #define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
889 #define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
890 #define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
891 #define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
892 #define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */
894 /* This is used for the transformation routines, as some of them
895 * change these values for the row. It also should enable using
896 * the routines for other purposes.
898 typedef struct png_row_info_struct
900 png_uint_32 width; /* width of row */
901 png_size_t rowbytes; /* number of bytes in row */
902 png_byte color_type; /* color type of row */
903 png_byte bit_depth; /* bit depth of row */
904 png_byte channels; /* number of channels (1, 2, 3, or 4) */
905 png_byte pixel_depth; /* bits per pixel (depth * channels) */
908 typedef png_row_info * png_row_infop;
909 typedef png_row_info * * png_row_infopp;
911 /* These are the function types for the I/O functions and for the functions
912 * that allow the user to override the default I/O functions with his or her
913 * own. The png_error_ptr type should match that of user-supplied warning
914 * and error functions, while the png_rw_ptr type should match that of the
915 * user read/write data functions. Note that the 'write' function must not
916 * modify the buffer it is passed. The 'read' function, on the other hand, is
917 * expected to return the read data in the buffer.
919 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
920 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
921 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
922 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
924 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
927 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
928 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
929 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
931 /* The following callback receives png_uint_32 row_number, int pass for the
932 * png_bytep data of the row. When transforming an interlaced image the
933 * row number is the row number within the sub-image of the interlace pass, so
934 * the value will increase to the height of the sub-image (not the full image)
935 * then reset to 0 for the next pass.
937 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
938 * find the output pixel (x,y) given an interlaced sub-image pixel
939 * (row,col,pass). (See below for these macros.)
941 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
945 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
946 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
947 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
951 #ifdef PNG_USER_CHUNKS_SUPPORTED
952 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
953 png_unknown_chunkp));
955 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
956 /* not used anywhere */
957 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
960 #ifdef PNG_SETJMP_SUPPORTED
961 /* This must match the function definition in <setjmp.h>, and the application
962 * must include this before png.h to obtain the definition of jmp_buf. The
963 * function is required to be PNG_NORETURN, but this is not checked. If the
964 * function does return the application will crash via an abort() or similar
967 * If you get a warning here while building the library you may need to make
968 * changes to ensure that pnglibconf.h records the calling convention used by
969 * your compiler. This may be very difficult - try using a different compiler
970 * to build the library!
972 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
975 /* Transform masks for the high-level interface */
976 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
977 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
978 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
979 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
980 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
981 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
982 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
983 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
984 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
985 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
986 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
987 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
988 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
989 /* Added to libpng-1.2.34 */
990 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
991 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
992 /* Added to libpng-1.4.0 */
993 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
994 /* Added to libpng-1.5.4 */
995 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
996 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
998 /* Flags for MNG supported features */
999 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
1000 #define PNG_FLAG_MNG_FILTER_64 0x04
1001 #define PNG_ALL_MNG_FEATURES 0x05
1003 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
1004 * this allowed the zlib default functions to be used on Windows
1005 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
1006 * ignores the first argument) should be completely compatible with the
1009 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
1011 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
1013 /* Section 3: exported functions
1014 * Here are the function definitions most commonly used. This is not
1015 * the place to find out how to use libpng. See libpng-manual.txt for the
1016 * full explanation, see example.c for the summary. This just provides
1017 * a simple one line description of the use of each function.
1019 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
1020 * pngconf.h and in the *.dfn files in the scripts directory.
1022 * PNG_EXPORT(ordinal, type, name, (args));
1024 * ordinal: ordinal that is used while building
1025 * *.def files. The ordinal value is only
1026 * relevant when preprocessing png.h with
1027 * the *.dfn files for building symbol table
1028 * entries, and are removed by pngconf.h.
1029 * type: return type of the function
1030 * name: function name
1031 * args: function arguments, with types
1033 * When we wish to append attributes to a function prototype we use
1034 * the PNG_EXPORTA() macro instead.
1036 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
1038 * ordinal, type, name, and args: same as in PNG_EXPORT().
1039 * attributes: function attributes
1042 /* Returns the version number of the library */
1043 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
1045 /* Tell lib we have already handled the first <num_bytes> magic bytes.
1046 * Handling more than 8 bytes from the beginning of the file is an error.
1048 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
1050 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
1051 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
1052 * signature, and non-zero otherwise. Having num_to_check == 0 or
1053 * start > 7 will always fail (ie return non-zero).
1055 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
1056 png_size_t num_to_check));
1058 /* Simple signature checking function. This is the same as calling
1059 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
1061 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
1063 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
1064 PNG_EXPORTA(4, png_structp, png_create_read_struct,
1065 (png_const_charp user_png_ver, png_voidp error_ptr,
1066 png_error_ptr error_fn, png_error_ptr warn_fn),
1069 /* Allocate and initialize png_ptr struct for writing, and any other memory */
1070 PNG_EXPORTA(5, png_structp, png_create_write_struct,
1071 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1072 png_error_ptr warn_fn),
1075 PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
1076 (png_const_structrp png_ptr));
1078 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
1081 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
1084 #ifdef PNG_SETJMP_SUPPORTED
1085 /* This function returns the jmp_buf built in to *png_ptr. It must be
1086 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
1087 * unless the default error function is overridden in which case NULL is
1088 * acceptable. The size of the jmp_buf is checked against the actual size
1089 * allocated by the library - the call will return NULL on a mismatch
1090 * indicating an ABI mismatch.
1092 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
1093 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
1094 # define png_jmpbuf(png_ptr) \
1095 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
1097 # define png_jmpbuf(png_ptr) \
1098 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
1100 /* This function should be used by libpng applications in place of
1101 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
1102 * will use it; otherwise it will call PNG_ABORT(). This function was
1103 * added in libpng-1.5.0.
1105 PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
1108 #ifdef PNG_READ_SUPPORTED
1109 /* Reset the compression stream */
1110 PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
1113 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1114 #ifdef PNG_USER_MEM_SUPPORTED
1115 PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1116 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1117 png_error_ptr warn_fn,
1118 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1120 PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1121 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1122 png_error_ptr warn_fn,
1123 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1127 /* Write the PNG file signature. */
1128 PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
1130 /* Write a PNG chunk - size, type, (optional) data, CRC. */
1131 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
1132 chunk_name, png_const_bytep data, png_size_t length));
1134 /* Write the start of a PNG chunk - length and chunk name. */
1135 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1136 png_const_bytep chunk_name, png_uint_32 length));
1138 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1139 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1140 png_const_bytep data, png_size_t length));
1142 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1143 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1145 /* Allocate and initialize the info structure */
1146 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1149 /* DEPRECATED: this function allowed init structures to be created using the
1150 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1151 * the API will be removed in the future.
1153 PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1154 png_size_t png_info_struct_size), PNG_DEPRECATED);
1156 /* Writes all the PNG information before the image. */
1157 PNG_EXPORT(20, void, png_write_info_before_PLTE,
1158 (png_structrp png_ptr, png_const_inforp info_ptr));
1159 PNG_EXPORT(21, void, png_write_info,
1160 (png_structrp png_ptr, png_const_inforp info_ptr));
1162 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1163 /* Read the information before the actual image data. */
1164 PNG_EXPORT(22, void, png_read_info,
1165 (png_structrp png_ptr, png_inforp info_ptr));
1168 #ifdef PNG_TIME_RFC1123_SUPPORTED
1169 /* Convert to a US string format: there is no localization support in this
1170 * routine. The original implementation used a 29 character buffer in
1171 * png_struct, this will be removed in future versions.
1173 #if PNG_LIBPNG_VER < 10700
1174 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1175 PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1176 png_const_timep ptime),PNG_DEPRECATED);
1178 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1179 png_const_timep ptime));
1182 #ifdef PNG_CONVERT_tIME_SUPPORTED
1183 /* Convert from a struct tm to png_time */
1184 PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1185 const struct tm * ttime));
1187 /* Convert from time_t to png_time. Uses gmtime() */
1188 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1189 #endif /* CONVERT_tIME */
1191 #ifdef PNG_READ_EXPAND_SUPPORTED
1192 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1193 PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1194 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1195 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1196 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1199 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1200 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1201 * of a tRNS chunk if present.
1203 PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1206 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1207 /* Use blue, green, red order for pixels. */
1208 PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1211 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1212 /* Expand the grayscale to 24-bit RGB if necessary. */
1213 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1216 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1217 /* Reduce RGB to grayscale. */
1218 #define PNG_ERROR_ACTION_NONE 1
1219 #define PNG_ERROR_ACTION_WARN 2
1220 #define PNG_ERROR_ACTION_ERROR 3
1221 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1223 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1224 int error_action, double red, double green))
1225 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1226 int error_action, png_fixed_point red, png_fixed_point green))
1228 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1232 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1233 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1234 png_colorp palette));
1237 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1238 /* How the alpha channel is interpreted - this affects how the color channels
1239 * of a PNG file are returned to the calling application when an alpha channel,
1240 * or a tRNS chunk in a palette file, is present.
1242 * This has no effect on the way pixels are written into a PNG output
1243 * datastream. The color samples in a PNG datastream are never premultiplied
1244 * with the alpha samples.
1246 * The default is to return data according to the PNG specification: the alpha
1247 * channel is a linear measure of the contribution of the pixel to the
1248 * corresponding composited pixel, and the color channels are unassociated
1249 * (not premultiplied). The gamma encoded color channels must be scaled
1250 * according to the contribution and to do this it is necessary to undo
1251 * the encoding, scale the color values, perform the composition and reencode
1252 * the values. This is the 'PNG' mode.
1254 * The alternative is to 'associate' the alpha with the color information by
1255 * storing color channel values that have been scaled by the alpha.
1256 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1257 * (the latter being the two common names for associated alpha color channels).
1259 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1260 * value is equal to the maximum value.
1262 * The final choice is to gamma encode the alpha channel as well. This is
1263 * broken because, in practice, no implementation that uses this choice
1264 * correctly undoes the encoding before handling alpha composition. Use this
1265 * choice only if other serious errors in the software or hardware you use
1266 * mandate it; the typical serious error is for dark halos to appear around
1267 * opaque areas of the composited PNG image because of arithmetic overflow.
1269 * The API function png_set_alpha_mode specifies which of these choices to use
1270 * with an enumerated 'mode' value and the gamma of the required output:
1272 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1273 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1274 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1275 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1276 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1277 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1279 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1280 double output_gamma))
1281 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1282 int mode, png_fixed_point output_gamma))
1285 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1286 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1287 * how to decode the output values, not how they are encoded.
1289 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1290 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1291 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1292 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1295 /* The following are examples of calls to png_set_alpha_mode to achieve the
1296 * required overall gamma correction and, where necessary, alpha
1297 * premultiplication.
1299 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1300 * This is the default libpng handling of the alpha channel - it is not
1301 * pre-multiplied into the color components. In addition the call states
1302 * that the output is for a sRGB system and causes all PNG files without gAMA
1303 * chunks to be assumed to be encoded using sRGB.
1305 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1306 * In this case the output is assumed to be something like an sRGB conformant
1307 * display preceeded by a power-law lookup table of power 1.45. This is how
1308 * early Mac systems behaved.
1310 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1311 * This is the classic Jim Blinn approach and will work in academic
1312 * environments where everything is done by the book. It has the shortcoming
1313 * of assuming that input PNG data with no gamma information is linear - this
1314 * is unlikely to be correct unless the PNG files where generated locally.
1315 * Most of the time the output precision will be so low as to show
1316 * significant banding in dark areas of the image.
1318 * png_set_expand_16(pp);
1319 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1320 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1321 * are assumed to have the sRGB encoding if not marked with a gamma value and
1322 * the output is always 16 bits per component. This permits accurate scaling
1323 * and processing of the data. If you know that your input PNG files were
1324 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1325 * correct value for your system.
1327 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1328 * If you just need to composite the PNG image onto an existing background
1329 * and if you control the code that does this you can use the optimization
1330 * setting. In this case you just copy completely opaque pixels to the
1331 * output. For pixels that are not completely transparent (you just skip
1332 * those) you do the composition math using png_composite or png_composite_16
1333 * below then encode the resultant 8-bit or 16-bit values to match the output
1337 * If neither the PNG nor the standard linear encoding work for you because
1338 * of the software or hardware you use then you have a big problem. The PNG
1339 * case will probably result in halos around the image. The linear encoding
1340 * will probably result in a washed out, too bright, image (it's actually too
1341 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1342 * substantially reduce the halos. Alternatively try:
1344 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1345 * This option will also reduce the halos, but there will be slight dark
1346 * halos round the opaque parts of the image where the background is light.
1347 * In the OPTIMIZED mode the halos will be light halos where the background
1348 * is dark. Take your pick - the halos are unavoidable unless you can get
1349 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1352 * When the default gamma of PNG files doesn't match the output gamma.
1353 * If you have PNG files with no gamma information png_set_alpha_mode allows
1354 * you to provide a default gamma, but it also sets the ouput gamma to the
1355 * matching value. If you know your PNG files have a gamma that doesn't
1356 * match the output you can take advantage of the fact that
1357 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1358 * default if it is not already set:
1360 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1361 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1362 * The first call sets both the default and the output gamma values, the
1363 * second call overrides the output gamma without changing the default. This
1364 * is easier than achieving the same effect with png_set_gamma. You must use
1365 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1366 * fire if more than one call to png_set_alpha_mode and png_set_background is
1367 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1371 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1372 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1375 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1376 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1377 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1380 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1381 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1382 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1385 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1386 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
1387 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1389 /* The values of the PNG_FILLER_ defines should NOT be changed */
1390 # define PNG_FILLER_BEFORE 0
1391 # define PNG_FILLER_AFTER 1
1392 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
1393 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1394 png_uint_32 filler, int flags));
1395 #endif /* READ_FILLER || WRITE_FILLER */
1397 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1398 /* Swap bytes in 16-bit depth files. */
1399 PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1402 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1403 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1404 PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1407 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1408 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1409 /* Swap packing order of pixels in bytes. */
1410 PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1413 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1414 /* Converts files to legal bit depths. */
1415 PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1419 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1420 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1421 /* Have the code handle the interlacing. Returns the number of passes.
1422 * MUST be called before png_read_update_info or png_start_read_image,
1423 * otherwise it will not have the desired effect. Note that it is still
1424 * necessary to call png_read_row or png_read_rows png_get_image_height
1425 * times for each pass.
1427 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1430 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1431 /* Invert monochrome files */
1432 PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1435 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1436 /* Handle alpha and tRNS by replacing with a background color. Prior to
1437 * libpng-1.5.4 this API must not be called before the PNG file header has been
1438 * read. Doing so will result in unexpected behavior and possible warnings or
1439 * errors if the PNG file contains a bKGD chunk.
1441 PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1442 png_const_color_16p background_color, int background_gamma_code,
1443 int need_expand, double background_gamma))
1444 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1445 png_const_color_16p background_color, int background_gamma_code,
1446 int need_expand, png_fixed_point background_gamma))
1448 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1449 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1450 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1451 # define PNG_BACKGROUND_GAMMA_FILE 2
1452 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1455 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1456 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1457 PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1460 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1461 #define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
1462 /* Strip the second byte of information from a 16-bit depth file. */
1463 PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1466 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1467 /* Turn on quantizing, and reduce the palette to the number of colors
1470 PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1471 png_colorp palette, int num_palette, int maximum_colors,
1472 png_const_uint_16p histogram, int full_quantize));
1475 #ifdef PNG_READ_GAMMA_SUPPORTED
1476 /* The threshold on gamma processing is configurable but hard-wired into the
1477 * library. The following is the floating point variant.
1479 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1481 /* Handle gamma correction. Screen_gamma=(display_exponent).
1482 * NOTE: this API simply sets the screen and file gamma values. It will
1483 * therefore override the value for gamma in a PNG file if it is called after
1484 * the file header has been read - use with care - call before reading the PNG
1485 * file for best results!
1487 * These routines accept the same gamma values as png_set_alpha_mode (described
1488 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1489 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1490 * is the inverse of a 'screen gamma' value.
1492 PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1493 double screen_gamma, double override_file_gamma))
1494 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1495 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1498 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1499 /* Set how many lines between output flushes - 0 for no flushing */
1500 PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1501 /* Flush the current PNG output buffer */
1502 PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1505 /* Optional update palette with requested transformations */
1506 PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1508 /* Optional call to update the users info structure */
1509 PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1510 png_inforp info_ptr));
1512 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1513 /* Read one or more rows of image data. */
1514 PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1515 png_bytepp display_row, png_uint_32 num_rows));
1518 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1519 /* Read a row of data. */
1520 PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1521 png_bytep display_row));
1524 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1525 /* Read the whole image into memory at once. */
1526 PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1529 /* Write a row of image data */
1530 PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1531 png_const_bytep row));
1533 /* Write a few rows of image data: (*row) is not written; however, the type
1534 * is declared as writeable to maintain compatibility with previous versions
1535 * of libpng and to allow the 'display_row' array from read_rows to be passed
1536 * unchanged to write_rows.
1538 PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1539 png_uint_32 num_rows));
1541 /* Write the image data */
1542 PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1544 /* Write the end of the PNG file. */
1545 PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1546 png_inforp info_ptr));
1548 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1549 /* Read the end of the PNG file. */
1550 PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1553 /* Free any memory associated with the png_info_struct */
1554 PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1555 png_infopp info_ptr_ptr));
1557 /* Free any memory associated with the png_struct and the png_info_structs */
1558 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1559 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1561 /* Free any memory associated with the png_struct and the png_info_structs */
1562 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1563 png_infopp info_ptr_ptr));
1565 /* Set the libpng method of handling chunk CRC errors */
1566 PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1569 /* Values for png_set_crc_action() say how to handle CRC errors in
1570 * ancillary and critical chunks, and whether to use the data contained
1571 * therein. Note that it is impossible to "discard" data in a critical
1572 * chunk. For versions prior to 0.90, the action was always error/quit,
1573 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1574 * chunks is warn/discard. These values should NOT be changed.
1576 * value action:critical action:ancillary
1578 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1579 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1580 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1581 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1582 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1583 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1585 #ifdef PNG_WRITE_SUPPORTED
1586 /* These functions give the user control over the scan-line filtering in
1587 * libpng and the compression methods used by zlib. These functions are
1588 * mainly useful for testing, as the defaults should work with most users.
1589 * Those users who are tight on memory or want faster performance at the
1590 * expense of compression can modify them. See the compression library
1591 * header file (zlib.h) for an explination of the compression functions.
1594 /* Set the filtering method(s) used by libpng. Currently, the only valid
1595 * value for "method" is 0.
1597 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1601 /* Flags for png_set_filter() to say which filters to use. The flags
1602 * are chosen so that they don't conflict with real filter types
1603 * below, in case they are supplied instead of the #defined constants.
1604 * These values should NOT be changed.
1606 #define PNG_NO_FILTERS 0x00
1607 #define PNG_FILTER_NONE 0x08
1608 #define PNG_FILTER_SUB 0x10
1609 #define PNG_FILTER_UP 0x20
1610 #define PNG_FILTER_AVG 0x40
1611 #define PNG_FILTER_PAETH 0x80
1612 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
1613 PNG_FILTER_AVG | PNG_FILTER_PAETH)
1615 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1616 * These defines should NOT be changed.
1618 #define PNG_FILTER_VALUE_NONE 0
1619 #define PNG_FILTER_VALUE_SUB 1
1620 #define PNG_FILTER_VALUE_UP 2
1621 #define PNG_FILTER_VALUE_AVG 3
1622 #define PNG_FILTER_VALUE_PAETH 4
1623 #define PNG_FILTER_VALUE_LAST 5
1625 #ifdef PNG_WRITE_SUPPORTED
1626 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
1627 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
1628 * defines, either the default (minimum-sum-of-absolute-differences), or
1629 * the experimental method (weighted-minimum-sum-of-absolute-differences).
1631 * Weights are factors >= 1.0, indicating how important it is to keep the
1632 * filter type consistent between rows. Larger numbers mean the current
1633 * filter is that many times as likely to be the same as the "num_weights"
1634 * previous filters. This is cumulative for each previous row with a weight.
1635 * There needs to be "num_weights" values in "filter_weights", or it can be
1636 * NULL if the weights aren't being specified. Weights have no influence on
1637 * the selection of the first row filter. Well chosen weights can (in theory)
1638 * improve the compression for a given image.
1640 * Costs are factors >= 1.0 indicating the relative decoding costs of a
1641 * filter type. Higher costs indicate more decoding expense, and are
1642 * therefore less likely to be selected over a filter with lower computational
1643 * costs. There needs to be a value in "filter_costs" for each valid filter
1644 * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
1645 * setting the costs. Costs try to improve the speed of decompression without
1646 * unduly increasing the compressed image size.
1648 * A negative weight or cost indicates the default value is to be used, and
1649 * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
1650 * The default values for both weights and costs are currently 1.0, but may
1651 * change if good general weighting/cost heuristics can be found. If both
1652 * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
1653 * to the UNWEIGHTED method, but with added encoding time/computation.
1655 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1656 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1657 png_const_doublep filter_costs))
1658 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1659 (png_structrp png_ptr, int heuristic_method, int num_weights,
1660 png_const_fixed_point_p filter_weights,
1661 png_const_fixed_point_p filter_costs))
1662 #endif /* WRITE_WEIGHTED_FILTER */
1664 /* Heuristic used for row filter selection. These defines should NOT be
1667 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1668 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1669 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1670 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1672 /* Set the library compression level. Currently, valid values range from
1673 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1674 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1675 * shown that zlib compression levels 3-6 usually perform as well as level 9
1676 * for PNG images, and do considerably fewer caclulations. In the future,
1677 * these values may not correspond directly to the zlib compression levels.
1679 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1680 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1683 PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1686 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1689 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1690 * smaller value of window_bits if it can do so safely.
1692 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1695 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1697 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1699 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1700 /* Also set zlib parameters for compressing non-IDAT chunks */
1701 PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1704 PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1707 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1710 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1711 * smaller value of window_bits if it can do so safely.
1713 PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1714 (png_structrp png_ptr, int window_bits));
1716 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1718 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1721 /* These next functions are called for input/output, memory, and error
1722 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1723 * and call standard C I/O routines such as fread(), fwrite(), and
1724 * fprintf(). These functions can be made to use other I/O routines
1725 * at run time for those applications that need to handle I/O in a
1726 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1730 #ifdef PNG_STDIO_SUPPORTED
1731 /* Initialize the input/output for the PNG file to the default functions. */
1732 PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1735 /* Replace the (error and abort), and warning functions with user
1736 * supplied functions. If no messages are to be printed you must still
1737 * write and use replacement functions. The replacement error_fn should
1738 * still do a longjmp to the last setjmp location if you are using this
1739 * method of error handling. If error_fn or warning_fn is NULL, the
1740 * default function will be used.
1743 PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1744 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1746 /* Return the user pointer associated with the error functions */
1747 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1749 /* Replace the default data output functions with a user supplied one(s).
1750 * If buffered output is not used, then output_flush_fn can be set to NULL.
1751 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1752 * output_flush_fn will be ignored (and thus can be NULL).
1753 * It is probably a mistake to use NULL for output_flush_fn if
1754 * write_data_fn is not also NULL unless you have built libpng with
1755 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1756 * default flush function, which uses the standard *FILE structure, will
1759 PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1760 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1762 /* Replace the default data input function with a user supplied one. */
1763 PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1764 png_rw_ptr read_data_fn));
1766 /* Return the user pointer associated with the I/O functions */
1767 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1769 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1770 png_read_status_ptr read_row_fn));
1772 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1773 png_write_status_ptr write_row_fn));
1775 #ifdef PNG_USER_MEM_SUPPORTED
1776 /* Replace the default memory allocation functions with user supplied one(s). */
1777 PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1778 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1779 /* Return the user pointer associated with the memory functions */
1780 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1783 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1784 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1785 png_user_transform_ptr read_user_transform_fn));
1788 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1789 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1790 png_user_transform_ptr write_user_transform_fn));
1793 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1794 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1795 png_voidp user_transform_ptr, int user_transform_depth,
1796 int user_transform_channels));
1797 /* Return the user pointer associated with the user transform functions */
1798 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1799 (png_const_structrp png_ptr));
1802 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1803 /* Return information about the row currently being processed. Note that these
1804 * APIs do not fail but will return unexpected results if called outside a user
1805 * transform callback. Also note that when transforming an interlaced image the
1806 * row number is the row number within the sub-image of the interlace pass, so
1807 * the value will increase to the height of the sub-image (not the full image)
1808 * then reset to 0 for the next pass.
1810 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1811 * find the output pixel (x,y) given an interlaced sub-image pixel
1812 * (row,col,pass). (See below for these macros.)
1814 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1815 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1818 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1819 /* This callback is called only for *unknown* chunks. If
1820 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1821 * chunks to be treated as unknown, however in this case the callback must do
1822 * any processing required by the chunk (e.g. by calling the appropriate
1825 * There is no write support - on write, by default, all the chunks in the
1826 * 'unknown' list are written in the specified position.
1828 * The integer return from the callback function is interpreted thus:
1830 * negative: An error occurred; png_chunk_error will be called.
1831 * zero: The chunk was not handled, the chunk will be saved. A critical
1832 * chunk will cause an error at this point unless it is to be saved.
1833 * positive: The chunk was handled, libpng will ignore/discard it.
1835 * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
1836 * how this behavior will change in libpng 1.7
1838 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1839 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1842 #ifdef PNG_USER_CHUNKS_SUPPORTED
1843 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1846 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1847 /* Sets the function callbacks for the push reader, and a pointer to a
1848 * user-defined structure available to the callback functions.
1850 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1851 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1852 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1854 /* Returns the user pointer associated with the push read functions */
1855 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1856 (png_const_structrp png_ptr));
1858 /* Function to be called when data becomes available */
1859 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1860 png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
1862 /* A function which may be called *only* within png_process_data to stop the
1863 * processing of any more data. The function returns the number of bytes
1864 * remaining, excluding any that libpng has cached internally. A subsequent
1865 * call to png_process_data must supply these bytes again. If the argument
1866 * 'save' is set to true the routine will first save all the pending data and
1867 * will always return 0.
1869 PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
1871 /* A function which may be called *only* outside (after) a call to
1872 * png_process_data. It returns the number of bytes of data to skip in the
1873 * input. Normally it will return 0, but if it returns a non-zero value the
1874 * application must skip than number of bytes of input data and pass the
1875 * following data to the next call to png_process_data.
1877 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1879 /* Function that combines rows. 'new_row' is a flag that should come from
1880 * the callback and be non-NULL if anything needs to be done; the library
1881 * stores its own version of the new data internally and ignores the passed
1884 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1885 png_bytep old_row, png_const_bytep new_row));
1886 #endif /* PROGRESSIVE_READ */
1888 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1889 png_alloc_size_t size), PNG_ALLOCATED);
1890 /* Added at libpng version 1.4.0 */
1891 PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1892 png_alloc_size_t size), PNG_ALLOCATED);
1894 /* Added at libpng version 1.2.4 */
1895 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1896 png_alloc_size_t size), PNG_ALLOCATED);
1898 /* Frees a pointer allocated by png_malloc() */
1899 PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1901 /* Free data that was allocated internally */
1902 PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1903 png_inforp info_ptr, png_uint_32 free_me, int num));
1905 /* Reassign responsibility for freeing existing data, whether allocated
1906 * by libpng or by the application; this works on the png_info structure passed
1907 * in, it does not change the state for other png_info structures.
1909 * It is unlikely that this function works correctly as of 1.6.0 and using it
1910 * may result either in memory leaks or double free of allocated data.
1912 PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1913 png_inforp info_ptr, int freer, png_uint_32 mask));
1915 /* Assignments for png_data_freer */
1916 #define PNG_DESTROY_WILL_FREE_DATA 1
1917 #define PNG_SET_WILL_FREE_DATA 1
1918 #define PNG_USER_WILL_FREE_DATA 2
1919 /* Flags for png_ptr->free_me and info_ptr->free_me */
1920 #define PNG_FREE_HIST 0x0008
1921 #define PNG_FREE_ICCP 0x0010
1922 #define PNG_FREE_SPLT 0x0020
1923 #define PNG_FREE_ROWS 0x0040
1924 #define PNG_FREE_PCAL 0x0080
1925 #define PNG_FREE_SCAL 0x0100
1926 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1927 # define PNG_FREE_UNKN 0x0200
1929 /* PNG_FREE_LIST 0x0400 removed in 1.6.0 because it is ignored */
1930 #define PNG_FREE_PLTE 0x1000
1931 #define PNG_FREE_TRNS 0x2000
1932 #define PNG_FREE_TEXT 0x4000
1933 #define PNG_FREE_ALL 0x7fff
1934 #define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1936 #ifdef PNG_USER_MEM_SUPPORTED
1937 PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1938 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1939 PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1940 png_voidp ptr), PNG_DEPRECATED);
1943 #ifdef PNG_ERROR_TEXT_SUPPORTED
1944 /* Fatal error in PNG image of libpng - can't continue */
1945 PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1946 png_const_charp error_message), PNG_NORETURN);
1948 /* The same, but the chunk name is prepended to the error string. */
1949 PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1950 png_const_charp error_message), PNG_NORETURN);
1953 /* Fatal error in PNG image of libpng - can't continue */
1954 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1955 # define png_error(s1,s2) png_err(s1)
1956 # define png_chunk_error(s1,s2) png_err(s1)
1959 #ifdef PNG_WARNINGS_SUPPORTED
1960 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1961 PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1962 png_const_charp warning_message));
1964 /* Non-fatal error in libpng, chunk name is prepended to message. */
1965 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1966 png_const_charp warning_message));
1968 # define png_warning(s1,s2) ((void)(s1))
1969 # define png_chunk_warning(s1,s2) ((void)(s1))
1972 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1973 /* Benign error in libpng. Can continue, but may have a problem.
1974 * User can choose whether to handle as a fatal error or as a warning. */
1975 PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1976 png_const_charp warning_message));
1978 #ifdef PNG_READ_SUPPORTED
1979 /* Same, chunk name is prepended to message (only during read) */
1980 PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1981 png_const_charp warning_message));
1984 PNG_EXPORT(109, void, png_set_benign_errors,
1985 (png_structrp png_ptr, int allowed));
1987 # ifdef PNG_ALLOW_BENIGN_ERRORS
1988 # define png_benign_error png_warning
1989 # define png_chunk_benign_error png_chunk_warning
1991 # define png_benign_error png_error
1992 # define png_chunk_benign_error png_chunk_error
1996 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
1997 * Similarly, the png_get_<chunk> calls are used to read values from the
1998 * png_info_struct, either storing the parameters in the passed variables, or
1999 * setting pointers into the png_info_struct where the data is stored. The
2000 * png_get_<chunk> functions return a non-zero value if the data was available
2001 * in info_ptr, or return zero and do not change any of the parameters if the
2002 * data was not available.
2004 * These functions should be used instead of directly accessing png_info
2005 * to avoid problems with future changes in the size and internal layout of
2008 /* Returns "flag" if chunk data is valid in info_ptr. */
2009 PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
2010 png_const_inforp info_ptr, png_uint_32 flag));
2012 /* Returns number of bytes needed to hold a transformed row. */
2013 PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
2014 png_const_inforp info_ptr));
2016 #ifdef PNG_INFO_IMAGE_SUPPORTED
2017 /* Returns row_pointers, which is an array of pointers to scanlines that was
2018 * returned from png_read_png().
2020 PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
2021 png_const_inforp info_ptr));
2023 /* Set row_pointers, which is an array of pointers to scanlines for use
2024 * by png_write_png().
2026 PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
2027 png_inforp info_ptr, png_bytepp row_pointers));
2030 /* Returns number of color channels in image. */
2031 PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
2032 png_const_inforp info_ptr));
2034 #ifdef PNG_EASY_ACCESS_SUPPORTED
2035 /* Returns image width in pixels. */
2036 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
2037 png_const_inforp info_ptr));
2039 /* Returns image height in pixels. */
2040 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
2041 png_const_inforp info_ptr));
2043 /* Returns image bit_depth. */
2044 PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
2045 png_const_inforp info_ptr));
2047 /* Returns image color_type. */
2048 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
2049 png_const_inforp info_ptr));
2051 /* Returns image filter_type. */
2052 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
2053 png_const_inforp info_ptr));
2055 /* Returns image interlace_type. */
2056 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
2057 png_const_inforp info_ptr));
2059 /* Returns image compression_type. */
2060 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
2061 png_const_inforp info_ptr));
2063 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
2064 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
2065 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2066 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
2067 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2068 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
2069 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2071 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
2072 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
2073 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2074 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
2075 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2077 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
2078 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
2079 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2080 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
2081 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2082 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
2083 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2084 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
2085 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2087 #endif /* EASY_ACCESS */
2089 #ifdef PNG_READ_SUPPORTED
2090 /* Returns pointer to signature string read from PNG header */
2091 PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
2092 png_const_inforp info_ptr));
2095 #ifdef PNG_bKGD_SUPPORTED
2096 PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
2097 png_inforp info_ptr, png_color_16p *background));
2100 #ifdef PNG_bKGD_SUPPORTED
2101 PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
2102 png_inforp info_ptr, png_const_color_16p background));
2105 #ifdef PNG_cHRM_SUPPORTED
2106 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
2107 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
2108 double *red_y, double *green_x, double *green_y, double *blue_x,
2110 PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
2111 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
2112 double *green_X, double *green_Y, double *green_Z, double *blue_X,
2113 double *blue_Y, double *blue_Z))
2114 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
2115 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2116 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
2117 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
2118 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
2119 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
2120 PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
2121 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2122 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
2123 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
2124 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
2125 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
2126 png_fixed_point *int_blue_Z))
2129 #ifdef PNG_cHRM_SUPPORTED
2130 PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
2131 png_inforp info_ptr,
2132 double white_x, double white_y, double red_x, double red_y, double green_x,
2133 double green_y, double blue_x, double blue_y))
2134 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
2135 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
2136 double green_X, double green_Y, double green_Z, double blue_X,
2137 double blue_Y, double blue_Z))
2138 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
2139 png_inforp info_ptr, png_fixed_point int_white_x,
2140 png_fixed_point int_white_y, png_fixed_point int_red_x,
2141 png_fixed_point int_red_y, png_fixed_point int_green_x,
2142 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2143 png_fixed_point int_blue_y))
2144 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
2145 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
2146 png_fixed_point int_red_Z, png_fixed_point int_green_X,
2147 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
2148 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
2149 png_fixed_point int_blue_Z))
2152 #ifdef PNG_gAMA_SUPPORTED
2153 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
2154 png_const_inforp info_ptr, double *file_gamma))
2155 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2156 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2157 png_fixed_point *int_file_gamma))
2160 #ifdef PNG_gAMA_SUPPORTED
2161 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2162 png_inforp info_ptr, double file_gamma))
2163 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2164 png_inforp info_ptr, png_fixed_point int_file_gamma))
2167 #ifdef PNG_hIST_SUPPORTED
2168 PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2169 png_inforp info_ptr, png_uint_16p *hist));
2172 #ifdef PNG_hIST_SUPPORTED
2173 PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2174 png_inforp info_ptr, png_const_uint_16p hist));
2177 PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2178 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2179 int *bit_depth, int *color_type, int *interlace_method,
2180 int *compression_method, int *filter_method));
2182 PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2183 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2184 int color_type, int interlace_method, int compression_method,
2185 int filter_method));
2187 #ifdef PNG_oFFs_SUPPORTED
2188 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2189 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2193 #ifdef PNG_oFFs_SUPPORTED
2194 PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2195 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2199 #ifdef PNG_pCAL_SUPPORTED
2200 PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2201 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2202 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2203 png_charpp *params));
2206 #ifdef PNG_pCAL_SUPPORTED
2207 PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2208 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2209 int type, int nparams, png_const_charp units, png_charpp params));
2212 #ifdef PNG_pHYs_SUPPORTED
2213 PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2214 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2218 #ifdef PNG_pHYs_SUPPORTED
2219 PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2220 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2223 PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2224 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2226 PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2227 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2229 #ifdef PNG_sBIT_SUPPORTED
2230 PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2231 png_inforp info_ptr, png_color_8p *sig_bit));
2234 #ifdef PNG_sBIT_SUPPORTED
2235 PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2236 png_inforp info_ptr, png_const_color_8p sig_bit));
2239 #ifdef PNG_sRGB_SUPPORTED
2240 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2241 png_const_inforp info_ptr, int *file_srgb_intent));
2244 #ifdef PNG_sRGB_SUPPORTED
2245 PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2246 png_inforp info_ptr, int srgb_intent));
2247 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2248 png_inforp info_ptr, int srgb_intent));
2251 #ifdef PNG_iCCP_SUPPORTED
2252 PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2253 png_inforp info_ptr, png_charpp name, int *compression_type,
2254 png_bytepp profile, png_uint_32 *proflen));
2257 #ifdef PNG_iCCP_SUPPORTED
2258 PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2259 png_inforp info_ptr, png_const_charp name, int compression_type,
2260 png_const_bytep profile, png_uint_32 proflen));
2263 #ifdef PNG_sPLT_SUPPORTED
2264 PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2265 png_inforp info_ptr, png_sPLT_tpp entries));
2268 #ifdef PNG_sPLT_SUPPORTED
2269 PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2270 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2273 #ifdef PNG_TEXT_SUPPORTED
2274 /* png_get_text also returns the number of text chunks in *num_text */
2275 PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2276 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2279 /* Note while png_set_text() will accept a structure whose text,
2280 * language, and translated keywords are NULL pointers, the structure
2281 * returned by png_get_text will always contain regular
2282 * zero-terminated C strings. They might be empty strings but
2283 * they will never be NULL pointers.
2286 #ifdef PNG_TEXT_SUPPORTED
2287 PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2288 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2291 #ifdef PNG_tIME_SUPPORTED
2292 PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2293 png_inforp info_ptr, png_timep *mod_time));
2296 #ifdef PNG_tIME_SUPPORTED
2297 PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2298 png_inforp info_ptr, png_const_timep mod_time));
2301 #ifdef PNG_tRNS_SUPPORTED
2302 PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2303 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2304 png_color_16p *trans_color));
2307 #ifdef PNG_tRNS_SUPPORTED
2308 PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2309 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2310 png_const_color_16p trans_color));
2313 #ifdef PNG_sCAL_SUPPORTED
2314 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2315 png_const_inforp info_ptr, int *unit, double *width, double *height))
2316 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2317 defined(PNG_FLOATING_POINT_SUPPORTED)
2318 /* NOTE: this API is currently implemented using floating point arithmetic,
2319 * consequently it can only be used on systems with floating point support.
2320 * In any case the range of values supported by png_fixed_point is small and it
2321 * is highly recommended that png_get_sCAL_s be used instead.
2323 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2324 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2325 png_fixed_point *width, png_fixed_point *height))
2327 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2328 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2329 png_charpp swidth, png_charpp sheight));
2331 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2332 png_inforp info_ptr, int unit, double width, double height))
2333 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2334 png_inforp info_ptr, int unit, png_fixed_point width,
2335 png_fixed_point height))
2336 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2337 png_inforp info_ptr, int unit,
2338 png_const_charp swidth, png_const_charp sheight));
2341 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2342 /* Provide the default handling for all unknown chunks or, optionally, for
2343 * specific unknown chunks.
2345 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2346 * ignored and the default was used, the per-chunk setting only had an effect on
2347 * write. If you wish to have chunk-specific handling on read in code that must
2348 * work on earlier versions you must use a user chunk callback to specify the
2349 * desired handling (keep or discard.)
2351 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2352 * parameter is interpreted as follows:
2355 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2356 * Known chunks: do normal libpng processing, do not keep the chunk (but
2357 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2358 * Unknown chunks: for a specific chunk use the global default, when used
2359 * as the default discard the chunk data.
2360 * PNG_HANDLE_CHUNK_NEVER:
2361 * Discard the chunk data.
2362 * PNG_HANDLE_CHUNK_IF_SAFE:
2363 * Keep the chunk data if the chunk is not critical else raise a chunk
2365 * PNG_HANDLE_CHUNK_ALWAYS:
2366 * Keep the chunk data.
2368 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2369 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2370 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2371 * it simply resets the behavior to the libpng default.
2373 * INTERACTION WTIH USER CHUNK CALLBACKS:
2374 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2375 * callback and the callback returns 0; the chunk is then always stored *unless*
2376 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2377 * the global default is *not* used in this case. (In effect the per-chunk
2378 * value is incremented to at least IF_SAFE.)
2380 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2381 * per-chunk defaults will be honored. If you want to preserve the current
2382 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2383 * as the default - if you don't do this libpng 1.6 will issue a warning.
2385 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2386 * earlier simply return '1' (handled).
2388 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2389 * If this is *not* set known chunks will always be handled by libpng and
2390 * will never be stored in the unknown chunk list. Known chunks listed to
2391 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2392 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2393 * by libpng, in addition critical chunks must either be processed by the
2394 * callback or saved.
2396 * The IHDR and IEND chunks must not be listed. Because this turns off the
2397 * default handling for chunks that would otherwise be recognized the
2398 * behavior of libpng transformations may well become incorrect!
2401 * When writing chunks the options only apply to the chunks specified by
2402 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2403 * required by png_set_ calls and will always write the core critical chunks
2404 * (as required for PLTE).
2406 * Each chunk in the png_set_unknown_chunks list is looked up in the
2407 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2408 * interpreted as follows:
2410 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2411 * Write safe-to-copy chunks and write other chunks if the global
2412 * default is set to _ALWAYS, otherwise don't write this chunk.
2413 * PNG_HANDLE_CHUNK_NEVER:
2414 * Do not write the chunk.
2415 * PNG_HANDLE_CHUNK_IF_SAFE:
2416 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2417 * PNG_HANDLE_CHUNK_ALWAYS:
2420 * Note that the default behavior is effectively the opposite of the read case -
2421 * in read unknown chunks are not stored by default, in write they are written
2422 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2423 * - on write the safe-to-copy bit is checked, on read the critical bit is
2424 * checked and on read if the chunk is critical an error will be raised.
2428 * If num_chunks is positive, then the "keep" parameter specifies the manner
2429 * for handling only those chunks appearing in the chunk_list array,
2430 * otherwise the chunk list array is ignored.
2432 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2433 * unknown chunks, as described above.
2435 * If num_chunks is negative, then the "keep" parameter specifies the manner
2436 * for handling all unknown chunks plus all chunks recognized by libpng
2437 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2438 * be processed by libpng.
2440 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2441 int keep, png_const_bytep chunk_list, int num_chunks));
2443 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2444 * the result is therefore true (non-zero) if special handling is required,
2445 * false for the default handling.
2447 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2448 png_const_bytep chunk_name));
2451 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2452 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2453 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2455 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2456 * unknowns to the location currently stored in the png_struct. This is
2457 * invariably the wrong value on write. To fix this call the following API
2458 * for each chunk in the list with the correct location. If you know your
2459 * code won't be compiled on earlier versions you can rely on
2460 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2461 * the correct thing.
2464 PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2465 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2467 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2468 png_inforp info_ptr, png_unknown_chunkpp entries));
2471 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2472 * If you need to turn it off for a chunk that your application has freed,
2473 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2475 PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2476 png_inforp info_ptr, int mask));
2478 #ifdef PNG_INFO_IMAGE_SUPPORTED
2479 /* The "params" pointer is currently not used and is for future expansion. */
2480 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2481 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2482 int transforms, png_voidp params));
2484 #ifdef PNG_WRITE_SUPPORTED
2485 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2486 int transforms, png_voidp params));
2490 PNG_EXPORT(180, png_const_charp, png_get_copyright,
2491 (png_const_structrp png_ptr));
2492 PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2493 (png_const_structrp png_ptr));
2494 PNG_EXPORT(182, png_const_charp, png_get_header_version,
2495 (png_const_structrp png_ptr));
2496 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2497 (png_const_structrp png_ptr));
2499 #ifdef PNG_MNG_FEATURES_SUPPORTED
2500 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2501 png_uint_32 mng_features_permitted));
2504 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2505 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2506 #define PNG_HANDLE_CHUNK_NEVER 1
2507 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2508 #define PNG_HANDLE_CHUNK_ALWAYS 3
2509 #define PNG_HANDLE_CHUNK_LAST 4
2511 /* Strip the prepended error numbers ("#nnn ") from error and warning
2512 * messages before passing them to the error or warning handler.
2514 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2515 PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2516 png_uint_32 strip_mode));
2519 /* Added in libpng-1.2.6 */
2520 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2521 PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2522 png_uint_32 user_width_max, png_uint_32 user_height_max));
2523 PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2524 (png_const_structrp png_ptr));
2525 PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2526 (png_const_structrp png_ptr));
2527 /* Added in libpng-1.4.0 */
2528 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2529 png_uint_32 user_chunk_cache_max));
2530 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2531 (png_const_structrp png_ptr));
2532 /* Added in libpng-1.4.1 */
2533 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2534 png_alloc_size_t user_chunk_cache_max));
2535 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2536 (png_const_structrp png_ptr));
2539 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2540 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2541 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2543 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2544 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2546 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2547 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2549 PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2550 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2551 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2552 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2553 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2556 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2557 png_const_inforp info_ptr))
2558 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2559 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2560 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2563 # ifdef PNG_pHYs_SUPPORTED
2564 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2565 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2568 #endif /* INCH_CONVERSIONS */
2570 /* Added in libpng-1.4.0 */
2571 #ifdef PNG_IO_STATE_SUPPORTED
2572 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2574 /* Removed from libpng 1.6; use png_get_io_chunk_type. */
2575 PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2578 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2579 (png_const_structrp png_ptr));
2581 /* The flags returned by png_get_io_state() are the following: */
2582 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2583 # define PNG_IO_READING 0x0001 /* currently reading */
2584 # define PNG_IO_WRITING 0x0002 /* currently writing */
2585 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2586 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2587 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2588 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2589 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2590 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2591 #endif /* IO_STATE */
2593 /* Interlace support. The following macros are always defined so that if
2594 * libpng interlace handling is turned off the macros may be used to handle
2595 * interlaced images within the application.
2597 #define PNG_INTERLACE_ADAM7_PASSES 7
2599 /* Two macros to return the first row and first column of the original,
2600 * full, image which appears in a given pass. 'pass' is in the range 0
2601 * to 6 and the result is in the range 0 to 7.
2603 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2604 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2606 /* A macro to return the offset between pixels in the output row for a pair of
2607 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2608 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2609 * COL_OFFSET is from one column to the next, within a row.
2611 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2612 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2614 /* Two macros to help evaluate the number of rows or columns in each
2615 * pass. This is expressed as a shift - effectively log2 of the number or
2616 * rows or columns in each 8x8 tile of the original image.
2618 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2619 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2621 /* Hence two macros to determine the number of rows or columns in a given
2622 * pass of an image given its height or width. In fact these macros may
2623 * return non-zero even though the sub-image is empty, because the other
2624 * dimension may be empty for a small image.
2626 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2627 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2628 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2629 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2631 /* For the reader row callbacks (both progressive and sequential) it is
2632 * necessary to find the row in the output image given a row in an interlaced
2633 * image, so two more macros:
2635 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2636 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2637 #define PNG_COL_FROM_PASS_COL(x_in, pass) \
2638 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2640 /* Two macros which return a boolean (0 or 1) saying whether the given row
2641 * or column is in a particular pass. These use a common utility macro that
2642 * returns a mask for a given pass - the offset 'off' selects the row or
2643 * column version. The mask has the appropriate bit set for each column in
2646 #define PNG_PASS_MASK(pass,off) ( \
2647 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2648 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2650 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2651 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2652 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2653 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2655 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2656 /* With these routines we avoid an integer divide, which will be slower on
2657 * most machines. However, it does take more operations than the corresponding
2658 * divide method, so it may be slower on a few RISC systems. There are two
2659 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2661 * Note that the rounding factors are NOT supposed to be the same! 128 and
2662 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2665 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2668 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2670 # define png_composite(composite, fg, alpha, bg) \
2671 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2672 * (png_uint_16)(alpha) \
2673 + (png_uint_16)(bg)*(png_uint_16)(255 \
2674 - (png_uint_16)(alpha)) + 128); \
2675 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); }
2677 # define png_composite_16(composite, fg, alpha, bg) \
2678 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2679 * (png_uint_32)(alpha) \
2680 + (png_uint_32)(bg)*(65535 \
2681 - (png_uint_32)(alpha)) + 32768); \
2682 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); }
2684 #else /* Standard method using integer division */
2686 # define png_composite(composite, fg, alpha, bg) \
2688 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2689 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2692 # define png_composite_16(composite, fg, alpha, bg) \
2694 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2695 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2697 #endif /* READ_COMPOSITE_NODIV */
2699 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2700 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2701 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2702 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2705 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2706 png_const_bytep buf));
2707 /* No png_get_int_16 -- may be added if there's a real need for it. */
2709 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2710 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2711 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2713 #ifdef PNG_SAVE_INT_32_SUPPORTED
2714 PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2717 /* Place a 16-bit number into a buffer in PNG byte order.
2718 * The parameter is declared unsigned int, not png_uint_16,
2719 * just to avoid potential problems on pre-ANSI C compilers.
2721 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2722 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2723 /* No png_save_int_16 -- may be added if there's a real need for it. */
2726 #ifdef PNG_USE_READ_MACROS
2727 /* Inline macros to do direct reads of bytes from the input buffer.
2728 * The png_get_int_32() routine assumes we are using two's complement
2729 * format for negative values, which is almost certainly true.
2731 # define PNG_get_uint_32(buf) \
2732 (((png_uint_32)(*(buf)) << 24) + \
2733 ((png_uint_32)(*((buf) + 1)) << 16) + \
2734 ((png_uint_32)(*((buf) + 2)) << 8) + \
2735 ((png_uint_32)(*((buf) + 3))))
2737 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2738 * function) incorrectly returned a value of type png_uint_32.
2740 # define PNG_get_uint_16(buf) \
2742 (((unsigned int)(*(buf)) << 8) + \
2743 ((unsigned int)(*((buf) + 1)))))
2745 # define PNG_get_int_32(buf) \
2746 ((png_int_32)((*(buf) & 0x80) \
2747 ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
2748 : (png_int_32)png_get_uint_32(buf)))
2750 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2751 * but defining a macro name prefixed with PNG_PREFIX.
2754 # define png_get_uint_32(buf) PNG_get_uint_32(buf)
2755 # define png_get_uint_16(buf) PNG_get_uint_16(buf)
2756 # define png_get_int_32(buf) PNG_get_int_32(buf)
2760 /* No macros; revert to the (redefined) function */
2761 # define PNG_get_uint_32 (png_get_uint_32)
2762 # define PNG_get_uint_16 (png_get_uint_16)
2763 # define PNG_get_int_32 (png_get_int_32)
2767 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2768 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2769 /*******************************************************************************
2771 *******************************************************************************
2773 * Please read the documentation in libpng-manual.txt (TODO: write said
2774 * documentation) if you don't understand what follows.
2776 * The simplified API hides the details of both libpng and the PNG file format
2777 * itself. It allows PNG files to be read into a very limited number of
2778 * in-memory bitmap formats or to be written from the same formats. If these
2779 * formats do not accomodate your needs then you can, and should, use the more
2780 * sophisticated APIs above - these support a wide variety of in-memory formats
2781 * and a wide variety of sophisticated transformations to those formats as well
2782 * as a wide variety of APIs to manipulate ancillary information.
2784 * To read a PNG file using the simplified API:
2786 * 1) Declare a 'png_image' structure (see below) on the stack and set the
2787 * version field to PNG_IMAGE_VERSION.
2788 * 2) Call the appropriate png_image_begin_read... function.
2789 * 3) Set the png_image 'format' member to the required sample format.
2790 * 4) Allocate a buffer for the image and, if required, the color-map.
2791 * 5) Call png_image_finish_read to read the image and, if required, the
2792 * color-map into your buffers.
2794 * There are no restrictions on the format of the PNG input itself; all valid
2795 * color types, bit depths, and interlace methods are acceptable, and the
2796 * input image is transformed as necessary to the requested in-memory format
2797 * during the png_image_finish_read() step. The only caveat is that if you
2798 * request a color-mapped image from a PNG that is full-color or makes
2799 * complex use of an alpha channel the transformation is extremely lossy and the
2800 * result may look terrible.
2802 * To write a PNG file using the simplified API:
2804 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2805 * 2) Initialize the members of the structure that describe the image, setting
2806 * the 'format' member to the format of the image samples.
2807 * 3) Call the appropriate png_image_write... function with a pointer to the
2808 * image and, if necessary, the color-map to write the PNG data.
2810 * png_image is a structure that describes the in-memory format of an image
2811 * when it is being read or defines the in-memory format of an image that you
2814 #define PNG_IMAGE_VERSION 1
2816 typedef struct png_control *png_controlp;
2819 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2820 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2821 png_uint_32 width; /* Image width in pixels (columns) */
2822 png_uint_32 height; /* Image height in pixels (rows) */
2823 png_uint_32 format; /* Image format as defined below */
2824 png_uint_32 flags; /* A bit mask containing informational flags */
2825 png_uint_32 colormap_entries;
2826 /* Number of entries in the color-map */
2828 /* In the event of an error or warning the following field will be set to a
2829 * non-zero value and the 'message' field will contain a '\0' terminated
2830 * string with the libpng error or warning message. If both warnings and
2831 * an error were encountered, only the error is recorded. If there
2832 * are multiple warnings, only the first one is recorded.
2834 * The upper 30 bits of this value are reserved, the low two bits contain
2835 * a value as follows:
2837 # define PNG_IMAGE_WARNING 1
2838 # define PNG_IMAGE_ERROR 2
2840 * The result is a two-bit code such that a value more than 1 indicates
2841 * a failure in the API just called:
2843 * 0 - no warning or error
2846 * 3 - error preceded by warning
2848 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2850 png_uint_32 warning_or_error;
2853 } png_image, *png_imagep;
2855 /* The samples of the image have one to four channels whose components have
2856 * original values in the range 0 to 1.0:
2858 * 1: A single gray or luminance channel (G).
2859 * 2: A gray/luminance channel and an alpha channel (GA).
2860 * 3: Three red, green, blue color channels (RGB).
2861 * 4: Three color channels and an alpha channel (RGBA).
2863 * The components are encoded in one of two ways:
2865 * a) As a small integer, value 0..255, contained in a single byte. For the
2866 * alpha channel the original value is simply value/255. For the color or
2867 * luminance channels the value is encoded according to the sRGB specification
2868 * and matches the 8-bit format expected by typical display devices.
2870 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2871 * channel and are suitable for passing to color management software.
2873 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2874 * channels can be converted to the original value by dividing by 65535; all
2875 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2876 * the sRGB specification. This encoding is identified by the
2877 * PNG_FORMAT_FLAG_LINEAR flag below.
2879 * When the simplified API needs to convert between sRGB and linear colorspaces,
2880 * the actual sRGB transfer curve defined in the sRGB specification (see the
2881 * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2882 * approximation used elsewhere in libpng.
2884 * When an alpha channel is present it is expected to denote pixel coverage
2885 * of the color or luminance channels and is returned as an associated alpha
2886 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2889 * The samples are either contained directly in the image data, between 1 and 8
2890 * bytes per pixel according to the encoding, or are held in a color-map indexed
2891 * by bytes in the image data. In the case of a color-map the color-map entries
2892 * are individual samples, encoded as above, and the image data has one byte per
2893 * pixel to select the relevant sample from the color-map.
2898 * #defines to be used in png_image::format. Each #define identifies a
2899 * particular layout of sample data and, if present, alpha values. There are
2900 * separate defines for each of the two component encodings.
2902 * A format is built up using single bit flag values. All combinations are
2903 * valid. Formats can be built up from the flag values or you can use one of
2904 * the predefined values below. When testing formats always use the FORMAT_FLAG
2905 * macros to test for individual features - future versions of the library may
2908 * When reading or writing color-mapped images the format should be set to the
2909 * format of the entries in the color-map then png_image_{read,write}_colormap
2910 * called to read or write the color-map and set the format correctly for the
2911 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2913 * NOTE: libpng can be built with particular features disabled, if you see
2914 * compiler errors because the definition of one of the following flags has been
2915 * compiled out it is because libpng does not have the required support. It is
2916 * possible, however, for the libpng configuration to enable the format on just
2917 * read or just write; in that case you may see an error at run time. You can
2918 * guard against this by checking for the definition of the appropriate
2919 * "_SUPPORTED" macro, one of:
2921 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2923 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2924 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2925 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2 byte channels else 1 byte */
2926 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2928 #ifdef PNG_FORMAT_BGR_SUPPORTED
2929 # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2932 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
2933 # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2936 /* Commonly used formats have predefined macros.
2938 * First the single byte (sRGB) formats:
2940 #define PNG_FORMAT_GRAY 0
2941 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2942 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2943 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2944 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2945 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2946 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2947 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2948 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2950 /* Then the linear 2-byte formats. When naming these "Y" is used to
2951 * indicate a luminance (gray) channel.
2953 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2954 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2955 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2956 #define PNG_FORMAT_LINEAR_RGB_ALPHA \
2957 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2959 /* With color-mapped formats the image data is one byte for each pixel, the byte
2960 * is an index into the color-map which is formatted as above. To obtain a
2961 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2962 * to one of the above definitions, or you can use one of the definitions below.
2964 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2965 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2966 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2967 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2968 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2969 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2973 * These are convenience macros to derive information from a png_image
2974 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2975 * actual image sample values - either the entries in the color-map or the
2976 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2977 * for the pixels and will always return 1 for color-mapped formats. The
2978 * remaining macros return information about the rows in the image and the
2981 * NOTE: All the macros that take a png_image::format parameter are compile time
2982 * constants if the format parameter is, itself, a constant. Therefore these
2983 * macros can be used in array declarations and case labels where required.
2984 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2985 * they can be used in #if tests.
2987 * First the information about the samples.
2989 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2990 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2991 /* Return the total number of channels in a given format: 1..4 */
2993 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2994 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2995 /* Return the size in bytes of a single component of a pixel or color-map
2996 * entry (as appropriate) in the image: 1 or 2.
2999 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\
3000 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
3001 /* This is the size of the sample data for one sample. If the image is
3002 * color-mapped it is the size of one color-map entry (and image pixels are
3003 * one byte in size), otherwise it is the size of one image pixel.
3006 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
3007 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
3008 /* The maximum size of the color-map required by the format expressed in a
3009 * count of components. This can be used to compile-time allocate a
3012 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
3014 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
3016 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
3017 * information from one of the png_image_begin_read_ APIs and dynamically
3018 * allocate the required memory.
3021 /* Corresponding information about the pixels */
3022 #define PNG_IMAGE_PIXEL_(test,fmt)\
3023 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
3025 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
3026 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
3027 /* The number of separate channels (components) in a pixel; 1 for a
3028 * color-mapped image.
3031 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
3032 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
3033 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
3037 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
3038 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
3040 /* Information about the whole row, or whole image */
3041 #define PNG_IMAGE_ROW_STRIDE(image)\
3042 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
3043 /* Return the total number of components in a single row of the image; this
3044 * is the minimum 'row stride', the minimum count of components between each
3045 * row. For a color-mapped image this is the minimum number of bytes in a
3049 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
3050 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
3051 /* Return the size, in bytes, of an image buffer given a png_image and a row
3052 * stride - the number of components to leave space for in each row.
3055 #define PNG_IMAGE_SIZE(image)\
3056 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
3057 /* Return the size, in bytes, of the image in memory given just a png_image;
3058 * the row stride is the minimum stride required for the image.
3061 #define PNG_IMAGE_COLORMAP_SIZE(image)\
3062 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
3063 /* Return the size, in bytes, of the color-map of this image. If the image
3064 * format is not a color-map format this will return a size sufficient for
3065 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
3066 * you don't want to allocate a color-map in this case.
3071 * Flags containing additional information about the image are held in the
3072 * 'flags' field of png_image.
3074 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
3075 /* This indicates the the RGB values of the in-memory bitmap do not
3076 * correspond to the red, green and blue end-points defined by sRGB.
3079 #define PNG_IMAGE_FLAG_FAST 0x02
3080 /* On write emphasise speed over compression; the resultant PNG file will be
3081 * larger but will be produced significantly faster, particular for large
3082 * images. Do not use this option for images which will be distributed, only
3083 * used it when producing intermediate files that will be read back in
3084 * repeatedly. For a typical 24-bit image the option will double the read
3085 * speed at the cost of increasing the image size by 25%, however for many
3086 * more compressible images the PNG file can be 10 times larger with only a
3087 * slight speed gain.
3090 #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
3091 /* On read if the image is a 16-bit per component image and there is no gAMA
3092 * or sRGB chunk assume that the components are sRGB encoded. Notice that
3093 * images output by the simplified API always have gamma information; setting
3094 * this flag only affects the interpretation of 16-bit images from an
3095 * external source. It is recommended that the application expose this flag
3096 * to the user; the user can normally easily recognize the difference between
3097 * linear and sRGB encoding. This flag has no effect on write - the data
3098 * passed to the write APIs must have the correct encoding (as defined
3101 * If the flag is not set (the default) input 16-bit per component data is
3102 * assumed to be linear.
3104 * NOTE: the flag can only be set after the png_image_begin_read_ call,
3105 * because that call initializes the 'flags' field.
3108 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
3112 * The png_image passed to the read APIs must have been initialized by setting
3113 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
3115 #ifdef PNG_STDIO_SUPPORTED
3116 PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
3117 const char *file_name));
3118 /* The named file is opened for read and the image header is filled in
3119 * from the PNG header in the file.
3122 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
3124 /* The PNG header is read from the stdio FILE object. */
3127 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
3128 png_const_voidp memory, png_size_t size));
3129 /* The PNG header is read from the given memory buffer. */
3131 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
3132 png_const_colorp background, void *buffer, png_int_32 row_stride,
3134 /* Finish reading the image into the supplied buffer and clean up the
3135 * png_image structure.
3137 * row_stride is the step, in byte or 2-byte units as appropriate,
3138 * between adjacent rows. A positive stride indicates that the top-most row
3139 * is first in the buffer - the normal top-down arrangement. A negative
3140 * stride indicates that the bottom-most row is first in the buffer.
3142 * background need only be supplied if an alpha channel must be removed from
3143 * a png_byte format and the removal is to be done by compositing on a solid
3144 * color; otherwise it may be NULL and any composition will be done directly
3145 * onto the buffer. The value is an sRGB color to use for the background,
3146 * for grayscale output the green channel is used.
3148 * background must be supplied when an alpha channel must be removed from a
3149 * single byte color-mapped output format, in other words if:
3151 * 1) The original format from png_image_begin_read_from_* had
3152 * PNG_FORMAT_FLAG_ALPHA set.
3153 * 2) The format set by the application does not.
3154 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3155 * PNG_FORMAT_FLAG_LINEAR *not* set.
3157 * For linear output removing the alpha channel is always done by compositing
3158 * on black and background is ignored.
3160 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3161 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3162 * image->colormap_entries will be updated to the actual number of entries
3163 * written to the colormap; this may be less than the original value.
3166 PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3167 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3168 * NULL. May be called at any time after the structure is initialized.
3170 #endif /* SIMPLIFIED_READ */
3172 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3173 #ifdef PNG_STDIO_SUPPORTED
3176 * For write you must initialize a png_image structure to describe the image to
3177 * be written. To do this use memset to set the whole structure to 0 then
3178 * initialize fields describing your image.
3180 * version: must be set to PNG_IMAGE_VERSION
3181 * opaque: must be initialized to NULL
3182 * width: image width in pixels
3183 * height: image height in rows
3184 * format: the format of the data (image and color-map) you wish to write
3185 * flags: set to 0 unless one of the defined flags applies; set
3186 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3187 * values do not correspond to the colors in sRGB.
3188 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3190 PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3191 const char *file, int convert_to_8bit, const void *buffer,
3192 png_int_32 row_stride, const void *colormap));
3193 /* Write the image to the named file. */
3195 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3196 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3197 const void *colormap));
3198 /* Write the image to the given (FILE*). */
3200 /* With both write APIs if image is in one of the linear formats with 16-bit
3201 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3202 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3203 * encoded PNG file is written.
3205 * With color-mapped data formats the colormap parameter point to a color-map
3206 * with at least image->colormap_entries encoded in the specified format. If
3207 * the format is linear the written PNG color-map will be converted to sRGB
3208 * regardless of the convert_to_8_bit flag.
3210 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3211 * from one row to the next in component sized units (1 or 2 bytes) and if
3212 * negative indicates a bottom-up row layout in the buffer.
3214 * Note that the write API does not support interlacing or sub-8-bit pixels.
3217 #endif /* SIMPLIFIED_WRITE */
3218 /*******************************************************************************
3219 * END OF SIMPLIFIED API
3220 ******************************************************************************/
3221 #endif /* SIMPLIFIED_{READ|WRITE} */
3223 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
3224 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
3225 (png_structrp png_ptr, int allowed));
3226 # ifdef PNG_GET_PALETTE_MAX_SUPPORTED
3227 PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
3228 png_const_infop info_ptr));
3230 #endif /* CHECK_FOR_INVALID_INDEX */
3232 /*******************************************************************************
3233 * IMPLEMENTATION OPTIONS
3234 *******************************************************************************
3236 * Support for arbitrary implementation-specific optimizations. The API allows
3237 * particular options to be turned on or off. 'Option' is the number of the
3238 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3239 * by the PNG_OPTION_ defines below.
3241 * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
3242 * are detected at run time, however sometimes it may be impossible
3243 * to do this in user mode, in which case it is necessary to discover
3244 * the capabilities in an OS specific way. Such capabilities are
3245 * listed here when libpng has support for them and must be turned
3246 * ON by the application if present.
3248 * SOFTWARE: sometimes software optimizations actually result in performance
3249 * decrease on some architectures or systems, or with some sets of
3250 * PNG images. 'Software' options allow such optimizations to be
3251 * selected at run time.
3253 #ifdef PNG_SET_OPTION_SUPPORTED
3254 #ifdef PNG_ARM_NEON_API_SUPPORTED
3255 # define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3257 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3258 #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3259 #define PNG_OPTION_NEXT 6 /* Next option - numbers must be even */
3261 /* Return values: NOTE: there are four values and 'off' is *not* zero */
3262 #define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3263 #define PNG_OPTION_INVALID 1 /* Option number out of range */
3264 #define PNG_OPTION_OFF 2
3265 #define PNG_OPTION_ON 3
3267 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3269 #endif /* SET_OPTION */
3271 /*******************************************************************************
3272 * END OF HARDWARE AND SOFTWARE OPTIONS
3273 ******************************************************************************/
3275 /* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3276 * defs, and in scripts/symbols.def.
3279 /* The last ordinal number (this is the *last* one already used; the next
3280 * one to use is one more than this.)
3282 #ifdef PNG_EXPORT_LAST_ORDINAL
3283 PNG_EXPORT_LAST_ORDINAL(244);
3290 #endif /* PNG_VERSION_INFO_ONLY */
3291 /* Do not put anything past this line */
projects / openjpeg.git / blob