2 /* png.h - header file for PNG reference library
4 * libpng version 1.6.13 - August 21, 2014
5 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 * This code is released under the libpng license (See LICENSE, below)
11 * Authors and maintainers:
12 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
13 * libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
14 * libpng versions 0.97, January 1998, through 1.6.13 - August 21, 2014: Glenn
15 * See also "Contributing Authors", below.
17 * Note about libpng version numbers:
19 * Due to various miscommunications, unforeseen code incompatibilities
20 * and occasional factors outside the authors' control, version numbering
21 * on the library has not always been consistent and straightforward.
22 * The following table summarizes matters since version 0.89c, which was
23 * the first widely used release:
25 * source png.h png.h shared-lib
26 * version string int version
27 * ------- ------ ----- ----------
28 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
29 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
30 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
31 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
32 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
33 * 0.97c 0.97 97 2.0.97
36 * 0.99a-m 0.99 99 2.0.99
37 * 1.00 1.00 100 2.1.0 [100 should be 10000]
38 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
39 * 1.0.1 png.h string is 10001 2.1.0
40 * 1.0.1a-e identical to the 10002 from here on, the shared library
41 * 1.0.2 source version) 10002 is 2.V where V is the source code
42 * 1.0.2a-b 10003 version, except as noted.
47 * 1.0.5 (+ 2 patches) 10005
49 * 1.0.5e-r 10100 (not source compatible)
50 * 1.0.5s-v 10006 (not binary compatible)
51 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
52 * 1.0.6d-f 10007 (still binary incompatible)
54 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
56 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
57 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
58 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
59 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
60 * 1.0.7 1 10007 (still compatible)
61 * 1.0.8beta1-4 1 10008 2.1.0.8beta1-4
62 * 1.0.8rc1 1 10008 2.1.0.8rc1
63 * 1.0.8 1 10008 2.1.0.8
64 * 1.0.9beta1-6 1 10009 2.1.0.9beta1-6
65 * 1.0.9rc1 1 10009 2.1.0.9rc1
66 * 1.0.9beta7-10 1 10009 2.1.0.9beta7-10
67 * 1.0.9rc2 1 10009 2.1.0.9rc2
68 * 1.0.9 1 10009 2.1.0.9
69 * 1.0.10beta1 1 10010 2.1.0.10beta1
70 * 1.0.10rc1 1 10010 2.1.0.10rc1
71 * 1.0.10 1 10010 2.1.0.10
72 * 1.0.11beta1-3 1 10011 2.1.0.11beta1-3
73 * 1.0.11rc1 1 10011 2.1.0.11rc1
74 * 1.0.11 1 10011 2.1.0.11
75 * 1.0.12beta1-2 2 10012 2.1.0.12beta1-2
76 * 1.0.12rc1 2 10012 2.1.0.12rc1
77 * 1.0.12 2 10012 2.1.0.12
78 * 1.1.0a-f - 10100 2.1.1.0a-f (branch abandoned)
79 * 1.2.0beta1-2 2 10200 2.1.2.0beta1-2
80 * 1.2.0beta3-5 3 10200 3.1.2.0beta3-5
81 * 1.2.0rc1 3 10200 3.1.2.0rc1
82 * 1.2.0 3 10200 3.1.2.0
83 * 1.2.1beta1-4 3 10201 3.1.2.1beta1-4
84 * 1.2.1rc1-2 3 10201 3.1.2.1rc1-2
85 * 1.2.1 3 10201 3.1.2.1
86 * 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6
87 * 1.0.13beta1 10 10013 10.so.0.1.0.13beta1
88 * 1.0.13rc1 10 10013 10.so.0.1.0.13rc1
89 * 1.2.2rc1 12 10202 12.so.0.1.2.2rc1
90 * 1.0.13 10 10013 10.so.0.1.0.13
91 * 1.2.2 12 10202 12.so.0.1.2.2
92 * 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6
93 * 1.2.3 12 10203 12.so.0.1.2.3
94 * 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3
95 * 1.0.14rc1 13 10014 10.so.0.1.0.14rc1
96 * 1.2.4rc1 13 10204 12.so.0.1.2.4rc1
97 * 1.0.14 10 10014 10.so.0.1.0.14
98 * 1.2.4 13 10204 12.so.0.1.2.4
99 * 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2
100 * 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3
101 * 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3
102 * 1.0.15 10 10015 10.so.0.1.0.15
103 * 1.2.5 13 10205 12.so.0.1.2.5
104 * 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4
105 * 1.0.16 10 10016 10.so.0.1.0.16
106 * 1.2.6 13 10206 12.so.0.1.2.6
107 * 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2
108 * 1.0.17rc1 10 10017 12.so.0.1.0.17rc1
109 * 1.2.7rc1 13 10207 12.so.0.1.2.7rc1
110 * 1.0.17 10 10017 12.so.0.1.0.17
111 * 1.2.7 13 10207 12.so.0.1.2.7
112 * 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5
113 * 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5
114 * 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5
115 * 1.0.18 10 10018 12.so.0.1.0.18
116 * 1.2.8 13 10208 12.so.0.1.2.8
117 * 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3
118 * 1.2.9beta4-11 13 10209 12.so.0.9[.0]
119 * 1.2.9rc1 13 10209 12.so.0.9[.0]
120 * 1.2.9 13 10209 12.so.0.9[.0]
121 * 1.2.10beta1-7 13 10210 12.so.0.10[.0]
122 * 1.2.10rc1-2 13 10210 12.so.0.10[.0]
123 * 1.2.10 13 10210 12.so.0.10[.0]
124 * 1.4.0beta1-5 14 10400 14.so.0.0[.0]
125 * 1.2.11beta1-4 13 10211 12.so.0.11[.0]
126 * 1.4.0beta7-8 14 10400 14.so.0.0[.0]
127 * 1.2.11 13 10211 12.so.0.11[.0]
128 * 1.2.12 13 10212 12.so.0.12[.0]
129 * 1.4.0beta9-14 14 10400 14.so.0.0[.0]
130 * 1.2.13 13 10213 12.so.0.13[.0]
131 * 1.4.0beta15-36 14 10400 14.so.0.0[.0]
132 * 1.4.0beta37-87 14 10400 14.so.14.0[.0]
133 * 1.4.0rc01 14 10400 14.so.14.0[.0]
134 * 1.4.0beta88-109 14 10400 14.so.14.0[.0]
135 * 1.4.0rc02-08 14 10400 14.so.14.0[.0]
136 * 1.4.0 14 10400 14.so.14.0[.0]
137 * 1.4.1beta01-03 14 10401 14.so.14.1[.0]
138 * 1.4.1rc01 14 10401 14.so.14.1[.0]
139 * 1.4.1beta04-12 14 10401 14.so.14.1[.0]
140 * 1.4.1 14 10401 14.so.14.1[.0]
141 * 1.4.2 14 10402 14.so.14.2[.0]
142 * 1.4.3 14 10403 14.so.14.3[.0]
143 * 1.4.4 14 10404 14.so.14.4[.0]
144 * 1.5.0beta01-58 15 10500 15.so.15.0[.0]
145 * 1.5.0rc01-07 15 10500 15.so.15.0[.0]
146 * 1.5.0 15 10500 15.so.15.0[.0]
147 * 1.5.1beta01-11 15 10501 15.so.15.1[.0]
148 * 1.5.1rc01-02 15 10501 15.so.15.1[.0]
149 * 1.5.1 15 10501 15.so.15.1[.0]
150 * 1.5.2beta01-03 15 10502 15.so.15.2[.0]
151 * 1.5.2rc01-03 15 10502 15.so.15.2[.0]
152 * 1.5.2 15 10502 15.so.15.2[.0]
153 * 1.5.3beta01-10 15 10503 15.so.15.3[.0]
154 * 1.5.3rc01-02 15 10503 15.so.15.3[.0]
155 * 1.5.3beta11 15 10503 15.so.15.3[.0]
157 * 1.5.4beta01-08 15 10504 15.so.15.4[.0]
158 * 1.5.4rc01 15 10504 15.so.15.4[.0]
159 * 1.5.4 15 10504 15.so.15.4[.0]
160 * 1.5.5beta01-08 15 10505 15.so.15.5[.0]
161 * 1.5.5rc01 15 10505 15.so.15.5[.0]
162 * 1.5.5 15 10505 15.so.15.5[.0]
163 * 1.5.6beta01-07 15 10506 15.so.15.6[.0]
164 * 1.5.6rc01-03 15 10506 15.so.15.6[.0]
165 * 1.5.6 15 10506 15.so.15.6[.0]
166 * 1.5.7beta01-05 15 10507 15.so.15.7[.0]
167 * 1.5.7rc01-03 15 10507 15.so.15.7[.0]
168 * 1.5.7 15 10507 15.so.15.7[.0]
169 * 1.6.0beta01-40 16 10600 16.so.16.0[.0]
170 * 1.6.0rc01-08 16 10600 16.so.16.0[.0]
171 * 1.6.0 16 10600 16.so.16.0[.0]
172 * 1.6.1beta01-09 16 10601 16.so.16.1[.0]
173 * 1.6.1rc01 16 10601 16.so.16.1[.0]
174 * 1.6.1 16 10601 16.so.16.1[.0]
175 * 1.6.2beta01 16 10602 16.so.16.2[.0]
176 * 1.6.2rc01-06 16 10602 16.so.16.2[.0]
177 * 1.6.2 16 10602 16.so.16.2[.0]
178 * 1.6.3beta01-11 16 10603 16.so.16.3[.0]
179 * 1.6.3rc01 16 10603 16.so.16.3[.0]
180 * 1.6.3 16 10603 16.so.16.3[.0]
181 * 1.6.4beta01-02 16 10604 16.so.16.4[.0]
182 * 1.6.4rc01 16 10604 16.so.16.4[.0]
183 * 1.6.4 16 10604 16.so.16.4[.0]
184 * 1.6.5 16 10605 16.so.16.5[.0]
185 * 1.6.6 16 10606 16.so.16.6[.0]
186 * 1.6.7beta01-04 16 10607 16.so.16.7[.0]
187 * 1.6.7rc01-03 16 10607 16.so.16.7[.0]
188 * 1.6.7 16 10607 16.so.16.7[.0]
189 * 1.6.8beta01-02 16 10608 16.so.16.8[.0]
190 * 1.6.8rc01-02 16 10608 16.so.16.8[.0]
191 * 1.6.8 16 10608 16.so.16.8[.0]
192 * 1.6.9beta01-04 16 10609 16.so.16.9[.0]
193 * 1.6.9rc01-02 16 10609 16.so.16.9[.0]
194 * 1.6.9 16 10609 16.so.16.9[.0]
195 * 1.6.10beta01-03 16 10610 16.so.16.10[.0]
196 * 1.6.10rc01-03 16 10610 16.so.16.10[.0]
197 * 1.6.10 16 10610 16.so.16.10[.0]
198 * 1.6.11beta01-06 16 10611 16.so.16.11[.0]
199 * 1.6.11rc01-02 16 10611 16.so.16.11[.0]
200 * 1.6.11 16 10611 16.so.16.11[.0]
201 * 1.6.12rc01-03 16 10612 16.so.16.12[.0]
202 * 1.6.12 16 10612 16.so.16.12[.0]
203 * 1.6.13beta01-04 16 10613 16.so.16.13[.0]
204 * 1.6.13rc01-02 16 10613 16.so.16.13[.0]
205 * 1.6.13 16 10613 16.so.16.13[.0]
207 * Henceforth the source version will match the shared-library major
208 * and minor numbers; the shared-library major version number will be
209 * used for changes in backward compatibility, as it is intended. The
210 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
211 * for applications, is an unsigned integer of the form xyyzz corresponding
212 * to the source version x.y.z (leading zeros in y and z). Beta versions
213 * were given the previous public release number plus a letter, until
214 * version 1.0.6j; from then on they were given the upcoming public
215 * release number plus "betaNN" or "rcNN".
217 * Binary incompatibility exists only when applications make direct access
218 * to the info_ptr or png_ptr members through png.h, and the compiled
219 * application is loaded with a different version of the library.
221 * DLLNUM will change each time there are forward or backward changes
222 * in binary compatibility (e.g., when a new feature is added).
224 * See libpng-manual.txt or libpng.3 for more information. The PNG
225 * specification is available as a W3C Recommendation and as an ISO
226 * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
230 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
232 * If you modify libpng you may insert additional notices immediately following
235 * This code is released under the libpng license.
237 * libpng versions 1.2.6, August 15, 2004, through 1.6.13, August 21, 2014, are
238 * Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
239 * distributed according to the same disclaimer and license as libpng-1.2.5
240 * with the following individual added to the list of Contributing Authors:
244 * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
245 * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
246 * distributed according to the same disclaimer and license as libpng-1.0.6
247 * with the following individuals added to the list of Contributing Authors:
249 * Simon-Pierre Cadieux
253 * and with the following additions to the disclaimer:
255 * There is no warranty against interference with your enjoyment of the
256 * library or against infringement. There is no warranty that our
257 * efforts or the library will fulfill any of your particular purposes
258 * or needs. This library is provided with all faults, and the entire
259 * risk of satisfactory quality, performance, accuracy, and effort is with
262 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
263 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
264 * distributed according to the same disclaimer and license as libpng-0.96,
265 * with the following individuals added to the list of Contributing Authors:
268 * Glenn Randers-Pehrson
271 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
272 * Copyright (c) 1996, 1997 Andreas Dilger
273 * Distributed according to the same disclaimer and license as libpng-0.88,
274 * with the following individuals added to the list of Contributing Authors:
283 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
284 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
286 * For the purposes of this copyright and license, "Contributing Authors"
287 * is defined as the following set of individuals:
295 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
296 * and Group 42, Inc. disclaim all warranties, expressed or implied,
297 * including, without limitation, the warranties of merchantability and of
298 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
299 * assume no liability for direct, indirect, incidental, special, exemplary,
300 * or consequential damages, which may result from the use of the PNG
301 * Reference Library, even if advised of the possibility of such damage.
303 * Permission is hereby granted to use, copy, modify, and distribute this
304 * source code, or portions hereof, for any purpose, without fee, subject
305 * to the following restrictions:
307 * 1. The origin of this source code must not be misrepresented.
309 * 2. Altered versions must be plainly marked as such and must not
310 * be misrepresented as being the original source.
312 * 3. This Copyright notice may not be removed or altered from
313 * any source or altered source distribution.
315 * The Contributing Authors and Group 42, Inc. specifically permit, without
316 * fee, and encourage the use of this source code as a component to
317 * supporting the PNG file format in commercial products. If you use this
318 * source code in a product, acknowledgment is not required but would be
323 * A "png_get_copyright" function is available, for convenient use in "about"
324 * boxes and the like:
326 * printf("%s", png_get_copyright(NULL));
328 * Also, the PNG logo (in PNG format, of course) is supplied in the
329 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
333 * Libpng is OSI Certified Open Source Software. OSI Certified is a
334 * certification mark of the Open Source Initiative.
338 * The contributing authors would like to thank all those who helped
339 * with testing, bug fixes, and patience. This wouldn't have been
340 * possible without all of you.
342 * Thanks to Frank J. T. Wojcik for helping with the documentation.
346 * Y2K compliance in libpng:
347 * =========================
351 * Since the PNG Development group is an ad-hoc body, we can't make
352 * an official declaration.
354 * This is your unofficial assurance that libpng from version 0.71 and
355 * upward through 1.6.13 are Y2K compliant. It is my belief that
356 * earlier versions were also Y2K compliant.
358 * Libpng only has two year fields. One is a 2-byte unsigned integer
359 * that will hold years up to 65535. The other, which is deprecated,
360 * holds the date in text format, and will hold years up to 9999.
363 * "png_uint_16 year" in png_time_struct.
366 * "char time_buffer[29]" in png_struct. This is no longer used
367 * in libpng-1.6.x and will be removed from libpng-1.7.0.
369 * There are seven time-related functions:
370 * png.c: png_convert_to_rfc_1123_buffer() in png.c
371 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
372 * png_convert_to_rfc_1152() in error prior to libpng-0.98)
373 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
374 * png_convert_from_time_t() in pngwrite.c
375 * png_get_tIME() in pngget.c
376 * png_handle_tIME() in pngrutil.c, called in pngread.c
377 * png_set_tIME() in pngset.c
378 * png_write_tIME() in pngwutil.c, called in pngwrite.c
380 * All handle dates properly in a Y2K environment. The
381 * png_convert_from_time_t() function calls gmtime() to convert from system
382 * clock time, which returns (year - 1900), which we properly convert to
383 * the full 4-digit year. There is a possibility that libpng applications
384 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
385 * function, or that they are incorrectly passing only a 2-digit year
386 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
387 * but this is not under our control. The libpng documentation has always
388 * stated that it works with 4-digit years, and the APIs have been
389 * documented as such.
391 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
392 * integer to hold the year, and can hold years as large as 65535.
394 * zlib, upon which libpng depends, is also Y2K compliant. It contains
395 * no date-related code.
397 * Glenn Randers-Pehrson
399 * PNG Development Group
405 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
406 * describes how to use libpng, and the file example.c summarizes it
407 * with some code on which to build. This file is useful for looking
408 * at the actual function definitions and structure components. If that
409 * file has been stripped from your copy of libpng, you can find it at
410 * <http://www.libpng.org/pub/png/libpng-manual.txt>
412 * If you just need to read a PNG file and don't want to read the documentation
413 * skip to the end of this file and read the section entitled 'simplified API'.
416 /* Version information for png.h - this should match the version in png.c */
417 #define PNG_LIBPNG_VER_STRING "1.6.13"
418 #define PNG_HEADER_VERSION_STRING \
419 " libpng version 1.6.13 - August 21, 2014\n"
421 #define PNG_LIBPNG_VER_SONUM 16
422 #define PNG_LIBPNG_VER_DLLNUM 16
424 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
425 #define PNG_LIBPNG_VER_MAJOR 1
426 #define PNG_LIBPNG_VER_MINOR 6
427 #define PNG_LIBPNG_VER_RELEASE 13
429 /* This should match the numeric part of the final component of
430 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
433 #define PNG_LIBPNG_VER_BUILD 0
436 #define PNG_LIBPNG_BUILD_ALPHA 1
437 #define PNG_LIBPNG_BUILD_BETA 2
438 #define PNG_LIBPNG_BUILD_RC 3
439 #define PNG_LIBPNG_BUILD_STABLE 4
440 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
442 /* Release-Specific Flags */
443 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
444 PNG_LIBPNG_BUILD_STABLE only */
445 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
446 PNG_LIBPNG_BUILD_SPECIAL */
447 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
448 PNG_LIBPNG_BUILD_PRIVATE */
450 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
452 /* Careful here. At one time, Guy wanted to use 082, but that would be octal.
453 * We must not include leading zeros.
454 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
455 * version 1.0.0 was mis-numbered 100 instead of 10000). From
456 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
458 #define PNG_LIBPNG_VER 10613 /* 1.6.13 */
460 /* Library configuration: these options cannot be changed after
461 * the library has been built.
464 /* If pnglibconf.h is missing, you can
465 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
467 # include "pnglibconf.h"
470 #ifndef PNG_VERSION_INFO_ONLY
471 /* Machine specific configuration. */
472 # include "pngconf.h"
476 * Added at libpng-1.2.8
478 * Ref MSDN: Private as priority over Special
479 * VS_FF_PRIVATEBUILD File *was not* built using standard release
480 * procedures. If this value is given, the StringFileInfo block must
481 * contain a PrivateBuild string.
483 * VS_FF_SPECIALBUILD File *was* built by the original company using
484 * standard release procedures but is a variation of the standard
485 * file of the same version number. If this value is given, the
486 * StringFileInfo block must contain a SpecialBuild string.
489 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
490 # define PNG_LIBPNG_BUILD_TYPE \
491 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
493 # ifdef PNG_LIBPNG_SPECIALBUILD
494 # define PNG_LIBPNG_BUILD_TYPE \
495 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
497 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
501 #ifndef PNG_VERSION_INFO_ONLY
503 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
506 #endif /* __cplusplus */
508 /* Version information for C files, stored in png.c. This had better match
511 #define png_libpng_ver png_get_header_ver(NULL)
513 /* This file is arranged in several sections:
515 * 1. Any configuration options that can be specified by for the application
516 * code when it is built. (Build time configuration is in pnglibconf.h)
517 * 2. Type definitions (base types are defined in pngconf.h), structure
519 * 3. Exported library functions.
522 * The library source code has additional files (principally pngpriv.h) that
523 * allow configuration of the library.
525 /* Section 1: run time configuration
526 * See pnglibconf.h for build time configuration
528 * Run time configuration allows the application to choose between
529 * implementations of certain arithmetic APIs. The default is set
530 * at build time and recorded in pnglibconf.h, but it is safe to
531 * override these (and only these) settings. Note that this won't
532 * change what the library does, only application code, and the
533 * settings can (and probably should) be made on a per-file basis
534 * by setting the #defines before including png.h
536 * Use macros to read integers from PNG data or use the exported
538 * PNG_USE_READ_MACROS: use the macros (see below) Note that
539 * the macros evaluate their argument multiple times.
540 * PNG_NO_USE_READ_MACROS: call the relevant library function.
542 * Use the alternative algorithm for compositing alpha samples that
543 * does not use division?
544 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
546 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
548 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
550 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
551 * APIs to png_warning.
552 * Otherwise the calls are mapped to png_error.
555 /* Section 2: type definitions, including structures and compile time
557 * See pngconf.h for base types that vary by machine/system
560 /* This triggers a compiler error in png.c, if png.c and png.h
561 * do not agree upon the version number.
563 typedef char* png_libpng_version_1_6_13;
565 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
567 * png_struct is the cache of information used while reading or writing a single
568 * PNG file. One of these is always required, although the simplified API
569 * (below) hides the creation and destruction of it.
571 typedef struct png_struct_def png_struct;
572 typedef const png_struct * png_const_structp;
573 typedef png_struct * png_structp;
574 typedef png_struct * * png_structpp;
576 /* png_info contains information read from or to be written to a PNG file. One
577 * or more of these must exist while reading or creating a PNG file. The
578 * information is not used by libpng during read but is used to control what
579 * gets written when a PNG file is created. "png_get_" function calls read
580 * information during read and "png_set_" functions calls write information
581 * when creating a PNG.
582 * been moved into a separate header file that is not accessible to
583 * applications. Read libpng-manual.txt or libpng.3 for more info.
585 typedef struct png_info_def png_info;
586 typedef png_info * png_infop;
587 typedef const png_info * png_const_infop;
588 typedef png_info * * png_infopp;
590 /* Types with names ending 'p' are pointer types. The corresponding types with
591 * names ending 'rp' are identical pointer types except that the pointer is
592 * marked 'restrict', which means that it is the only pointer to the object
593 * passed to the function. Applications should not use the 'restrict' types;
594 * it is always valid to pass 'p' to a pointer with a function argument of the
595 * corresponding 'rp' type. Different compilers have different rules with
596 * regard to type matching in the presence of 'restrict'. For backward
597 * compatibility libpng callbacks never have 'restrict' in their parameters and,
598 * consequentially, writing portable application code is extremely difficult if
599 * an attempt is made to use 'restrict'.
601 typedef png_struct * PNG_RESTRICT png_structrp;
602 typedef const png_struct * PNG_RESTRICT png_const_structrp;
603 typedef png_info * PNG_RESTRICT png_inforp;
604 typedef const png_info * PNG_RESTRICT png_const_inforp;
606 /* Three color definitions. The order of the red, green, and blue, (and the
607 * exact size) is not important, although the size of the fields need to
608 * be png_byte or png_uint_16 (as defined below).
610 typedef struct png_color_struct
616 typedef png_color * png_colorp;
617 typedef const png_color * png_const_colorp;
618 typedef png_color * * png_colorpp;
620 typedef struct png_color_16_struct
622 png_byte index; /* used for palette files */
623 png_uint_16 red; /* for use in red green blue files */
626 png_uint_16 gray; /* for use in grayscale files */
628 typedef png_color_16 * png_color_16p;
629 typedef const png_color_16 * png_const_color_16p;
630 typedef png_color_16 * * png_color_16pp;
632 typedef struct png_color_8_struct
634 png_byte red; /* for use in red green blue files */
637 png_byte gray; /* for use in grayscale files */
638 png_byte alpha; /* for alpha channel files */
640 typedef png_color_8 * png_color_8p;
641 typedef const png_color_8 * png_const_color_8p;
642 typedef png_color_8 * * png_color_8pp;
645 * The following two structures are used for the in-core representation
648 typedef struct png_sPLT_entry_struct
654 png_uint_16 frequency;
656 typedef png_sPLT_entry * png_sPLT_entryp;
657 typedef const png_sPLT_entry * png_const_sPLT_entryp;
658 typedef png_sPLT_entry * * png_sPLT_entrypp;
660 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples
661 * occupy the LSB of their respective members, and the MSB of each member
662 * is zero-filled. The frequency member always occupies the full 16 bits.
665 typedef struct png_sPLT_struct
667 png_charp name; /* palette name */
668 png_byte depth; /* depth of palette samples */
669 png_sPLT_entryp entries; /* palette entries */
670 png_int_32 nentries; /* number of palette entries */
672 typedef png_sPLT_t * png_sPLT_tp;
673 typedef const png_sPLT_t * png_const_sPLT_tp;
674 typedef png_sPLT_t * * png_sPLT_tpp;
676 #ifdef PNG_TEXT_SUPPORTED
677 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
678 * and whether that contents is compressed or not. The "key" field
679 * points to a regular zero-terminated C string. The "text" fields can be a
680 * regular C string, an empty string, or a NULL pointer.
681 * However, the structure returned by png_get_text() will always contain
682 * the "text" field as a regular zero-terminated C string (possibly
683 * empty), never a NULL pointer, so it can be safely used in printf() and
684 * other string-handling functions. Note that the "itxt_length", "lang", and
685 * "lang_key" members of the structure only exist when the library is built
686 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
687 * default without iTXt support. Also note that when iTXt *is* supported,
688 * the "lang" and "lang_key" fields contain NULL pointers when the
689 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
690 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
691 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
692 * which is always 0 or 1, or its "compression method" which is always 0.
694 typedef struct png_text_struct
696 int compression; /* compression value:
701 png_charp key; /* keyword, 1-79 character description of "text" */
702 png_charp text; /* comment, may be an empty string (ie "")
704 png_size_t text_length; /* length of the text string */
705 png_size_t itxt_length; /* length of the itxt string */
706 png_charp lang; /* language code, 0-79 characters
708 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
709 chars or a NULL pointer */
711 typedef png_text * png_textp;
712 typedef const png_text * png_const_textp;
713 typedef png_text * * png_textpp;
716 /* Supported compression types for text in PNG files (tEXt, and zTXt).
717 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
718 #define PNG_TEXT_COMPRESSION_NONE_WR -3
719 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
720 #define PNG_TEXT_COMPRESSION_NONE -1
721 #define PNG_TEXT_COMPRESSION_zTXt 0
722 #define PNG_ITXT_COMPRESSION_NONE 1
723 #define PNG_ITXT_COMPRESSION_zTXt 2
724 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
726 /* png_time is a way to hold the time in an machine independent way.
727 * Two conversions are provided, both from time_t and struct tm. There
728 * is no portable way to convert to either of these structures, as far
729 * as I know. If you know of a portable way, send it to me. As a side
730 * note - PNG has always been Year 2000 compliant!
732 typedef struct png_time_struct
734 png_uint_16 year; /* full year, as in, 1995 */
735 png_byte month; /* month of year, 1 - 12 */
736 png_byte day; /* day of month, 1 - 31 */
737 png_byte hour; /* hour of day, 0 - 23 */
738 png_byte minute; /* minute of hour, 0 - 59 */
739 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
741 typedef png_time * png_timep;
742 typedef const png_time * png_const_timep;
743 typedef png_time * * png_timepp;
745 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
746 defined(PNG_USER_CHUNKS_SUPPORTED)
747 /* png_unknown_chunk is a structure to hold queued chunks for which there is
748 * no specific support. The idea is that we can use this to queue
749 * up private chunks for output even though the library doesn't actually
750 * know about their semantics.
752 * The data in the structure is set by libpng on read and used on write.
754 typedef struct png_unknown_chunk_t
756 png_byte name[5]; /* Textual chunk name with '\0' terminator */
757 png_byte *data; /* Data, should not be modified on read! */
760 /* On write 'location' must be set using the flag values listed below.
761 * Notice that on read it is set by libpng however the values stored have
762 * more bits set than are listed below. Always treat the value as a
763 * bitmask. On write set only one bit - setting multiple bits may cause the
764 * chunk to be written in multiple places.
766 png_byte location; /* mode of operation at read time */
770 typedef png_unknown_chunk * png_unknown_chunkp;
771 typedef const png_unknown_chunk * png_const_unknown_chunkp;
772 typedef png_unknown_chunk * * png_unknown_chunkpp;
775 /* Flag values for the unknown chunk location byte. */
776 #define PNG_HAVE_IHDR 0x01
777 #define PNG_HAVE_PLTE 0x02
778 #define PNG_AFTER_IDAT 0x08
780 /* Maximum positive integer used in PNG is (2^31)-1 */
781 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
782 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
783 #define PNG_SIZE_MAX ((png_size_t)(-1))
785 /* These are constants for fixed point values encoded in the
786 * PNG specification manner (x100000)
788 #define PNG_FP_1 100000
789 #define PNG_FP_HALF 50000
790 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
791 #define PNG_FP_MIN (-PNG_FP_MAX)
793 /* These describe the color_type field in png_info. */
794 /* color type masks */
795 #define PNG_COLOR_MASK_PALETTE 1
796 #define PNG_COLOR_MASK_COLOR 2
797 #define PNG_COLOR_MASK_ALPHA 4
799 /* color types. Note that not all combinations are legal */
800 #define PNG_COLOR_TYPE_GRAY 0
801 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
802 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
803 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
804 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
806 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
807 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
809 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
810 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
811 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
813 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
814 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
815 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
816 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
818 /* These are for the interlacing type. These values should NOT be changed. */
819 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
820 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
821 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
823 /* These are for the oFFs chunk. These values should NOT be changed. */
824 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
825 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
826 #define PNG_OFFSET_LAST 2 /* Not a valid value */
828 /* These are for the pCAL chunk. These values should NOT be changed. */
829 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
830 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
831 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
832 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
833 #define PNG_EQUATION_LAST 4 /* Not a valid value */
835 /* These are for the sCAL chunk. These values should NOT be changed. */
836 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
837 #define PNG_SCALE_METER 1 /* meters per pixel */
838 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
839 #define PNG_SCALE_LAST 3 /* Not a valid value */
841 /* These are for the pHYs chunk. These values should NOT be changed. */
842 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
843 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
844 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
846 /* These are for the sRGB chunk. These values should NOT be changed. */
847 #define PNG_sRGB_INTENT_PERCEPTUAL 0
848 #define PNG_sRGB_INTENT_RELATIVE 1
849 #define PNG_sRGB_INTENT_SATURATION 2
850 #define PNG_sRGB_INTENT_ABSOLUTE 3
851 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
853 /* This is for text chunks */
854 #define PNG_KEYWORD_MAX_LENGTH 79
856 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
857 #define PNG_MAX_PALETTE_LENGTH 256
859 /* These determine if an ancillary chunk's data has been successfully read
860 * from the PNG header, or if the application has filled in the corresponding
861 * data in the info_struct to be written into the output file. The values
862 * of the PNG_INFO_<chunk> defines should NOT be changed.
864 #define PNG_INFO_gAMA 0x0001
865 #define PNG_INFO_sBIT 0x0002
866 #define PNG_INFO_cHRM 0x0004
867 #define PNG_INFO_PLTE 0x0008
868 #define PNG_INFO_tRNS 0x0010
869 #define PNG_INFO_bKGD 0x0020
870 #define PNG_INFO_hIST 0x0040
871 #define PNG_INFO_pHYs 0x0080
872 #define PNG_INFO_oFFs 0x0100
873 #define PNG_INFO_tIME 0x0200
874 #define PNG_INFO_pCAL 0x0400
875 #define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
876 #define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
877 #define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
878 #define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
879 #define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */
881 /* This is used for the transformation routines, as some of them
882 * change these values for the row. It also should enable using
883 * the routines for other purposes.
885 typedef struct png_row_info_struct
887 png_uint_32 width; /* width of row */
888 png_size_t rowbytes; /* number of bytes in row */
889 png_byte color_type; /* color type of row */
890 png_byte bit_depth; /* bit depth of row */
891 png_byte channels; /* number of channels (1, 2, 3, or 4) */
892 png_byte pixel_depth; /* bits per pixel (depth * channels) */
895 typedef png_row_info * png_row_infop;
896 typedef png_row_info * * png_row_infopp;
898 /* These are the function types for the I/O functions and for the functions
899 * that allow the user to override the default I/O functions with his or her
900 * own. The png_error_ptr type should match that of user-supplied warning
901 * and error functions, while the png_rw_ptr type should match that of the
902 * user read/write data functions. Note that the 'write' function must not
903 * modify the buffer it is passed. The 'read' function, on the other hand, is
904 * expected to return the read data in the buffer.
906 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
907 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
908 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
909 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
911 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
914 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
915 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
916 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
918 /* The following callback receives png_uint_32 row_number, int pass for the
919 * png_bytep data of the row. When transforming an interlaced image the
920 * row number is the row number within the sub-image of the interlace pass, so
921 * the value will increase to the height of the sub-image (not the full image)
922 * then reset to 0 for the next pass.
924 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
925 * find the output pixel (x,y) given an interlaced sub-image pixel
926 * (row,col,pass). (See below for these macros.)
928 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
932 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
933 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
934 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
938 #ifdef PNG_USER_CHUNKS_SUPPORTED
939 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
940 png_unknown_chunkp));
942 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
943 /* not used anywhere */
944 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
947 #ifdef PNG_SETJMP_SUPPORTED
948 /* This must match the function definition in <setjmp.h>, and the application
949 * must include this before png.h to obtain the definition of jmp_buf. The
950 * function is required to be PNG_NORETURN, but this is not checked. If the
951 * function does return the application will crash via an abort() or similar
954 * If you get a warning here while building the library you may need to make
955 * changes to ensure that pnglibconf.h records the calling convention used by
956 * your compiler. This may be very difficult - try using a different compiler
957 * to build the library!
959 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
962 /* Transform masks for the high-level interface */
963 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
964 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
965 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
966 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
967 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
968 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
969 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
970 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
971 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
972 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
973 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
974 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
975 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
976 /* Added to libpng-1.2.34 */
977 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
978 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
979 /* Added to libpng-1.4.0 */
980 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
981 /* Added to libpng-1.5.4 */
982 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
983 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
985 /* Flags for MNG supported features */
986 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
987 #define PNG_FLAG_MNG_FILTER_64 0x04
988 #define PNG_ALL_MNG_FEATURES 0x05
990 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
991 * this allowed the zlib default functions to be used on Windows
992 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
993 * ignores the first argument) should be completely compatible with the
996 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
998 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
1000 /* Section 3: exported functions
1001 * Here are the function definitions most commonly used. This is not
1002 * the place to find out how to use libpng. See libpng-manual.txt for the
1003 * full explanation, see example.c for the summary. This just provides
1004 * a simple one line description of the use of each function.
1006 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
1007 * pngconf.h and in the *.dfn files in the scripts directory.
1009 * PNG_EXPORT(ordinal, type, name, (args));
1011 * ordinal: ordinal that is used while building
1012 * *.def files. The ordinal value is only
1013 * relevant when preprocessing png.h with
1014 * the *.dfn files for building symbol table
1015 * entries, and are removed by pngconf.h.
1016 * type: return type of the function
1017 * name: function name
1018 * args: function arguments, with types
1020 * When we wish to append attributes to a function prototype we use
1021 * the PNG_EXPORTA() macro instead.
1023 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
1025 * ordinal, type, name, and args: same as in PNG_EXPORT().
1026 * attributes: function attributes
1029 /* Returns the version number of the library */
1030 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
1032 /* Tell lib we have already handled the first <num_bytes> magic bytes.
1033 * Handling more than 8 bytes from the beginning of the file is an error.
1035 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
1037 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
1038 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
1039 * signature, and non-zero otherwise. Having num_to_check == 0 or
1040 * start > 7 will always fail (ie return non-zero).
1042 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
1043 png_size_t num_to_check));
1045 /* Simple signature checking function. This is the same as calling
1046 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
1048 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
1050 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
1051 PNG_EXPORTA(4, png_structp, png_create_read_struct,
1052 (png_const_charp user_png_ver, png_voidp error_ptr,
1053 png_error_ptr error_fn, png_error_ptr warn_fn),
1056 /* Allocate and initialize png_ptr struct for writing, and any other memory */
1057 PNG_EXPORTA(5, png_structp, png_create_write_struct,
1058 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1059 png_error_ptr warn_fn),
1062 PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
1063 (png_const_structrp png_ptr));
1065 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
1068 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
1071 #ifdef PNG_SETJMP_SUPPORTED
1072 /* This function returns the jmp_buf built in to *png_ptr. It must be
1073 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
1074 * unless the default error function is overridden in which case NULL is
1075 * acceptable. The size of the jmp_buf is checked against the actual size
1076 * allocated by the library - the call will return NULL on a mismatch
1077 * indicating an ABI mismatch.
1079 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
1080 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
1081 # define png_jmpbuf(png_ptr) \
1082 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
1084 # define png_jmpbuf(png_ptr) \
1085 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
1087 /* This function should be used by libpng applications in place of
1088 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
1089 * will use it; otherwise it will call PNG_ABORT(). This function was
1090 * added in libpng-1.5.0.
1092 PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
1095 #ifdef PNG_READ_SUPPORTED
1096 /* Reset the compression stream */
1097 PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
1100 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1101 #ifdef PNG_USER_MEM_SUPPORTED
1102 PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1103 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1104 png_error_ptr warn_fn,
1105 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1107 PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1108 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1109 png_error_ptr warn_fn,
1110 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1114 /* Write the PNG file signature. */
1115 PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
1117 /* Write a PNG chunk - size, type, (optional) data, CRC. */
1118 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
1119 chunk_name, png_const_bytep data, png_size_t length));
1121 /* Write the start of a PNG chunk - length and chunk name. */
1122 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1123 png_const_bytep chunk_name, png_uint_32 length));
1125 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1126 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1127 png_const_bytep data, png_size_t length));
1129 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1130 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1132 /* Allocate and initialize the info structure */
1133 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1136 /* DEPRECATED: this function allowed init structures to be created using the
1137 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1138 * the API will be removed in the future.
1140 PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1141 png_size_t png_info_struct_size), PNG_DEPRECATED);
1143 /* Writes all the PNG information before the image. */
1144 PNG_EXPORT(20, void, png_write_info_before_PLTE,
1145 (png_structrp png_ptr, png_const_inforp info_ptr));
1146 PNG_EXPORT(21, void, png_write_info,
1147 (png_structrp png_ptr, png_const_inforp info_ptr));
1149 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1150 /* Read the information before the actual image data. */
1151 PNG_EXPORT(22, void, png_read_info,
1152 (png_structrp png_ptr, png_inforp info_ptr));
1155 #ifdef PNG_TIME_RFC1123_SUPPORTED
1156 /* Convert to a US string format: there is no localization support in this
1157 * routine. The original implementation used a 29 character buffer in
1158 * png_struct, this will be removed in future versions.
1160 #if PNG_LIBPNG_VER < 10700
1161 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1162 PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1163 png_const_timep ptime),PNG_DEPRECATED);
1165 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1166 png_const_timep ptime));
1169 #ifdef PNG_CONVERT_tIME_SUPPORTED
1170 /* Convert from a struct tm to png_time */
1171 PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1172 const struct tm * ttime));
1174 /* Convert from time_t to png_time. Uses gmtime() */
1175 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1176 #endif /* PNG_CONVERT_tIME_SUPPORTED */
1178 #ifdef PNG_READ_EXPAND_SUPPORTED
1179 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1180 PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1181 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1182 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1183 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1186 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1187 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1188 * of a tRNS chunk if present.
1190 PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1193 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1194 /* Use blue, green, red order for pixels. */
1195 PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1198 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1199 /* Expand the grayscale to 24-bit RGB if necessary. */
1200 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1203 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1204 /* Reduce RGB to grayscale. */
1205 #define PNG_ERROR_ACTION_NONE 1
1206 #define PNG_ERROR_ACTION_WARN 2
1207 #define PNG_ERROR_ACTION_ERROR 3
1208 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1210 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1211 int error_action, double red, double green))
1212 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1213 int error_action, png_fixed_point red, png_fixed_point green))
1215 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1219 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1220 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1221 png_colorp palette));
1224 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1225 /* How the alpha channel is interpreted - this affects how the color channels
1226 * of a PNG file are returned to the calling application when an alpha channel,
1227 * or a tRNS chunk in a palette file, is present.
1229 * This has no effect on the way pixels are written into a PNG output
1230 * datastream. The color samples in a PNG datastream are never premultiplied
1231 * with the alpha samples.
1233 * The default is to return data according to the PNG specification: the alpha
1234 * channel is a linear measure of the contribution of the pixel to the
1235 * corresponding composited pixel, and the color channels are unassociated
1236 * (not premultiplied). The gamma encoded color channels must be scaled
1237 * according to the contribution and to do this it is necessary to undo
1238 * the encoding, scale the color values, perform the composition and reencode
1239 * the values. This is the 'PNG' mode.
1241 * The alternative is to 'associate' the alpha with the color information by
1242 * storing color channel values that have been scaled by the alpha.
1243 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1244 * (the latter being the two common names for associated alpha color channels).
1246 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1247 * value is equal to the maximum value.
1249 * The final choice is to gamma encode the alpha channel as well. This is
1250 * broken because, in practice, no implementation that uses this choice
1251 * correctly undoes the encoding before handling alpha composition. Use this
1252 * choice only if other serious errors in the software or hardware you use
1253 * mandate it; the typical serious error is for dark halos to appear around
1254 * opaque areas of the composited PNG image because of arithmetic overflow.
1256 * The API function png_set_alpha_mode specifies which of these choices to use
1257 * with an enumerated 'mode' value and the gamma of the required output:
1259 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1260 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1261 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1262 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1263 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1264 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1266 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1267 double output_gamma))
1268 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1269 int mode, png_fixed_point output_gamma))
1272 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1273 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1274 * how to decode the output values, not how they are encoded.
1276 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1277 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1278 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1279 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1282 /* The following are examples of calls to png_set_alpha_mode to achieve the
1283 * required overall gamma correction and, where necessary, alpha
1284 * premultiplication.
1286 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1287 * This is the default libpng handling of the alpha channel - it is not
1288 * pre-multiplied into the color components. In addition the call states
1289 * that the output is for a sRGB system and causes all PNG files without gAMA
1290 * chunks to be assumed to be encoded using sRGB.
1292 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1293 * In this case the output is assumed to be something like an sRGB conformant
1294 * display preceeded by a power-law lookup table of power 1.45. This is how
1295 * early Mac systems behaved.
1297 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1298 * This is the classic Jim Blinn approach and will work in academic
1299 * environments where everything is done by the book. It has the shortcoming
1300 * of assuming that input PNG data with no gamma information is linear - this
1301 * is unlikely to be correct unless the PNG files where generated locally.
1302 * Most of the time the output precision will be so low as to show
1303 * significant banding in dark areas of the image.
1305 * png_set_expand_16(pp);
1306 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1307 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1308 * are assumed to have the sRGB encoding if not marked with a gamma value and
1309 * the output is always 16 bits per component. This permits accurate scaling
1310 * and processing of the data. If you know that your input PNG files were
1311 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1312 * correct value for your system.
1314 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1315 * If you just need to composite the PNG image onto an existing background
1316 * and if you control the code that does this you can use the optimization
1317 * setting. In this case you just copy completely opaque pixels to the
1318 * output. For pixels that are not completely transparent (you just skip
1319 * those) you do the composition math using png_composite or png_composite_16
1320 * below then encode the resultant 8-bit or 16-bit values to match the output
1324 * If neither the PNG nor the standard linear encoding work for you because
1325 * of the software or hardware you use then you have a big problem. The PNG
1326 * case will probably result in halos around the image. The linear encoding
1327 * will probably result in a washed out, too bright, image (it's actually too
1328 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1329 * substantially reduce the halos. Alternatively try:
1331 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1332 * This option will also reduce the halos, but there will be slight dark
1333 * halos round the opaque parts of the image where the background is light.
1334 * In the OPTIMIZED mode the halos will be light halos where the background
1335 * is dark. Take your pick - the halos are unavoidable unless you can get
1336 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1339 * When the default gamma of PNG files doesn't match the output gamma.
1340 * If you have PNG files with no gamma information png_set_alpha_mode allows
1341 * you to provide a default gamma, but it also sets the ouput gamma to the
1342 * matching value. If you know your PNG files have a gamma that doesn't
1343 * match the output you can take advantage of the fact that
1344 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1345 * default if it is not already set:
1347 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1348 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1349 * The first call sets both the default and the output gamma values, the
1350 * second call overrides the output gamma without changing the default. This
1351 * is easier than achieving the same effect with png_set_gamma. You must use
1352 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1353 * fire if more than one call to png_set_alpha_mode and png_set_background is
1354 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1358 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1359 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1362 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1363 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1364 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1367 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1368 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1369 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1372 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1373 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
1374 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1376 /* The values of the PNG_FILLER_ defines should NOT be changed */
1377 # define PNG_FILLER_BEFORE 0
1378 # define PNG_FILLER_AFTER 1
1379 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
1380 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1381 png_uint_32 filler, int flags));
1382 #endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
1384 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1385 /* Swap bytes in 16-bit depth files. */
1386 PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1389 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1390 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1391 PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1394 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1395 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1396 /* Swap packing order of pixels in bytes. */
1397 PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1400 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1401 /* Converts files to legal bit depths. */
1402 PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1406 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1407 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1408 /* Have the code handle the interlacing. Returns the number of passes.
1409 * MUST be called before png_read_update_info or png_start_read_image,
1410 * otherwise it will not have the desired effect. Note that it is still
1411 * necessary to call png_read_row or png_read_rows png_get_image_height
1412 * times for each pass.
1414 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1417 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1418 /* Invert monochrome files */
1419 PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1422 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1423 /* Handle alpha and tRNS by replacing with a background color. Prior to
1424 * libpng-1.5.4 this API must not be called before the PNG file header has been
1425 * read. Doing so will result in unexpected behavior and possible warnings or
1426 * errors if the PNG file contains a bKGD chunk.
1428 PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1429 png_const_color_16p background_color, int background_gamma_code,
1430 int need_expand, double background_gamma))
1431 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1432 png_const_color_16p background_color, int background_gamma_code,
1433 int need_expand, png_fixed_point background_gamma))
1435 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1436 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1437 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1438 # define PNG_BACKGROUND_GAMMA_FILE 2
1439 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1442 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1443 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1444 PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1447 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1448 #define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
1449 /* Strip the second byte of information from a 16-bit depth file. */
1450 PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1453 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1454 /* Turn on quantizing, and reduce the palette to the number of colors
1457 PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1458 png_colorp palette, int num_palette, int maximum_colors,
1459 png_const_uint_16p histogram, int full_quantize));
1462 #ifdef PNG_READ_GAMMA_SUPPORTED
1463 /* The threshold on gamma processing is configurable but hard-wired into the
1464 * library. The following is the floating point variant.
1466 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1468 /* Handle gamma correction. Screen_gamma=(display_exponent).
1469 * NOTE: this API simply sets the screen and file gamma values. It will
1470 * therefore override the value for gamma in a PNG file if it is called after
1471 * the file header has been read - use with care - call before reading the PNG
1472 * file for best results!
1474 * These routines accept the same gamma values as png_set_alpha_mode (described
1475 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1476 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1477 * is the inverse of a 'screen gamma' value.
1479 PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1480 double screen_gamma, double override_file_gamma))
1481 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1482 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1485 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1486 /* Set how many lines between output flushes - 0 for no flushing */
1487 PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1488 /* Flush the current PNG output buffer */
1489 PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1492 /* Optional update palette with requested transformations */
1493 PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1495 /* Optional call to update the users info structure */
1496 PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1497 png_inforp info_ptr));
1499 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1500 /* Read one or more rows of image data. */
1501 PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1502 png_bytepp display_row, png_uint_32 num_rows));
1505 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1506 /* Read a row of data. */
1507 PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1508 png_bytep display_row));
1511 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1512 /* Read the whole image into memory at once. */
1513 PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1516 /* Write a row of image data */
1517 PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1518 png_const_bytep row));
1520 /* Write a few rows of image data: (*row) is not written; however, the type
1521 * is declared as writeable to maintain compatibility with previous versions
1522 * of libpng and to allow the 'display_row' array from read_rows to be passed
1523 * unchanged to write_rows.
1525 PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1526 png_uint_32 num_rows));
1528 /* Write the image data */
1529 PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1531 /* Write the end of the PNG file. */
1532 PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1533 png_inforp info_ptr));
1535 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1536 /* Read the end of the PNG file. */
1537 PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1540 /* Free any memory associated with the png_info_struct */
1541 PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1542 png_infopp info_ptr_ptr));
1544 /* Free any memory associated with the png_struct and the png_info_structs */
1545 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1546 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1548 /* Free any memory associated with the png_struct and the png_info_structs */
1549 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1550 png_infopp info_ptr_ptr));
1552 /* Set the libpng method of handling chunk CRC errors */
1553 PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1556 /* Values for png_set_crc_action() say how to handle CRC errors in
1557 * ancillary and critical chunks, and whether to use the data contained
1558 * therein. Note that it is impossible to "discard" data in a critical
1559 * chunk. For versions prior to 0.90, the action was always error/quit,
1560 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1561 * chunks is warn/discard. These values should NOT be changed.
1563 * value action:critical action:ancillary
1565 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1566 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1567 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1568 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1569 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1570 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1572 /* These functions give the user control over the scan-line filtering in
1573 * libpng and the compression methods used by zlib. These functions are
1574 * mainly useful for testing, as the defaults should work with most users.
1575 * Those users who are tight on memory or want faster performance at the
1576 * expense of compression can modify them. See the compression library
1577 * header file (zlib.h) for an explination of the compression functions.
1580 /* Set the filtering method(s) used by libpng. Currently, the only valid
1581 * value for "method" is 0.
1583 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1586 /* Flags for png_set_filter() to say which filters to use. The flags
1587 * are chosen so that they don't conflict with real filter types
1588 * below, in case they are supplied instead of the #defined constants.
1589 * These values should NOT be changed.
1591 #define PNG_NO_FILTERS 0x00
1592 #define PNG_FILTER_NONE 0x08
1593 #define PNG_FILTER_SUB 0x10
1594 #define PNG_FILTER_UP 0x20
1595 #define PNG_FILTER_AVG 0x40
1596 #define PNG_FILTER_PAETH 0x80
1597 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
1598 PNG_FILTER_AVG | PNG_FILTER_PAETH)
1600 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1601 * These defines should NOT be changed.
1603 #define PNG_FILTER_VALUE_NONE 0
1604 #define PNG_FILTER_VALUE_SUB 1
1605 #define PNG_FILTER_VALUE_UP 2
1606 #define PNG_FILTER_VALUE_AVG 3
1607 #define PNG_FILTER_VALUE_PAETH 4
1608 #define PNG_FILTER_VALUE_LAST 5
1610 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
1611 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
1612 * defines, either the default (minimum-sum-of-absolute-differences), or
1613 * the experimental method (weighted-minimum-sum-of-absolute-differences).
1615 * Weights are factors >= 1.0, indicating how important it is to keep the
1616 * filter type consistent between rows. Larger numbers mean the current
1617 * filter is that many times as likely to be the same as the "num_weights"
1618 * previous filters. This is cumulative for each previous row with a weight.
1619 * There needs to be "num_weights" values in "filter_weights", or it can be
1620 * NULL if the weights aren't being specified. Weights have no influence on
1621 * the selection of the first row filter. Well chosen weights can (in theory)
1622 * improve the compression for a given image.
1624 * Costs are factors >= 1.0 indicating the relative decoding costs of a
1625 * filter type. Higher costs indicate more decoding expense, and are
1626 * therefore less likely to be selected over a filter with lower computational
1627 * costs. There needs to be a value in "filter_costs" for each valid filter
1628 * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
1629 * setting the costs. Costs try to improve the speed of decompression without
1630 * unduly increasing the compressed image size.
1632 * A negative weight or cost indicates the default value is to be used, and
1633 * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
1634 * The default values for both weights and costs are currently 1.0, but may
1635 * change if good general weighting/cost heuristics can be found. If both
1636 * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
1637 * to the UNWEIGHTED method, but with added encoding time/computation.
1639 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1640 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1641 png_const_doublep filter_costs))
1642 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1643 (png_structrp png_ptr, int heuristic_method, int num_weights,
1644 png_const_fixed_point_p filter_weights,
1645 png_const_fixed_point_p filter_costs))
1646 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1648 /* Heuristic used for row filter selection. These defines should NOT be
1651 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1652 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1653 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1654 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1656 #ifdef PNG_WRITE_SUPPORTED
1657 /* Set the library compression level. Currently, valid values range from
1658 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1659 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1660 * shown that zlib compression levels 3-6 usually perform as well as level 9
1661 * for PNG images, and do considerably fewer caclulations. In the future,
1662 * these values may not correspond directly to the zlib compression levels.
1664 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1667 PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1670 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1673 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1674 * smaller value of window_bits if it can do so safely.
1676 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1679 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1683 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1684 /* Also set zlib parameters for compressing non-IDAT chunks */
1685 PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1688 PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1691 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1694 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1695 * smaller value of window_bits if it can do so safely.
1697 PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1698 (png_structrp png_ptr, int window_bits));
1700 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1702 #endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
1704 /* These next functions are called for input/output, memory, and error
1705 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1706 * and call standard C I/O routines such as fread(), fwrite(), and
1707 * fprintf(). These functions can be made to use other I/O routines
1708 * at run time for those applications that need to handle I/O in a
1709 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1713 #ifdef PNG_STDIO_SUPPORTED
1714 /* Initialize the input/output for the PNG file to the default functions. */
1715 PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1718 /* Replace the (error and abort), and warning functions with user
1719 * supplied functions. If no messages are to be printed you must still
1720 * write and use replacement functions. The replacement error_fn should
1721 * still do a longjmp to the last setjmp location if you are using this
1722 * method of error handling. If error_fn or warning_fn is NULL, the
1723 * default function will be used.
1726 PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1727 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1729 /* Return the user pointer associated with the error functions */
1730 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1732 /* Replace the default data output functions with a user supplied one(s).
1733 * If buffered output is not used, then output_flush_fn can be set to NULL.
1734 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1735 * output_flush_fn will be ignored (and thus can be NULL).
1736 * It is probably a mistake to use NULL for output_flush_fn if
1737 * write_data_fn is not also NULL unless you have built libpng with
1738 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1739 * default flush function, which uses the standard *FILE structure, will
1742 PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1743 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1745 /* Replace the default data input function with a user supplied one. */
1746 PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1747 png_rw_ptr read_data_fn));
1749 /* Return the user pointer associated with the I/O functions */
1750 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1752 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1753 png_read_status_ptr read_row_fn));
1755 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1756 png_write_status_ptr write_row_fn));
1758 #ifdef PNG_USER_MEM_SUPPORTED
1759 /* Replace the default memory allocation functions with user supplied one(s). */
1760 PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1761 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1762 /* Return the user pointer associated with the memory functions */
1763 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1766 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1767 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1768 png_user_transform_ptr read_user_transform_fn));
1771 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1772 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1773 png_user_transform_ptr write_user_transform_fn));
1776 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1777 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1778 png_voidp user_transform_ptr, int user_transform_depth,
1779 int user_transform_channels));
1780 /* Return the user pointer associated with the user transform functions */
1781 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1782 (png_const_structrp png_ptr));
1785 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1786 /* Return information about the row currently being processed. Note that these
1787 * APIs do not fail but will return unexpected results if called outside a user
1788 * transform callback. Also note that when transforming an interlaced image the
1789 * row number is the row number within the sub-image of the interlace pass, so
1790 * the value will increase to the height of the sub-image (not the full image)
1791 * then reset to 0 for the next pass.
1793 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1794 * find the output pixel (x,y) given an interlaced sub-image pixel
1795 * (row,col,pass). (See below for these macros.)
1797 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1798 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1801 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1802 /* This callback is called only for *unknown* chunks. If
1803 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1804 * chunks to be treated as unknown, however in this case the callback must do
1805 * any processing required by the chunk (e.g. by calling the appropriate
1808 * There is no write support - on write, by default, all the chunks in the
1809 * 'unknown' list are written in the specified position.
1811 * The integer return from the callback function is interpreted thus:
1813 * negative: An error occured, png_chunk_error will be called.
1814 * zero: The chunk was not handled, the chunk will be saved. A critical
1815 * chunk will cause an error at this point unless it is to be saved.
1816 * positive: The chunk was handled, libpng will ignore/discard it.
1818 * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
1819 * how this behavior will change in libpng 1.7
1821 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1822 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1825 #ifdef PNG_USER_CHUNKS_SUPPORTED
1826 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1829 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1830 /* Sets the function callbacks for the push reader, and a pointer to a
1831 * user-defined structure available to the callback functions.
1833 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1834 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1835 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1837 /* Returns the user pointer associated with the push read functions */
1838 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1839 (png_const_structrp png_ptr));
1841 /* Function to be called when data becomes available */
1842 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1843 png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
1845 /* A function which may be called *only* within png_process_data to stop the
1846 * processing of any more data. The function returns the number of bytes
1847 * remaining, excluding any that libpng has cached internally. A subsequent
1848 * call to png_process_data must supply these bytes again. If the argument
1849 * 'save' is set to true the routine will first save all the pending data and
1850 * will always return 0.
1852 PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
1854 /* A function which may be called *only* outside (after) a call to
1855 * png_process_data. It returns the number of bytes of data to skip in the
1856 * input. Normally it will return 0, but if it returns a non-zero value the
1857 * application must skip than number of bytes of input data and pass the
1858 * following data to the next call to png_process_data.
1860 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1862 /* Function that combines rows. 'new_row' is a flag that should come from
1863 * the callback and be non-NULL if anything needs to be done; the library
1864 * stores its own version of the new data internally and ignores the passed
1867 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1868 png_bytep old_row, png_const_bytep new_row));
1869 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1871 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1872 png_alloc_size_t size), PNG_ALLOCATED);
1873 /* Added at libpng version 1.4.0 */
1874 PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1875 png_alloc_size_t size), PNG_ALLOCATED);
1877 /* Added at libpng version 1.2.4 */
1878 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1879 png_alloc_size_t size), PNG_ALLOCATED);
1881 /* Frees a pointer allocated by png_malloc() */
1882 PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1884 /* Free data that was allocated internally */
1885 PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1886 png_inforp info_ptr, png_uint_32 free_me, int num));
1888 /* Reassign responsibility for freeing existing data, whether allocated
1889 * by libpng or by the application; this works on the png_info structure passed
1890 * in, it does not change the state for other png_info structures.
1892 * It is unlikely that this function works correctly as of 1.6.0 and using it
1893 * may result either in memory leaks or double free of allocated data.
1895 PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1896 png_inforp info_ptr, int freer, png_uint_32 mask));
1898 /* Assignments for png_data_freer */
1899 #define PNG_DESTROY_WILL_FREE_DATA 1
1900 #define PNG_SET_WILL_FREE_DATA 1
1901 #define PNG_USER_WILL_FREE_DATA 2
1902 /* Flags for png_ptr->free_me and info_ptr->free_me */
1903 #define PNG_FREE_HIST 0x0008
1904 #define PNG_FREE_ICCP 0x0010
1905 #define PNG_FREE_SPLT 0x0020
1906 #define PNG_FREE_ROWS 0x0040
1907 #define PNG_FREE_PCAL 0x0080
1908 #define PNG_FREE_SCAL 0x0100
1909 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1910 # define PNG_FREE_UNKN 0x0200
1912 /* PNG_FREE_LIST 0x0400 removed in 1.6.0 because it is ignored */
1913 #define PNG_FREE_PLTE 0x1000
1914 #define PNG_FREE_TRNS 0x2000
1915 #define PNG_FREE_TEXT 0x4000
1916 #define PNG_FREE_ALL 0x7fff
1917 #define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1919 #ifdef PNG_USER_MEM_SUPPORTED
1920 PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1921 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1922 PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1923 png_voidp ptr), PNG_DEPRECATED);
1926 #ifdef PNG_ERROR_TEXT_SUPPORTED
1927 /* Fatal error in PNG image of libpng - can't continue */
1928 PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1929 png_const_charp error_message), PNG_NORETURN);
1931 /* The same, but the chunk name is prepended to the error string. */
1932 PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1933 png_const_charp error_message), PNG_NORETURN);
1936 /* Fatal error in PNG image of libpng - can't continue */
1937 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1938 # define png_error(s1,s2) png_err(s1)
1939 # define png_chunk_error(s1,s2) png_err(s1)
1942 #ifdef PNG_WARNINGS_SUPPORTED
1943 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1944 PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1945 png_const_charp warning_message));
1947 /* Non-fatal error in libpng, chunk name is prepended to message. */
1948 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1949 png_const_charp warning_message));
1951 # define png_warning(s1,s2) ((void)(s1))
1952 # define png_chunk_warning(s1,s2) ((void)(s1))
1955 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1956 /* Benign error in libpng. Can continue, but may have a problem.
1957 * User can choose whether to handle as a fatal error or as a warning. */
1958 PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1959 png_const_charp warning_message));
1961 #ifdef PNG_READ_SUPPORTED
1962 /* Same, chunk name is prepended to message (only during read) */
1963 PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1964 png_const_charp warning_message));
1967 PNG_EXPORT(109, void, png_set_benign_errors,
1968 (png_structrp png_ptr, int allowed));
1970 # ifdef PNG_ALLOW_BENIGN_ERRORS
1971 # define png_benign_error png_warning
1972 # define png_chunk_benign_error png_chunk_warning
1974 # define png_benign_error png_error
1975 # define png_chunk_benign_error png_chunk_error
1979 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
1980 * Similarly, the png_get_<chunk> calls are used to read values from the
1981 * png_info_struct, either storing the parameters in the passed variables, or
1982 * setting pointers into the png_info_struct where the data is stored. The
1983 * png_get_<chunk> functions return a non-zero value if the data was available
1984 * in info_ptr, or return zero and do not change any of the parameters if the
1985 * data was not available.
1987 * These functions should be used instead of directly accessing png_info
1988 * to avoid problems with future changes in the size and internal layout of
1991 /* Returns "flag" if chunk data is valid in info_ptr. */
1992 PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1993 png_const_inforp info_ptr, png_uint_32 flag));
1995 /* Returns number of bytes needed to hold a transformed row. */
1996 PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1997 png_const_inforp info_ptr));
1999 #ifdef PNG_INFO_IMAGE_SUPPORTED
2000 /* Returns row_pointers, which is an array of pointers to scanlines that was
2001 * returned from png_read_png().
2003 PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
2004 png_const_inforp info_ptr));
2006 /* Set row_pointers, which is an array of pointers to scanlines for use
2007 * by png_write_png().
2009 PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
2010 png_inforp info_ptr, png_bytepp row_pointers));
2013 /* Returns number of color channels in image. */
2014 PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
2015 png_const_inforp info_ptr));
2017 #ifdef PNG_EASY_ACCESS_SUPPORTED
2018 /* Returns image width in pixels. */
2019 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
2020 png_const_inforp info_ptr));
2022 /* Returns image height in pixels. */
2023 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
2024 png_const_inforp info_ptr));
2026 /* Returns image bit_depth. */
2027 PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
2028 png_const_inforp info_ptr));
2030 /* Returns image color_type. */
2031 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
2032 png_const_inforp info_ptr));
2034 /* Returns image filter_type. */
2035 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
2036 png_const_inforp info_ptr));
2038 /* Returns image interlace_type. */
2039 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
2040 png_const_inforp info_ptr));
2042 /* Returns image compression_type. */
2043 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
2044 png_const_inforp info_ptr));
2046 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
2047 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
2048 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2049 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
2050 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2051 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
2052 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2054 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
2055 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
2056 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2057 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
2058 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2060 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
2061 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
2062 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2063 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
2064 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2065 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
2066 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2067 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
2068 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2070 #endif /* PNG_EASY_ACCESS_SUPPORTED */
2072 #ifdef PNG_READ_SUPPORTED
2073 /* Returns pointer to signature string read from PNG header */
2074 PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
2075 png_const_inforp info_ptr));
2078 #ifdef PNG_bKGD_SUPPORTED
2079 PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
2080 png_inforp info_ptr, png_color_16p *background));
2083 #ifdef PNG_bKGD_SUPPORTED
2084 PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
2085 png_inforp info_ptr, png_const_color_16p background));
2088 #ifdef PNG_cHRM_SUPPORTED
2089 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
2090 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
2091 double *red_y, double *green_x, double *green_y, double *blue_x,
2093 PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
2094 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
2095 double *green_X, double *green_Y, double *green_Z, double *blue_X,
2096 double *blue_Y, double *blue_Z))
2097 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
2098 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2099 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
2100 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
2101 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
2102 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
2103 PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
2104 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2105 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
2106 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
2107 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
2108 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
2109 png_fixed_point *int_blue_Z))
2112 #ifdef PNG_cHRM_SUPPORTED
2113 PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
2114 png_inforp info_ptr,
2115 double white_x, double white_y, double red_x, double red_y, double green_x,
2116 double green_y, double blue_x, double blue_y))
2117 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
2118 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
2119 double green_X, double green_Y, double green_Z, double blue_X,
2120 double blue_Y, double blue_Z))
2121 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
2122 png_inforp info_ptr, png_fixed_point int_white_x,
2123 png_fixed_point int_white_y, png_fixed_point int_red_x,
2124 png_fixed_point int_red_y, png_fixed_point int_green_x,
2125 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2126 png_fixed_point int_blue_y))
2127 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
2128 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
2129 png_fixed_point int_red_Z, png_fixed_point int_green_X,
2130 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
2131 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
2132 png_fixed_point int_blue_Z))
2135 #ifdef PNG_gAMA_SUPPORTED
2136 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
2137 png_const_inforp info_ptr, double *file_gamma))
2138 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2139 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2140 png_fixed_point *int_file_gamma))
2143 #ifdef PNG_gAMA_SUPPORTED
2144 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2145 png_inforp info_ptr, double file_gamma))
2146 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2147 png_inforp info_ptr, png_fixed_point int_file_gamma))
2150 #ifdef PNG_hIST_SUPPORTED
2151 PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2152 png_inforp info_ptr, png_uint_16p *hist));
2155 #ifdef PNG_hIST_SUPPORTED
2156 PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2157 png_inforp info_ptr, png_const_uint_16p hist));
2160 PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2161 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2162 int *bit_depth, int *color_type, int *interlace_method,
2163 int *compression_method, int *filter_method));
2165 PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2166 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2167 int color_type, int interlace_method, int compression_method,
2168 int filter_method));
2170 #ifdef PNG_oFFs_SUPPORTED
2171 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2172 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2176 #ifdef PNG_oFFs_SUPPORTED
2177 PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2178 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2182 #ifdef PNG_pCAL_SUPPORTED
2183 PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2184 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2185 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2186 png_charpp *params));
2189 #ifdef PNG_pCAL_SUPPORTED
2190 PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2191 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2192 int type, int nparams, png_const_charp units, png_charpp params));
2195 #ifdef PNG_pHYs_SUPPORTED
2196 PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2197 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2201 #ifdef PNG_pHYs_SUPPORTED
2202 PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2203 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2206 PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2207 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2209 PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2210 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2212 #ifdef PNG_sBIT_SUPPORTED
2213 PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2214 png_inforp info_ptr, png_color_8p *sig_bit));
2217 #ifdef PNG_sBIT_SUPPORTED
2218 PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2219 png_inforp info_ptr, png_const_color_8p sig_bit));
2222 #ifdef PNG_sRGB_SUPPORTED
2223 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2224 png_const_inforp info_ptr, int *file_srgb_intent));
2227 #ifdef PNG_sRGB_SUPPORTED
2228 PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2229 png_inforp info_ptr, int srgb_intent));
2230 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2231 png_inforp info_ptr, int srgb_intent));
2234 #ifdef PNG_iCCP_SUPPORTED
2235 PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2236 png_inforp info_ptr, png_charpp name, int *compression_type,
2237 png_bytepp profile, png_uint_32 *proflen));
2240 #ifdef PNG_iCCP_SUPPORTED
2241 PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2242 png_inforp info_ptr, png_const_charp name, int compression_type,
2243 png_const_bytep profile, png_uint_32 proflen));
2246 #ifdef PNG_sPLT_SUPPORTED
2247 PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2248 png_inforp info_ptr, png_sPLT_tpp entries));
2251 #ifdef PNG_sPLT_SUPPORTED
2252 PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2253 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2256 #ifdef PNG_TEXT_SUPPORTED
2257 /* png_get_text also returns the number of text chunks in *num_text */
2258 PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2259 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2262 /* Note while png_set_text() will accept a structure whose text,
2263 * language, and translated keywords are NULL pointers, the structure
2264 * returned by png_get_text will always contain regular
2265 * zero-terminated C strings. They might be empty strings but
2266 * they will never be NULL pointers.
2269 #ifdef PNG_TEXT_SUPPORTED
2270 PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2271 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2274 #ifdef PNG_tIME_SUPPORTED
2275 PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2276 png_inforp info_ptr, png_timep *mod_time));
2279 #ifdef PNG_tIME_SUPPORTED
2280 PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2281 png_inforp info_ptr, png_const_timep mod_time));
2284 #ifdef PNG_tRNS_SUPPORTED
2285 PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2286 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2287 png_color_16p *trans_color));
2290 #ifdef PNG_tRNS_SUPPORTED
2291 PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2292 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2293 png_const_color_16p trans_color));
2296 #ifdef PNG_sCAL_SUPPORTED
2297 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2298 png_const_inforp info_ptr, int *unit, double *width, double *height))
2299 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2300 defined(PNG_FLOATING_POINT_SUPPORTED)
2301 /* NOTE: this API is currently implemented using floating point arithmetic,
2302 * consequently it can only be used on systems with floating point support.
2303 * In any case the range of values supported by png_fixed_point is small and it
2304 * is highly recommended that png_get_sCAL_s be used instead.
2306 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2307 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2308 png_fixed_point *width, png_fixed_point *height))
2310 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2311 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2312 png_charpp swidth, png_charpp sheight));
2314 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2315 png_inforp info_ptr, int unit, double width, double height))
2316 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2317 png_inforp info_ptr, int unit, png_fixed_point width,
2318 png_fixed_point height))
2319 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2320 png_inforp info_ptr, int unit,
2321 png_const_charp swidth, png_const_charp sheight));
2322 #endif /* PNG_sCAL_SUPPORTED */
2324 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2325 /* Provide the default handling for all unknown chunks or, optionally, for
2326 * specific unknown chunks.
2328 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2329 * ignored and the default was used, the per-chunk setting only had an effect on
2330 * write. If you wish to have chunk-specific handling on read in code that must
2331 * work on earlier versions you must use a user chunk callback to specify the
2332 * desired handling (keep or discard.)
2334 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2335 * parameter is interpreted as follows:
2338 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2339 * Known chunks: do normal libpng processing, do not keep the chunk (but
2340 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2341 * Unknown chunks: for a specific chunk use the global default, when used
2342 * as the default discard the chunk data.
2343 * PNG_HANDLE_CHUNK_NEVER:
2344 * Discard the chunk data.
2345 * PNG_HANDLE_CHUNK_IF_SAFE:
2346 * Keep the chunk data if the chunk is not critical else raise a chunk
2348 * PNG_HANDLE_CHUNK_ALWAYS:
2349 * Keep the chunk data.
2351 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2352 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2353 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2354 * it simply resets the behavior to the libpng default.
2356 * INTERACTION WTIH USER CHUNK CALLBACKS:
2357 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2358 * callback and the callback returns 0; the chunk is then always stored *unless*
2359 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2360 * the global default is *not* used in this case. (In effect the per-chunk
2361 * value is incremented to at least IF_SAFE.)
2363 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2364 * per-chunk defaults will be honored. If you want to preserve the current
2365 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2366 * as the default - if you don't do this libpng 1.6 will issue a warning.
2368 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2369 * earlier simply return '1' (handled).
2371 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2372 * If this is *not* set known chunks will always be handled by libpng and
2373 * will never be stored in the unknown chunk list. Known chunks listed to
2374 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2375 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2376 * by libpng, in addition critical chunks must either be processed by the
2377 * callback or saved.
2379 * The IHDR and IEND chunks must not be listed. Because this turns off the
2380 * default handling for chunks that would otherwise be recognized the
2381 * behavior of libpng transformations may well become incorrect!
2384 * When writing chunks the options only apply to the chunks specified by
2385 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2386 * required by png_set_ calls and will always write the core critical chunks
2387 * (as required for PLTE).
2389 * Each chunk in the png_set_unknown_chunks list is looked up in the
2390 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2391 * interpreted as follows:
2393 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2394 * Write safe-to-copy chunks and write other chunks if the global
2395 * default is set to _ALWAYS, otherwise don't write this chunk.
2396 * PNG_HANDLE_CHUNK_NEVER:
2397 * Do not write the chunk.
2398 * PNG_HANDLE_CHUNK_IF_SAFE:
2399 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2400 * PNG_HANDLE_CHUNK_ALWAYS:
2403 * Note that the default behavior is effectively the opposite of the read case -
2404 * in read unknown chunks are not stored by default, in write they are written
2405 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2406 * - on write the safe-to-copy bit is checked, on read the critical bit is
2407 * checked and on read if the chunk is critical an error will be raised.
2411 * If num_chunks is positive, then the "keep" parameter specifies the manner
2412 * for handling only those chunks appearing in the chunk_list array,
2413 * otherwise the chunk list array is ignored.
2415 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2416 * unknown chunks, as described above.
2418 * If num_chunks is negative, then the "keep" parameter specifies the manner
2419 * for handling all unknown chunks plus all chunks recognized by libpng
2420 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2421 * be processed by libpng.
2423 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2424 int keep, png_const_bytep chunk_list, int num_chunks));
2426 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2427 * the result is therefore true (non-zero) if special handling is required,
2428 * false for the default handling.
2430 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2431 png_const_bytep chunk_name));
2434 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2435 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2436 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2438 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2439 * unknowns to the location currently stored in the png_struct. This is
2440 * invariably the wrong value on write. To fix this call the following API
2441 * for each chunk in the list with the correct location. If you know your
2442 * code won't be compiled on earlier versions you can rely on
2443 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2444 * the correct thing.
2447 PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2448 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2450 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2451 png_inforp info_ptr, png_unknown_chunkpp entries));
2454 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2455 * If you need to turn it off for a chunk that your application has freed,
2456 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2458 PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2459 png_inforp info_ptr, int mask));
2461 #ifdef PNG_INFO_IMAGE_SUPPORTED
2462 /* The "params" pointer is currently not used and is for future expansion. */
2463 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2464 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2465 int transforms, png_voidp params));
2467 #ifdef PNG_WRITE_SUPPORTED
2468 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2469 int transforms, png_voidp params));
2473 PNG_EXPORT(180, png_const_charp, png_get_copyright,
2474 (png_const_structrp png_ptr));
2475 PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2476 (png_const_structrp png_ptr));
2477 PNG_EXPORT(182, png_const_charp, png_get_header_version,
2478 (png_const_structrp png_ptr));
2479 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2480 (png_const_structrp png_ptr));
2482 #ifdef PNG_MNG_FEATURES_SUPPORTED
2483 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2484 png_uint_32 mng_features_permitted));
2487 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2488 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2489 #define PNG_HANDLE_CHUNK_NEVER 1
2490 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2491 #define PNG_HANDLE_CHUNK_ALWAYS 3
2492 #define PNG_HANDLE_CHUNK_LAST 4
2494 /* Strip the prepended error numbers ("#nnn ") from error and warning
2495 * messages before passing them to the error or warning handler.
2497 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2498 PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2499 png_uint_32 strip_mode));
2502 /* Added in libpng-1.2.6 */
2503 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2504 PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2505 png_uint_32 user_width_max, png_uint_32 user_height_max));
2506 PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2507 (png_const_structrp png_ptr));
2508 PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2509 (png_const_structrp png_ptr));
2510 /* Added in libpng-1.4.0 */
2511 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2512 png_uint_32 user_chunk_cache_max));
2513 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2514 (png_const_structrp png_ptr));
2515 /* Added in libpng-1.4.1 */
2516 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2517 png_alloc_size_t user_chunk_cache_max));
2518 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2519 (png_const_structrp png_ptr));
2522 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2523 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2524 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2526 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2527 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2529 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2530 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2532 PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2533 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2534 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2535 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2536 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2539 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2540 png_const_inforp info_ptr))
2541 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2542 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2543 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2546 # ifdef PNG_pHYs_SUPPORTED
2547 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2548 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2550 # endif /* PNG_pHYs_SUPPORTED */
2551 #endif /* PNG_INCH_CONVERSIONS_SUPPORTED */
2553 /* Added in libpng-1.4.0 */
2554 #ifdef PNG_IO_STATE_SUPPORTED
2555 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2557 /* Removed from libpng 1.6; use png_get_io_chunk_type. */
2558 PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2561 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2562 (png_const_structrp png_ptr));
2564 /* The flags returned by png_get_io_state() are the following: */
2565 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2566 # define PNG_IO_READING 0x0001 /* currently reading */
2567 # define PNG_IO_WRITING 0x0002 /* currently writing */
2568 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2569 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2570 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2571 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2572 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2573 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2574 #endif /* ?PNG_IO_STATE_SUPPORTED */
2576 /* Interlace support. The following macros are always defined so that if
2577 * libpng interlace handling is turned off the macros may be used to handle
2578 * interlaced images within the application.
2580 #define PNG_INTERLACE_ADAM7_PASSES 7
2582 /* Two macros to return the first row and first column of the original,
2583 * full, image which appears in a given pass. 'pass' is in the range 0
2584 * to 6 and the result is in the range 0 to 7.
2586 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2587 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2589 /* A macro to return the offset between pixels in the output row for a pair of
2590 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2591 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2592 * COL_OFFSET is from one column to the next, within a row.
2594 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2595 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2597 /* Two macros to help evaluate the number of rows or columns in each
2598 * pass. This is expressed as a shift - effectively log2 of the number or
2599 * rows or columns in each 8x8 tile of the original image.
2601 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2602 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2604 /* Hence two macros to determine the number of rows or columns in a given
2605 * pass of an image given its height or width. In fact these macros may
2606 * return non-zero even though the sub-image is empty, because the other
2607 * dimension may be empty for a small image.
2609 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2610 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2611 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2612 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2614 /* For the reader row callbacks (both progressive and sequential) it is
2615 * necessary to find the row in the output image given a row in an interlaced
2616 * image, so two more macros:
2618 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2619 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2620 #define PNG_COL_FROM_PASS_COL(x_in, pass) \
2621 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2623 /* Two macros which return a boolean (0 or 1) saying whether the given row
2624 * or column is in a particular pass. These use a common utility macro that
2625 * returns a mask for a given pass - the offset 'off' selects the row or
2626 * column version. The mask has the appropriate bit set for each column in
2629 #define PNG_PASS_MASK(pass,off) ( \
2630 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2631 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2633 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2634 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2635 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2636 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2638 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2639 /* With these routines we avoid an integer divide, which will be slower on
2640 * most machines. However, it does take more operations than the corresponding
2641 * divide method, so it may be slower on a few RISC systems. There are two
2642 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2644 * Note that the rounding factors are NOT supposed to be the same! 128 and
2645 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2648 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2651 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2653 # define png_composite(composite, fg, alpha, bg) \
2654 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2655 * (png_uint_16)(alpha) \
2656 + (png_uint_16)(bg)*(png_uint_16)(255 \
2657 - (png_uint_16)(alpha)) + 128); \
2658 (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
2660 # define png_composite_16(composite, fg, alpha, bg) \
2661 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2662 * (png_uint_32)(alpha) \
2663 + (png_uint_32)(bg)*(65535 \
2664 - (png_uint_32)(alpha)) + 32768); \
2665 (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
2667 #else /* Standard method using integer division */
2669 # define png_composite(composite, fg, alpha, bg) \
2670 (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2671 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2674 # define png_composite_16(composite, fg, alpha, bg) \
2675 (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2676 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2678 #endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
2680 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2681 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2682 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2683 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2686 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2687 png_const_bytep buf));
2688 /* No png_get_int_16 -- may be added if there's a real need for it. */
2690 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2691 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2692 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2694 #ifdef PNG_SAVE_INT_32_SUPPORTED
2695 PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2698 /* Place a 16-bit number into a buffer in PNG byte order.
2699 * The parameter is declared unsigned int, not png_uint_16,
2700 * just to avoid potential problems on pre-ANSI C compilers.
2702 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2703 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2704 /* No png_save_int_16 -- may be added if there's a real need for it. */
2707 #ifdef PNG_USE_READ_MACROS
2708 /* Inline macros to do direct reads of bytes from the input buffer.
2709 * The png_get_int_32() routine assumes we are using two's complement
2710 * format for negative values, which is almost certainly true.
2712 # define PNG_get_uint_32(buf) \
2713 (((png_uint_32)(*(buf)) << 24) + \
2714 ((png_uint_32)(*((buf) + 1)) << 16) + \
2715 ((png_uint_32)(*((buf) + 2)) << 8) + \
2716 ((png_uint_32)(*((buf) + 3))))
2718 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2719 * function) incorrectly returned a value of type png_uint_32.
2721 # define PNG_get_uint_16(buf) \
2723 (((unsigned int)(*(buf)) << 8) + \
2724 ((unsigned int)(*((buf) + 1)))))
2726 # define PNG_get_int_32(buf) \
2727 ((png_int_32)((*(buf) & 0x80) \
2728 ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
2729 : (png_int_32)png_get_uint_32(buf)))
2731 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2732 * but defining a macro name prefixed with PNG_PREFIX.
2735 # define png_get_uint_32(buf) PNG_get_uint_32(buf)
2736 # define png_get_uint_16(buf) PNG_get_uint_16(buf)
2737 # define png_get_int_32(buf) PNG_get_int_32(buf)
2741 /* No macros; revert to the (redefined) function */
2742 # define PNG_get_uint_32 (png_get_uint_32)
2743 # define PNG_get_uint_16 (png_get_uint_16)
2744 # define PNG_get_int_32 (png_get_int_32)
2748 /*******************************************************************************
2750 *******************************************************************************
2752 * Please read the documentation in libpng-manual.txt (TODO: write said
2753 * documentation) if you don't understand what follows.
2755 * The simplified API hides the details of both libpng and the PNG file format
2756 * itself. It allows PNG files to be read into a very limited number of
2757 * in-memory bitmap formats or to be written from the same formats. If these
2758 * formats do not accomodate your needs then you can, and should, use the more
2759 * sophisticated APIs above - these support a wide variety of in-memory formats
2760 * and a wide variety of sophisticated transformations to those formats as well
2761 * as a wide variety of APIs to manipulate ancillary information.
2763 * To read a PNG file using the simplified API:
2765 * 1) Declare a 'png_image' structure (see below) on the stack and set the
2766 * version field to PNG_IMAGE_VERSION.
2767 * 2) Call the appropriate png_image_begin_read... function.
2768 * 3) Set the png_image 'format' member to the required sample format.
2769 * 4) Allocate a buffer for the image and, if required, the color-map.
2770 * 5) Call png_image_finish_read to read the image and, if required, the
2771 * color-map into your buffers.
2773 * There are no restrictions on the format of the PNG input itself; all valid
2774 * color types, bit depths, and interlace methods are acceptable, and the
2775 * input image is transformed as necessary to the requested in-memory format
2776 * during the png_image_finish_read() step. The only caveat is that if you
2777 * request a color-mapped image from a PNG that is full-color or makes
2778 * complex use of an alpha channel the transformation is extremely lossy and the
2779 * result may look terrible.
2781 * To write a PNG file using the simplified API:
2783 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2784 * 2) Initialize the members of the structure that describe the image, setting
2785 * the 'format' member to the format of the image samples.
2786 * 3) Call the appropriate png_image_write... function with a pointer to the
2787 * image and, if necessary, the color-map to write the PNG data.
2789 * png_image is a structure that describes the in-memory format of an image
2790 * when it is being read or defines the in-memory format of an image that you
2793 #define PNG_IMAGE_VERSION 1
2795 typedef struct png_control *png_controlp;
2798 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2799 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2800 png_uint_32 width; /* Image width in pixels (columns) */
2801 png_uint_32 height; /* Image height in pixels (rows) */
2802 png_uint_32 format; /* Image format as defined below */
2803 png_uint_32 flags; /* A bit mask containing informational flags */
2804 png_uint_32 colormap_entries;
2805 /* Number of entries in the color-map */
2807 /* In the event of an error or warning the following field will be set to a
2808 * non-zero value and the 'message' field will contain a '\0' terminated
2809 * string with the libpng error or warning message. If both warnings and
2810 * an error were encountered, only the error is recorded. If there
2811 * are multiple warnings, only the first one is recorded.
2813 * The upper 30 bits of this value are reserved, the low two bits contain
2814 * a value as follows:
2816 # define PNG_IMAGE_WARNING 1
2817 # define PNG_IMAGE_ERROR 2
2819 * The result is a two bit code such that a value more than 1 indicates
2820 * a failure in the API just called:
2822 * 0 - no warning or error
2825 * 3 - error preceded by warning
2827 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2829 png_uint_32 warning_or_error;
2832 } png_image, *png_imagep;
2834 /* The samples of the image have one to four channels whose components have
2835 * original values in the range 0 to 1.0:
2837 * 1: A single gray or luminance channel (G).
2838 * 2: A gray/luminance channel and an alpha channel (GA).
2839 * 3: Three red, green, blue color channels (RGB).
2840 * 4: Three color channels and an alpha channel (RGBA).
2842 * The components are encoded in one of two ways:
2844 * a) As a small integer, value 0..255, contained in a single byte. For the
2845 * alpha channel the original value is simply value/255. For the color or
2846 * luminance channels the value is encoded according to the sRGB specification
2847 * and matches the 8-bit format expected by typical display devices.
2849 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2850 * channel and are suitable for passing to color management software.
2852 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2853 * channels can be converted to the original value by dividing by 65535; all
2854 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2855 * the sRGB specification. This encoding is identified by the
2856 * PNG_FORMAT_FLAG_LINEAR flag below.
2858 * When the simplified API needs to convert between sRGB and linear colorspaces,
2859 * the actual sRGB transfer curve defined in the sRGB specification (see the
2860 * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2861 * approximation used elsewhere in libpng.
2863 * When an alpha channel is present it is expected to denote pixel coverage
2864 * of the color or luminance channels and is returned as an associated alpha
2865 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2868 * The samples are either contained directly in the image data, between 1 and 8
2869 * bytes per pixel according to the encoding, or are held in a color-map indexed
2870 * by bytes in the image data. In the case of a color-map the color-map entries
2871 * are individual samples, encoded as above, and the image data has one byte per
2872 * pixel to select the relevant sample from the color-map.
2877 * #defines to be used in png_image::format. Each #define identifies a
2878 * particular layout of sample data and, if present, alpha values. There are
2879 * separate defines for each of the two component encodings.
2881 * A format is built up using single bit flag values. All combinations are
2882 * valid. Formats can be built up from the flag values or you can use one of
2883 * the predefined values below. When testing formats always use the FORMAT_FLAG
2884 * macros to test for individual features - future versions of the library may
2887 * When reading or writing color-mapped images the format should be set to the
2888 * format of the entries in the color-map then png_image_{read,write}_colormap
2889 * called to read or write the color-map and set the format correctly for the
2890 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2892 * NOTE: libpng can be built with particular features disabled, if you see
2893 * compiler errors because the definition of one of the following flags has been
2894 * compiled out it is because libpng does not have the required support. It is
2895 * possible, however, for the libpng configuration to enable the format on just
2896 * read or just write; in that case you may see an error at run time. You can
2897 * guard against this by checking for the definition of the appropriate
2898 * "_SUPPORTED" macro, one of:
2900 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2902 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2903 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2904 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2 byte channels else 1 byte */
2905 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2907 #ifdef PNG_FORMAT_BGR_SUPPORTED
2908 # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2911 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
2912 # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2915 /* Commonly used formats have predefined macros.
2917 * First the single byte (sRGB) formats:
2919 #define PNG_FORMAT_GRAY 0
2920 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2921 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2922 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2923 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2924 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2925 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2926 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2927 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2929 /* Then the linear 2-byte formats. When naming these "Y" is used to
2930 * indicate a luminance (gray) channel.
2932 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2933 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2934 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2935 #define PNG_FORMAT_LINEAR_RGB_ALPHA \
2936 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2938 /* With color-mapped formats the image data is one byte for each pixel, the byte
2939 * is an index into the color-map which is formatted as above. To obtain a
2940 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2941 * to one of the above definitions, or you can use one of the definitions below.
2943 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2944 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2945 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2946 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2947 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2948 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2952 * These are convenience macros to derive information from a png_image
2953 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2954 * actual image sample values - either the entries in the color-map or the
2955 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2956 * for the pixels and will always return 1 for color-mapped formats. The
2957 * remaining macros return information about the rows in the image and the
2960 * NOTE: All the macros that take a png_image::format parameter are compile time
2961 * constants if the format parameter is, itself, a constant. Therefore these
2962 * macros can be used in array declarations and case labels where required.
2963 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2964 * they can be used in #if tests.
2966 * First the information about the samples.
2968 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2969 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2970 /* Return the total number of channels in a given format: 1..4 */
2972 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2973 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2974 /* Return the size in bytes of a single component of a pixel or color-map
2975 * entry (as appropriate) in the image: 1 or 2.
2978 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2979 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2980 /* This is the size of the sample data for one sample. If the image is
2981 * color-mapped it is the size of one color-map entry (and image pixels are
2982 * one byte in size), otherwise it is the size of one image pixel.
2985 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2986 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2987 /* The maximum size of the color-map required by the format expressed in a
2988 * count of components. This can be used to compile-time allocate a
2991 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2993 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2995 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2996 * information from one of the png_image_begin_read_ APIs and dynamically
2997 * allocate the required memory.
3000 /* Corresponding information about the pixels */
3001 #define PNG_IMAGE_PIXEL_(test,fmt)\
3002 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
3004 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
3005 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
3006 /* The number of separate channels (components) in a pixel; 1 for a
3007 * color-mapped image.
3010 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
3011 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
3012 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
3016 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
3017 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
3019 /* Information about the whole row, or whole image */
3020 #define PNG_IMAGE_ROW_STRIDE(image)\
3021 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
3022 /* Return the total number of components in a single row of the image; this
3023 * is the minimum 'row stride', the minimum count of components between each
3024 * row. For a color-mapped image this is the minimum number of bytes in a
3028 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
3029 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
3030 /* Return the size, in bytes, of an image buffer given a png_image and a row
3031 * stride - the number of components to leave space for in each row.
3034 #define PNG_IMAGE_SIZE(image)\
3035 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
3036 /* Return the size, in bytes, of the image in memory given just a png_image;
3037 * the row stride is the minimum stride required for the image.
3040 #define PNG_IMAGE_COLORMAP_SIZE(image)\
3041 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
3042 /* Return the size, in bytes, of the color-map of this image. If the image
3043 * format is not a color-map format this will return a size sufficient for
3044 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
3045 * you don't want to allocate a color-map in this case.
3050 * Flags containing additional information about the image are held in the
3051 * 'flags' field of png_image.
3053 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
3054 /* This indicates the the RGB values of the in-memory bitmap do not
3055 * correspond to the red, green and blue end-points defined by sRGB.
3058 #define PNG_IMAGE_FLAG_FAST 0x02
3059 /* On write emphasise speed over compression; the resultant PNG file will be
3060 * larger but will be produced significantly faster, particular for large
3061 * images. Do not use this option for images which will be distributed, only
3062 * used it when producing intermediate files that will be read back in
3063 * repeatedly. For a typical 24-bit image the option will double the read
3064 * speed at the cost of increasing the image size by 25%, however for many
3065 * more compressible images the PNG file can be 10 times larger with only a
3066 * slight speed gain.
3069 #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
3070 /* On read if the image is a 16-bit per component image and there is no gAMA
3071 * or sRGB chunk assume that the components are sRGB encoded. Notice that
3072 * images output by the simplified API always have gamma information; setting
3073 * this flag only affects the interpretation of 16-bit images from an
3074 * external source. It is recommended that the application expose this flag
3075 * to the user; the user can normally easily recognize the difference between
3076 * linear and sRGB encoding. This flag has no effect on write - the data
3077 * passed to the write APIs must have the correct encoding (as defined
3080 * If the flag is not set (the default) input 16-bit per component data is
3081 * assumed to be linear.
3083 * NOTE: the flag can only be set after the png_image_begin_read_ call,
3084 * because that call initializes the 'flags' field.
3087 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
3091 * The png_image passed to the read APIs must have been initialized by setting
3092 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
3094 #ifdef PNG_STDIO_SUPPORTED
3095 PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
3096 const char *file_name));
3097 /* The named file is opened for read and the image header is filled in
3098 * from the PNG header in the file.
3101 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
3103 /* The PNG header is read from the stdio FILE object. */
3104 #endif /* PNG_STDIO_SUPPORTED */
3106 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
3107 png_const_voidp memory, png_size_t size));
3108 /* The PNG header is read from the given memory buffer. */
3110 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
3111 png_const_colorp background, void *buffer, png_int_32 row_stride,
3113 /* Finish reading the image into the supplied buffer and clean up the
3114 * png_image structure.
3116 * row_stride is the step, in byte or 2-byte units as appropriate,
3117 * between adjacent rows. A positive stride indicates that the top-most row
3118 * is first in the buffer - the normal top-down arrangement. A negative
3119 * stride indicates that the bottom-most row is first in the buffer.
3121 * background need only be supplied if an alpha channel must be removed from
3122 * a png_byte format and the removal is to be done by compositing on a solid
3123 * color; otherwise it may be NULL and any composition will be done directly
3124 * onto the buffer. The value is an sRGB color to use for the background,
3125 * for grayscale output the green channel is used.
3127 * background must be supplied when an alpha channel must be removed from a
3128 * single byte color-mapped output format, in other words if:
3130 * 1) The original format from png_image_begin_read_from_* had
3131 * PNG_FORMAT_FLAG_ALPHA set.
3132 * 2) The format set by the application does not.
3133 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3134 * PNG_FORMAT_FLAG_LINEAR *not* set.
3136 * For linear output removing the alpha channel is always done by compositing
3137 * on black and background is ignored.
3139 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3140 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3141 * image->colormap_entries will be updated to the actual number of entries
3142 * written to the colormap; this may be less than the original value.
3145 PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3146 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3147 * NULL. May be called at any time after the structure is initialized.
3149 #endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
3151 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3152 #ifdef PNG_STDIO_SUPPORTED
3155 * For write you must initialize a png_image structure to describe the image to
3156 * be written. To do this use memset to set the whole structure to 0 then
3157 * initialize fields describing your image.
3159 * version: must be set to PNG_IMAGE_VERSION
3160 * opaque: must be initialized to NULL
3161 * width: image width in pixels
3162 * height: image height in rows
3163 * format: the format of the data (image and color-map) you wish to write
3164 * flags: set to 0 unless one of the defined flags applies; set
3165 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3166 * values do not correspond to the colors in sRGB.
3167 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3169 PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3170 const char *file, int convert_to_8bit, const void *buffer,
3171 png_int_32 row_stride, const void *colormap));
3172 /* Write the image to the named file. */
3174 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3175 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3176 const void *colormap));
3177 /* Write the image to the given (FILE*). */
3179 /* With both write APIs if image is in one of the linear formats with 16-bit
3180 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3181 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3182 * encoded PNG file is written.
3184 * With color-mapped data formats the colormap parameter point to a color-map
3185 * with at least image->colormap_entries encoded in the specified format. If
3186 * the format is linear the written PNG color-map will be converted to sRGB
3187 * regardless of the convert_to_8_bit flag.
3189 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3190 * from one row to the next in component sized units (1 or 2 bytes) and if
3191 * negative indicates a bottom-up row layout in the buffer.
3193 * Note that the write API does not support interlacing or sub-8-bit pixels.
3195 #endif /* PNG_STDIO_SUPPORTED */
3196 #endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
3197 /*******************************************************************************
3198 * END OF SIMPLIFIED API
3199 ******************************************************************************/
3201 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
3202 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
3203 (png_structrp png_ptr, int allowed));
3204 # ifdef PNG_GET_PALETTE_MAX_SUPPORTED
3205 PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
3206 png_const_infop info_ptr));
3208 #endif /* CHECK_FOR_INVALID_INDEX */
3210 /*******************************************************************************
3211 * IMPLEMENTATION OPTIONS
3212 *******************************************************************************
3214 * Support for arbitrary implementation-specific optimizations. The API allows
3215 * particular options to be turned on or off. 'Option' is the number of the
3216 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3217 * by the PNG_OPTION_ defines below.
3219 * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
3220 * are detected at run time, however sometimes it may be impossible
3221 * to do this in user mode, in which case it is necessary to discover
3222 * the capabilities in an OS specific way. Such capabilities are
3223 * listed here when libpng has support for them and must be turned
3224 * ON by the application if present.
3226 * SOFTWARE: sometimes software optimizations actually result in performance
3227 * decrease on some architectures or systems, or with some sets of
3228 * PNG images. 'Software' options allow such optimizations to be
3229 * selected at run time.
3231 #ifdef PNG_SET_OPTION_SUPPORTED
3232 #ifdef PNG_ARM_NEON_API_SUPPORTED
3233 # define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3235 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3236 #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3237 #define PNG_OPTION_NEXT 6 /* Next option - numbers must be even */
3239 /* Return values: NOTE: there are four values and 'off' is *not* zero */
3240 #define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3241 #define PNG_OPTION_INVALID 1 /* Option number out of range */
3242 #define PNG_OPTION_OFF 2
3243 #define PNG_OPTION_ON 3
3245 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3249 /*******************************************************************************
3250 * END OF HARDWARE AND SOFTWARE OPTIONS
3251 ******************************************************************************/
3253 /* Maintainer: Put new public prototypes here ^, in libpng.3, and project
3254 * defs, scripts/pnglibconf.h, and scripts/pnglibconf.h.prebuilt
3257 /* The last ordinal number (this is the *last* one already used; the next
3258 * one to use is one more than this.) Maintainer, remember to add an entry to
3259 * scripts/symbols.def as well.
3261 #ifdef PNG_EXPORT_LAST_ORDINAL
3262 PNG_EXPORT_LAST_ORDINAL(244);
3269 #endif /* PNG_VERSION_INFO_ONLY */
3270 /* Do not put anything past this line */
projects / platform / upstream / libpng.git / blob