2 /* png.h - header file for PNG reference library
4 * libpng version 1.6.0 - February 14, 2013
5 * Copyright (c) 1998-2013 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 1.6.0 - February 14, 2013: 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]
173 * Henceforth the source version will match the shared-library major
174 * and minor numbers; the shared-library major version number will be
175 * used for changes in backward compatibility, as it is intended. The
176 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
177 * for applications, is an unsigned integer of the form xyyzz corresponding
178 * to the source version x.y.z (leading zeros in y and z). Beta versions
179 * were given the previous public release number plus a letter, until
180 * version 1.0.6j; from then on they were given the upcoming public
181 * release number plus "betaNN" or "rcNN".
183 * Binary incompatibility exists only when applications make direct access
184 * to the info_ptr or png_ptr members through png.h, and the compiled
185 * application is loaded with a different version of the library.
187 * DLLNUM will change each time there are forward or backward changes
188 * in binary compatibility (e.g., when a new feature is added).
190 * See libpng-manual.txt or libpng.3 for more information. The PNG
191 * specification is available as a W3C Recommendation and as an ISO
192 * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
196 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
198 * If you modify libpng you may insert additional notices immediately following
201 * This code is released under the libpng license.
203 * libpng versions 1.2.6, August 15, 2004, through 1.6.0, February 14, 2013, are
204 * Copyright (c) 2004, 2006-2013 Glenn Randers-Pehrson, and are
205 * distributed according to the same disclaimer and license as libpng-1.2.5
206 * with the following individual added to the list of Contributing Authors:
210 * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
211 * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
212 * distributed according to the same disclaimer and license as libpng-1.0.6
213 * with the following individuals added to the list of Contributing Authors:
215 * Simon-Pierre Cadieux
219 * and with the following additions to the disclaimer:
221 * There is no warranty against interference with your enjoyment of the
222 * library or against infringement. There is no warranty that our
223 * efforts or the library will fulfill any of your particular purposes
224 * or needs. This library is provided with all faults, and the entire
225 * risk of satisfactory quality, performance, accuracy, and effort is with
228 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
229 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
230 * distributed according to the same disclaimer and license as libpng-0.96,
231 * with the following individuals added to the list of Contributing Authors:
234 * Glenn Randers-Pehrson
237 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
238 * Copyright (c) 1996, 1997 Andreas Dilger
239 * Distributed according to the same disclaimer and license as libpng-0.88,
240 * with the following individuals added to the list of Contributing Authors:
249 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
250 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
252 * For the purposes of this copyright and license, "Contributing Authors"
253 * is defined as the following set of individuals:
261 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
262 * and Group 42, Inc. disclaim all warranties, expressed or implied,
263 * including, without limitation, the warranties of merchantability and of
264 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
265 * assume no liability for direct, indirect, incidental, special, exemplary,
266 * or consequential damages, which may result from the use of the PNG
267 * Reference Library, even if advised of the possibility of such damage.
269 * Permission is hereby granted to use, copy, modify, and distribute this
270 * source code, or portions hereof, for any purpose, without fee, subject
271 * to the following restrictions:
273 * 1. The origin of this source code must not be misrepresented.
275 * 2. Altered versions must be plainly marked as such and must not
276 * be misrepresented as being the original source.
278 * 3. This Copyright notice may not be removed or altered from
279 * any source or altered source distribution.
281 * The Contributing Authors and Group 42, Inc. specifically permit, without
282 * fee, and encourage the use of this source code as a component to
283 * supporting the PNG file format in commercial products. If you use this
284 * source code in a product, acknowledgment is not required but would be
289 * A "png_get_copyright" function is available, for convenient use in "about"
290 * boxes and the like:
292 * printf("%s", png_get_copyright(NULL));
294 * Also, the PNG logo (in PNG format, of course) is supplied in the
295 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
299 * Libpng is OSI Certified Open Source Software. OSI Certified is a
300 * certification mark of the Open Source Initiative.
304 * The contributing authors would like to thank all those who helped
305 * with testing, bug fixes, and patience. This wouldn't have been
306 * possible without all of you.
308 * Thanks to Frank J. T. Wojcik for helping with the documentation.
312 * Y2K compliance in libpng:
313 * =========================
317 * Since the PNG Development group is an ad-hoc body, we can't make
318 * an official declaration.
320 * This is your unofficial assurance that libpng from version 0.71 and
321 * upward through 1.6.0 are Y2K compliant. It is my belief that
322 * earlier versions were also Y2K compliant.
324 * Libpng only has two year fields. One is a 2-byte unsigned integer
325 * that will hold years up to 65535. The other, which is deprecated,
326 * holds the date in text format, and will hold years up to 9999.
329 * "png_uint_16 year" in png_time_struct.
332 * "char time_buffer[29]" in png_struct. This is no longer used
333 * in libpng-1.6.x and will be removed from libpng-1.7.0.
335 * There are seven time-related functions:
336 * png.c: png_convert_to_rfc_1123_buffer() in png.c
337 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
338 * png_convert_to_rfc_1152() in error prior to libpng-0.98)
339 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
340 * png_convert_from_time_t() in pngwrite.c
341 * png_get_tIME() in pngget.c
342 * png_handle_tIME() in pngrutil.c, called in pngread.c
343 * png_set_tIME() in pngset.c
344 * png_write_tIME() in pngwutil.c, called in pngwrite.c
346 * All handle dates properly in a Y2K environment. The
347 * png_convert_from_time_t() function calls gmtime() to convert from system
348 * clock time, which returns (year - 1900), which we properly convert to
349 * the full 4-digit year. There is a possibility that libpng applications
350 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
351 * function, or that they are incorrectly passing only a 2-digit year
352 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
353 * but this is not under our control. The libpng documentation has always
354 * stated that it works with 4-digit years, and the APIs have been
355 * documented as such.
357 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
358 * integer to hold the year, and can hold years as large as 65535.
360 * zlib, upon which libpng depends, is also Y2K compliant. It contains
361 * no date-related code.
363 * Glenn Randers-Pehrson
365 * PNG Development Group
371 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
372 * describes how to use libpng, and the file example.c summarizes it
373 * with some code on which to build. This file is useful for looking
374 * at the actual function definitions and structure components.
376 * If you just need to read a PNG file and don't want to read the documentation
377 * skip to the end of this file and read the section entitled 'simplified API'.
380 /* Version information for png.h - this should match the version in png.c */
381 #define PNG_LIBPNG_VER_STRING "1.6.0"
382 #define PNG_HEADER_VERSION_STRING \
383 " libpng version 1.6.0 - February 14, 2013\n"
385 #define PNG_LIBPNG_VER_SONUM 16
386 #define PNG_LIBPNG_VER_DLLNUM 16
388 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
389 #define PNG_LIBPNG_VER_MAJOR 1
390 #define PNG_LIBPNG_VER_MINOR 6
391 #define PNG_LIBPNG_VER_RELEASE 0
393 /* This should match the numeric part of the final component of
394 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
397 #define PNG_LIBPNG_VER_BUILD 0
400 #define PNG_LIBPNG_BUILD_ALPHA 1
401 #define PNG_LIBPNG_BUILD_BETA 2
402 #define PNG_LIBPNG_BUILD_RC 3
403 #define PNG_LIBPNG_BUILD_STABLE 4
404 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
406 /* Release-Specific Flags */
407 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
408 PNG_LIBPNG_BUILD_STABLE only */
409 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
410 PNG_LIBPNG_BUILD_SPECIAL */
411 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
412 PNG_LIBPNG_BUILD_PRIVATE */
414 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
416 /* Careful here. At one time, Guy wanted to use 082, but that would be octal.
417 * We must not include leading zeros.
418 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
419 * version 1.0.0 was mis-numbered 100 instead of 10000). From
420 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
422 #define PNG_LIBPNG_VER 10600 /* 1.6.0 */
424 /* Library configuration: these options cannot be changed after
425 * the library has been built.
428 /* If pnglibconf.h is missing, you can
429 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
431 # include "pnglibconf.h"
434 #ifndef PNG_VERSION_INFO_ONLY
435 /* Machine specific configuration. */
436 # include "pngconf.h"
440 * Added at libpng-1.2.8
442 * Ref MSDN: Private as priority over Special
443 * VS_FF_PRIVATEBUILD File *was not* built using standard release
444 * procedures. If this value is given, the StringFileInfo block must
445 * contain a PrivateBuild string.
447 * VS_FF_SPECIALBUILD File *was* built by the original company using
448 * standard release procedures but is a variation of the standard
449 * file of the same version number. If this value is given, the
450 * StringFileInfo block must contain a SpecialBuild string.
453 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
454 # define PNG_LIBPNG_BUILD_TYPE \
455 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
457 # ifdef PNG_LIBPNG_SPECIALBUILD
458 # define PNG_LIBPNG_BUILD_TYPE \
459 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
461 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
465 #ifndef PNG_VERSION_INFO_ONLY
467 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
470 #endif /* __cplusplus */
472 /* Version information for C files, stored in png.c. This had better match
475 #define png_libpng_ver png_get_header_ver(NULL)
477 /* This file is arranged in several sections:
479 * 1. Any configuration options that can be specified by for the application
480 * code when it is built. (Build time configuration is in pnglibconf.h)
481 * 2. Type definitions (base types are defined in pngconf.h), structure
483 * 3. Exported library functions.
486 * The library source code has additional files (principally pngpriv.h) that
487 * allow configuration of the library.
489 /* Section 1: run time configuration
490 * See pnglibconf.h for build time configuration
492 * Run time configuration allows the application to choose between
493 * implementations of certain arithmetic APIs. The default is set
494 * at build time and recorded in pnglibconf.h, but it is safe to
495 * override these (and only these) settings. Note that this won't
496 * change what the library does, only application code, and the
497 * settings can (and probably should) be made on a per-file basis
498 * by setting the #defines before including png.h
500 * Use macros to read integers from PNG data or use the exported
502 * PNG_USE_READ_MACROS: use the macros (see below) Note that
503 * the macros evaluate their argument multiple times.
504 * PNG_NO_USE_READ_MACROS: call the relevant library function.
506 * Use the alternative algorithm for compositing alpha samples that
507 * does not use division?
508 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
510 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
512 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
514 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
515 * APIs to png_warning.
516 * Otherwise the calls are mapped to png_error.
519 /* Section 2: type definitions, including structures and compile time
521 * See pngconf.h for base types that vary by machine/system
524 /* This triggers a compiler error in png.c, if png.c and png.h
525 * do not agree upon the version number.
527 typedef char* png_libpng_version_1_6_0;
529 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
531 * png_struct is the cache of information used while reading or writing a single
532 * PNG file. One of these is always required, although the simplified API
533 * (below) hides the creation and destruction of it.
535 typedef struct png_struct_def png_struct;
536 typedef const png_struct * png_const_structp;
537 typedef png_struct * png_structp;
538 typedef png_struct * * png_structpp;
540 /* png_info contains information read from or to be written to a PNG file. One
541 * or more of these must exist while reading or creating a PNG file. The
542 * information is not used by libpng during read but is used to control what
543 * gets written when a PNG file is created. "png_get_" function calls read
544 * information during read and "png_set_" functions calls write information
545 * when creating a PNG.
546 * been moved into a separate header file that is not accessible to
547 * applications. Read libpng-manual.txt or libpng.3 for more info.
549 typedef struct png_info_def png_info;
550 typedef png_info * png_infop;
551 typedef const png_info * png_const_infop;
552 typedef png_info * * png_infopp;
554 /* Types with names ending 'p' are pointer types. The corresponding types with
555 * names ending 'rp' are identical pointer types except that the pointer is
556 * marked 'restrict', which means that it is the only pointer to the object
557 * passed to the function. Applications should not use the 'restrict' types;
558 * it is always valid to pass 'p' to a pointer with a function argument of the
559 * corresponding 'rp' type. Different compilers have different rules with
560 * regard to type matching in the presence of 'restrict'. For backward
561 * compatibility libpng callbacks never have 'restrict' in their parameters and,
562 * consequentially, writing portable application code is extremely difficult if
563 * an attempt is made to use 'restrict'.
565 typedef png_struct * PNG_RESTRICT png_structrp;
566 typedef const png_struct * PNG_RESTRICT png_const_structrp;
567 typedef png_info * PNG_RESTRICT png_inforp;
568 typedef const png_info * PNG_RESTRICT png_const_inforp;
570 /* Three color definitions. The order of the red, green, and blue, (and the
571 * exact size) is not important, although the size of the fields need to
572 * be png_byte or png_uint_16 (as defined below).
574 typedef struct png_color_struct
580 typedef png_color * png_colorp;
581 typedef const png_color * png_const_colorp;
582 typedef png_color * * png_colorpp;
584 typedef struct png_color_16_struct
586 png_byte index; /* used for palette files */
587 png_uint_16 red; /* for use in red green blue files */
590 png_uint_16 gray; /* for use in grayscale files */
592 typedef png_color_16 * png_color_16p;
593 typedef const png_color_16 * png_const_color_16p;
594 typedef png_color_16 * * png_color_16pp;
596 typedef struct png_color_8_struct
598 png_byte red; /* for use in red green blue files */
601 png_byte gray; /* for use in grayscale files */
602 png_byte alpha; /* for alpha channel files */
604 typedef png_color_8 * png_color_8p;
605 typedef const png_color_8 * png_const_color_8p;
606 typedef png_color_8 * * png_color_8pp;
609 * The following two structures are used for the in-core representation
612 typedef struct png_sPLT_entry_struct
618 png_uint_16 frequency;
620 typedef png_sPLT_entry * png_sPLT_entryp;
621 typedef const png_sPLT_entry * png_const_sPLT_entryp;
622 typedef png_sPLT_entry * * png_sPLT_entrypp;
624 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples
625 * occupy the LSB of their respective members, and the MSB of each member
626 * is zero-filled. The frequency member always occupies the full 16 bits.
629 typedef struct png_sPLT_struct
631 png_charp name; /* palette name */
632 png_byte depth; /* depth of palette samples */
633 png_sPLT_entryp entries; /* palette entries */
634 png_int_32 nentries; /* number of palette entries */
636 typedef png_sPLT_t * png_sPLT_tp;
637 typedef const png_sPLT_t * png_const_sPLT_tp;
638 typedef png_sPLT_t * * png_sPLT_tpp;
640 #ifdef PNG_TEXT_SUPPORTED
641 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
642 * and whether that contents is compressed or not. The "key" field
643 * points to a regular zero-terminated C string. The "text" fields can be a
644 * regular C string, an empty string, or a NULL pointer.
645 * However, the structure returned by png_get_text() will always contain
646 * the "text" field as a regular zero-terminated C string (possibly
647 * empty), never a NULL pointer, so it can be safely used in printf() and
648 * other string-handling functions. Note that the "itxt_length", "lang", and
649 * "lang_key" members of the structure only exist when the library is built
650 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
651 * default without iTXt support. Also note that when iTXt *is* supported,
652 * the "lang" and "lang_key" fields contain NULL pointers when the
653 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
654 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
655 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
656 * which is always 0 or 1, or its "compression method" which is always 0.
658 typedef struct png_text_struct
660 int compression; /* compression value:
665 png_charp key; /* keyword, 1-79 character description of "text" */
666 png_charp text; /* comment, may be an empty string (ie "")
668 png_size_t text_length; /* length of the text string */
669 png_size_t itxt_length; /* length of the itxt string */
670 png_charp lang; /* language code, 0-79 characters
672 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
673 chars or a NULL pointer */
675 typedef png_text * png_textp;
676 typedef const png_text * png_const_textp;
677 typedef png_text * * png_textpp;
680 /* Supported compression types for text in PNG files (tEXt, and zTXt).
681 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
682 #define PNG_TEXT_COMPRESSION_NONE_WR -3
683 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
684 #define PNG_TEXT_COMPRESSION_NONE -1
685 #define PNG_TEXT_COMPRESSION_zTXt 0
686 #define PNG_ITXT_COMPRESSION_NONE 1
687 #define PNG_ITXT_COMPRESSION_zTXt 2
688 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
690 /* png_time is a way to hold the time in an machine independent way.
691 * Two conversions are provided, both from time_t and struct tm. There
692 * is no portable way to convert to either of these structures, as far
693 * as I know. If you know of a portable way, send it to me. As a side
694 * note - PNG has always been Year 2000 compliant!
696 typedef struct png_time_struct
698 png_uint_16 year; /* full year, as in, 1995 */
699 png_byte month; /* month of year, 1 - 12 */
700 png_byte day; /* day of month, 1 - 31 */
701 png_byte hour; /* hour of day, 0 - 23 */
702 png_byte minute; /* minute of hour, 0 - 59 */
703 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
705 typedef png_time * png_timep;
706 typedef const png_time * png_const_timep;
707 typedef png_time * * png_timepp;
709 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
710 /* png_unknown_chunk is a structure to hold queued chunks for which there is
711 * no specific support. The idea is that we can use this to queue
712 * up private chunks for output even though the library doesn't actually
713 * know about their semantics.
715 * The data in the structure is set by libpng on read and used on write.
717 typedef struct png_unknown_chunk_t
719 png_byte name[5]; /* Textual chunk name with '\0' terminator */
720 png_byte *data; /* Data, should not be modified on read! */
723 /* On write 'location' must be set using the flag values listed below.
724 * Notice that on read it is set by libpng however the values stored have
725 * more bits set than are listed below. Always treat the value as a
726 * bitmask. On write set only one bit - setting multiple bits may cause the
727 * chunk to be written in multiple places.
729 png_byte location; /* mode of operation at read time */
733 typedef png_unknown_chunk * png_unknown_chunkp;
734 typedef const png_unknown_chunk * png_const_unknown_chunkp;
735 typedef png_unknown_chunk * * png_unknown_chunkpp;
738 /* Flag values for the unknown chunk location byte. */
739 #define PNG_HAVE_IHDR 0x01
740 #define PNG_HAVE_PLTE 0x02
741 #define PNG_AFTER_IDAT 0x08
743 /* Maximum positive integer used in PNG is (2^31)-1 */
744 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
745 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
746 #define PNG_SIZE_MAX ((png_size_t)(-1))
748 /* These are constants for fixed point values encoded in the
749 * PNG specification manner (x100000)
751 #define PNG_FP_1 100000
752 #define PNG_FP_HALF 50000
753 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
754 #define PNG_FP_MIN (-PNG_FP_MAX)
756 /* These describe the color_type field in png_info. */
757 /* color type masks */
758 #define PNG_COLOR_MASK_PALETTE 1
759 #define PNG_COLOR_MASK_COLOR 2
760 #define PNG_COLOR_MASK_ALPHA 4
762 /* color types. Note that not all combinations are legal */
763 #define PNG_COLOR_TYPE_GRAY 0
764 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
765 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
766 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
767 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
769 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
770 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
772 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
773 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
774 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
776 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
777 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
778 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
779 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
781 /* These are for the interlacing type. These values should NOT be changed. */
782 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
783 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
784 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
786 /* These are for the oFFs chunk. These values should NOT be changed. */
787 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
788 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
789 #define PNG_OFFSET_LAST 2 /* Not a valid value */
791 /* These are for the pCAL chunk. These values should NOT be changed. */
792 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
793 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
794 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
795 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
796 #define PNG_EQUATION_LAST 4 /* Not a valid value */
798 /* These are for the sCAL chunk. These values should NOT be changed. */
799 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
800 #define PNG_SCALE_METER 1 /* meters per pixel */
801 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
802 #define PNG_SCALE_LAST 3 /* Not a valid value */
804 /* These are for the pHYs chunk. These values should NOT be changed. */
805 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
806 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
807 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
809 /* These are for the sRGB chunk. These values should NOT be changed. */
810 #define PNG_sRGB_INTENT_PERCEPTUAL 0
811 #define PNG_sRGB_INTENT_RELATIVE 1
812 #define PNG_sRGB_INTENT_SATURATION 2
813 #define PNG_sRGB_INTENT_ABSOLUTE 3
814 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
816 /* This is for text chunks */
817 #define PNG_KEYWORD_MAX_LENGTH 79
819 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
820 #define PNG_MAX_PALETTE_LENGTH 256
822 /* These determine if an ancillary chunk's data has been successfully read
823 * from the PNG header, or if the application has filled in the corresponding
824 * data in the info_struct to be written into the output file. The values
825 * of the PNG_INFO_<chunk> defines should NOT be changed.
827 #define PNG_INFO_gAMA 0x0001
828 #define PNG_INFO_sBIT 0x0002
829 #define PNG_INFO_cHRM 0x0004
830 #define PNG_INFO_PLTE 0x0008
831 #define PNG_INFO_tRNS 0x0010
832 #define PNG_INFO_bKGD 0x0020
833 #define PNG_INFO_hIST 0x0040
834 #define PNG_INFO_pHYs 0x0080
835 #define PNG_INFO_oFFs 0x0100
836 #define PNG_INFO_tIME 0x0200
837 #define PNG_INFO_pCAL 0x0400
838 #define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
839 #define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
840 #define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
841 #define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
842 #define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */
844 /* This is used for the transformation routines, as some of them
845 * change these values for the row. It also should enable using
846 * the routines for other purposes.
848 typedef struct png_row_info_struct
850 png_uint_32 width; /* width of row */
851 png_size_t rowbytes; /* number of bytes in row */
852 png_byte color_type; /* color type of row */
853 png_byte bit_depth; /* bit depth of row */
854 png_byte channels; /* number of channels (1, 2, 3, or 4) */
855 png_byte pixel_depth; /* bits per pixel (depth * channels) */
858 typedef png_row_info * png_row_infop;
859 typedef png_row_info * * png_row_infopp;
861 /* These are the function types for the I/O functions and for the functions
862 * that allow the user to override the default I/O functions with his or her
863 * own. The png_error_ptr type should match that of user-supplied warning
864 * and error functions, while the png_rw_ptr type should match that of the
865 * user read/write data functions. Note that the 'write' function must not
866 * modify the buffer it is passed. The 'read' function, on the other hand, is
867 * expected to return the read data in the buffer.
869 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
870 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
871 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
872 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
874 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
877 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
878 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
879 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
881 /* The following callback receives png_uint_32 row_number, int pass for the
882 * png_bytep data of the row. When transforming an interlaced image the
883 * row number is the row number within the sub-image of the interlace pass, so
884 * the value will increase to the height of the sub-image (not the full image)
885 * then reset to 0 for the next pass.
887 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
888 * find the output pixel (x,y) given an interlaced sub-image pixel
889 * (row,col,pass). (See below for these macros.)
891 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
895 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
896 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
897 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
901 #ifdef PNG_USER_CHUNKS_SUPPORTED
902 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
903 png_unknown_chunkp));
905 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
906 /* not used anywhere */
907 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
910 #ifdef PNG_SETJMP_SUPPORTED
911 /* This must match the function definition in <setjmp.h>, and the application
912 * must include this before png.h to obtain the definition of jmp_buf. The
913 * function is required to be PNG_NORETURN, but this is not checked. If the
914 * function does return the application will crash via an abort() or similar
917 * If you get a warning here while building the library you may need to make
918 * changes to ensure that pnglibconf.h records the calling convention used by
919 * your compiler. This may be very difficult - try using a different compiler
920 * to build the library!
922 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
925 /* Transform masks for the high-level interface */
926 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
927 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
928 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
929 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
930 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
931 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
932 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
933 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
934 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
935 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
936 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
937 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
938 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
939 /* Added to libpng-1.2.34 */
940 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
941 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
942 /* Added to libpng-1.4.0 */
943 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
944 /* Added to libpng-1.5.4 */
945 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
946 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
948 /* Flags for MNG supported features */
949 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
950 #define PNG_FLAG_MNG_FILTER_64 0x04
951 #define PNG_ALL_MNG_FEATURES 0x05
953 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
954 * this allowed the zlib default functions to be used on Windows
955 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
956 * ignores the first argument) should be completely compatible with the
959 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
961 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
963 /* Section 3: exported functions
964 * Here are the function definitions most commonly used. This is not
965 * the place to find out how to use libpng. See libpng-manual.txt for the
966 * full explanation, see example.c for the summary. This just provides
967 * a simple one line description of the use of each function.
969 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
970 * pngconf.h and in the *.dfn files in the scripts directory.
972 * PNG_EXPORT(ordinal, type, name, (args));
974 * ordinal: ordinal that is used while building
975 * *.def files. The ordinal value is only
976 * relevant when preprocessing png.h with
977 * the *.dfn files for building symbol table
978 * entries, and are removed by pngconf.h.
979 * type: return type of the function
980 * name: function name
981 * args: function arguments, with types
983 * When we wish to append attributes to a function prototype we use
984 * the PNG_EXPORTA() macro instead.
986 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
988 * ordinal, type, name, and args: same as in PNG_EXPORT().
989 * attributes: function attributes
992 /* Returns the version number of the library */
993 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
995 /* Tell lib we have already handled the first <num_bytes> magic bytes.
996 * Handling more than 8 bytes from the beginning of the file is an error.
998 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
1000 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
1001 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
1002 * signature, and non-zero otherwise. Having num_to_check == 0 or
1003 * start > 7 will always fail (ie return non-zero).
1005 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
1006 png_size_t num_to_check));
1008 /* Simple signature checking function. This is the same as calling
1009 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
1011 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
1013 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
1014 PNG_EXPORTA(4, png_structp, png_create_read_struct,
1015 (png_const_charp user_png_ver, png_voidp error_ptr,
1016 png_error_ptr error_fn, png_error_ptr warn_fn),
1019 /* Allocate and initialize png_ptr struct for writing, and any other memory */
1020 PNG_EXPORTA(5, png_structp, png_create_write_struct,
1021 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1022 png_error_ptr warn_fn),
1025 PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
1026 (png_const_structrp png_ptr));
1028 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
1031 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
1034 #ifdef PNG_SETJMP_SUPPORTED
1035 /* This function returns the jmp_buf built in to *png_ptr. It must be
1036 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
1037 * unless the default error function is overridden in which case NULL is
1038 * acceptable. The size of the jmp_buf is checked against the actual size
1039 * allocated by the library - the call will return NULL on a mismatch
1040 * indicating an ABI mismatch.
1042 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
1043 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
1044 # define png_jmpbuf(png_ptr) \
1045 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
1047 # define png_jmpbuf(png_ptr) \
1048 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
1050 /* This function should be used by libpng applications in place of
1051 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
1052 * will use it; otherwise it will call PNG_ABORT(). This function was
1053 * added in libpng-1.5.0.
1055 PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
1058 #ifdef PNG_READ_SUPPORTED
1059 /* Reset the compression stream */
1060 PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
1063 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1064 #ifdef PNG_USER_MEM_SUPPORTED
1065 PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1066 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1067 png_error_ptr warn_fn,
1068 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1070 PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1071 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1072 png_error_ptr warn_fn,
1073 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1077 /* Write the PNG file signature. */
1078 PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
1080 /* Write a PNG chunk - size, type, (optional) data, CRC. */
1081 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
1082 chunk_name, png_const_bytep data, png_size_t length));
1084 /* Write the start of a PNG chunk - length and chunk name. */
1085 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1086 png_const_bytep chunk_name, png_uint_32 length));
1088 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1089 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1090 png_const_bytep data, png_size_t length));
1092 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1093 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1095 /* Allocate and initialize the info structure */
1096 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1099 /* DEPRECATED: this function allowed init structures to be created using the
1100 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1101 * the API will be removed in the future.
1103 PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1104 png_size_t png_info_struct_size), PNG_DEPRECATED);
1106 /* Writes all the PNG information before the image. */
1107 PNG_EXPORT(20, void, png_write_info_before_PLTE,
1108 (png_structrp png_ptr, png_const_inforp info_ptr));
1109 PNG_EXPORT(21, void, png_write_info,
1110 (png_structrp png_ptr, png_const_inforp info_ptr));
1112 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1113 /* Read the information before the actual image data. */
1114 PNG_EXPORT(22, void, png_read_info,
1115 (png_structrp png_ptr, png_inforp info_ptr));
1118 #ifdef PNG_TIME_RFC1123_SUPPORTED
1119 /* Convert to a US string format: there is no localization support in this
1120 * routine. The original implementation used a 29 character buffer in
1121 * png_struct, this will be removed in future versions.
1123 #if PNG_LIBPNG_VER < 10700
1124 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1125 PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1126 png_const_timep ptime),PNG_DEPRECATED);
1128 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1129 png_const_timep ptime));
1132 #ifdef PNG_CONVERT_tIME_SUPPORTED
1133 /* Convert from a struct tm to png_time */
1134 PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1135 const struct tm * ttime));
1137 /* Convert from time_t to png_time. Uses gmtime() */
1138 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1139 #endif /* PNG_CONVERT_tIME_SUPPORTED */
1141 #ifdef PNG_READ_EXPAND_SUPPORTED
1142 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1143 PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1144 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1145 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1146 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1149 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1150 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1151 * of a tRNS chunk if present.
1153 PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1156 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1157 /* Use blue, green, red order for pixels. */
1158 PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1161 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1162 /* Expand the grayscale to 24-bit RGB if necessary. */
1163 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1166 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1167 /* Reduce RGB to grayscale. */
1168 #define PNG_ERROR_ACTION_NONE 1
1169 #define PNG_ERROR_ACTION_WARN 2
1170 #define PNG_ERROR_ACTION_ERROR 3
1171 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1173 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1174 int error_action, double red, double green))
1175 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1176 int error_action, png_fixed_point red, png_fixed_point green))
1178 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1182 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1183 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1184 png_colorp palette));
1187 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1188 /* How the alpha channel is interpreted - this affects how the color channels of
1189 * a PNG file are returned when an alpha channel, or tRNS chunk in a palette
1192 * This has no effect on the way pixels are written into a PNG output
1193 * datastream. The color samples in a PNG datastream are never premultiplied
1194 * with the alpha samples.
1196 * The default is to return data according to the PNG specification: the alpha
1197 * channel is a linear measure of the contribution of the pixel to the
1198 * corresponding composited pixel. The gamma encoded color channels must be
1199 * scaled according to the contribution and to do this it is necessary to undo
1200 * the encoding, scale the color values, perform the composition and reencode
1201 * the values. This is the 'PNG' mode.
1203 * The alternative is to 'associate' the alpha with the color information by
1204 * storing color channel values that have been scaled by the alpha. The
1205 * advantage is that the color channels can be resampled (the image can be
1206 * scaled) in this form. The disadvantage is that normal practice is to store
1207 * linear, not (gamma) encoded, values and this requires 16-bit channels for
1208 * still images rather than the 8-bit channels that are just about sufficient if
1209 * gamma encoding is used. In addition all non-transparent pixel values,
1210 * including completely opaque ones, must be gamma encoded to produce the final
1211 * image. This is the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' mode (the
1212 * latter being the two common names for associated alpha color channels.)
1214 * Since it is not necessary to perform arithmetic on opaque color values so
1215 * long as they are not to be resampled and are in the final color space it is
1216 * possible to optimize the handling of alpha by storing the opaque pixels in
1217 * the PNG format (adjusted for the output color space) while storing partially
1218 * opaque pixels in the standard, linear, format. The accuracy required for
1219 * standard alpha composition is relatively low, because the pixels are
1220 * isolated, therefore typically the accuracy loss in storing 8-bit linear
1221 * values is acceptable. (This is not true if the alpha channel is used to
1222 * simulate transparency over large areas - use 16 bits or the PNG mode in
1223 * this case!) This is the 'OPTIMIZED' mode. For this mode a pixel is
1224 * treated as opaque only if the alpha value is equal to the maximum value.
1226 * The final choice is to gamma encode the alpha channel as well. This is
1227 * broken because, in practice, no implementation that uses this choice
1228 * correctly undoes the encoding before handling alpha composition. Use this
1229 * choice only if other serious errors in the software or hardware you use
1230 * mandate it; the typical serious error is for dark halos to appear around
1231 * opaque areas of the composited PNG image because of arithmetic overflow.
1233 * The API function png_set_alpha_mode specifies which of these choices to use
1234 * with an enumerated 'mode' value and the gamma of the required output:
1236 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1237 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1238 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1239 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1240 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1241 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1243 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1244 double output_gamma))
1245 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1246 int mode, png_fixed_point output_gamma))
1249 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1250 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1251 * how to decode the output values, not how they are encoded. The values used
1252 * correspond to the normal numbers used to describe the overall gamma of a
1253 * computer display system; for example 2.2 for an sRGB conformant system. The
1254 * values are scaled by 100000 in the _fixed version of the API (so 220000 for
1257 * The inverse of the value is always used to provide a default for the PNG file
1258 * encoding if it has no gAMA chunk and if png_set_gamma() has not been called
1259 * to override the PNG gamma information.
1261 * When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
1262 * opaque pixels however pixels with lower alpha values are not encoded,
1263 * regardless of the output gamma setting.
1265 * When the standard Porter Duff handling is requested with mode 1 the output
1266 * encoding is set to be linear and the output_gamma value is only relevant
1267 * as a default for input data that has no gamma information. The linear output
1268 * encoding will be overridden if png_set_gamma() is called - the results may be
1269 * highly unexpected!
1271 * The following numbers are derived from the sRGB standard and the research
1272 * behind it. sRGB is defined to be approximated by a PNG gAMA chunk value of
1273 * 0.45455 (1/2.2) for PNG. The value implicitly includes any viewing
1274 * correction required to take account of any differences in the color
1275 * environment of the original scene and the intended display environment; the
1276 * value expresses how to *decode* the image for display, not how the original
1277 * data was *encoded*.
1279 * sRGB provides a peg for the PNG standard by defining a viewing environment.
1280 * sRGB itself, and earlier TV standards, actually use a more complex transform
1281 * (a linear portion then a gamma 2.4 power law) than PNG can express. (PNG is
1282 * limited to simple power laws.) By saying that an image for direct display on
1283 * an sRGB conformant system should be stored with a gAMA chunk value of 45455
1284 * (11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
1285 * makes it possible to derive values for other display systems and
1288 * The Mac value is deduced from the sRGB based on an assumption that the actual
1289 * extra viewing correction used in early Mac display systems was implemented as
1290 * a power 1.45 lookup table.
1292 * Any system where a programmable lookup table is used or where the behavior of
1293 * the final display device characteristics can be changed requires system
1294 * specific code to obtain the current characteristic. However this can be
1295 * difficult and most PNG gamma correction only requires an approximate value.
1297 * By default, if png_set_alpha_mode() is not called, libpng assumes that all
1298 * values are unencoded, linear, values and that the output device also has a
1299 * linear characteristic. This is only very rarely correct - it is invariably
1300 * better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
1301 * default if you don't know what the right answer is!
1303 * The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
1304 * 10.6) which used a correction table to implement a somewhat lower gamma on an
1305 * otherwise sRGB system.
1307 * Both these values are reserved (not simple gamma values) in order to allow
1308 * more precise correction internally in the future.
1310 * NOTE: the following values can be passed to either the fixed or floating
1311 * point APIs, but the floating point API will also accept floating point
1314 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1315 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1316 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1317 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1320 /* The following are examples of calls to png_set_alpha_mode to achieve the
1321 * required overall gamma correction and, where necessary, alpha
1322 * premultiplication.
1324 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1325 * This is the default libpng handling of the alpha channel - it is not
1326 * pre-multiplied into the color components. In addition the call states
1327 * that the output is for a sRGB system and causes all PNG files without gAMA
1328 * chunks to be assumed to be encoded using sRGB.
1330 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1331 * In this case the output is assumed to be something like an sRGB conformant
1332 * display preceeded by a power-law lookup table of power 1.45. This is how
1333 * early Mac systems behaved.
1335 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1336 * This is the classic Jim Blinn approach and will work in academic
1337 * environments where everything is done by the book. It has the shortcoming
1338 * of assuming that input PNG data with no gamma information is linear - this
1339 * is unlikely to be correct unless the PNG files where generated locally.
1340 * Most of the time the output precision will be so low as to show
1341 * significant banding in dark areas of the image.
1343 * png_set_expand_16(pp);
1344 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1345 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1346 * are assumed to have the sRGB encoding if not marked with a gamma value and
1347 * the output is always 16 bits per component. This permits accurate scaling
1348 * and processing of the data. If you know that your input PNG files were
1349 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1350 * correct value for your system.
1352 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1353 * If you just need to composite the PNG image onto an existing background
1354 * and if you control the code that does this you can use the optimization
1355 * setting. In this case you just copy completely opaque pixels to the
1356 * output. For pixels that are not completely transparent (you just skip
1357 * those) you do the composition math using png_composite or png_composite_16
1358 * below then encode the resultant 8-bit or 16-bit values to match the output
1362 * If neither the PNG nor the standard linear encoding work for you because
1363 * of the software or hardware you use then you have a big problem. The PNG
1364 * case will probably result in halos around the image. The linear encoding
1365 * will probably result in a washed out, too bright, image (it's actually too
1366 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1367 * substantially reduce the halos. Alternatively try:
1369 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1370 * This option will also reduce the halos, but there will be slight dark
1371 * halos round the opaque parts of the image where the background is light.
1372 * In the OPTIMIZED mode the halos will be light halos where the background
1373 * is dark. Take your pick - the halos are unavoidable unless you can get
1374 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1377 * When the default gamma of PNG files doesn't match the output gamma.
1378 * If you have PNG files with no gamma information png_set_alpha_mode allows
1379 * you to provide a default gamma, but it also sets the ouput gamma to the
1380 * matching value. If you know your PNG files have a gamma that doesn't
1381 * match the output you can take advantage of the fact that
1382 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1383 * default if it is not already set:
1385 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1386 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1387 * The first call sets both the default and the output gamma values, the
1388 * second call overrides the output gamma without changing the default. This
1389 * is easier than achieving the same effect with png_set_gamma. You must use
1390 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1391 * fire if more than one call to png_set_alpha_mode and png_set_background is
1392 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1396 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1397 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1400 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1401 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1402 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1405 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1406 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1407 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1410 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1411 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
1412 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1414 /* The values of the PNG_FILLER_ defines should NOT be changed */
1415 # define PNG_FILLER_BEFORE 0
1416 # define PNG_FILLER_AFTER 1
1417 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
1418 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1419 png_uint_32 filler, int flags));
1420 #endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
1422 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1423 /* Swap bytes in 16-bit depth files. */
1424 PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1427 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1428 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1429 PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1432 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1433 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1434 /* Swap packing order of pixels in bytes. */
1435 PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1438 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1439 /* Converts files to legal bit depths. */
1440 PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1444 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1445 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1446 /* Have the code handle the interlacing. Returns the number of passes.
1447 * MUST be called before png_read_update_info or png_start_read_image,
1448 * otherwise it will not have the desired effect. Note that it is still
1449 * necessary to call png_read_row or png_read_rows png_get_image_height
1450 * times for each pass.
1452 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1455 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1456 /* Invert monochrome files */
1457 PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1460 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1461 /* Handle alpha and tRNS by replacing with a background color. Prior to
1462 * libpng-1.5.4 this API must not be called before the PNG file header has been
1463 * read. Doing so will result in unexpected behavior and possible warnings or
1464 * errors if the PNG file contains a bKGD chunk.
1466 PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1467 png_const_color_16p background_color, int background_gamma_code,
1468 int need_expand, double background_gamma))
1469 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1470 png_const_color_16p background_color, int background_gamma_code,
1471 int need_expand, png_fixed_point background_gamma))
1473 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1474 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1475 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1476 # define PNG_BACKGROUND_GAMMA_FILE 2
1477 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1480 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1481 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1482 PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1485 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1486 #define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
1487 /* Strip the second byte of information from a 16-bit depth file. */
1488 PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1491 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1492 /* Turn on quantizing, and reduce the palette to the number of colors
1495 PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1496 png_colorp palette, int num_palette, int maximum_colors,
1497 png_const_uint_16p histogram, int full_quantize));
1500 #ifdef PNG_READ_GAMMA_SUPPORTED
1501 /* The threshold on gamma processing is configurable but hard-wired into the
1502 * library. The following is the floating point variant.
1504 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1506 /* Handle gamma correction. Screen_gamma=(display_exponent).
1507 * NOTE: this API simply sets the screen and file gamma values. It will
1508 * therefore override the value for gamma in a PNG file if it is called after
1509 * the file header has been read - use with care - call before reading the PNG
1510 * file for best results!
1512 * These routines accept the same gamma values as png_set_alpha_mode (described
1513 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1514 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1515 * is the inverse of a 'screen gamma' value.
1517 PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1518 double screen_gamma, double override_file_gamma))
1519 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1520 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1523 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1524 /* Set how many lines between output flushes - 0 for no flushing */
1525 PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1526 /* Flush the current PNG output buffer */
1527 PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1530 /* Optional update palette with requested transformations */
1531 PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1533 /* Optional call to update the users info structure */
1534 PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1535 png_inforp info_ptr));
1537 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1538 /* Read one or more rows of image data. */
1539 PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1540 png_bytepp display_row, png_uint_32 num_rows));
1543 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1544 /* Read a row of data. */
1545 PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1546 png_bytep display_row));
1549 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1550 /* Read the whole image into memory at once. */
1551 PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1554 /* Write a row of image data */
1555 PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1556 png_const_bytep row));
1558 /* Write a few rows of image data: (*row) is not written; however, the type
1559 * is declared as writeable to maintain compatibility with previous versions
1560 * of libpng and to allow the 'display_row' array from read_rows to be passed
1561 * unchanged to write_rows.
1563 PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1564 png_uint_32 num_rows));
1566 /* Write the image data */
1567 PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1569 /* Write the end of the PNG file. */
1570 PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1571 png_inforp info_ptr));
1573 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1574 /* Read the end of the PNG file. */
1575 PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1578 /* Free any memory associated with the png_info_struct */
1579 PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1580 png_infopp info_ptr_ptr));
1582 /* Free any memory associated with the png_struct and the png_info_structs */
1583 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1584 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1586 /* Free any memory associated with the png_struct and the png_info_structs */
1587 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1588 png_infopp info_ptr_ptr));
1590 /* Set the libpng method of handling chunk CRC errors */
1591 PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1594 /* Values for png_set_crc_action() say how to handle CRC errors in
1595 * ancillary and critical chunks, and whether to use the data contained
1596 * therein. Note that it is impossible to "discard" data in a critical
1597 * chunk. For versions prior to 0.90, the action was always error/quit,
1598 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1599 * chunks is warn/discard. These values should NOT be changed.
1601 * value action:critical action:ancillary
1603 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1604 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1605 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1606 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1607 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1608 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1610 /* These functions give the user control over the scan-line filtering in
1611 * libpng and the compression methods used by zlib. These functions are
1612 * mainly useful for testing, as the defaults should work with most users.
1613 * Those users who are tight on memory or want faster performance at the
1614 * expense of compression can modify them. See the compression library
1615 * header file (zlib.h) for an explination of the compression functions.
1618 /* Set the filtering method(s) used by libpng. Currently, the only valid
1619 * value for "method" is 0.
1621 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1624 /* Flags for png_set_filter() to say which filters to use. The flags
1625 * are chosen so that they don't conflict with real filter types
1626 * below, in case they are supplied instead of the #defined constants.
1627 * These values should NOT be changed.
1629 #define PNG_NO_FILTERS 0x00
1630 #define PNG_FILTER_NONE 0x08
1631 #define PNG_FILTER_SUB 0x10
1632 #define PNG_FILTER_UP 0x20
1633 #define PNG_FILTER_AVG 0x40
1634 #define PNG_FILTER_PAETH 0x80
1635 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
1636 PNG_FILTER_AVG | PNG_FILTER_PAETH)
1638 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1639 * These defines should NOT be changed.
1641 #define PNG_FILTER_VALUE_NONE 0
1642 #define PNG_FILTER_VALUE_SUB 1
1643 #define PNG_FILTER_VALUE_UP 2
1644 #define PNG_FILTER_VALUE_AVG 3
1645 #define PNG_FILTER_VALUE_PAETH 4
1646 #define PNG_FILTER_VALUE_LAST 5
1648 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
1649 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
1650 * defines, either the default (minimum-sum-of-absolute-differences), or
1651 * the experimental method (weighted-minimum-sum-of-absolute-differences).
1653 * Weights are factors >= 1.0, indicating how important it is to keep the
1654 * filter type consistent between rows. Larger numbers mean the current
1655 * filter is that many times as likely to be the same as the "num_weights"
1656 * previous filters. This is cumulative for each previous row with a weight.
1657 * There needs to be "num_weights" values in "filter_weights", or it can be
1658 * NULL if the weights aren't being specified. Weights have no influence on
1659 * the selection of the first row filter. Well chosen weights can (in theory)
1660 * improve the compression for a given image.
1662 * Costs are factors >= 1.0 indicating the relative decoding costs of a
1663 * filter type. Higher costs indicate more decoding expense, and are
1664 * therefore less likely to be selected over a filter with lower computational
1665 * costs. There needs to be a value in "filter_costs" for each valid filter
1666 * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
1667 * setting the costs. Costs try to improve the speed of decompression without
1668 * unduly increasing the compressed image size.
1670 * A negative weight or cost indicates the default value is to be used, and
1671 * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
1672 * The default values for both weights and costs are currently 1.0, but may
1673 * change if good general weighting/cost heuristics can be found. If both
1674 * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
1675 * to the UNWEIGHTED method, but with added encoding time/computation.
1677 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1678 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1679 png_const_doublep filter_costs))
1680 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1681 (png_structrp png_ptr, int heuristic_method, int num_weights,
1682 png_const_fixed_point_p filter_weights,
1683 png_const_fixed_point_p filter_costs))
1684 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1686 /* Heuristic used for row filter selection. These defines should NOT be
1689 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1690 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1691 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1692 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1694 #ifdef PNG_WRITE_SUPPORTED
1695 /* Set the library compression level. Currently, valid values range from
1696 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1697 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1698 * shown that zlib compression levels 3-6 usually perform as well as level 9
1699 * for PNG images, and do considerably fewer caclulations. In the future,
1700 * these values may not correspond directly to the zlib compression levels.
1702 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1705 PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1708 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1711 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1712 * smaller value of window_bits if it can do so safely.
1714 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1717 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1721 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1722 /* Also set zlib parameters for compressing non-IDAT chunks */
1723 PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1726 PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1729 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1732 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1733 * smaller value of window_bits if it can do so safely.
1735 PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1736 (png_structrp png_ptr, int window_bits));
1738 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1740 #endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
1742 /* These next functions are called for input/output, memory, and error
1743 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1744 * and call standard C I/O routines such as fread(), fwrite(), and
1745 * fprintf(). These functions can be made to use other I/O routines
1746 * at run time for those applications that need to handle I/O in a
1747 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1751 #ifdef PNG_STDIO_SUPPORTED
1752 /* Initialize the input/output for the PNG file to the default functions. */
1753 PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1756 /* Replace the (error and abort), and warning functions with user
1757 * supplied functions. If no messages are to be printed you must still
1758 * write and use replacement functions. The replacement error_fn should
1759 * still do a longjmp to the last setjmp location if you are using this
1760 * method of error handling. If error_fn or warning_fn is NULL, the
1761 * default function will be used.
1764 PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1765 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1767 /* Return the user pointer associated with the error functions */
1768 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1770 /* Replace the default data output functions with a user supplied one(s).
1771 * If buffered output is not used, then output_flush_fn can be set to NULL.
1772 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1773 * output_flush_fn will be ignored (and thus can be NULL).
1774 * It is probably a mistake to use NULL for output_flush_fn if
1775 * write_data_fn is not also NULL unless you have built libpng with
1776 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1777 * default flush function, which uses the standard *FILE structure, will
1780 PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1781 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1783 /* Replace the default data input function with a user supplied one. */
1784 PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1785 png_rw_ptr read_data_fn));
1787 /* Return the user pointer associated with the I/O functions */
1788 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1790 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1791 png_read_status_ptr read_row_fn));
1793 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1794 png_write_status_ptr write_row_fn));
1796 #ifdef PNG_USER_MEM_SUPPORTED
1797 /* Replace the default memory allocation functions with user supplied one(s). */
1798 PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1799 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1800 /* Return the user pointer associated with the memory functions */
1801 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1804 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1805 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1806 png_user_transform_ptr read_user_transform_fn));
1809 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1810 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1811 png_user_transform_ptr write_user_transform_fn));
1814 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1815 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1816 png_voidp user_transform_ptr, int user_transform_depth,
1817 int user_transform_channels));
1818 /* Return the user pointer associated with the user transform functions */
1819 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1820 (png_const_structrp png_ptr));
1823 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1824 /* Return information about the row currently being processed. Note that these
1825 * APIs do not fail but will return unexpected results if called outside a user
1826 * transform callback. Also note that when transforming an interlaced image the
1827 * row number is the row number within the sub-image of the interlace pass, so
1828 * the value will increase to the height of the sub-image (not the full image)
1829 * then reset to 0 for the next pass.
1831 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1832 * find the output pixel (x,y) given an interlaced sub-image pixel
1833 * (row,col,pass). (See below for these macros.)
1835 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1836 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1839 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1840 /* This callback is called only for *unknown* chunks, if
1841 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1842 * chunks to be treated as unknown, however in this case the callback must do
1843 * any processing required by the chunk (e.g. by calling the appropriate
1846 * There is no write support - on write, by default, all the chunks in the
1847 * 'unknown' list are written in the specified position.
1849 * The integer return from the callback function is interpreted thus:
1851 * negative: An error occured, png_chunk_error will be called.
1852 * zero: The chunk was not handled, the chunk will be discarded unless
1853 * png_set_keep_unknown_chunks has been used to set a 'keep' behavior
1854 * for this particular chunk, in which case that will be used. A
1855 * critical chunk will cause an error at this point unless it is to be
1857 * positive: The chunk was handled, libpng will ignore/discard it.
1859 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1860 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1863 #ifdef PNG_USER_CHUNKS_SUPPORTED
1864 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1867 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1868 /* Sets the function callbacks for the push reader, and a pointer to a
1869 * user-defined structure available to the callback functions.
1871 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1872 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1873 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1875 /* Returns the user pointer associated with the push read functions */
1876 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1877 (png_const_structrp png_ptr));
1879 /* Function to be called when data becomes available */
1880 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1881 png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
1883 /* A function which may be called *only* within png_process_data to stop the
1884 * processing of any more data. The function returns the number of bytes
1885 * remaining, excluding any that libpng has cached internally. A subsequent
1886 * call to png_process_data must supply these bytes again. If the argument
1887 * 'save' is set to true the routine will first save all the pending data and
1888 * will always return 0.
1890 PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
1892 /* A function which may be called *only* outside (after) a call to
1893 * png_process_data. It returns the number of bytes of data to skip in the
1894 * input. Normally it will return 0, but if it returns a non-zero value the
1895 * application must skip than number of bytes of input data and pass the
1896 * following data to the next call to png_process_data.
1898 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1900 #ifdef PNG_READ_INTERLACING_SUPPORTED
1901 /* Function that combines rows. 'new_row' is a flag that should come from
1902 * the callback and be non-NULL if anything needs to be done; the library
1903 * stores its own version of the new data internally and ignores the passed
1906 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1907 png_bytep old_row, png_const_bytep new_row));
1908 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1909 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1911 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1912 png_alloc_size_t size), PNG_ALLOCATED);
1913 /* Added at libpng version 1.4.0 */
1914 PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1915 png_alloc_size_t size), PNG_ALLOCATED);
1917 /* Added at libpng version 1.2.4 */
1918 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1919 png_alloc_size_t size), PNG_ALLOCATED);
1921 /* Frees a pointer allocated by png_malloc() */
1922 PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1924 /* Free data that was allocated internally */
1925 PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1926 png_inforp info_ptr, png_uint_32 free_me, int num));
1928 /* Reassign responsibility for freeing existing data, whether allocated
1929 * by libpng or by the application; this works on the png_info structure passed
1930 * in, it does not change the state for other png_info structures.
1932 * It is unlikely that this function works correctly as of 1.6.0 and using it
1933 * may result either in memory leaks or double free of allocated data.
1935 PNG_EXPORTA(99, void, png_data_freer, (png_const_structrp png_ptr,
1936 png_inforp info_ptr, int freer, png_uint_32 mask), PNG_DEPRECATED);
1938 /* Assignments for png_data_freer */
1939 #define PNG_DESTROY_WILL_FREE_DATA 1
1940 #define PNG_SET_WILL_FREE_DATA 1
1941 #define PNG_USER_WILL_FREE_DATA 2
1942 /* Flags for png_ptr->free_me and info_ptr->free_me */
1943 #define PNG_FREE_HIST 0x0008
1944 #define PNG_FREE_ICCP 0x0010
1945 #define PNG_FREE_SPLT 0x0020
1946 #define PNG_FREE_ROWS 0x0040
1947 #define PNG_FREE_PCAL 0x0080
1948 #define PNG_FREE_SCAL 0x0100
1949 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1950 # define PNG_FREE_UNKN 0x0200
1952 /* PNG_FREE_LIST 0x0400 removed in 1.6.0 because it is ignored */
1953 #define PNG_FREE_PLTE 0x1000
1954 #define PNG_FREE_TRNS 0x2000
1955 #define PNG_FREE_TEXT 0x4000
1956 #define PNG_FREE_ALL 0x7fff
1957 #define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1959 #ifdef PNG_USER_MEM_SUPPORTED
1960 PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1961 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1962 PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1963 png_voidp ptr), PNG_DEPRECATED);
1966 #ifdef PNG_ERROR_TEXT_SUPPORTED
1967 /* Fatal error in PNG image of libpng - can't continue */
1968 PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1969 png_const_charp error_message), PNG_NORETURN);
1971 /* The same, but the chunk name is prepended to the error string. */
1972 PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1973 png_const_charp error_message), PNG_NORETURN);
1976 /* Fatal error in PNG image of libpng - can't continue */
1977 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1980 #ifdef PNG_WARNINGS_SUPPORTED
1981 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1982 PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1983 png_const_charp warning_message));
1985 /* Non-fatal error in libpng, chunk name is prepended to message. */
1986 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1987 png_const_charp warning_message));
1990 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1991 /* Benign error in libpng. Can continue, but may have a problem.
1992 * User can choose whether to handle as a fatal error or as a warning. */
1993 PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1994 png_const_charp warning_message));
1996 #ifdef PNG_READ_SUPPORTED
1997 /* Same, chunk name is prepended to message (only during read) */
1998 PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1999 png_const_charp warning_message));
2002 PNG_EXPORT(109, void, png_set_benign_errors,
2003 (png_structrp png_ptr, int allowed));
2005 # ifdef PNG_ALLOW_BENIGN_ERRORS
2006 # define png_benign_error png_warning
2007 # define png_chunk_benign_error png_chunk_warning
2009 # define png_benign_error png_error
2010 # define png_chunk_benign_error png_chunk_error
2014 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
2015 * Similarly, the png_get_<chunk> calls are used to read values from the
2016 * png_info_struct, either storing the parameters in the passed variables, or
2017 * setting pointers into the png_info_struct where the data is stored. The
2018 * png_get_<chunk> functions return a non-zero value if the data was available
2019 * in info_ptr, or return zero and do not change any of the parameters if the
2020 * data was not available.
2022 * These functions should be used instead of directly accessing png_info
2023 * to avoid problems with future changes in the size and internal layout of
2026 /* Returns "flag" if chunk data is valid in info_ptr. */
2027 PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
2028 png_const_inforp info_ptr, png_uint_32 flag));
2030 /* Returns number of bytes needed to hold a transformed row. */
2031 PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
2032 png_const_inforp info_ptr));
2034 #ifdef PNG_INFO_IMAGE_SUPPORTED
2035 /* Returns row_pointers, which is an array of pointers to scanlines that was
2036 * returned from png_read_png().
2038 PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
2039 png_const_inforp info_ptr));
2041 /* Set row_pointers, which is an array of pointers to scanlines for use
2042 * by png_write_png().
2044 PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
2045 png_inforp info_ptr, png_bytepp row_pointers));
2048 /* Returns number of color channels in image. */
2049 PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
2050 png_const_inforp info_ptr));
2052 #ifdef PNG_EASY_ACCESS_SUPPORTED
2053 /* Returns image width in pixels. */
2054 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
2055 png_const_inforp info_ptr));
2057 /* Returns image height in pixels. */
2058 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
2059 png_const_inforp info_ptr));
2061 /* Returns image bit_depth. */
2062 PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
2063 png_const_inforp info_ptr));
2065 /* Returns image color_type. */
2066 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
2067 png_const_inforp info_ptr));
2069 /* Returns image filter_type. */
2070 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
2071 png_const_inforp info_ptr));
2073 /* Returns image interlace_type. */
2074 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
2075 png_const_inforp info_ptr));
2077 /* Returns image compression_type. */
2078 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
2079 png_const_inforp info_ptr));
2081 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
2082 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
2083 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2084 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
2085 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2086 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
2087 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2089 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
2090 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
2091 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2092 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
2093 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2095 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
2096 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
2097 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2098 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
2099 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2100 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
2101 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2102 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
2103 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2105 #endif /* PNG_EASY_ACCESS_SUPPORTED */
2107 #ifdef PNG_READ_SUPPORTED
2108 /* Returns pointer to signature string read from PNG header */
2109 PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
2110 png_const_inforp info_ptr));
2113 #ifdef PNG_bKGD_SUPPORTED
2114 PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
2115 png_inforp info_ptr, png_color_16p *background));
2118 #ifdef PNG_bKGD_SUPPORTED
2119 PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
2120 png_inforp info_ptr, png_const_color_16p background));
2123 #ifdef PNG_cHRM_SUPPORTED
2124 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
2125 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
2126 double *red_y, double *green_x, double *green_y, double *blue_x,
2128 PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
2129 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
2130 double *green_X, double *green_Y, double *green_Z, double *blue_X,
2131 double *blue_Y, double *blue_Z))
2132 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
2133 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2134 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
2135 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
2136 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
2137 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
2138 PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
2139 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2140 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
2141 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
2142 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
2143 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
2144 png_fixed_point *int_blue_Z))
2147 #ifdef PNG_cHRM_SUPPORTED
2148 PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
2149 png_inforp info_ptr,
2150 double white_x, double white_y, double red_x, double red_y, double green_x,
2151 double green_y, double blue_x, double blue_y))
2152 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
2153 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
2154 double green_X, double green_Y, double green_Z, double blue_X,
2155 double blue_Y, double blue_Z))
2156 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
2157 png_inforp info_ptr, png_fixed_point int_white_x,
2158 png_fixed_point int_white_y, png_fixed_point int_red_x,
2159 png_fixed_point int_red_y, png_fixed_point int_green_x,
2160 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2161 png_fixed_point int_blue_y))
2162 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
2163 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
2164 png_fixed_point int_red_Z, png_fixed_point int_green_X,
2165 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
2166 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
2167 png_fixed_point int_blue_Z))
2170 #ifdef PNG_gAMA_SUPPORTED
2171 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
2172 png_const_inforp info_ptr, double *file_gamma))
2173 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2174 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2175 png_fixed_point *int_file_gamma))
2178 #ifdef PNG_gAMA_SUPPORTED
2179 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2180 png_inforp info_ptr, double file_gamma))
2181 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2182 png_inforp info_ptr, png_fixed_point int_file_gamma))
2185 #ifdef PNG_hIST_SUPPORTED
2186 PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2187 png_inforp info_ptr, png_uint_16p *hist));
2190 #ifdef PNG_hIST_SUPPORTED
2191 PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2192 png_inforp info_ptr, png_const_uint_16p hist));
2195 PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2196 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2197 int *bit_depth, int *color_type, int *interlace_method,
2198 int *compression_method, int *filter_method));
2200 PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2201 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2202 int color_type, int interlace_method, int compression_method,
2203 int filter_method));
2205 #ifdef PNG_oFFs_SUPPORTED
2206 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2207 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2211 #ifdef PNG_oFFs_SUPPORTED
2212 PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2213 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2217 #ifdef PNG_pCAL_SUPPORTED
2218 PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2219 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2220 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2221 png_charpp *params));
2224 #ifdef PNG_pCAL_SUPPORTED
2225 PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2226 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2227 int type, int nparams, png_const_charp units, png_charpp params));
2230 #ifdef PNG_pHYs_SUPPORTED
2231 PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2232 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2236 #ifdef PNG_pHYs_SUPPORTED
2237 PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2238 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2241 PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2242 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2244 PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2245 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2247 #ifdef PNG_sBIT_SUPPORTED
2248 PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2249 png_inforp info_ptr, png_color_8p *sig_bit));
2252 #ifdef PNG_sBIT_SUPPORTED
2253 PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2254 png_inforp info_ptr, png_const_color_8p sig_bit));
2257 #ifdef PNG_sRGB_SUPPORTED
2258 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2259 png_const_inforp info_ptr, int *file_srgb_intent));
2262 #ifdef PNG_sRGB_SUPPORTED
2263 PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2264 png_inforp info_ptr, int srgb_intent));
2265 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2266 png_inforp info_ptr, int srgb_intent));
2269 #ifdef PNG_iCCP_SUPPORTED
2270 PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2271 png_inforp info_ptr, png_charpp name, int *compression_type,
2272 png_bytepp profile, png_uint_32 *proflen));
2275 #ifdef PNG_iCCP_SUPPORTED
2276 PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2277 png_inforp info_ptr, png_const_charp name, int compression_type,
2278 png_const_bytep profile, png_uint_32 proflen));
2281 #ifdef PNG_sPLT_SUPPORTED
2282 PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2283 png_inforp info_ptr, png_sPLT_tpp entries));
2286 #ifdef PNG_sPLT_SUPPORTED
2287 PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2288 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2291 #ifdef PNG_TEXT_SUPPORTED
2292 /* png_get_text also returns the number of text chunks in *num_text */
2293 PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2294 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2297 /* Note while png_set_text() will accept a structure whose text,
2298 * language, and translated keywords are NULL pointers, the structure
2299 * returned by png_get_text will always contain regular
2300 * zero-terminated C strings. They might be empty strings but
2301 * they will never be NULL pointers.
2304 #ifdef PNG_TEXT_SUPPORTED
2305 PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2306 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2309 #ifdef PNG_tIME_SUPPORTED
2310 PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2311 png_inforp info_ptr, png_timep *mod_time));
2314 #ifdef PNG_tIME_SUPPORTED
2315 PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2316 png_inforp info_ptr, png_const_timep mod_time));
2319 #ifdef PNG_tRNS_SUPPORTED
2320 PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2321 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2322 png_color_16p *trans_color));
2325 #ifdef PNG_tRNS_SUPPORTED
2326 PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2327 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2328 png_const_color_16p trans_color));
2331 #ifdef PNG_sCAL_SUPPORTED
2332 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2333 png_const_inforp info_ptr, int *unit, double *width, double *height))
2334 #if (defined PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2335 (defined PNG_FLOATING_POINT_SUPPORTED)
2336 /* NOTE: this API is currently implemented using floating point arithmetic,
2337 * consequently it can only be used on systems with floating point support.
2338 * In any case the range of values supported by png_fixed_point is small and it
2339 * is highly recommended that png_get_sCAL_s be used instead.
2341 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2342 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2343 png_fixed_point *width, png_fixed_point *height))
2345 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2346 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2347 png_charpp swidth, png_charpp sheight));
2349 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2350 png_inforp info_ptr, int unit, double width, double height))
2351 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2352 png_inforp info_ptr, int unit, png_fixed_point width,
2353 png_fixed_point height))
2354 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2355 png_inforp info_ptr, int unit,
2356 png_const_charp swidth, png_const_charp sheight));
2357 #endif /* PNG_sCAL_SUPPORTED */
2359 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2360 /* Provide the default handling for all unknown chunks or, optionally, for
2361 * specific unknown chunks.
2363 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2364 * ignored and the default was used, the per-chunk setting only had an effect on
2365 * write. If you wish to have chunk-specific handling on read in code that must
2366 * work on earlier versions you must use a user chunk callback to specify the
2367 * desired handling (keep or discard.)
2369 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2370 * parameter is interpreted as follows:
2373 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2374 * Known chunks: do normal libpng processing, do not keep the chunk (but
2375 * set the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2376 * Unknown chunks: for a specific chunk use the global default, when used
2377 * as the default discard the chunk data.
2378 * PNG_HANDLE_CHUNK_NEVER:
2379 * Discard the chunk data.
2380 * PNG_HANDLE_CHUNK_IF_SAFE:
2381 * Keep the chunk data if the chunk is not critical else raise a chunk
2383 * PNG_HANDLE_CHUNK_ALWAYS:
2384 * Keep the chunk data.
2386 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2387 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2388 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2389 * it simply resets the behavior to the libpng default.
2391 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2392 * callback and the callback returns 0; the chunk is then always stored *unless*
2393 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2394 * the global default is *not* used in this case. (In effect the per-chunk
2395 * value is incremented to at least IF_SAFE.)
2397 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2398 * If this is *not* set known chunks will always be handled by libpng and
2399 * will never be stored in the unknown chunk list. Known chunks listed to
2400 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2401 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2402 * by libpng, in addition critical chunks must either be processed by the
2403 * callback or saved.
2405 * The IHDR and IEND chunks must not be listed. Because this turns off the
2406 * default handling for chunks that would otherwise be recognized the
2407 * behavior of libpng transformations may well become incorrect!
2410 * When writing chunks the options only apply to the chunks specified by
2411 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2412 * required by png_set_ calls and will always write the core critical chunks
2413 * (as required for PLTE).
2415 * Each chunk in the png_set_unknown_chunks list is looked up in the
2416 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2417 * interpreted as follows:
2419 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2420 * Write safe-to-copy chunks and write other chunks if the global
2421 * default is set to _ALWAYS, otherwise don't write this chunk.
2422 * PNG_HANDLE_CHUNK_NEVER:
2423 * Do not write the chunk.
2424 * PNG_HANDLE_CHUNK_IF_SAFE:
2425 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2426 * PNG_HANDLE_CHUNK_ALWAYS:
2429 * Note that the default behavior is effectively the opposite of the read case -
2430 * in read unknown chunks are not stored by default, in write they are written
2431 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2432 * - on write the safe-to-copy bit is checked, on read the critical bit is
2433 * checked and on read if the chunk is critical an error will be raised.
2437 * If num_chunks is positive, then the "keep" parameter specifies the manner
2438 * for handling only those chunks appearing in the chunk_list array,
2439 * otherwise the chunk list array is ignored.
2441 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2442 * unknown chunks, as described above.
2444 * If num_chunks is negative, then the "keep" parameter specifies the manner
2445 * for handling all unknown chunks plus all chunks recognized by libpng
2446 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2447 * be processed by libpng.
2449 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2450 int keep, png_const_bytep chunk_list, int num_chunks));
2452 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2453 * the result is therefore true (non-zero) if special handling is required,
2454 * false for the default handling.
2456 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2457 png_const_bytep chunk_name));
2460 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2461 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2462 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2464 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2465 * unknowns to the location currently stored in the png_struct. This is
2466 * invariably the wrong value on write. To fix this call the following API
2467 * for each chunk in the list with the correct location. If you know your
2468 * code won't be compiled on earlier versions you can rely on
2469 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2470 * the correct thing.
2473 PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2474 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2476 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2477 png_inforp info_ptr, png_unknown_chunkpp entries));
2480 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2481 * If you need to turn it off for a chunk that your application has freed,
2482 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2484 PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2485 png_inforp info_ptr, int mask));
2487 #ifdef PNG_INFO_IMAGE_SUPPORTED
2488 /* The "params" pointer is currently not used and is for future expansion. */
2489 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2490 int transforms, png_voidp params));
2491 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2492 int transforms, png_voidp params));
2495 PNG_EXPORT(180, png_const_charp, png_get_copyright,
2496 (png_const_structrp png_ptr));
2497 PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2498 (png_const_structrp png_ptr));
2499 PNG_EXPORT(182, png_const_charp, png_get_header_version,
2500 (png_const_structrp png_ptr));
2501 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2502 (png_const_structrp png_ptr));
2504 #ifdef PNG_MNG_FEATURES_SUPPORTED
2505 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2506 png_uint_32 mng_features_permitted));
2509 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2510 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2511 #define PNG_HANDLE_CHUNK_NEVER 1
2512 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2513 #define PNG_HANDLE_CHUNK_ALWAYS 3
2514 #define PNG_HANDLE_CHUNK_LAST 4
2516 /* Strip the prepended error numbers ("#nnn ") from error and warning
2517 * messages before passing them to the error or warning handler.
2519 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2520 PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2521 png_uint_32 strip_mode));
2524 /* Added in libpng-1.2.6 */
2525 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2526 PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2527 png_uint_32 user_width_max, png_uint_32 user_height_max));
2528 PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2529 (png_const_structrp png_ptr));
2530 PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2531 (png_const_structrp png_ptr));
2532 /* Added in libpng-1.4.0 */
2533 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2534 png_uint_32 user_chunk_cache_max));
2535 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2536 (png_const_structrp png_ptr));
2537 /* Added in libpng-1.4.1 */
2538 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2539 png_alloc_size_t user_chunk_cache_max));
2540 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2541 (png_const_structrp png_ptr));
2544 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2545 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2546 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2548 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2549 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2551 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2552 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2554 PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2555 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2556 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2557 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2558 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2561 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2562 png_const_inforp info_ptr))
2563 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2564 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2565 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2568 # ifdef PNG_pHYs_SUPPORTED
2569 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2570 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2572 # endif /* PNG_pHYs_SUPPORTED */
2573 #endif /* PNG_INCH_CONVERSIONS_SUPPORTED */
2575 /* Added in libpng-1.4.0 */
2576 #ifdef PNG_IO_STATE_SUPPORTED
2577 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2579 /* Removed from libpng 1.6; use png_get_io_chunk_type. */
2580 PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2583 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2584 (png_const_structrp png_ptr));
2586 /* The flags returned by png_get_io_state() are the following: */
2587 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2588 # define PNG_IO_READING 0x0001 /* currently reading */
2589 # define PNG_IO_WRITING 0x0002 /* currently writing */
2590 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2591 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2592 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2593 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2594 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2595 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2596 #endif /* ?PNG_IO_STATE_SUPPORTED */
2598 /* Interlace support. The following macros are always defined so that if
2599 * libpng interlace handling is turned off the macros may be used to handle
2600 * interlaced images within the application.
2602 #define PNG_INTERLACE_ADAM7_PASSES 7
2604 /* Two macros to return the first row and first column of the original,
2605 * full, image which appears in a given pass. 'pass' is in the range 0
2606 * to 6 and the result is in the range 0 to 7.
2608 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2609 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2611 /* A macro to return the offset between pixels in the output row for a pair of
2612 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2613 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2614 * COL_OFFSET is from one column to the next, within a row.
2616 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2617 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2619 /* Two macros to help evaluate the number of rows or columns in each
2620 * pass. This is expressed as a shift - effectively log2 of the number or
2621 * rows or columns in each 8x8 tile of the original image.
2623 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2624 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2626 /* Hence two macros to determine the number of rows or columns in a given
2627 * pass of an image given its height or width. In fact these macros may
2628 * return non-zero even though the sub-image is empty, because the other
2629 * dimension may be empty for a small image.
2631 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2632 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2633 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2634 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2636 /* For the reader row callbacks (both progressive and sequential) it is
2637 * necessary to find the row in the output image given a row in an interlaced
2638 * image, so two more macros:
2640 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2641 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2642 #define PNG_COL_FROM_PASS_COL(x_in, pass) \
2643 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2645 /* Two macros which return a boolean (0 or 1) saying whether the given row
2646 * or column is in a particular pass. These use a common utility macro that
2647 * returns a mask for a given pass - the offset 'off' selects the row or
2648 * column version. The mask has the appropriate bit set for each column in
2651 #define PNG_PASS_MASK(pass,off) ( \
2652 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2653 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2655 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2656 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2657 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2658 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2660 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2661 /* With these routines we avoid an integer divide, which will be slower on
2662 * most machines. However, it does take more operations than the corresponding
2663 * divide method, so it may be slower on a few RISC systems. There are two
2664 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2666 * Note that the rounding factors are NOT supposed to be the same! 128 and
2667 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2670 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2673 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2675 # define png_composite(composite, fg, alpha, bg) \
2676 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2677 * (png_uint_16)(alpha) \
2678 + (png_uint_16)(bg)*(png_uint_16)(255 \
2679 - (png_uint_16)(alpha)) + 128); \
2680 (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
2682 # define png_composite_16(composite, fg, alpha, bg) \
2683 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2684 * (png_uint_32)(alpha) \
2685 + (png_uint_32)(bg)*(65535 \
2686 - (png_uint_32)(alpha)) + 32768); \
2687 (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
2689 #else /* Standard method using integer division */
2691 # define png_composite(composite, fg, alpha, bg) \
2692 (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2693 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2696 # define png_composite_16(composite, fg, alpha, bg) \
2697 (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2698 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2700 #endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
2702 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2703 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2704 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2705 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2708 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2709 png_const_bytep buf));
2710 /* No png_get_int_16 -- may be added if there's a real need for it. */
2712 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2713 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2714 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2716 #ifdef PNG_SAVE_INT_32_SUPPORTED
2717 PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2720 /* Place a 16-bit number into a buffer in PNG byte order.
2721 * The parameter is declared unsigned int, not png_uint_16,
2722 * just to avoid potential problems on pre-ANSI C compilers.
2724 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2725 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2726 /* No png_save_int_16 -- may be added if there's a real need for it. */
2729 #ifdef PNG_USE_READ_MACROS
2730 /* Inline macros to do direct reads of bytes from the input buffer.
2731 * The png_get_int_32() routine assumes we are using two's complement
2732 * format for negative values, which is almost certainly true.
2734 # define PNG_get_uint_32(buf) \
2735 (((png_uint_32)(*(buf)) << 24) + \
2736 ((png_uint_32)(*((buf) + 1)) << 16) + \
2737 ((png_uint_32)(*((buf) + 2)) << 8) + \
2738 ((png_uint_32)(*((buf) + 3))))
2740 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2741 * function) incorrectly returned a value of type png_uint_32.
2743 # define PNG_get_uint_16(buf) \
2745 (((unsigned int)(*(buf)) << 8) + \
2746 ((unsigned int)(*((buf) + 1)))))
2748 # define PNG_get_int_32(buf) \
2749 ((png_int_32)((*(buf) & 0x80) \
2750 ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
2751 : (png_int_32)png_get_uint_32(buf)))
2753 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2754 * but defining a macro name prefixed with PNG_PREFIX.
2757 # define png_get_uint_32(buf) PNG_get_uint_32(buf)
2758 # define png_get_uint_16(buf) PNG_get_uint_16(buf)
2759 # define png_get_int_32(buf) PNG_get_int_32(buf)
2763 /* No macros; revert to the (redefined) function */
2764 # define PNG_get_uint_32 (png_get_uint_32)
2765 # define PNG_get_uint_16 (png_get_uint_16)
2766 # define PNG_get_int_32 (png_get_int_32)
2770 /*******************************************************************************
2772 *******************************************************************************
2774 * Please read the documentation in libpng-manual.txt (TODO: write said
2775 * documentation) if you don't understand what follows.
2777 * The simplified API hides the details of both libpng and the PNG file format
2778 * itself. It allows PNG files to be read into a very limited number of
2779 * in-memory bitmap formats or to be written from the same formats. If these
2780 * formats do not accomodate your needs then you can, and should, use the more
2781 * sophisticated APIs above - these support a wide variety of in-memory formats
2782 * and a wide variety of sophisticated transformations to those formats as well
2783 * as a wide variety of APIs to manipulate ancillary information.
2785 * To read a PNG file using the simplified API:
2787 * 1) Declare a 'png_image' structure (see below) on the stack and set the
2788 * version field to PNG_IMAGE_VERSION.
2789 * 2) Call the appropriate png_image_begin_read... function.
2790 * 3) Set the png_image 'format' member to the required sample format.
2791 * 4) Allocate a buffer for the image and, if required, the color-map.
2792 * 5) Call png_image_finish_read to read the image and, if required, the
2793 * color-map into your buffers.
2795 * There are no restrictions on the format of the PNG input itself; all valid
2796 * color types, bit depths, and interlace methods are acceptable, and the
2797 * input image is transformed as necessary to the requested in-memory format
2798 * during the png_image_finish_read() step. The only caveat is that if you
2799 * request a color-mapped image from a PNG that is full-color or makes
2800 * complex use of an alpha channel the transformation is extremely lossy and the
2801 * result may look terrible.
2803 * To write a PNG file using the simplified API:
2805 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2806 * 2) Initialize the members of the structure that describe the image, setting
2807 * the 'format' member to the format of the image samples.
2808 * 3) Call the appropriate png_image_write... function with a pointer to the
2809 * image and, if necessary, the color-map to write the PNG data.
2811 * png_image is a structure that describes the in-memory format of an image
2812 * when it is being read or defines the in-memory format of an image that you
2815 #define PNG_IMAGE_VERSION 1
2817 typedef struct png_control *png_controlp;
2820 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2821 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2822 png_uint_32 width; /* Image width in pixels (columns) */
2823 png_uint_32 height; /* Image height in pixels (rows) */
2824 png_uint_32 format; /* Image format as defined below */
2825 png_uint_32 flags; /* A bit mask containing informational flags */
2826 png_uint_32 colormap_entries;
2827 /* Number of entries in the color-map */
2829 /* In the event of an error or warning the following field will be set to a
2830 * non-zero value and the 'message' field will contain a '\0' terminated
2831 * string with the libpng error or warning message. If both warnings and
2832 * an error were encountered, only the error is recorded. If there
2833 * are multiple warnings, only the first one is recorded.
2835 * The upper 30 bits of this value are reserved, the low two bits contain
2836 * a value as follows:
2838 # define PNG_IMAGE_WARNING 1
2839 # define PNG_IMAGE_ERROR 2
2841 * The result is a two bit code such that a value more than 1 indicates
2842 * a failure in the API just called:
2844 * 0 - no warning or error
2847 * 3 - error preceded by warning
2849 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2851 png_uint_32 warning_or_error;
2854 } png_image, *png_imagep;
2856 /* The samples of the image have one to four channels whose components have
2857 * original values in the range 0 to 1.0:
2859 * 1: A single gray or luminance channel (G).
2860 * 2: A gray/luminance channel and an alpha channel (GA).
2861 * 3: Three red, green, blue color channels (RGB).
2862 * 4: Three color channels and an alpha channel (RGBA).
2864 * The components are encoded in one of two ways:
2866 * a) As a small integer, value 0..255, contained in a single byte. For the
2867 * alpha channel the original value is simply value/255. For the color or
2868 * luminance channels the value is encoded according to the sRGB specification
2869 * and matches the 8-bit format expected by typical display devices.
2871 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2872 * channel and are suitable for passing to color management software.
2874 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2875 * channels can be converted to the original value by dividing by 65535; all
2876 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2877 * the sRGB specification. This encoding is identified by the
2878 * PNG_FORMAT_FLAG_LINEAR flag below.
2880 * When the simplified API needs to convert between sRGB and linear colorspaces,
2881 * the actual sRGB transfer curve defined in the sRGB specification (see the
2882 * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2883 * approximation used elsewhere in libpng.
2885 * When an alpha channel is present it is expected to denote pixel coverage
2886 * of the color or luminance channels and is returned as an associated alpha
2887 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2890 * The samples are either contained directly in the image data, between 1 and 8
2891 * bytes per pixel according to the encoding, or are held in a color-map indexed
2892 * by bytes in the image data. In the case of a color-map the color-map entries
2893 * are individual samples, encoded as above, and the image data has one byte per
2894 * pixel to select the relevant sample from the color-map.
2899 * #defines to be used in png_image::format. Each #define identifies a
2900 * particular layout of sample data and, if present, alpha values. There are
2901 * separate defines for each of the two component encodings.
2903 * A format is built up using single bit flag values. All combinations are
2904 * valid. Formats can be built up from the flag values or you can use one of
2905 * the predefined values below. When testing formats always use the FORMAT_FLAG
2906 * macros to test for individual features - future versions of the library may
2909 * When reading or writing color-mapped images the format should be set to the
2910 * format of the entries in the color-map then png_image_{read,write}_colormap
2911 * called to read or write the color-map and set the format correctly for the
2912 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2914 * NOTE: libpng can be built with particular features disabled, if you see
2915 * compiler errors because the definition of one of the following flags has been
2916 * compiled out it is because libpng does not have the required support. It is
2917 * possible, however, for the libpng configuration to enable the format on just
2918 * read or just write; in that case you may see an error at run time. You can
2919 * guard against this by checking for the definition of the appropriate
2920 * "_SUPPORTED" macro, one of:
2922 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2924 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2925 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2926 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2 byte channels else 1 byte */
2927 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2929 #ifdef PNG_FORMAT_BGR_SUPPORTED
2930 # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2933 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
2934 # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2937 /* Commonly used formats have predefined macros.
2939 * First the single byte (sRGB) formats:
2941 #define PNG_FORMAT_GRAY 0
2942 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2943 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2944 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2945 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2946 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2947 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2948 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2949 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2951 /* Then the linear 2-byte formats. When naming these "Y" is used to
2952 * indicate a luminance (gray) channel.
2954 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2955 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2956 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2957 #define PNG_FORMAT_LINEAR_RGB_ALPHA \
2958 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2960 /* With color-mapped formats the image data is one byte for each pixel, the byte
2961 * is an index into the color-map which is formatted as above. To obtain a
2962 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2963 * to one of the above definitions, or you can use one of the definitions below.
2965 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2966 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2967 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2968 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2969 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2970 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2974 * These are convenience macros to derive information from a png_image
2975 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2976 * actual image sample values - either the entries in the color-map or the
2977 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2978 * for the pixels and will always return 1 for color-mapped formats. The
2979 * remaining macros return information about the rows in the image and the
2982 * NOTE: All the macros that take a png_image::format parameter are compile time
2983 * constants if the format parameter is, itself, a constant. Therefore these
2984 * macros can be used in array declarations and case labels where required.
2985 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2986 * they can be used in #if tests.
2988 * First the information about the samples.
2990 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2991 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2992 /* Return the total number of channels in a given format: 1..4 */
2994 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2995 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2996 /* Return the size in bytes of a single component of a pixel or color-map
2997 * entry (as appropriate) in the image: 1 or 2.
3000 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\
3001 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
3002 /* This is the size of the sample data for one sample. If the image is
3003 * color-mapped it is the size of one color-map entry (and image pixels are
3004 * one byte in size), otherwise it is the size of one image pixel.
3007 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
3008 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
3009 /* The maximum size of the color-map required by the format expressed in a
3010 * count of components. This can be used to compile-time allocate a
3013 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
3015 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
3017 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
3018 * information from one of the png_image_begin_read_ APIs and dynamically
3019 * allocate the required memory.
3022 /* Corresponding information about the pixels */
3023 #define PNG_IMAGE_PIXEL_(test,fmt)\
3024 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
3026 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
3027 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
3028 /* The number of separate channels (components) in a pixel; 1 for a
3029 * color-mapped image.
3032 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
3033 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
3034 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
3038 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
3039 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
3041 /* Information about the whole row, or whole image */
3042 #define PNG_IMAGE_ROW_STRIDE(image)\
3043 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
3044 /* Return the total number of components in a single row of the image; this
3045 * is the minimum 'row stride', the minimum count of components between each
3046 * row. For a color-mapped image this is the minimum number of bytes in a
3050 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
3051 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
3052 /* Return the size, in bytes, of an image buffer given a png_image and a row
3053 * stride - the number of components to leave space for in each row.
3056 #define PNG_IMAGE_SIZE(image)\
3057 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
3058 /* Return the size, in bytes, of the image in memory given just a png_image;
3059 * the row stride is the minimum stride required for the image.
3062 #define PNG_IMAGE_COLORMAP_SIZE(image)\
3063 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
3064 /* Return the size, in bytes, of the color-map of this image. If the image
3065 * format is not a color-map format this will return a size sufficient for
3066 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
3067 * you don't want to allocate a color-map in this case.
3072 * Flags containing additional information about the image are held in the
3073 * 'flags' field of png_image.
3075 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
3076 /* This indicates the the RGB values of the in-memory bitmap do not
3077 * correspond to the red, green and blue end-points defined by sRGB.
3080 #define PNG_IMAGE_FLAG_FAST 0x02
3081 /* On write emphasise speed over compression; the resultant PNG file will be
3082 * larger but will be produced significantly faster, particular for large
3083 * images. Do not use this option for images which will be distributed, only
3084 * used it when producing intermediate files that will be read back in
3085 * repeatedly. For a typical 24-bit image the option will double the read
3086 * speed at the cost of increasing the image size by 25%, however for many
3087 * more compressible images the PNG file can be 10 times larger with only a
3088 * slight speed gain.
3091 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
3095 * The png_image passed to the read APIs must have been initialized by setting
3096 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
3098 #ifdef PNG_STDIO_SUPPORTED
3099 PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
3100 const char *file_name));
3101 /* The named file is opened for read and the image header is filled in
3102 * from the PNG header in the file.
3105 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
3107 /* The PNG header is read from the stdio FILE object. */
3108 #endif /* PNG_STDIO_SUPPORTED */
3110 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
3111 png_const_voidp memory, png_size_t size));
3112 /* The PNG header is read from the given memory buffer. */
3114 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
3115 png_const_colorp background, void *buffer, png_int_32 row_stride,
3117 /* Finish reading the image into the supplied buffer and clean up the
3118 * png_image structure.
3120 * row_stride is the step, in byte or 2-byte units as appropriate,
3121 * between adjacent rows. A positive stride indicates that the top-most row
3122 * is first in the buffer - the normal top-down arrangement. A negative
3123 * stride indicates that the bottom-most row is first in the buffer.
3125 * background need only be supplied if an alpha channel must be removed from
3126 * a png_byte format and the removal is to be done by compositing on a solid
3127 * color; otherwise it may be NULL and any composition will be done directly
3128 * onto the buffer. The value is an sRGB color to use for the background,
3129 * for grayscale output the green channel is used.
3131 * background must be supplied when an alpha channel must be removed from a
3132 * single byte color-mapped output format, in other words if:
3134 * 1) The original format from png_image_begin_read_from_* had
3135 * PNG_FORMAT_FLAG_ALPHA set.
3136 * 2) The format set by the application does not.
3137 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3138 * PNG_FORMAT_FLAG_LINEAR *not* set.
3140 * For linear output removing the alpha channel is always done by compositing
3141 * on black and background is ignored.:
3143 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3144 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3145 * image->colormap_entries will be updated to the actual number of entries
3146 * written to the colormap; this may be less than the original value.
3149 PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3150 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3151 * NULL. May be called at any time after the structure is initialized.
3153 #endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
3155 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3158 * For write you must initialize a png_image structure to describe the image to
3159 * be written. To do this use memset to set the whole structure to 0 then
3160 * initialize fields describing your image.
3162 * version: must be set to PNG_IMAGE_VERSION
3163 * opaque: must be initialized to NULL
3164 * width: image width in pixels
3165 * height: image height in rows
3166 * format: the format of the data (image and color-map) you wish to write
3167 * flags: set to 0 unless one of the defined flags applies; set
3168 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3169 * values do not correspond to the colors in sRGB.
3170 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3172 PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3173 const char *file, int convert_to_8bit, const void *buffer,
3174 png_int_32 row_stride, const void *colormap));
3175 /* Write the image to the named file. */
3177 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3178 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3179 const void *colormap));
3180 /* Write the image to the given (FILE*). */
3182 /* With both write APIs if image is in one of the linear formats with 16-bit
3183 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3184 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3185 * encoded PNG file is written.
3187 * With color-mapped data formats the colormap parameter point to a color-map
3188 * with at least image->colormap_entries encoded in the specified format. If
3189 * the format is linear the written PNG color-map will be converted to sRGB
3190 * regardless of the convert_to_8_bit flag.
3192 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3193 * from one row to the next in component sized units (1 or 2 bytes) and if
3194 * negative indicates a bottom-up row layout in the buffer.
3196 * Note that the write API does not support interlacing or sub-8-bit pixels.
3198 #endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
3199 /*******************************************************************************
3200 * END OF SIMPLIFIED API
3201 ******************************************************************************/
3203 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
3204 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
3205 (png_structrp png_ptr, int allowed));
3206 # ifdef PNG_GET_PALETTE_MAX_SUPPORTED
3207 PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
3208 png_const_infop info_ptr));
3210 #endif /* CHECK_FOR_INVALID_INDEX */
3212 /* Maintainer: Put new public prototypes here ^, in libpng.3, and project
3213 * defs, scripts/pnglibconf.h, and scripts/pnglibconf.h.prebuilt
3216 /* The last ordinal number (this is the *last* one already used; the next
3217 * one to use is one more than this.) Maintainer, remember to add an entry to
3218 * scripts/symbols.def as well.
3220 #ifdef PNG_EXPORT_LAST_ORDINAL
3221 PNG_EXPORT_LAST_ORDINAL(243);
3228 #endif /* PNG_VERSION_INFO_ONLY */
3229 /* Do not put anything past this line */
projects / l4.git / blob