2 /* png.h - header file for PNG reference library
4 * libpng version 1.5.4 - July 7, 2011
5 * Copyright (c) 1998-2011 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 1.5.4 - July 7, 2011: 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]
161 * Henceforth the source version will match the shared-library major
162 * and minor numbers; the shared-library major version number will be
163 * used for changes in backward compatibility, as it is intended. The
164 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
165 * for applications, is an unsigned integer of the form xyyzz corresponding
166 * to the source version x.y.z (leading zeros in y and z). Beta versions
167 * were given the previous public release number plus a letter, until
168 * version 1.0.6j; from then on they were given the upcoming public
169 * release number plus "betaNN" or "rcN".
171 * Binary incompatibility exists only when applications make direct access
172 * to the info_ptr or png_ptr members through png.h, and the compiled
173 * application is loaded with a different version of the library.
175 * DLLNUM will change each time there are forward or backward changes
176 * in binary compatibility (e.g., when a new feature is added).
178 * See libpng-manual.txt or libpng.3 for more information. The PNG
179 * specification is available as a W3C Recommendation and as an ISO
180 * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
184 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
186 * If you modify libpng you may insert additional notices immediately following
189 * This code is released under the libpng license.
191 * libpng versions 1.2.6, August 15, 2004, through 1.5.4, July 7, 2011, are
192 * Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
193 * distributed according to the same disclaimer and license as libpng-1.2.5
194 * with the following individual added to the list of Contributing Authors:
198 * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
199 * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
200 * distributed according to the same disclaimer and license as libpng-1.0.6
201 * with the following individuals added to the list of Contributing Authors:
203 * Simon-Pierre Cadieux
207 * and with the following additions to the disclaimer:
209 * There is no warranty against interference with your enjoyment of the
210 * library or against infringement. There is no warranty that our
211 * efforts or the library will fulfill any of your particular purposes
212 * or needs. This library is provided with all faults, and the entire
213 * risk of satisfactory quality, performance, accuracy, and effort is with
216 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
217 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
218 * distributed according to the same disclaimer and license as libpng-0.96,
219 * with the following individuals added to the list of Contributing Authors:
222 * Glenn Randers-Pehrson
225 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
226 * Copyright (c) 1996, 1997 Andreas Dilger
227 * Distributed according to the same disclaimer and license as libpng-0.88,
228 * with the following individuals added to the list of Contributing Authors:
237 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
238 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
240 * For the purposes of this copyright and license, "Contributing Authors"
241 * is defined as the following set of individuals:
249 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
250 * and Group 42, Inc. disclaim all warranties, expressed or implied,
251 * including, without limitation, the warranties of merchantability and of
252 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
253 * assume no liability for direct, indirect, incidental, special, exemplary,
254 * or consequential damages, which may result from the use of the PNG
255 * Reference Library, even if advised of the possibility of such damage.
257 * Permission is hereby granted to use, copy, modify, and distribute this
258 * source code, or portions hereof, for any purpose, without fee, subject
259 * to the following restrictions:
261 * 1. The origin of this source code must not be misrepresented.
263 * 2. Altered versions must be plainly marked as such and must not
264 * be misrepresented as being the original source.
266 * 3. This Copyright notice may not be removed or altered from
267 * any source or altered source distribution.
269 * The Contributing Authors and Group 42, Inc. specifically permit, without
270 * fee, and encourage the use of this source code as a component to
271 * supporting the PNG file format in commercial products. If you use this
272 * source code in a product, acknowledgment is not required but would be
277 * A "png_get_copyright" function is available, for convenient use in "about"
278 * boxes and the like:
280 * printf("%s", png_get_copyright(NULL));
282 * Also, the PNG logo (in PNG format, of course) is supplied in the
283 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
287 * Libpng is OSI Certified Open Source Software. OSI Certified is a
288 * certification mark of the Open Source Initiative.
292 * The contributing authors would like to thank all those who helped
293 * with testing, bug fixes, and patience. This wouldn't have been
294 * possible without all of you.
296 * Thanks to Frank J. T. Wojcik for helping with the documentation.
300 * Y2K compliance in libpng:
301 * =========================
305 * Since the PNG Development group is an ad-hoc body, we can't make
306 * an official declaration.
308 * This is your unofficial assurance that libpng from version 0.71 and
309 * upward through 1.5.4 are Y2K compliant. It is my belief that
310 * earlier versions were also Y2K compliant.
312 * Libpng only has two year fields. One is a 2-byte unsigned integer
313 * that will hold years up to 65535. The other holds the date in text
314 * format, and will hold years up to 9999.
317 * "png_uint_16 year" in png_time_struct.
320 * "png_char time_buffer" in png_struct
322 * There are seven time-related functions:
323 * png.c: png_convert_to_rfc_1123() in png.c
324 * (formerly png_convert_to_rfc_1152() in error)
325 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
326 * png_convert_from_time_t() in pngwrite.c
327 * png_get_tIME() in pngget.c
328 * png_handle_tIME() in pngrutil.c, called in pngread.c
329 * png_set_tIME() in pngset.c
330 * png_write_tIME() in pngwutil.c, called in pngwrite.c
332 * All handle dates properly in a Y2K environment. The
333 * png_convert_from_time_t() function calls gmtime() to convert from system
334 * clock time, which returns (year - 1900), which we properly convert to
335 * the full 4-digit year. There is a possibility that applications using
336 * libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
337 * function, or that they are incorrectly passing only a 2-digit year
338 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
339 * but this is not under our control. The libpng documentation has always
340 * stated that it works with 4-digit years, and the APIs have been
341 * documented as such.
343 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
344 * integer to hold the year, and can hold years as large as 65535.
346 * zlib, upon which libpng depends, is also Y2K compliant. It contains
347 * no date-related code.
349 * Glenn Randers-Pehrson
351 * PNG Development Group
357 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
358 * describes how to use libpng, and the file example.c summarizes it
359 * with some code on which to build. This file is useful for looking
360 * at the actual function definitions and structure components.
363 /* Version information for png.h - this should match the version in png.c */
364 #define PNG_LIBPNG_VER_STRING "1.5.4"
365 #define PNG_HEADER_VERSION_STRING \
366 " libpng version 1.5.4 - July 7, 2011\n"
368 #define PNG_LIBPNG_VER_SONUM 15
369 #define PNG_LIBPNG_VER_DLLNUM 15
371 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
372 #define PNG_LIBPNG_VER_MAJOR 1
373 #define PNG_LIBPNG_VER_MINOR 5
374 #define PNG_LIBPNG_VER_RELEASE 4
375 /* This should match the numeric part of the final component of
376 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
379 #define PNG_LIBPNG_VER_BUILD 0
382 #define PNG_LIBPNG_BUILD_ALPHA 1
383 #define PNG_LIBPNG_BUILD_BETA 2
384 #define PNG_LIBPNG_BUILD_RC 3
385 #define PNG_LIBPNG_BUILD_STABLE 4
386 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
388 /* Release-Specific Flags */
389 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
390 PNG_LIBPNG_BUILD_STABLE only */
391 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
392 PNG_LIBPNG_BUILD_SPECIAL */
393 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
394 PNG_LIBPNG_BUILD_PRIVATE */
396 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
398 /* Careful here. At one time, Guy wanted to use 082, but that would be octal.
399 * We must not include leading zeros.
400 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
401 * version 1.0.0 was mis-numbered 100 instead of 10000). From
402 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
404 #define PNG_LIBPNG_VER 10504 /* 1.5.4 */
406 /* Library configuration: these options cannot be changed after
407 * the library has been built.
410 /* If pnglibconf.h is missing, you can
411 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
413 # include "pnglibconf.h"
416 #ifndef PNG_VERSION_INFO_ONLY
417 # ifndef PNG_BUILDING_SYMBOL_TABLE
419 * Standard header files (not needed for the version info or while
420 * building symbol table -- see scripts/pnglibconf.dfa)
422 # ifdef PNG_SETJMP_SUPPORTED
426 /* Need the time information for converting tIME chunks, it
429 # ifdef PNG_CONVERT_tIME_SUPPORTED
430 /* "time.h" functions are not supported on all operating systems */
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.
485 * The library source code has additional files (principally pngpriv.h) that
486 * allow configuration of the library.
488 /* Section 1: run time configuration
489 * See pnglibconf.h for build time configuration
491 * Run time configuration allows the application to choose between
492 * implementations of certain arithmetic APIs. The default is set
493 * at build time and recorded in pnglibconf.h, but it is safe to
494 * override these (and only these) settings. Note that this won't
495 * change what the library does, only application code, and the
496 * settings can (and probably should) be made on a per-file basis
497 * by setting the #defines before including png.h
499 * Use macros to read integers from PNG data or use the exported
501 * PNG_USE_READ_MACROS: use the macros (see below) Note that
502 * the macros evaluate their argument multiple times.
503 * PNG_NO_USE_READ_MACROS: call the relevant library function.
505 * Use the alternative algorithm for compositing alpha samples that
506 * does not use division?
507 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
509 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
511 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
513 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
514 * APIs to png_warning.
515 * Otherwise the calls are mapped to png_error.
518 /* Section 2: type definitions, including structures and compile time
520 * See pngconf.h for base types that vary by machine/system
523 /* This triggers a compiler error in png.c, if png.c and png.h
524 * do not agree upon the version number.
526 typedef char* png_libpng_version_1_5_4;
528 /* Three color definitions. The order of the red, green, and blue, (and the
529 * exact size) is not important, although the size of the fields need to
530 * be png_byte or png_uint_16 (as defined below).
532 typedef struct png_color_struct
538 typedef png_color FAR * png_colorp;
539 typedef PNG_CONST png_color FAR * png_const_colorp;
540 typedef png_color FAR * FAR * png_colorpp;
542 typedef struct png_color_16_struct
544 png_byte index; /* used for palette files */
545 png_uint_16 red; /* for use in red green blue files */
548 png_uint_16 gray; /* for use in grayscale files */
550 typedef png_color_16 FAR * png_color_16p;
551 typedef PNG_CONST png_color_16 FAR * png_const_color_16p;
552 typedef png_color_16 FAR * FAR * png_color_16pp;
554 typedef struct png_color_8_struct
556 png_byte red; /* for use in red green blue files */
559 png_byte gray; /* for use in grayscale files */
560 png_byte alpha; /* for alpha channel files */
562 typedef png_color_8 FAR * png_color_8p;
563 typedef PNG_CONST png_color_8 FAR * png_const_color_8p;
564 typedef png_color_8 FAR * FAR * png_color_8pp;
567 * The following two structures are used for the in-core representation
570 typedef struct png_sPLT_entry_struct
576 png_uint_16 frequency;
578 typedef png_sPLT_entry FAR * png_sPLT_entryp;
579 typedef PNG_CONST png_sPLT_entry FAR * png_const_sPLT_entryp;
580 typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;
582 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples
583 * occupy the LSB of their respective members, and the MSB of each member
584 * is zero-filled. The frequency member always occupies the full 16 bits.
587 typedef struct png_sPLT_struct
589 png_charp name; /* palette name */
590 png_byte depth; /* depth of palette samples */
591 png_sPLT_entryp entries; /* palette entries */
592 png_int_32 nentries; /* number of palette entries */
594 typedef png_sPLT_t FAR * png_sPLT_tp;
595 typedef PNG_CONST png_sPLT_t FAR * png_const_sPLT_tp;
596 typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;
598 #ifdef PNG_TEXT_SUPPORTED
599 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
600 * and whether that contents is compressed or not. The "key" field
601 * points to a regular zero-terminated C string. The "text", "lang", and
602 * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
603 * However, the structure returned by png_get_text() will always contain
604 * regular zero-terminated C strings (possibly empty), never NULL pointers,
605 * so they can be safely used in printf() and other string-handling functions.
607 typedef struct png_text_struct
609 int compression; /* compression value:
614 png_charp key; /* keyword, 1-79 character description of "text" */
615 png_charp text; /* comment, may be an empty string (ie "")
617 png_size_t text_length; /* length of the text string */
618 png_size_t itxt_length; /* length of the itxt string */
619 png_charp lang; /* language code, 0-79 characters
621 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
622 chars or a NULL pointer */
624 typedef png_text FAR * png_textp;
625 typedef PNG_CONST png_text FAR * png_const_textp;
626 typedef png_text FAR * FAR * png_textpp;
629 /* Supported compression types for text in PNG files (tEXt, and zTXt).
630 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
631 #define PNG_TEXT_COMPRESSION_NONE_WR -3
632 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
633 #define PNG_TEXT_COMPRESSION_NONE -1
634 #define PNG_TEXT_COMPRESSION_zTXt 0
635 #define PNG_ITXT_COMPRESSION_NONE 1
636 #define PNG_ITXT_COMPRESSION_zTXt 2
637 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
639 /* png_time is a way to hold the time in an machine independent way.
640 * Two conversions are provided, both from time_t and struct tm. There
641 * is no portable way to convert to either of these structures, as far
642 * as I know. If you know of a portable way, send it to me. As a side
643 * note - PNG has always been Year 2000 compliant!
645 typedef struct png_time_struct
647 png_uint_16 year; /* full year, as in, 1995 */
648 png_byte month; /* month of year, 1 - 12 */
649 png_byte day; /* day of month, 1 - 31 */
650 png_byte hour; /* hour of day, 0 - 23 */
651 png_byte minute; /* minute of hour, 0 - 59 */
652 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
654 typedef png_time FAR * png_timep;
655 typedef PNG_CONST png_time FAR * png_const_timep;
656 typedef png_time FAR * FAR * png_timepp;
658 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
659 defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
660 /* png_unknown_chunk is a structure to hold queued chunks for which there is
661 * no specific support. The idea is that we can use this to queue
662 * up private chunks for output even though the library doesn't actually
663 * know about their semantics.
665 typedef struct png_unknown_chunk_t
671 /* libpng-using applications should NOT directly modify this byte. */
672 png_byte location; /* mode of operation at read time */
677 typedef png_unknown_chunk FAR * png_unknown_chunkp;
678 typedef PNG_CONST png_unknown_chunk FAR * png_const_unknown_chunkp;
679 typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
682 /* Values for the unknown chunk location byte */
684 #define PNG_HAVE_IHDR 0x01
685 #define PNG_HAVE_PLTE 0x02
686 #define PNG_AFTER_IDAT 0x08
688 /* The complete definition of png_info has, as of libpng-1.5.0,
689 * been moved into a separate header file that is not accessible to
690 * applications. Read libpng-manual.txt or libpng.3 for more info.
692 typedef struct png_info_def png_info;
693 typedef png_info FAR * png_infop;
694 typedef PNG_CONST png_info FAR * png_const_infop;
695 typedef png_info FAR * FAR * png_infopp;
697 /* Maximum positive integer used in PNG is (2^31)-1 */
698 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
699 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
700 #define PNG_SIZE_MAX ((png_size_t)(-1))
702 /* These are constants for fixed point values encoded in the
703 * PNG specification manner (x100000)
705 #define PNG_FP_1 100000
706 #define PNG_FP_HALF 50000
707 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
708 #define PNG_FP_MIN (-PNG_FP_MAX)
710 /* These describe the color_type field in png_info. */
711 /* color type masks */
712 #define PNG_COLOR_MASK_PALETTE 1
713 #define PNG_COLOR_MASK_COLOR 2
714 #define PNG_COLOR_MASK_ALPHA 4
716 /* color types. Note that not all combinations are legal */
717 #define PNG_COLOR_TYPE_GRAY 0
718 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
719 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
720 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
721 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
723 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
724 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
726 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
727 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
728 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
730 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
731 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
732 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
733 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
735 /* These are for the interlacing type. These values should NOT be changed. */
736 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
737 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
738 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
740 /* These are for the oFFs chunk. These values should NOT be changed. */
741 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
742 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
743 #define PNG_OFFSET_LAST 2 /* Not a valid value */
745 /* These are for the pCAL chunk. These values should NOT be changed. */
746 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
747 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
748 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
749 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
750 #define PNG_EQUATION_LAST 4 /* Not a valid value */
752 /* These are for the sCAL chunk. These values should NOT be changed. */
753 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
754 #define PNG_SCALE_METER 1 /* meters per pixel */
755 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
756 #define PNG_SCALE_LAST 3 /* Not a valid value */
758 /* These are for the pHYs chunk. These values should NOT be changed. */
759 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
760 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
761 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
763 /* These are for the sRGB chunk. These values should NOT be changed. */
764 #define PNG_sRGB_INTENT_PERCEPTUAL 0
765 #define PNG_sRGB_INTENT_RELATIVE 1
766 #define PNG_sRGB_INTENT_SATURATION 2
767 #define PNG_sRGB_INTENT_ABSOLUTE 3
768 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
770 /* This is for text chunks */
771 #define PNG_KEYWORD_MAX_LENGTH 79
773 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
774 #define PNG_MAX_PALETTE_LENGTH 256
776 /* These determine if an ancillary chunk's data has been successfully read
777 * from the PNG header, or if the application has filled in the corresponding
778 * data in the info_struct to be written into the output file. The values
779 * of the PNG_INFO_<chunk> defines should NOT be changed.
781 #define PNG_INFO_gAMA 0x0001
782 #define PNG_INFO_sBIT 0x0002
783 #define PNG_INFO_cHRM 0x0004
784 #define PNG_INFO_PLTE 0x0008
785 #define PNG_INFO_tRNS 0x0010
786 #define PNG_INFO_bKGD 0x0020
787 #define PNG_INFO_hIST 0x0040
788 #define PNG_INFO_pHYs 0x0080
789 #define PNG_INFO_oFFs 0x0100
790 #define PNG_INFO_tIME 0x0200
791 #define PNG_INFO_pCAL 0x0400
792 #define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
793 #define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
794 #define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
795 #define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
796 #define PNG_INFO_IDAT 0x8000L /* ESR, 1.0.6 */
798 /* This is used for the transformation routines, as some of them
799 * change these values for the row. It also should enable using
800 * the routines for other purposes.
802 typedef struct png_row_info_struct
804 png_uint_32 width; /* width of row */
805 png_size_t rowbytes; /* number of bytes in row */
806 png_byte color_type; /* color type of row */
807 png_byte bit_depth; /* bit depth of row */
808 png_byte channels; /* number of channels (1, 2, 3, or 4) */
809 png_byte pixel_depth; /* bits per pixel (depth * channels) */
812 typedef png_row_info FAR * png_row_infop;
813 typedef png_row_info FAR * FAR * png_row_infopp;
815 /* The complete definition of png_struct has, as of libpng-1.5.0,
816 * been moved into a separate header file that is not accessible to
817 * applications. Read libpng-manual.txt or libpng.3 for more info.
819 typedef struct png_struct_def png_struct;
820 typedef PNG_CONST png_struct FAR * png_const_structp;
821 typedef png_struct FAR * png_structp;
823 /* These are the function types for the I/O functions and for the functions
824 * that allow the user to override the default I/O functions with his or her
825 * own. The png_error_ptr type should match that of user-supplied warning
826 * and error functions, while the png_rw_ptr type should match that of the
827 * user read/write data functions. Note that the 'write' function must not
828 * modify the buffer it is passed. The 'read' function, on the other hand, is
829 * expected to return the read data in the buffer.
831 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
832 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
833 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
834 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
836 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
839 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
840 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
841 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
843 /* The following callback receives png_uint_32 row_number, int pass for the
844 * png_bytep data of the row. When transforming an interlaced image the
845 * row number is the row number within the sub-image of the interlace pass, so
846 * the value will increase to the height of the sub-image (not the full image)
847 * then reset to 0 for the next pass.
849 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
850 * find the output pixel (x,y) given an interlaced sub-image pixel
851 * (row,col,pass). (See below for these macros.)
853 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
857 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
858 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
859 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
863 #ifdef PNG_USER_CHUNKS_SUPPORTED
864 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
865 png_unknown_chunkp));
867 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
868 typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp));
871 #ifdef PNG_SETJMP_SUPPORTED
872 /* This must match the function definition in <setjmp.h>, and the application
873 * must include this before png.h to obtain the definition of jmp_buf. The
874 * function is required to be PNG_NORETURN, but this is not checked. If the
875 * function does return the application will crash via an abort() or similar
878 * If you get a warning here while building the library you may need to make
879 * changes to ensure that pnglibconf.h records the calling convention used by
880 * your compiler. This may be very difficult - try using a different compiler
881 * to build the library!
883 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
886 /* Transform masks for the high-level interface */
887 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
888 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
889 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
890 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
891 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
892 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
893 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
894 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
895 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
896 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
897 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
898 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
899 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
900 /* Added to libpng-1.2.34 */
901 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
902 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
903 /* Added to libpng-1.4.0 */
904 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
905 /* Added to libpng-1.5.4 */
906 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
907 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
909 /* Flags for MNG supported features */
910 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
911 #define PNG_FLAG_MNG_FILTER_64 0x04
912 #define PNG_ALL_MNG_FEATURES 0x05
914 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
915 * this allowed the zlib default functions to be used on Windows
916 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
917 * ignores the first argument) should be completely compatible with the
920 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
922 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
924 typedef png_struct FAR * FAR * png_structpp;
926 /* Section 3: exported functions
927 * Here are the function definitions most commonly used. This is not
928 * the place to find out how to use libpng. See libpng-manual.txt for the
929 * full explanation, see example.c for the summary. This just provides
930 * a simple one line description of the use of each function.
932 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
933 * pngconf.h and in the *.dfn files in the scripts directory.
935 * PNG_EXPORT(ordinal, type, name, (args));
937 * ordinal: ordinal that is used while building
938 * *.def files. The ordinal value is only
939 * relevant when preprocessing png.h with
940 * the *.dfn files for building symbol table
941 * entries, and are removed by pngconf.h.
942 * type: return type of the function
943 * name: function name
944 * args: function arguments, with types
946 * When we wish to append attributes to a function prototype we use
947 * the PNG_EXPORTA() macro instead.
949 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
951 * ordinal, type, name, and args: same as in PNG_EXPORT().
952 * attributes: function attributes
955 /* Returns the version number of the library */
956 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
958 /* Tell lib we have already handled the first <num_bytes> magic bytes.
959 * Handling more than 8 bytes from the beginning of the file is an error.
961 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structp png_ptr, int num_bytes));
963 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
964 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
965 * signature, and non-zero otherwise. Having num_to_check == 0 or
966 * start > 7 will always fail (ie return non-zero).
968 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
969 png_size_t num_to_check));
971 /* Simple signature checking function. This is the same as calling
972 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
974 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
976 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
977 PNG_EXPORTA(4, png_structp, png_create_read_struct,
978 (png_const_charp user_png_ver, png_voidp error_ptr,
979 png_error_ptr error_fn, png_error_ptr warn_fn),
982 /* Allocate and initialize png_ptr struct for writing, and any other memory */
983 PNG_EXPORTA(5, png_structp, png_create_write_struct,
984 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
985 png_error_ptr warn_fn),
988 PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
989 (png_const_structp png_ptr));
991 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structp png_ptr,
994 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
997 #ifdef PNG_SETJMP_SUPPORTED
998 /* This function returns the jmp_buf built in to *png_ptr. It must be
999 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
1000 * unless the default error function is overridden in which case NULL is
1001 * acceptable. The size of the jmp_buf is checked against the actual size
1002 * allocated by the library - the call will return NULL on a mismatch
1003 * indicating an ABI mismatch.
1005 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structp png_ptr,
1006 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
1007 # define png_jmpbuf(png_ptr) \
1008 (*png_set_longjmp_fn((png_ptr), longjmp, sizeof (jmp_buf)))
1010 # define png_jmpbuf(png_ptr) \
1011 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
1013 /* This function should be used by libpng applications in place of
1014 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
1015 * will use it; otherwise it will call PNG_ABORT(). This function was
1016 * added in libpng-1.5.0.
1018 PNG_EXPORTA(9, void, png_longjmp, (png_structp png_ptr, int val),
1021 #ifdef PNG_READ_SUPPORTED
1022 /* Reset the compression stream */
1023 PNG_EXPORT(10, int, png_reset_zstream, (png_structp png_ptr));
1026 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1027 #ifdef PNG_USER_MEM_SUPPORTED
1028 PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1029 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1030 png_error_ptr warn_fn,
1031 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1033 PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1034 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1035 png_error_ptr warn_fn,
1036 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1040 /* Write the PNG file signature. */
1041 PNG_EXPORT(13, void, png_write_sig, (png_structp png_ptr));
1043 /* Write a PNG chunk - size, type, (optional) data, CRC. */
1044 PNG_EXPORT(14, void, png_write_chunk, (png_structp png_ptr, png_const_bytep
1045 chunk_name, png_const_bytep data, png_size_t length));
1047 /* Write the start of a PNG chunk - length and chunk name. */
1048 PNG_EXPORT(15, void, png_write_chunk_start, (png_structp png_ptr,
1049 png_const_bytep chunk_name, png_uint_32 length));
1051 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1052 PNG_EXPORT(16, void, png_write_chunk_data, (png_structp png_ptr,
1053 png_const_bytep data, png_size_t length));
1055 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1056 PNG_EXPORT(17, void, png_write_chunk_end, (png_structp png_ptr));
1058 /* Allocate and initialize the info structure */
1059 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_structp png_ptr),
1062 PNG_EXPORT(19, void, png_info_init_3, (png_infopp info_ptr,
1063 png_size_t png_info_struct_size));
1065 /* Writes all the PNG information before the image. */
1066 PNG_EXPORT(20, void, png_write_info_before_PLTE,
1067 (png_structp png_ptr, png_infop info_ptr));
1068 PNG_EXPORT(21, void, png_write_info,
1069 (png_structp png_ptr, png_infop info_ptr));
1071 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1072 /* Read the information before the actual image data. */
1073 PNG_EXPORT(22, void, png_read_info,
1074 (png_structp png_ptr, png_infop info_ptr));
1077 #ifdef PNG_TIME_RFC1123_SUPPORTED
1078 PNG_EXPORT(23, png_const_charp, png_convert_to_rfc1123,
1079 (png_structp png_ptr,
1080 png_const_timep ptime));
1083 #ifdef PNG_CONVERT_tIME_SUPPORTED
1084 /* Convert from a struct tm to png_time */
1085 PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1086 PNG_CONST struct tm FAR * ttime));
1088 /* Convert from time_t to png_time. Uses gmtime() */
1089 PNG_EXPORT(25, void, png_convert_from_time_t,
1090 (png_timep ptime, time_t ttime));
1091 #endif /* PNG_CONVERT_tIME_SUPPORTED */
1093 #ifdef PNG_READ_EXPAND_SUPPORTED
1094 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1095 PNG_EXPORT(26, void, png_set_expand, (png_structp png_ptr));
1096 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structp png_ptr));
1097 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structp png_ptr));
1098 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structp png_ptr));
1101 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1102 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1103 * of a tRNS chunk if present.
1105 PNG_EXPORT(221, void, png_set_expand_16, (png_structp png_ptr));
1108 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1109 /* Use blue, green, red order for pixels. */
1110 PNG_EXPORT(30, void, png_set_bgr, (png_structp png_ptr));
1113 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1114 /* Expand the grayscale to 24-bit RGB if necessary. */
1115 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structp png_ptr));
1118 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1119 /* Reduce RGB to grayscale. */
1120 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structp png_ptr,
1121 int error_action, double red, double green));
1122 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structp png_ptr,
1123 int error_action, png_fixed_point red, png_fixed_point green));
1125 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structp
1129 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1130 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1131 png_colorp palette));
1134 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1135 /* How the alpha channel is interpreted - this affects how the color channels of
1136 * a PNG file are returned when an alpha channel, or tRNS chunk in a palette
1139 * This has no effect on the way pixels are written into a PNG output
1140 * datastream. The color samples in a PNG datastream are never premultiplied
1141 * with the alpha samples.
1143 * The default is to return data according to the PNG specification: the alpha
1144 * channel is a linear measure of the contribution of the pixel to the
1145 * corresponding composited pixel. The gamma encoded color channels must be
1146 * scaled according to the contribution and to do this it is necessary to undo
1147 * the encoding, scale the color values, perform the composition and reencode
1148 * the values. This is the 'PNG' mode.
1150 * The alternative is to 'associate' the alpha with the color information by
1151 * storing color channel values that have been scaled by the alpha. The
1152 * advantage is that the color channels can be resampled (the image can be
1153 * scaled) in this form. The disadvantage is that normal practice is to store
1154 * linear, not (gamma) encoded, values and this requires 16-bit channels for
1155 * still images rather than the 8-bit channels that are just about sufficient if
1156 * gamma encoding is used. In addition all non-transparent pixel values,
1157 * including completely opaque ones, must be gamma encoded to produce the final
1158 * image. This is the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' mode (the
1159 * latter being the two common names for associated alpha color channels.)
1161 * Since it is not necessary to perform arithmetic on opaque color values so
1162 * long as they are not to be resampled and are in the final color space it is
1163 * possible to optimize the handling of alpha by storing the opaque pixels in
1164 * the PNG format (adjusted for the output color space) while storing partially
1165 * opaque pixels in the standard, linear, format. The accuracy required for
1166 * standard alpha composition is relatively low, because the pixels are
1167 * isolated, therefore typically the accuracy loss in storing 8-bit linear
1168 * values is acceptable. (This is not true if the alpha channel is used to
1169 * simulate transparency over large areas - use 16 bits or the PNG mode in
1170 * this case!) This is the 'OPTIMIZED' mode. For this mode a pixel is
1171 * treated as opaque only if the alpha value is equal to the maximum value.
1173 * The final choice is to gamma encode the alpha channel as well. This is
1174 * broken because, in practice, no implementation that uses this choice
1175 * correctly undoes the encoding before handling alpha composition. Use this
1176 * choice only if other serious errors in the software or hardware you use
1177 * mandate it; the typical serious error is for dark halos to appear around
1178 * opaque areas of the composited PNG image because of arithmetic overflow.
1180 * The API function png_set_alpha_mode specifies which of these choices to use
1181 * with an enumerated 'mode' value and the gamma of the required output:
1183 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1184 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1185 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1186 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1187 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1188 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1190 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structp png_ptr, int mode,
1191 double output_gamma));
1192 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structp png_ptr,
1193 int mode, png_fixed_point output_gamma));
1196 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1197 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1198 * how to decode the output values, not how they are encoded. The values used
1199 * correspond to the normal numbers used to describe the overall gamma of a
1200 * computer display system; for example 2.2 for an sRGB conformant system. The
1201 * values are scaled by 100000 in the _fixed version of the API (so 220000 for
1204 * The inverse of the value is always used to provide a default for the PNG file
1205 * encoding if it has no gAMA chunk and if png_set_gamma() has not been called
1206 * to override the PNG gamma information.
1208 * When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
1209 * opaque pixels however pixels with lower alpha values are not encoded,
1210 * regardless of the output gamma setting.
1212 * When the standard Porter Duff handling is requested with mode 1 the output
1213 * encoding is set to be linear and the output_gamma value is only relevant
1214 * as a default for input data that has no gamma information. The linear output
1215 * encoding will be overridden if png_set_gamma() is called - the results may be
1216 * highly unexpected!
1218 * The following numbers are derived from the sRGB standard and the research
1219 * behind it. sRGB is defined to be approximated by a PNG gAMA chunk value of
1220 * 0.45455 (1/2.2) for PNG. The value implicitly includes any viewing
1221 * correction required to take account of any differences in the color
1222 * environment of the original scene and the intended display environment; the
1223 * value expresses how to *decode* the image for display, not how the original
1224 * data was *encoded*.
1226 * sRGB provides a peg for the PNG standard by defining a viewing environment.
1227 * sRGB itself, and earlier TV standards, actually use a more complex transform
1228 * (a linear portion then a gamma 2.4 power law) than PNG can express. (PNG is
1229 * limited to simple power laws.) By saying that an image for direct display on
1230 * an sRGB conformant system should be stored with a gAMA chunk value of 45455
1231 * (11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
1232 * makes it possible to derive values for other display systems and
1235 * The Mac value is deduced from the sRGB based on an assumption that the actual
1236 * extra viewing correction used in early Mac display systems was implemented as
1237 * a power 1.45 lookup table.
1239 * Any system where a programmable lookup table is used or where the behavior of
1240 * the final display device characteristics can be changed requires system
1241 * specific code to obtain the current characteristic. However this can be
1242 * difficult and most PNG gamma correction only requires an approximate value.
1244 * By default, if png_set_alpha_mode() is not called, libpng assumes that all
1245 * values are unencoded, linear, values and that the output device also has a
1246 * linear characteristic. This is only very rarely correct - it is invariably
1247 * better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
1248 * default if you don't know what the right answer is!
1250 * The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
1251 * 10.6) which used a correction table to implement a somewhat lower gamma on an
1252 * otherwise sRGB system.
1254 * Both these values are reserved (not simple gamma values) in order to allow
1255 * more precise correction internally in the future.
1257 * NOTE: the following values can be passed to either the fixed or floating
1258 * point APIs, but the floating point API will also accept floating point
1261 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1262 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1263 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1264 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1267 /* The following are examples of calls to png_set_alpha_mode to achieve the
1268 * required overall gamma correction and, where necessary, alpha
1269 * premultiplication.
1271 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1272 * This is the default libpng handling of the alpha channel - it is not
1273 * pre-multiplied into the color components. In addition the call states
1274 * that the output is for a sRGB system and causes all PNG files without gAMA
1275 * chunks to be assumed to be encoded using sRGB.
1277 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1278 * In this case the output is assumed to be something like an sRGB conformant
1279 * display preceeded by a power-law lookup table of power 1.45. This is how
1280 * early Mac systems behaved.
1282 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1283 * This is the classic Jim Blinn approach and will work in academic
1284 * environments where everything is done by the book. It has the shortcoming
1285 * of assuming that input PNG data with no gamma information is linear - this
1286 * is unlikely to be correct unless the PNG files where generated locally.
1287 * Most of the time the output precision will be so low as to show
1288 * significant banding in dark areas of the image.
1290 * png_set_expand_16(pp);
1291 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1292 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1293 * are assumed to have the sRGB encoding if not marked with a gamma value and
1294 * the output is always 16 bits per component. This permits accurate scaling
1295 * and processing of the data. If you know that your input PNG files were
1296 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1297 * correct value for your system.
1299 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1300 * If you just need to composite the PNG image onto an existing background
1301 * and if you control the code that does this you can use the optimization
1302 * setting. In this case you just copy completely opaque pixels to the
1303 * output. For pixels that are not completely transparent (you just skip
1304 * those) you do the composition math using png_composite or png_composite_16
1305 * below then encode the resultant 8-bit or 16-bit values to match the output
1309 * If neither the PNG nor the standard linear encoding work for you because
1310 * of the software or hardware you use then you have a big problem. The PNG
1311 * case will probably result in halos around the image. The linear encoding
1312 * will probably result in a washed out, too bright, image (it's actually too
1313 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1314 * substantially reduce the halos. Alternatively try:
1316 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1317 * This option will also reduce the halos, but there will be slight dark
1318 * halos round the opaque parts of the image where the background is light.
1319 * In the OPTIMIZED mode the halos will be light halos where the background
1320 * is dark. Take your pick - the halos are unavoidable unless you can get
1321 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1324 * When the default gamma of PNG files doesn't match the output gamma.
1325 * If you have PNG files with no gamma information png_set_alpha_mode allows
1326 * you to provide a default gamma, but it also sets the ouput gamma to the
1327 * matching value. If you know your PNG files have a gamma that doesn't
1328 * match the output you can take advantage of the fact that
1329 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1330 * default if it is not already set:
1332 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1333 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1334 * The first call sets both the default and the output gamma values, the
1335 * second call overrides the output gamma without changing the default. This
1336 * is easier than achieving the same effect with png_set_gamma. You must use
1337 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1338 * fire if more than one call to png_set_alpha_mode and png_set_background is
1339 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1343 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1344 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structp png_ptr));
1347 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1348 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1349 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structp png_ptr));
1352 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1353 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1354 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structp png_ptr));
1357 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1358 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
1359 PNG_EXPORT(39, void, png_set_filler, (png_structp png_ptr, png_uint_32 filler,
1361 /* The values of the PNG_FILLER_ defines should NOT be changed */
1362 # define PNG_FILLER_BEFORE 0
1363 # define PNG_FILLER_AFTER 1
1364 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
1365 PNG_EXPORT(40, void, png_set_add_alpha,
1366 (png_structp png_ptr, png_uint_32 filler,
1368 #endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
1370 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1371 /* Swap bytes in 16-bit depth files. */
1372 PNG_EXPORT(41, void, png_set_swap, (png_structp png_ptr));
1375 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1376 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1377 PNG_EXPORT(42, void, png_set_packing, (png_structp png_ptr));
1380 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1381 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1382 /* Swap packing order of pixels in bytes. */
1383 PNG_EXPORT(43, void, png_set_packswap, (png_structp png_ptr));
1386 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1387 /* Converts files to legal bit depths. */
1388 PNG_EXPORT(44, void, png_set_shift, (png_structp png_ptr, png_const_color_8p
1392 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1393 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1394 /* Have the code handle the interlacing. Returns the number of passes.
1395 * MUST be called before png_read_update_info or png_start_read_image,
1396 * otherwise it will not have the desired effect. Note that it is still
1397 * necessary to call png_read_row or png_read_rows png_get_image_height
1398 * times for each pass.
1400 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structp png_ptr));
1403 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1404 /* Invert monochrome files */
1405 PNG_EXPORT(46, void, png_set_invert_mono, (png_structp png_ptr));
1408 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1409 /* Handle alpha and tRNS by replacing with a background color. Prior to
1410 * libpng-1.5.4 this API must not be called before the PNG file header has been
1411 * read. Doing so will result in unexpected behavior and possible warnings or
1412 * errors if the PNG file contains a bKGD chunk.
1414 PNG_FP_EXPORT(47, void, png_set_background, (png_structp png_ptr,
1415 png_const_color_16p background_color, int background_gamma_code,
1416 int need_expand, double background_gamma));
1417 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structp png_ptr,
1418 png_const_color_16p background_color, int background_gamma_code,
1419 int need_expand, png_fixed_point background_gamma));
1421 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1422 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1423 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1424 # define PNG_BACKGROUND_GAMMA_FILE 2
1425 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1428 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1429 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1430 PNG_EXPORT(229, void, png_set_scale_16, (png_structp png_ptr));
1433 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1434 #define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
1435 /* Strip the second byte of information from a 16-bit depth file. */
1436 PNG_EXPORT(48, void, png_set_strip_16, (png_structp png_ptr));
1439 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1440 /* Turn on quantizing, and reduce the palette to the number of colors
1443 PNG_EXPORT(49, void, png_set_quantize,
1444 (png_structp png_ptr, png_colorp palette,
1445 int num_palette, int maximum_colors, png_const_uint_16p histogram,
1446 int full_quantize));
1449 #ifdef PNG_READ_GAMMA_SUPPORTED
1450 /* The threshold on gamma processing is configurable but hard-wired into the
1451 * library. The following is the floating point variant.
1453 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1455 /* Handle gamma correction. Screen_gamma=(display_exponent).
1456 * NOTE: this API simply sets the screen and file gamma values. It will
1457 * therefore override the value for gamma in a PNG file if it is called after
1458 * the file header has been read - use with care - call before reading the PNG
1459 * file for best results!
1461 * These routines accept the same gamma values as png_set_alpha_mode (described
1462 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1463 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1464 * is the inverse of a 'screen gamma' value.
1466 PNG_FP_EXPORT(50, void, png_set_gamma,
1467 (png_structp png_ptr, double screen_gamma,
1468 double override_file_gamma));
1469 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structp png_ptr,
1470 png_fixed_point screen_gamma, png_fixed_point override_file_gamma));
1473 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1474 /* Set how many lines between output flushes - 0 for no flushing */
1475 PNG_EXPORT(51, void, png_set_flush, (png_structp png_ptr, int nrows));
1476 /* Flush the current PNG output buffer */
1477 PNG_EXPORT(52, void, png_write_flush, (png_structp png_ptr));
1480 /* Optional update palette with requested transformations */
1481 PNG_EXPORT(53, void, png_start_read_image, (png_structp png_ptr));
1483 /* Optional call to update the users info structure */
1484 PNG_EXPORT(54, void, png_read_update_info,
1485 (png_structp png_ptr, png_infop info_ptr));
1487 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1488 /* Read one or more rows of image data. */
1489 PNG_EXPORT(55, void, png_read_rows, (png_structp png_ptr, png_bytepp row,
1490 png_bytepp display_row, png_uint_32 num_rows));
1493 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1494 /* Read a row of data. */
1495 PNG_EXPORT(56, void, png_read_row, (png_structp png_ptr, png_bytep row,
1496 png_bytep display_row));
1499 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1500 /* Read the whole image into memory at once. */
1501 PNG_EXPORT(57, void, png_read_image, (png_structp png_ptr, png_bytepp image));
1504 /* Write a row of image data */
1505 PNG_EXPORT(58, void, png_write_row,
1506 (png_structp png_ptr, png_const_bytep row));
1508 /* Write a few rows of image data: (*row) is not written; however, the type
1509 * is declared as writeable to maintain compatibility with previous versions
1510 * of libpng and to allow the 'display_row' array from read_rows to be passed
1511 * unchanged to write_rows.
1513 PNG_EXPORT(59, void, png_write_rows, (png_structp png_ptr, png_bytepp row,
1514 png_uint_32 num_rows));
1516 /* Write the image data */
1517 PNG_EXPORT(60, void, png_write_image,
1518 (png_structp png_ptr, png_bytepp image));
1520 /* Write the end of the PNG file. */
1521 PNG_EXPORT(61, void, png_write_end,
1522 (png_structp png_ptr, png_infop info_ptr));
1524 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1525 /* Read the end of the PNG file. */
1526 PNG_EXPORT(62, void, png_read_end, (png_structp png_ptr, png_infop info_ptr));
1529 /* Free any memory associated with the png_info_struct */
1530 PNG_EXPORT(63, void, png_destroy_info_struct, (png_structp png_ptr,
1531 png_infopp info_ptr_ptr));
1533 /* Free any memory associated with the png_struct and the png_info_structs */
1534 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1535 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1537 /* Free any memory associated with the png_struct and the png_info_structs */
1538 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1539 png_infopp info_ptr_ptr));
1541 /* Set the libpng method of handling chunk CRC errors */
1542 PNG_EXPORT(66, void, png_set_crc_action,
1543 (png_structp png_ptr, int crit_action, int ancil_action));
1545 /* Values for png_set_crc_action() say how to handle CRC errors in
1546 * ancillary and critical chunks, and whether to use the data contained
1547 * therein. Note that it is impossible to "discard" data in a critical
1548 * chunk. For versions prior to 0.90, the action was always error/quit,
1549 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1550 * chunks is warn/discard. These values should NOT be changed.
1552 * value action:critical action:ancillary
1554 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1555 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1556 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1557 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1558 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1559 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1561 /* These functions give the user control over the scan-line filtering in
1562 * libpng and the compression methods used by zlib. These functions are
1563 * mainly useful for testing, as the defaults should work with most users.
1564 * Those users who are tight on memory or want faster performance at the
1565 * expense of compression can modify them. See the compression library
1566 * header file (zlib.h) for an explination of the compression functions.
1569 /* Set the filtering method(s) used by libpng. Currently, the only valid
1570 * value for "method" is 0.
1572 PNG_EXPORT(67, void, png_set_filter,
1573 (png_structp png_ptr, int method, int filters));
1575 /* Flags for png_set_filter() to say which filters to use. The flags
1576 * are chosen so that they don't conflict with real filter types
1577 * below, in case they are supplied instead of the #defined constants.
1578 * These values should NOT be changed.
1580 #define PNG_NO_FILTERS 0x00
1581 #define PNG_FILTER_NONE 0x08
1582 #define PNG_FILTER_SUB 0x10
1583 #define PNG_FILTER_UP 0x20
1584 #define PNG_FILTER_AVG 0x40
1585 #define PNG_FILTER_PAETH 0x80
1586 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
1587 PNG_FILTER_AVG | PNG_FILTER_PAETH)
1589 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1590 * These defines should NOT be changed.
1592 #define PNG_FILTER_VALUE_NONE 0
1593 #define PNG_FILTER_VALUE_SUB 1
1594 #define PNG_FILTER_VALUE_UP 2
1595 #define PNG_FILTER_VALUE_AVG 3
1596 #define PNG_FILTER_VALUE_PAETH 4
1597 #define PNG_FILTER_VALUE_LAST 5
1599 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
1600 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
1601 * defines, either the default (minimum-sum-of-absolute-differences), or
1602 * the experimental method (weighted-minimum-sum-of-absolute-differences).
1604 * Weights are factors >= 1.0, indicating how important it is to keep the
1605 * filter type consistent between rows. Larger numbers mean the current
1606 * filter is that many times as likely to be the same as the "num_weights"
1607 * previous filters. This is cumulative for each previous row with a weight.
1608 * There needs to be "num_weights" values in "filter_weights", or it can be
1609 * NULL if the weights aren't being specified. Weights have no influence on
1610 * the selection of the first row filter. Well chosen weights can (in theory)
1611 * improve the compression for a given image.
1613 * Costs are factors >= 1.0 indicating the relative decoding costs of a
1614 * filter type. Higher costs indicate more decoding expense, and are
1615 * therefore less likely to be selected over a filter with lower computational
1616 * costs. There needs to be a value in "filter_costs" for each valid filter
1617 * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
1618 * setting the costs. Costs try to improve the speed of decompression without
1619 * unduly increasing the compressed image size.
1621 * A negative weight or cost indicates the default value is to be used, and
1622 * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
1623 * The default values for both weights and costs are currently 1.0, but may
1624 * change if good general weighting/cost heuristics can be found. If both
1625 * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
1626 * to the UNWEIGHTED method, but with added encoding time/computation.
1628 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structp png_ptr,
1629 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1630 png_const_doublep filter_costs));
1631 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1632 (png_structp png_ptr,
1633 int heuristic_method, int num_weights, png_const_fixed_point_p
1634 filter_weights, png_const_fixed_point_p filter_costs));
1635 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1637 /* Heuristic used for row filter selection. These defines should NOT be
1640 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1641 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1642 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1643 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1645 #ifdef PNG_WRITE_SUPPORTED
1646 /* Set the library compression level. Currently, valid values range from
1647 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1648 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1649 * shown that zlib compression levels 3-6 usually perform as well as level 9
1650 * for PNG images, and do considerably fewer caclulations. In the future,
1651 * these values may not correspond directly to the zlib compression levels.
1653 PNG_EXPORT(69, void, png_set_compression_level,
1654 (png_structp png_ptr, int level));
1656 PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structp png_ptr,
1659 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structp png_ptr,
1662 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1663 * smaller value of window_bits if it can do so safely.
1665 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structp png_ptr,
1668 PNG_EXPORT(73, void, png_set_compression_method, (png_structp png_ptr,
1672 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1673 /* Also set zlib parameters for compressing non-IDAT chunks */
1674 PNG_EXPORT(222, void, png_set_text_compression_level,
1675 (png_structp png_ptr, int level));
1677 PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structp png_ptr,
1680 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structp png_ptr,
1683 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1684 * smaller value of window_bits if it can do so safely.
1686 PNG_EXPORT(225, void, png_set_text_compression_window_bits, (png_structp
1687 png_ptr, int window_bits));
1689 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structp png_ptr,
1691 #endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
1693 /* These next functions are called for input/output, memory, and error
1694 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1695 * and call standard C I/O routines such as fread(), fwrite(), and
1696 * fprintf(). These functions can be made to use other I/O routines
1697 * at run time for those applications that need to handle I/O in a
1698 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1702 #ifdef PNG_STDIO_SUPPORTED
1703 /* Initialize the input/output for the PNG file to the default functions. */
1704 PNG_EXPORT(74, void, png_init_io, (png_structp png_ptr, png_FILE_p fp));
1707 /* Replace the (error and abort), and warning functions with user
1708 * supplied functions. If no messages are to be printed you must still
1709 * write and use replacement functions. The replacement error_fn should
1710 * still do a longjmp to the last setjmp location if you are using this
1711 * method of error handling. If error_fn or warning_fn is NULL, the
1712 * default function will be used.
1715 PNG_EXPORT(75, void, png_set_error_fn,
1716 (png_structp png_ptr, png_voidp error_ptr,
1717 png_error_ptr error_fn, png_error_ptr warning_fn));
1719 /* Return the user pointer associated with the error functions */
1720 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structp png_ptr));
1722 /* Replace the default data output functions with a user supplied one(s).
1723 * If buffered output is not used, then output_flush_fn can be set to NULL.
1724 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1725 * output_flush_fn will be ignored (and thus can be NULL).
1726 * It is probably a mistake to use NULL for output_flush_fn if
1727 * write_data_fn is not also NULL unless you have built libpng with
1728 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1729 * default flush function, which uses the standard *FILE structure, will
1732 PNG_EXPORT(77, void, png_set_write_fn, (png_structp png_ptr, png_voidp io_ptr,
1733 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1735 /* Replace the default data input function with a user supplied one. */
1736 PNG_EXPORT(78, void, png_set_read_fn, (png_structp png_ptr, png_voidp io_ptr,
1737 png_rw_ptr read_data_fn));
1739 /* Return the user pointer associated with the I/O functions */
1740 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_structp png_ptr));
1742 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structp png_ptr,
1743 png_read_status_ptr read_row_fn));
1745 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structp png_ptr,
1746 png_write_status_ptr write_row_fn));
1748 #ifdef PNG_USER_MEM_SUPPORTED
1749 /* Replace the default memory allocation functions with user supplied one(s). */
1750 PNG_EXPORT(82, void, png_set_mem_fn, (png_structp png_ptr, png_voidp mem_ptr,
1751 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1752 /* Return the user pointer associated with the memory functions */
1753 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structp png_ptr));
1756 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1757 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structp png_ptr,
1758 png_user_transform_ptr read_user_transform_fn));
1761 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1762 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structp png_ptr,
1763 png_user_transform_ptr write_user_transform_fn));
1766 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1767 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structp png_ptr,
1768 png_voidp user_transform_ptr, int user_transform_depth,
1769 int user_transform_channels));
1770 /* Return the user pointer associated with the user transform functions */
1771 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1772 (png_const_structp png_ptr));
1775 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1776 /* Return information about the row currently being processed. Note that these
1777 * APIs do not fail but will return unexpected results if called outside a user
1778 * transform callback. Also note that when transforming an interlaced image the
1779 * row number is the row number within the sub-image of the interlace pass, so
1780 * the value will increase to the height of the sub-image (not the full image)
1781 * then reset to 0 for the next pass.
1783 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1784 * find the output pixel (x,y) given an interlaced sub-image pixel
1785 * (row,col,pass). (See below for these macros.)
1787 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structp));
1788 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structp));
1791 #ifdef PNG_USER_CHUNKS_SUPPORTED
1792 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structp png_ptr,
1793 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1794 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structp png_ptr));
1797 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1798 /* Sets the function callbacks for the push reader, and a pointer to a
1799 * user-defined structure available to the callback functions.
1801 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structp png_ptr,
1802 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1803 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1805 /* Returns the user pointer associated with the push read functions */
1806 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr, (png_const_structp png_ptr));
1808 /* Function to be called when data becomes available */
1809 PNG_EXPORT(92, void, png_process_data,
1810 (png_structp png_ptr, png_infop info_ptr,
1811 png_bytep buffer, png_size_t buffer_size));
1813 /* A function which may be called *only* within png_process_data to stop the
1814 * processing of any more data. The function returns the number of bytes
1815 * remaining, excluding any that libpng has cached internally. A subsequent
1816 * call to png_process_data must supply these bytes again. If the argument
1817 * 'save' is set to true the routine will first save all the pending data and
1818 * will always return 0.
1820 PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structp, int save));
1822 /* A function which may be called *only* outside (after) a call to
1823 * png_process_data. It returns the number of bytes of data to skip in the
1824 * input. Normally it will return 0, but if it returns a non-zero value the
1825 * application must skip than number of bytes of input data and pass the
1826 * following data to the next call to png_process_data.
1828 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structp));
1830 /* Function that combines rows. 'new_row' is a flag that should come from
1831 * the callback and be non-NULL if anything needs to be done; the library
1832 * stores its own version of the new data internally and ignores the passed
1835 PNG_EXPORT(93, void, png_progressive_combine_row, (png_structp png_ptr,
1836 png_bytep old_row, png_const_bytep new_row));
1837 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1839 PNG_EXPORTA(94, png_voidp, png_malloc,
1840 (png_structp png_ptr, png_alloc_size_t size),
1842 /* Added at libpng version 1.4.0 */
1843 PNG_EXPORTA(95, png_voidp, png_calloc,
1844 (png_structp png_ptr, png_alloc_size_t size),
1847 /* Added at libpng version 1.2.4 */
1848 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_structp png_ptr,
1849 png_alloc_size_t size), PNG_ALLOCATED);
1851 /* Frees a pointer allocated by png_malloc() */
1852 PNG_EXPORT(97, void, png_free, (png_structp png_ptr, png_voidp ptr));
1854 /* Free data that was allocated internally */
1855 PNG_EXPORT(98, void, png_free_data,
1856 (png_structp png_ptr, png_infop info_ptr, png_uint_32 free_me, int num));
1858 /* Reassign responsibility for freeing existing data, whether allocated
1859 * by libpng or by the application */
1860 PNG_EXPORT(99, void, png_data_freer,
1861 (png_structp png_ptr, png_infop info_ptr, int freer, png_uint_32 mask));
1863 /* Assignments for png_data_freer */
1864 #define PNG_DESTROY_WILL_FREE_DATA 1
1865 #define PNG_SET_WILL_FREE_DATA 1
1866 #define PNG_USER_WILL_FREE_DATA 2
1867 /* Flags for png_ptr->free_me and info_ptr->free_me */
1868 #define PNG_FREE_HIST 0x0008
1869 #define PNG_FREE_ICCP 0x0010
1870 #define PNG_FREE_SPLT 0x0020
1871 #define PNG_FREE_ROWS 0x0040
1872 #define PNG_FREE_PCAL 0x0080
1873 #define PNG_FREE_SCAL 0x0100
1874 #define PNG_FREE_UNKN 0x0200
1875 #define PNG_FREE_LIST 0x0400
1876 #define PNG_FREE_PLTE 0x1000
1877 #define PNG_FREE_TRNS 0x2000
1878 #define PNG_FREE_TEXT 0x4000
1879 #define PNG_FREE_ALL 0x7fff
1880 #define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1882 #ifdef PNG_USER_MEM_SUPPORTED
1883 PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_structp png_ptr,
1884 png_alloc_size_t size), PNG_ALLOCATED);
1885 PNG_EXPORT(101, void, png_free_default, (png_structp png_ptr, png_voidp ptr));
1888 #ifdef PNG_ERROR_TEXT_SUPPORTED
1889 /* Fatal error in PNG image of libpng - can't continue */
1890 PNG_EXPORTA(102, void, png_error,
1891 (png_structp png_ptr, png_const_charp error_message),
1894 /* The same, but the chunk name is prepended to the error string. */
1895 PNG_EXPORTA(103, void, png_chunk_error, (png_structp png_ptr,
1896 png_const_charp error_message), PNG_NORETURN);
1899 /* Fatal error in PNG image of libpng - can't continue */
1900 PNG_EXPORTA(104, void, png_err, (png_structp png_ptr), PNG_NORETURN);
1903 #ifdef PNG_WARNINGS_SUPPORTED
1904 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1905 PNG_EXPORT(105, void, png_warning, (png_structp png_ptr,
1906 png_const_charp warning_message));
1908 /* Non-fatal error in libpng, chunk name is prepended to message. */
1909 PNG_EXPORT(106, void, png_chunk_warning, (png_structp png_ptr,
1910 png_const_charp warning_message));
1913 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1914 /* Benign error in libpng. Can continue, but may have a problem.
1915 * User can choose whether to handle as a fatal error or as a warning. */
1916 # undef png_benign_error
1917 PNG_EXPORT(107, void, png_benign_error, (png_structp png_ptr,
1918 png_const_charp warning_message));
1920 /* Same, chunk name is prepended to message. */
1921 # undef png_chunk_benign_error
1922 PNG_EXPORT(108, void, png_chunk_benign_error, (png_structp png_ptr,
1923 png_const_charp warning_message));
1925 PNG_EXPORT(109, void, png_set_benign_errors,
1926 (png_structp png_ptr, int allowed));
1928 # ifdef PNG_ALLOW_BENIGN_ERRORS
1929 # define png_benign_error png_warning
1930 # define png_chunk_benign_error png_chunk_warning
1932 # define png_benign_error png_error
1933 # define png_chunk_benign_error png_chunk_error
1937 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
1938 * Similarly, the png_get_<chunk> calls are used to read values from the
1939 * png_info_struct, either storing the parameters in the passed variables, or
1940 * setting pointers into the png_info_struct where the data is stored. The
1941 * png_get_<chunk> functions return a non-zero value if the data was available
1942 * in info_ptr, or return zero and do not change any of the parameters if the
1943 * data was not available.
1945 * These functions should be used instead of directly accessing png_info
1946 * to avoid problems with future changes in the size and internal layout of
1949 /* Returns "flag" if chunk data is valid in info_ptr. */
1950 PNG_EXPORT(110, png_uint_32, png_get_valid,
1951 (png_const_structp png_ptr, png_const_infop info_ptr,
1954 /* Returns number of bytes needed to hold a transformed row. */
1955 PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structp png_ptr,
1956 png_const_infop info_ptr));
1958 #ifdef PNG_INFO_IMAGE_SUPPORTED
1959 /* Returns row_pointers, which is an array of pointers to scanlines that was
1960 * returned from png_read_png().
1962 PNG_EXPORT(112, png_bytepp, png_get_rows,
1963 (png_const_structp png_ptr, png_const_infop info_ptr));
1964 /* Set row_pointers, which is an array of pointers to scanlines for use
1965 * by png_write_png().
1967 PNG_EXPORT(113, void, png_set_rows, (png_structp png_ptr,
1968 png_infop info_ptr, png_bytepp row_pointers));
1971 /* Returns number of color channels in image. */
1972 PNG_EXPORT(114, png_byte, png_get_channels,
1973 (png_const_structp png_ptr, png_const_infop info_ptr));
1975 #ifdef PNG_EASY_ACCESS_SUPPORTED
1976 /* Returns image width in pixels. */
1977 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structp png_ptr,
1978 png_const_infop info_ptr));
1980 /* Returns image height in pixels. */
1981 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structp png_ptr,
1982 png_const_infop info_ptr));
1984 /* Returns image bit_depth. */
1985 PNG_EXPORT(117, png_byte, png_get_bit_depth,
1986 (png_const_structp png_ptr, png_const_infop info_ptr));
1988 /* Returns image color_type. */
1989 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structp png_ptr,
1990 png_const_infop info_ptr));
1992 /* Returns image filter_type. */
1993 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structp png_ptr,
1994 png_const_infop info_ptr));
1996 /* Returns image interlace_type. */
1997 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structp png_ptr,
1998 png_const_infop info_ptr));
2000 /* Returns image compression_type. */
2001 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structp png_ptr,
2002 png_const_infop info_ptr));
2004 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
2005 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
2006 (png_const_structp png_ptr, png_const_infop info_ptr));
2007 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
2008 (png_const_structp png_ptr, png_const_infop info_ptr));
2009 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
2010 (png_const_structp png_ptr, png_const_infop info_ptr));
2012 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
2013 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
2014 (png_const_structp png_ptr, png_const_infop info_ptr));
2015 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
2016 (png_const_structp png_ptr, png_const_infop info_ptr));
2018 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
2019 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
2020 (png_const_structp png_ptr, png_const_infop info_ptr));
2021 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
2022 (png_const_structp png_ptr, png_const_infop info_ptr));
2023 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
2024 (png_const_structp png_ptr, png_const_infop info_ptr));
2025 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
2026 (png_const_structp png_ptr, png_const_infop info_ptr));
2028 #endif /* PNG_EASY_ACCESS_SUPPORTED */
2030 /* Returns pointer to signature string read from PNG header */
2031 PNG_EXPORT(130, png_const_bytep, png_get_signature,
2032 (png_const_structp png_ptr, png_infop info_ptr));
2034 #ifdef PNG_bKGD_SUPPORTED
2035 PNG_EXPORT(131, png_uint_32, png_get_bKGD,
2036 (png_const_structp png_ptr, png_infop info_ptr,
2037 png_color_16p *background));
2040 #ifdef PNG_bKGD_SUPPORTED
2041 PNG_EXPORT(132, void, png_set_bKGD, (png_structp png_ptr, png_infop info_ptr,
2042 png_const_color_16p background));
2045 #ifdef PNG_cHRM_SUPPORTED
2046 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structp png_ptr,
2047 png_const_infop info_ptr, double *white_x, double *white_y, double *red_x,
2048 double *red_y, double *green_x, double *green_y, double *blue_x,
2050 #ifdef PNG_FIXED_POINT_SUPPORTED /* Otherwise not implemented */
2051 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
2052 (png_const_structp png_ptr,
2053 png_const_infop info_ptr, png_fixed_point *int_white_x,
2054 png_fixed_point *int_white_y, png_fixed_point *int_red_x,
2055 png_fixed_point *int_red_y, png_fixed_point *int_green_x,
2056 png_fixed_point *int_green_y, png_fixed_point *int_blue_x,
2057 png_fixed_point *int_blue_y));
2061 #ifdef PNG_cHRM_SUPPORTED
2062 PNG_FP_EXPORT(135, void, png_set_cHRM,
2063 (png_structp png_ptr, png_infop info_ptr,
2064 double white_x, double white_y, double red_x, double red_y, double green_x,
2065 double green_y, double blue_x, double blue_y));
2066 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_structp png_ptr,
2067 png_infop info_ptr, png_fixed_point int_white_x,
2068 png_fixed_point int_white_y, png_fixed_point int_red_x,
2069 png_fixed_point int_red_y, png_fixed_point int_green_x,
2070 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2071 png_fixed_point int_blue_y));
2074 #ifdef PNG_gAMA_SUPPORTED
2075 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA,
2076 (png_const_structp png_ptr, png_const_infop info_ptr,
2077 double *file_gamma));
2078 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2079 (png_const_structp png_ptr, png_const_infop info_ptr,
2080 png_fixed_point *int_file_gamma));
2083 #ifdef PNG_gAMA_SUPPORTED
2084 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_structp png_ptr,
2085 png_infop info_ptr, double file_gamma));
2086 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_structp png_ptr,
2087 png_infop info_ptr, png_fixed_point int_file_gamma));
2090 #ifdef PNG_hIST_SUPPORTED
2091 PNG_EXPORT(141, png_uint_32, png_get_hIST,
2092 (png_const_structp png_ptr, png_const_infop info_ptr,
2093 png_uint_16p *hist));
2096 #ifdef PNG_hIST_SUPPORTED
2097 PNG_EXPORT(142, void, png_set_hIST, (png_structp png_ptr,
2098 png_infop info_ptr, png_const_uint_16p hist));
2101 PNG_EXPORT(143, png_uint_32, png_get_IHDR,
2102 (png_structp png_ptr, png_infop info_ptr,
2103 png_uint_32 *width, png_uint_32 *height, int *bit_depth, int *color_type,
2104 int *interlace_method, int *compression_method, int *filter_method));
2106 PNG_EXPORT(144, void, png_set_IHDR,
2107 (png_structp png_ptr, png_infop info_ptr,
2108 png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
2109 int interlace_method, int compression_method, int filter_method));
2111 #ifdef PNG_oFFs_SUPPORTED
2112 PNG_EXPORT(145, png_uint_32, png_get_oFFs,
2113 (png_const_structp png_ptr, png_const_infop info_ptr,
2114 png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type));
2117 #ifdef PNG_oFFs_SUPPORTED
2118 PNG_EXPORT(146, void, png_set_oFFs,
2119 (png_structp png_ptr, png_infop info_ptr,
2120 png_int_32 offset_x, png_int_32 offset_y, int unit_type));
2123 #ifdef PNG_pCAL_SUPPORTED
2124 PNG_EXPORT(147, png_uint_32, png_get_pCAL,
2125 (png_const_structp png_ptr, png_const_infop info_ptr,
2126 png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type,
2128 png_charp *units, png_charpp *params));
2131 #ifdef PNG_pCAL_SUPPORTED
2132 PNG_EXPORT(148, void, png_set_pCAL, (png_structp png_ptr,
2134 png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
2135 int nparams, png_const_charp units, png_charpp params));
2138 #ifdef PNG_pHYs_SUPPORTED
2139 PNG_EXPORT(149, png_uint_32, png_get_pHYs,
2140 (png_const_structp png_ptr, png_const_infop info_ptr,
2141 png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
2144 #ifdef PNG_pHYs_SUPPORTED
2145 PNG_EXPORT(150, void, png_set_pHYs,
2146 (png_structp png_ptr, png_infop info_ptr,
2147 png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2150 PNG_EXPORT(151, png_uint_32, png_get_PLTE,
2151 (png_const_structp png_ptr, png_const_infop info_ptr,
2152 png_colorp *palette, int *num_palette));
2154 PNG_EXPORT(152, void, png_set_PLTE,
2155 (png_structp png_ptr, png_infop info_ptr,
2156 png_const_colorp palette, int num_palette));
2158 #ifdef PNG_sBIT_SUPPORTED
2159 PNG_EXPORT(153, png_uint_32, png_get_sBIT,
2160 (png_const_structp png_ptr, png_infop info_ptr,
2161 png_color_8p *sig_bit));
2164 #ifdef PNG_sBIT_SUPPORTED
2165 PNG_EXPORT(154, void, png_set_sBIT,
2166 (png_structp png_ptr, png_infop info_ptr, png_const_color_8p sig_bit));
2169 #ifdef PNG_sRGB_SUPPORTED
2170 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structp png_ptr,
2171 png_const_infop info_ptr, int *file_srgb_intent));
2174 #ifdef PNG_sRGB_SUPPORTED
2175 PNG_EXPORT(156, void, png_set_sRGB,
2176 (png_structp png_ptr, png_infop info_ptr, int srgb_intent));
2177 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_structp png_ptr,
2178 png_infop info_ptr, int srgb_intent));
2181 #ifdef PNG_iCCP_SUPPORTED
2182 PNG_EXPORT(158, png_uint_32, png_get_iCCP,
2183 (png_const_structp png_ptr, png_const_infop info_ptr,
2184 png_charpp name, int *compression_type, png_bytepp profile,
2185 png_uint_32 *proflen));
2188 #ifdef PNG_iCCP_SUPPORTED
2189 PNG_EXPORT(159, void, png_set_iCCP,
2190 (png_structp png_ptr, png_infop info_ptr,
2191 png_const_charp name, int compression_type, png_const_bytep profile,
2192 png_uint_32 proflen));
2195 #ifdef PNG_sPLT_SUPPORTED
2196 PNG_EXPORT(160, png_uint_32, png_get_sPLT,
2197 (png_const_structp png_ptr, png_const_infop info_ptr,
2198 png_sPLT_tpp entries));
2201 #ifdef PNG_sPLT_SUPPORTED
2202 PNG_EXPORT(161, void, png_set_sPLT,
2203 (png_structp png_ptr, png_infop info_ptr,
2204 png_const_sPLT_tp entries, int nentries));
2207 #ifdef PNG_TEXT_SUPPORTED
2208 /* png_get_text also returns the number of text chunks in *num_text */
2209 PNG_EXPORT(162, png_uint_32, png_get_text,
2210 (png_const_structp png_ptr, png_const_infop info_ptr,
2211 png_textp *text_ptr, int *num_text));
2214 /* Note while png_set_text() will accept a structure whose text,
2215 * language, and translated keywords are NULL pointers, the structure
2216 * returned by png_get_text will always contain regular
2217 * zero-terminated C strings. They might be empty strings but
2218 * they will never be NULL pointers.
2221 #ifdef PNG_TEXT_SUPPORTED
2222 PNG_EXPORT(163, void, png_set_text,
2223 (png_structp png_ptr, png_infop info_ptr,
2224 png_const_textp text_ptr, int num_text));
2227 #ifdef PNG_tIME_SUPPORTED
2228 PNG_EXPORT(164, png_uint_32, png_get_tIME,
2229 (png_const_structp png_ptr, png_infop info_ptr, png_timep *mod_time));
2232 #ifdef PNG_tIME_SUPPORTED
2233 PNG_EXPORT(165, void, png_set_tIME,
2234 (png_structp png_ptr, png_infop info_ptr, png_const_timep mod_time));
2237 #ifdef PNG_tRNS_SUPPORTED
2238 PNG_EXPORT(166, png_uint_32, png_get_tRNS,
2239 (png_const_structp png_ptr, png_infop info_ptr,
2240 png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color));
2243 #ifdef PNG_tRNS_SUPPORTED
2244 PNG_EXPORT(167, void, png_set_tRNS,
2245 (png_structp png_ptr, png_infop info_ptr,
2246 png_const_bytep trans_alpha, int num_trans,
2247 png_const_color_16p trans_color));
2250 #ifdef PNG_sCAL_SUPPORTED
2251 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL,
2252 (png_const_structp png_ptr, png_const_infop info_ptr,
2253 int *unit, double *width, double *height));
2254 #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
2255 /* NOTE: this API is currently implemented using floating point arithmetic,
2256 * consequently it can only be used on systems with floating point support.
2257 * In any case the range of values supported by png_fixed_point is small and it
2258 * is highly recommended that png_get_sCAL_s be used instead.
2260 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2261 (png_structp png_ptr, png_const_infop info_ptr, int *unit,
2262 png_fixed_point *width,
2263 png_fixed_point *height));
2265 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2266 (png_const_structp png_ptr, png_const_infop info_ptr,
2267 int *unit, png_charpp swidth, png_charpp sheight));
2269 PNG_FP_EXPORT(170, void, png_set_sCAL,
2270 (png_structp png_ptr, png_infop info_ptr,
2271 int unit, double width, double height));
2272 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_structp png_ptr,
2273 png_infop info_ptr, int unit, png_fixed_point width,
2274 png_fixed_point height));
2275 PNG_EXPORT(171, void, png_set_sCAL_s,
2276 (png_structp png_ptr, png_infop info_ptr,
2277 int unit, png_const_charp swidth, png_const_charp sheight));
2278 #endif /* PNG_sCAL_SUPPORTED */
2280 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2281 /* Provide a list of chunks and how they are to be handled, if the built-in
2282 handling or default unknown chunk handling is not desired. Any chunks not
2283 listed will be handled in the default manner. The IHDR and IEND chunks
2285 keep = 0: follow default behaviour
2287 = 2: keep only if safe-to-copy
2288 = 3: keep even if unsafe-to-copy
2290 PNG_EXPORT(172, void, png_set_keep_unknown_chunks,
2291 (png_structp png_ptr, int keep,
2292 png_const_bytep chunk_list, int num_chunks));
2293 PNG_EXPORT(173, int, png_handle_as_unknown, (png_structp png_ptr,
2294 png_const_bytep chunk_name));
2296 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
2297 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_structp png_ptr,
2298 png_infop info_ptr, png_const_unknown_chunkp unknowns,
2300 PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2301 (png_structp png_ptr, png_infop info_ptr, int chunk, int location));
2302 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structp png_ptr,
2303 png_const_infop info_ptr, png_unknown_chunkpp entries));
2306 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2307 * If you need to turn it off for a chunk that your application has freed,
2308 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2310 PNG_EXPORT(177, void, png_set_invalid,
2311 (png_structp png_ptr, png_infop info_ptr, int mask));
2313 #ifdef PNG_INFO_IMAGE_SUPPORTED
2314 /* The "params" pointer is currently not used and is for future expansion. */
2315 PNG_EXPORT(178, void, png_read_png, (png_structp png_ptr, png_infop info_ptr,
2316 int transforms, png_voidp params));
2317 PNG_EXPORT(179, void, png_write_png, (png_structp png_ptr, png_infop info_ptr,
2318 int transforms, png_voidp params));
2321 PNG_EXPORT(180, png_const_charp, png_get_copyright,
2322 (png_const_structp png_ptr));
2323 PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2324 (png_const_structp png_ptr));
2325 PNG_EXPORT(182, png_const_charp, png_get_header_version,
2326 (png_const_structp png_ptr));
2327 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2328 (png_const_structp png_ptr));
2330 #ifdef PNG_MNG_FEATURES_SUPPORTED
2331 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structp png_ptr,
2332 png_uint_32 mng_features_permitted));
2335 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2336 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2337 #define PNG_HANDLE_CHUNK_NEVER 1
2338 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2339 #define PNG_HANDLE_CHUNK_ALWAYS 3
2341 /* Strip the prepended error numbers ("#nnn ") from error and warning
2342 * messages before passing them to the error or warning handler.
2344 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2345 PNG_EXPORT(185, void, png_set_strip_error_numbers,
2346 (png_structp png_ptr,
2347 png_uint_32 strip_mode));
2350 /* Added in libpng-1.2.6 */
2351 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2352 PNG_EXPORT(186, void, png_set_user_limits, (png_structp png_ptr,
2353 png_uint_32 user_width_max, png_uint_32 user_height_max));
2354 PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2355 (png_const_structp png_ptr));
2356 PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2357 (png_const_structp png_ptr));
2358 /* Added in libpng-1.4.0 */
2359 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structp png_ptr,
2360 png_uint_32 user_chunk_cache_max));
2361 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2362 (png_const_structp png_ptr));
2363 /* Added in libpng-1.4.1 */
2364 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structp png_ptr,
2365 png_alloc_size_t user_chunk_cache_max));
2366 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2367 (png_const_structp png_ptr));
2370 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2371 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2372 (png_const_structp png_ptr, png_const_infop info_ptr));
2374 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2375 (png_const_structp png_ptr, png_const_infop info_ptr));
2377 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2378 (png_const_structp png_ptr, png_const_infop info_ptr));
2380 PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2381 (png_const_structp png_ptr, png_const_infop info_ptr));
2382 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2383 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2384 (png_structp png_ptr, png_const_infop info_ptr));
2387 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structp png_ptr,
2388 png_const_infop info_ptr));
2389 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2390 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2391 (png_structp png_ptr, png_const_infop info_ptr));
2394 # ifdef PNG_pHYs_SUPPORTED
2395 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structp png_ptr,
2396 png_const_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2398 # endif /* PNG_pHYs_SUPPORTED */
2399 #endif /* PNG_INCH_CONVERSIONS_SUPPORTED */
2401 /* Added in libpng-1.4.0 */
2402 #ifdef PNG_IO_STATE_SUPPORTED
2403 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_structp png_ptr));
2405 PNG_EXPORTA(200, png_const_bytep, png_get_io_chunk_name,
2406 (png_structp png_ptr), PNG_DEPRECATED);
2407 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2408 (png_const_structp png_ptr));
2410 /* The flags returned by png_get_io_state() are the following: */
2411 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2412 # define PNG_IO_READING 0x0001 /* currently reading */
2413 # define PNG_IO_WRITING 0x0002 /* currently writing */
2414 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2415 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2416 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2417 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2418 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2419 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2420 #endif /* ?PNG_IO_STATE_SUPPORTED */
2422 /* Interlace support. The following macros are always defined so that if
2423 * libpng interlace handling is turned off the macros may be used to handle
2424 * interlaced images within the application.
2426 #define PNG_INTERLACE_ADAM7_PASSES 7
2428 /* Two macros to return the first row and first column of the original,
2429 * full, image which appears in a given pass. 'pass' is in the range 0
2430 * to 6 and the result is in the range 0 to 7.
2432 #define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
2433 #define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
2435 /* Two macros to help evaluate the number of rows or columns in each
2436 * pass. This is expressed as a shift - effectively log2 of the number or
2437 * rows or columns in each 8x8 tile of the original image.
2439 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2440 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2442 /* Hence two macros to determine the number of rows or columns in a given
2443 * pass of an image given its height or width. In fact these macros may
2444 * return non-zero even though the sub-image is empty, because the other
2445 * dimension may be empty for a small image.
2447 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2448 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2449 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2450 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2452 /* For the reader row callbacks (both progressive and sequential) it is
2453 * necessary to find the row in the output image given a row in an interlaced
2454 * image, so two more macros:
2456 #define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
2457 (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2458 #define PNG_COL_FROM_PASS_COL(xIn, pass) \
2459 (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2461 /* Two macros which return a boolean (0 or 1) saying whether the given row
2462 * or column is in a particular pass. These use a common utility macro that
2463 * returns a mask for a given pass - the offset 'off' selects the row or
2464 * column version. The mask has the appropriate bit set for each column in
2467 #define PNG_PASS_MASK(pass,off) ( \
2468 ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
2469 ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
2471 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2472 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2473 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2474 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2476 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2477 /* With these routines we avoid an integer divide, which will be slower on
2478 * most machines. However, it does take more operations than the corresponding
2479 * divide method, so it may be slower on a few RISC systems. There are two
2480 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2482 * Note that the rounding factors are NOT supposed to be the same! 128 and
2483 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2486 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2489 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2491 # define png_composite(composite, fg, alpha, bg) \
2492 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2493 * (png_uint_16)(alpha) \
2494 + (png_uint_16)(bg)*(png_uint_16)(255 \
2495 - (png_uint_16)(alpha)) + (png_uint_16)128); \
2496 (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
2498 # define png_composite_16(composite, fg, alpha, bg) \
2499 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2500 * (png_uint_32)(alpha) \
2501 + (png_uint_32)(bg)*(png_uint_32)(65535L \
2502 - (png_uint_32)(alpha)) + (png_uint_32)32768L); \
2503 (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
2505 #else /* Standard method using integer division */
2507 # define png_composite(composite, fg, alpha, bg) \
2508 (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2509 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2510 (png_uint_16)127) / 255)
2512 # define png_composite_16(composite, fg, alpha, bg) \
2513 (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2514 (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) + \
2515 (png_uint_32)32767) / (png_uint_32)65535L)
2516 #endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
2518 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2519 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2520 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2521 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2524 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_structp png_ptr,
2525 png_const_bytep buf));
2526 /* No png_get_int_16 -- may be added if there's a real need for it. */
2528 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2529 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2530 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2532 #ifdef PNG_SAVE_INT_32_SUPPORTED
2533 PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2536 /* Place a 16-bit number into a buffer in PNG byte order.
2537 * The parameter is declared unsigned int, not png_uint_16,
2538 * just to avoid potential problems on pre-ANSI C compilers.
2540 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2541 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2542 /* No png_save_int_16 -- may be added if there's a real need for it. */
2545 #ifdef PNG_USE_READ_MACROS
2546 /* Inline macros to do direct reads of bytes from the input buffer.
2547 * The png_get_int_32() routine assumes we are using two's complement
2548 * format for negative values, which is almost certainly true.
2550 # define png_get_uint_32(buf) \
2551 (((png_uint_32)(*(buf)) << 24) + \
2552 ((png_uint_32)(*((buf) + 1)) << 16) + \
2553 ((png_uint_32)(*((buf) + 2)) << 8) + \
2554 ((png_uint_32)(*((buf) + 3))))
2556 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2557 * function) incorrectly returned a value of type png_uint_32.
2559 # define png_get_uint_16(buf) \
2561 (((unsigned int)(*(buf)) << 8) + \
2562 ((unsigned int)(*((buf) + 1)))))
2564 # define png_get_int_32(buf) \
2565 ((png_int_32)((*(buf) & 0x80) \
2566 ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
2567 : (png_int_32)png_get_uint_32(buf)))
2570 /* Maintainer: Put new public prototypes here ^, in libpng.3, and project
2574 /* The last ordinal number (this is the *last* one already used; the next
2575 * one to use is one more than this.) Maintainer, remember to add an entry to
2576 * scripts/symbols.def as well.
2578 #ifdef PNG_EXPORT_LAST_ORDINAL
2579 PNG_EXPORT_LAST_ORDINAL(229);
2586 #endif /* PNG_VERSION_INFO_ONLY */
2587 /* Do not put anything past this line */
projects / l4.git / blob