[LIBPNG] Update to v1.6.21. CORE-11128
[reactos.git] / reactos / include / reactos / libs / libpng / png.h
1
2 /* png.h - header file for PNG reference library
3 *
4 * libpng version 1.6.21, January 15, 2016
5 *
6 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 *
10 * This code is released under the libpng license (See LICENSE, below)
11 *
12 * Authors and maintainers:
13 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
14 * libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
15 * libpng versions 0.97, January 1998, through 1.6.21, January 15, 2016:
16 * Glenn Randers-Pehrson.
17 * See also "Contributing Authors", below.
18 */
19
20 /*
21 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
22 *
23 * If you modify libpng you may insert additional notices immediately following
24 * this sentence.
25 *
26 * This code is released under the libpng license.
27 *
28 * libpng versions 1.0.7, July 1, 2000, through 1.6.21, January 15, 2016, are
29 * Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
30 * derived from libpng-1.0.6, and are distributed according to the same
31 * disclaimer and license as libpng-1.0.6 with the following individuals
32 * added to the list of Contributing Authors:
33 *
34 * Simon-Pierre Cadieux
35 * Eric S. Raymond
36 * Mans Rullgard
37 * Cosmin Truta
38 * Gilles Vollant
39 * James Yu
40 *
41 * and with the following additions to the disclaimer:
42 *
43 * There is no warranty against interference with your enjoyment of the
44 * library or against infringement. There is no warranty that our
45 * efforts or the library will fulfill any of your particular purposes
46 * or needs. This library is provided with all faults, and the entire
47 * risk of satisfactory quality, performance, accuracy, and effort is with
48 * the user.
49 *
50 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
51 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
52 * libpng-0.96, and are distributed according to the same disclaimer and
53 * license as libpng-0.96, with the following individuals added to the list
54 * of Contributing Authors:
55 *
56 * Tom Lane
57 * Glenn Randers-Pehrson
58 * Willem van Schaik
59 *
60 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
61 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
62 * and are distributed according to the same disclaimer and license as
63 * libpng-0.88, with the following individuals added to the list of
64 * Contributing Authors:
65 *
66 * John Bowler
67 * Kevin Bracey
68 * Sam Bushell
69 * Magnus Holmgren
70 * Greg Roelofs
71 * Tom Tanner
72 *
73 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
74 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
75 *
76 * For the purposes of this copyright and license, "Contributing Authors"
77 * is defined as the following set of individuals:
78 *
79 * Andreas Dilger
80 * Dave Martindale
81 * Guy Eric Schalnat
82 * Paul Schmidt
83 * Tim Wegner
84 *
85 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
86 * and Group 42, Inc. disclaim all warranties, expressed or implied,
87 * including, without limitation, the warranties of merchantability and of
88 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
89 * assume no liability for direct, indirect, incidental, special, exemplary,
90 * or consequential damages, which may result from the use of the PNG
91 * Reference Library, even if advised of the possibility of such damage.
92 *
93 * Permission is hereby granted to use, copy, modify, and distribute this
94 * source code, or portions hereof, for any purpose, without fee, subject
95 * to the following restrictions:
96 *
97 * 1. The origin of this source code must not be misrepresented.
98 *
99 * 2. Altered versions must be plainly marked as such and must not
100 * be misrepresented as being the original source.
101 *
102 * 3. This Copyright notice may not be removed or altered from any
103 * source or altered source distribution.
104 *
105 * The Contributing Authors and Group 42, Inc. specifically permit, without
106 * fee, and encourage the use of this source code as a component to
107 * supporting the PNG file format in commercial products. If you use this
108 * source code in a product, acknowledgment is not required but would be
109 * appreciated.
110 *
111 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
112 */
113
114 /*
115 * A "png_get_copyright" function is available, for convenient use in "about"
116 * boxes and the like:
117 *
118 * printf("%s", png_get_copyright(NULL));
119 *
120 * Also, the PNG logo (in PNG format, of course) is supplied in the
121 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
122 */
123
124 /*
125 * Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
126 * a certification mark of the Open Source Initiative. OSI has not addressed
127 * the additional disclaimers inserted at version 1.0.7.
128 */
129
130 /*
131 * The contributing authors would like to thank all those who helped
132 * with testing, bug fixes, and patience. This wouldn't have been
133 * possible without all of you.
134 *
135 * Thanks to Frank J. T. Wojcik for helping with the documentation.
136 */
137
138 /* Note about libpng version numbers:
139 *
140 * Due to various miscommunications, unforeseen code incompatibilities
141 * and occasional factors outside the authors' control, version numbering
142 * on the library has not always been consistent and straightforward.
143 * The following table summarizes matters since version 0.89c, which was
144 * the first widely used release:
145 *
146 * source png.h png.h shared-lib
147 * version string int version
148 * ------- ------ ----- ----------
149 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
150 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
151 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
152 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
153 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
154 * 0.97c 0.97 97 2.0.97
155 * 0.98 0.98 98 2.0.98
156 * 0.99 0.99 98 2.0.99
157 * 0.99a-m 0.99 99 2.0.99
158 * 1.00 1.00 100 2.1.0 [100 should be 10000]
159 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
160 * 1.0.1 png.h string is 10001 2.1.0
161 * 1.0.1a-e identical to the 10002 from here on, the shared library
162 * 1.0.2 source version) 10002 is 2.V where V is the source code
163 * 1.0.2a-b 10003 version, except as noted.
164 * 1.0.3 10003
165 * 1.0.3a-d 10004
166 * 1.0.4 10004
167 * 1.0.4a-f 10005
168 * 1.0.5 (+ 2 patches) 10005
169 * 1.0.5a-d 10006
170 * 1.0.5e-r 10100 (not source compatible)
171 * 1.0.5s-v 10006 (not binary compatible)
172 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
173 * 1.0.6d-f 10007 (still binary incompatible)
174 * 1.0.6g 10007
175 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
176 * 1.0.6i 10007 10.6i
177 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
178 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
179 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
180 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
181 * 1.0.7 1 10007 (still compatible)
182 * ...
183 * 1.0.19 10 10019 10.so.0.19[.0]
184 * ...
185 * 1.2.53 13 10253 12.so.0.53[.0]
186 * ...
187 * 1.5.23 15 10523 15.so.15.23[.0]
188 * ...
189 * 1.6.21 16 10621 16.so.16.21[.0]
190 *
191 * Henceforth the source version will match the shared-library major
192 * and minor numbers; the shared-library major version number will be
193 * used for changes in backward compatibility, as it is intended. The
194 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
195 * for applications, is an unsigned integer of the form xyyzz corresponding
196 * to the source version x.y.z (leading zeros in y and z). Beta versions
197 * were given the previous public release number plus a letter, until
198 * version 1.0.6j; from then on they were given the upcoming public
199 * release number plus "betaNN" or "rcNN".
200 *
201 * Binary incompatibility exists only when applications make direct access
202 * to the info_ptr or png_ptr members through png.h, and the compiled
203 * application is loaded with a different version of the library.
204 *
205 * DLLNUM will change each time there are forward or backward changes
206 * in binary compatibility (e.g., when a new feature is added).
207 *
208 * See libpng.txt or libpng.3 for more information. The PNG specification
209 * is available as a W3C Recommendation and as an ISO Specification,
210 * <http://www.w3.org/TR/2003/REC-PNG-20031110/
211 */
212
213 /*
214 * Y2K compliance in libpng:
215 * =========================
216 *
217 * January 15, 2016
218 *
219 * Since the PNG Development group is an ad-hoc body, we can't make
220 * an official declaration.
221 *
222 * This is your unofficial assurance that libpng from version 0.71 and
223 * upward through 1.6.21 are Y2K compliant. It is my belief that
224 * earlier versions were also Y2K compliant.
225 *
226 * Libpng only has two year fields. One is a 2-byte unsigned integer
227 * that will hold years up to 65535. The other, which is deprecated,
228 * holds the date in text format, and will hold years up to 9999.
229 *
230 * The integer is
231 * "png_uint_16 year" in png_time_struct.
232 *
233 * The string is
234 * "char time_buffer[29]" in png_struct. This is no longer used
235 * in libpng-1.6.x and will be removed from libpng-1.7.0.
236 *
237 * There are seven time-related functions:
238 * png.c: png_convert_to_rfc_1123_buffer() in png.c
239 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
240 * png_convert_to_rfc_1152() in error prior to libpng-0.98)
241 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
242 * png_convert_from_time_t() in pngwrite.c
243 * png_get_tIME() in pngget.c
244 * png_handle_tIME() in pngrutil.c, called in pngread.c
245 * png_set_tIME() in pngset.c
246 * png_write_tIME() in pngwutil.c, called in pngwrite.c
247 *
248 * All handle dates properly in a Y2K environment. The
249 * png_convert_from_time_t() function calls gmtime() to convert from system
250 * clock time, which returns (year - 1900), which we properly convert to
251 * the full 4-digit year. There is a possibility that libpng applications
252 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
253 * function, or that they are incorrectly passing only a 2-digit year
254 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
255 * but this is not under our control. The libpng documentation has always
256 * stated that it works with 4-digit years, and the APIs have been
257 * documented as such.
258 *
259 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
260 * integer to hold the year, and can hold years as large as 65535.
261 *
262 * zlib, upon which libpng depends, is also Y2K compliant. It contains
263 * no date-related code.
264 *
265 * Glenn Randers-Pehrson
266 * libpng maintainer
267 * PNG Development Group
268 */
269
270 #ifndef PNG_H
271 #define PNG_H
272
273 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
274 * describes how to use libpng, and the file example.c summarizes it
275 * with some code on which to build. This file is useful for looking
276 * at the actual function definitions and structure components. If that
277 * file has been stripped from your copy of libpng, you can find it at
278 * <http://www.libpng.org/pub/png/libpng-manual.txt>
279 *
280 * If you just need to read a PNG file and don't want to read the documentation
281 * skip to the end of this file and read the section entitled 'simplified API'.
282 */
283
284 /* Version information for png.h - this should match the version in png.c */
285 #define PNG_LIBPNG_VER_STRING "1.6.21"
286 #define PNG_HEADER_VERSION_STRING \
287 " libpng version 1.6.21 - January 15, 2016\n"
288
289 #define PNG_LIBPNG_VER_SONUM 16
290 #define PNG_LIBPNG_VER_DLLNUM 16
291
292 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
293 #define PNG_LIBPNG_VER_MAJOR 1
294 #define PNG_LIBPNG_VER_MINOR 6
295 #define PNG_LIBPNG_VER_RELEASE 21
296
297 /* This should match the numeric part of the final component of
298 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
299 */
300
301 #define PNG_LIBPNG_VER_BUILD 0
302
303 /* Release Status */
304 #define PNG_LIBPNG_BUILD_ALPHA 1
305 #define PNG_LIBPNG_BUILD_BETA 2
306 #define PNG_LIBPNG_BUILD_RC 3
307 #define PNG_LIBPNG_BUILD_STABLE 4
308 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
309
310 /* Release-Specific Flags */
311 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
312 PNG_LIBPNG_BUILD_STABLE only */
313 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
314 PNG_LIBPNG_BUILD_SPECIAL */
315 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
316 PNG_LIBPNG_BUILD_PRIVATE */
317
318 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
319
320 /* Careful here. At one time, Guy wanted to use 082, but that would be octal.
321 * We must not include leading zeros.
322 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
323 * version 1.0.0 was mis-numbered 100 instead of 10000). From
324 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
325 */
326 #define PNG_LIBPNG_VER 10621 /* 1.6.21 */
327
328 /* Library configuration: these options cannot be changed after
329 * the library has been built.
330 */
331 #ifndef PNGLCONF_H
332 /* If pnglibconf.h is missing, you can
333 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
334 */
335 # include "pnglibconf.h"
336 #endif
337
338 #ifndef PNG_VERSION_INFO_ONLY
339 /* Machine specific configuration. */
340 # include "pngconf.h"
341 #endif
342
343 /*
344 * Added at libpng-1.2.8
345 *
346 * Ref MSDN: Private as priority over Special
347 * VS_FF_PRIVATEBUILD File *was not* built using standard release
348 * procedures. If this value is given, the StringFileInfo block must
349 * contain a PrivateBuild string.
350 *
351 * VS_FF_SPECIALBUILD File *was* built by the original company using
352 * standard release procedures but is a variation of the standard
353 * file of the same version number. If this value is given, the
354 * StringFileInfo block must contain a SpecialBuild string.
355 */
356
357 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
358 # define PNG_LIBPNG_BUILD_TYPE \
359 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
360 #else
361 # ifdef PNG_LIBPNG_SPECIALBUILD
362 # define PNG_LIBPNG_BUILD_TYPE \
363 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
364 # else
365 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
366 # endif
367 #endif
368
369 #ifndef PNG_VERSION_INFO_ONLY
370
371 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
372 #ifdef __cplusplus
373 extern "C" {
374 #endif /* __cplusplus */
375
376 /* Version information for C files, stored in png.c. This had better match
377 * the version above.
378 */
379 #define png_libpng_ver png_get_header_ver(NULL)
380
381 /* This file is arranged in several sections:
382 *
383 * 1. [omitted]
384 * 2. Any configuration options that can be specified by for the application
385 * code when it is built. (Build time configuration is in pnglibconf.h)
386 * 3. Type definitions (base types are defined in pngconf.h), structure
387 * definitions.
388 * 4. Exported library functions.
389 * 5. Simplified API.
390 * 6. Implementation options.
391 *
392 * The library source code has additional files (principally pngpriv.h) that
393 * allow configuration of the library.
394 */
395
396 /* Section 1: [omitted] */
397
398 /* Section 2: run time configuration
399 * See pnglibconf.h for build time configuration
400 *
401 * Run time configuration allows the application to choose between
402 * implementations of certain arithmetic APIs. The default is set
403 * at build time and recorded in pnglibconf.h, but it is safe to
404 * override these (and only these) settings. Note that this won't
405 * change what the library does, only application code, and the
406 * settings can (and probably should) be made on a per-file basis
407 * by setting the #defines before including png.h
408 *
409 * Use macros to read integers from PNG data or use the exported
410 * functions?
411 * PNG_USE_READ_MACROS: use the macros (see below) Note that
412 * the macros evaluate their argument multiple times.
413 * PNG_NO_USE_READ_MACROS: call the relevant library function.
414 *
415 * Use the alternative algorithm for compositing alpha samples that
416 * does not use division?
417 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
418 * algorithm.
419 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
420 *
421 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
422 * false?
423 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
424 * APIs to png_warning.
425 * Otherwise the calls are mapped to png_error.
426 */
427
428 /* Section 3: type definitions, including structures and compile time
429 * constants.
430 * See pngconf.h for base types that vary by machine/system
431 */
432
433 /* This triggers a compiler error in png.c, if png.c and png.h
434 * do not agree upon the version number.
435 */
436 typedef char* png_libpng_version_1_6_21;
437
438 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
439 *
440 * png_struct is the cache of information used while reading or writing a single
441 * PNG file. One of these is always required, although the simplified API
442 * (below) hides the creation and destruction of it.
443 */
444 typedef struct png_struct_def png_struct;
445 typedef const png_struct * png_const_structp;
446 typedef png_struct * png_structp;
447 typedef png_struct * * png_structpp;
448
449 /* png_info contains information read from or to be written to a PNG file. One
450 * or more of these must exist while reading or creating a PNG file. The
451 * information is not used by libpng during read but is used to control what
452 * gets written when a PNG file is created. "png_get_" function calls read
453 * information during read and "png_set_" functions calls write information
454 * when creating a PNG.
455 * been moved into a separate header file that is not accessible to
456 * applications. Read libpng-manual.txt or libpng.3 for more info.
457 */
458 typedef struct png_info_def png_info;
459 typedef png_info * png_infop;
460 typedef const png_info * png_const_infop;
461 typedef png_info * * png_infopp;
462
463 /* Types with names ending 'p' are pointer types. The corresponding types with
464 * names ending 'rp' are identical pointer types except that the pointer is
465 * marked 'restrict', which means that it is the only pointer to the object
466 * passed to the function. Applications should not use the 'restrict' types;
467 * it is always valid to pass 'p' to a pointer with a function argument of the
468 * corresponding 'rp' type. Different compilers have different rules with
469 * regard to type matching in the presence of 'restrict'. For backward
470 * compatibility libpng callbacks never have 'restrict' in their parameters and,
471 * consequentially, writing portable application code is extremely difficult if
472 * an attempt is made to use 'restrict'.
473 */
474 typedef png_struct * PNG_RESTRICT png_structrp;
475 typedef const png_struct * PNG_RESTRICT png_const_structrp;
476 typedef png_info * PNG_RESTRICT png_inforp;
477 typedef const png_info * PNG_RESTRICT png_const_inforp;
478
479 /* Three color definitions. The order of the red, green, and blue, (and the
480 * exact size) is not important, although the size of the fields need to
481 * be png_byte or png_uint_16 (as defined below).
482 */
483 typedef struct png_color_struct
484 {
485 png_byte red;
486 png_byte green;
487 png_byte blue;
488 } png_color;
489 typedef png_color * png_colorp;
490 typedef const png_color * png_const_colorp;
491 typedef png_color * * png_colorpp;
492
493 typedef struct png_color_16_struct
494 {
495 png_byte index; /* used for palette files */
496 png_uint_16 red; /* for use in red green blue files */
497 png_uint_16 green;
498 png_uint_16 blue;
499 png_uint_16 gray; /* for use in grayscale files */
500 } png_color_16;
501 typedef png_color_16 * png_color_16p;
502 typedef const png_color_16 * png_const_color_16p;
503 typedef png_color_16 * * png_color_16pp;
504
505 typedef struct png_color_8_struct
506 {
507 png_byte red; /* for use in red green blue files */
508 png_byte green;
509 png_byte blue;
510 png_byte gray; /* for use in grayscale files */
511 png_byte alpha; /* for alpha channel files */
512 } png_color_8;
513 typedef png_color_8 * png_color_8p;
514 typedef const png_color_8 * png_const_color_8p;
515 typedef png_color_8 * * png_color_8pp;
516
517 /*
518 * The following two structures are used for the in-core representation
519 * of sPLT chunks.
520 */
521 typedef struct png_sPLT_entry_struct
522 {
523 png_uint_16 red;
524 png_uint_16 green;
525 png_uint_16 blue;
526 png_uint_16 alpha;
527 png_uint_16 frequency;
528 } png_sPLT_entry;
529 typedef png_sPLT_entry * png_sPLT_entryp;
530 typedef const png_sPLT_entry * png_const_sPLT_entryp;
531 typedef png_sPLT_entry * * png_sPLT_entrypp;
532
533 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples
534 * occupy the LSB of their respective members, and the MSB of each member
535 * is zero-filled. The frequency member always occupies the full 16 bits.
536 */
537
538 typedef struct png_sPLT_struct
539 {
540 png_charp name; /* palette name */
541 png_byte depth; /* depth of palette samples */
542 png_sPLT_entryp entries; /* palette entries */
543 png_int_32 nentries; /* number of palette entries */
544 } png_sPLT_t;
545 typedef png_sPLT_t * png_sPLT_tp;
546 typedef const png_sPLT_t * png_const_sPLT_tp;
547 typedef png_sPLT_t * * png_sPLT_tpp;
548
549 #ifdef PNG_TEXT_SUPPORTED
550 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
551 * and whether that contents is compressed or not. The "key" field
552 * points to a regular zero-terminated C string. The "text" fields can be a
553 * regular C string, an empty string, or a NULL pointer.
554 * However, the structure returned by png_get_text() will always contain
555 * the "text" field as a regular zero-terminated C string (possibly
556 * empty), never a NULL pointer, so it can be safely used in printf() and
557 * other string-handling functions. Note that the "itxt_length", "lang", and
558 * "lang_key" members of the structure only exist when the library is built
559 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
560 * default without iTXt support. Also note that when iTXt *is* supported,
561 * the "lang" and "lang_key" fields contain NULL pointers when the
562 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
563 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
564 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
565 * which is always 0 or 1, or its "compression method" which is always 0.
566 */
567 typedef struct png_text_struct
568 {
569 int compression; /* compression value:
570 -1: tEXt, none
571 0: zTXt, deflate
572 1: iTXt, none
573 2: iTXt, deflate */
574 png_charp key; /* keyword, 1-79 character description of "text" */
575 png_charp text; /* comment, may be an empty string (ie "")
576 or a NULL pointer */
577 png_size_t text_length; /* length of the text string */
578 png_size_t itxt_length; /* length of the itxt string */
579 png_charp lang; /* language code, 0-79 characters
580 or a NULL pointer */
581 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
582 chars or a NULL pointer */
583 } png_text;
584 typedef png_text * png_textp;
585 typedef const png_text * png_const_textp;
586 typedef png_text * * png_textpp;
587 #endif
588
589 /* Supported compression types for text in PNG files (tEXt, and zTXt).
590 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
591 #define PNG_TEXT_COMPRESSION_NONE_WR -3
592 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
593 #define PNG_TEXT_COMPRESSION_NONE -1
594 #define PNG_TEXT_COMPRESSION_zTXt 0
595 #define PNG_ITXT_COMPRESSION_NONE 1
596 #define PNG_ITXT_COMPRESSION_zTXt 2
597 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
598
599 /* png_time is a way to hold the time in an machine independent way.
600 * Two conversions are provided, both from time_t and struct tm. There
601 * is no portable way to convert to either of these structures, as far
602 * as I know. If you know of a portable way, send it to me. As a side
603 * note - PNG has always been Year 2000 compliant!
604 */
605 typedef struct png_time_struct
606 {
607 png_uint_16 year; /* full year, as in, 1995 */
608 png_byte month; /* month of year, 1 - 12 */
609 png_byte day; /* day of month, 1 - 31 */
610 png_byte hour; /* hour of day, 0 - 23 */
611 png_byte minute; /* minute of hour, 0 - 59 */
612 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
613 } png_time;
614 typedef png_time * png_timep;
615 typedef const png_time * png_const_timep;
616 typedef png_time * * png_timepp;
617
618 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
619 defined(PNG_USER_CHUNKS_SUPPORTED)
620 /* png_unknown_chunk is a structure to hold queued chunks for which there is
621 * no specific support. The idea is that we can use this to queue
622 * up private chunks for output even though the library doesn't actually
623 * know about their semantics.
624 *
625 * The data in the structure is set by libpng on read and used on write.
626 */
627 typedef struct png_unknown_chunk_t
628 {
629 png_byte name[5]; /* Textual chunk name with '\0' terminator */
630 png_byte *data; /* Data, should not be modified on read! */
631 png_size_t size;
632
633 /* On write 'location' must be set using the flag values listed below.
634 * Notice that on read it is set by libpng however the values stored have
635 * more bits set than are listed below. Always treat the value as a
636 * bitmask. On write set only one bit - setting multiple bits may cause the
637 * chunk to be written in multiple places.
638 */
639 png_byte location; /* mode of operation at read time */
640 }
641 png_unknown_chunk;
642
643 typedef png_unknown_chunk * png_unknown_chunkp;
644 typedef const png_unknown_chunk * png_const_unknown_chunkp;
645 typedef png_unknown_chunk * * png_unknown_chunkpp;
646 #endif
647
648 /* Flag values for the unknown chunk location byte. */
649 #define PNG_HAVE_IHDR 0x01
650 #define PNG_HAVE_PLTE 0x02
651 #define PNG_AFTER_IDAT 0x08
652
653 /* Maximum positive integer used in PNG is (2^31)-1 */
654 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
655 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
656 #define PNG_SIZE_MAX ((png_size_t)(-1))
657
658 /* These are constants for fixed point values encoded in the
659 * PNG specification manner (x100000)
660 */
661 #define PNG_FP_1 100000
662 #define PNG_FP_HALF 50000
663 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
664 #define PNG_FP_MIN (-PNG_FP_MAX)
665
666 /* These describe the color_type field in png_info. */
667 /* color type masks */
668 #define PNG_COLOR_MASK_PALETTE 1
669 #define PNG_COLOR_MASK_COLOR 2
670 #define PNG_COLOR_MASK_ALPHA 4
671
672 /* color types. Note that not all combinations are legal */
673 #define PNG_COLOR_TYPE_GRAY 0
674 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
675 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
676 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
677 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
678 /* aliases */
679 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
680 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
681
682 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
683 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
684 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
685
686 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
687 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
688 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
689 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
690
691 /* These are for the interlacing type. These values should NOT be changed. */
692 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
693 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
694 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
695
696 /* These are for the oFFs chunk. These values should NOT be changed. */
697 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
698 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
699 #define PNG_OFFSET_LAST 2 /* Not a valid value */
700
701 /* These are for the pCAL chunk. These values should NOT be changed. */
702 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
703 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
704 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
705 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
706 #define PNG_EQUATION_LAST 4 /* Not a valid value */
707
708 /* These are for the sCAL chunk. These values should NOT be changed. */
709 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
710 #define PNG_SCALE_METER 1 /* meters per pixel */
711 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
712 #define PNG_SCALE_LAST 3 /* Not a valid value */
713
714 /* These are for the pHYs chunk. These values should NOT be changed. */
715 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
716 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
717 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
718
719 /* These are for the sRGB chunk. These values should NOT be changed. */
720 #define PNG_sRGB_INTENT_PERCEPTUAL 0
721 #define PNG_sRGB_INTENT_RELATIVE 1
722 #define PNG_sRGB_INTENT_SATURATION 2
723 #define PNG_sRGB_INTENT_ABSOLUTE 3
724 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
725
726 /* This is for text chunks */
727 #define PNG_KEYWORD_MAX_LENGTH 79
728
729 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
730 #define PNG_MAX_PALETTE_LENGTH 256
731
732 /* These determine if an ancillary chunk's data has been successfully read
733 * from the PNG header, or if the application has filled in the corresponding
734 * data in the info_struct to be written into the output file. The values
735 * of the PNG_INFO_<chunk> defines should NOT be changed.
736 */
737 #define PNG_INFO_gAMA 0x0001
738 #define PNG_INFO_sBIT 0x0002
739 #define PNG_INFO_cHRM 0x0004
740 #define PNG_INFO_PLTE 0x0008
741 #define PNG_INFO_tRNS 0x0010
742 #define PNG_INFO_bKGD 0x0020
743 #define PNG_INFO_hIST 0x0040
744 #define PNG_INFO_pHYs 0x0080
745 #define PNG_INFO_oFFs 0x0100
746 #define PNG_INFO_tIME 0x0200
747 #define PNG_INFO_pCAL 0x0400
748 #define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
749 #define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
750 #define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
751 #define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
752 #if INT_MAX >= 0x8000 /* else this might break */
753 #define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */
754 #endif
755
756 /* This is used for the transformation routines, as some of them
757 * change these values for the row. It also should enable using
758 * the routines for other purposes.
759 */
760 typedef struct png_row_info_struct
761 {
762 png_uint_32 width; /* width of row */
763 png_size_t rowbytes; /* number of bytes in row */
764 png_byte color_type; /* color type of row */
765 png_byte bit_depth; /* bit depth of row */
766 png_byte channels; /* number of channels (1, 2, 3, or 4) */
767 png_byte pixel_depth; /* bits per pixel (depth * channels) */
768 } png_row_info;
769
770 typedef png_row_info * png_row_infop;
771 typedef png_row_info * * png_row_infopp;
772
773 /* These are the function types for the I/O functions and for the functions
774 * that allow the user to override the default I/O functions with his or her
775 * own. The png_error_ptr type should match that of user-supplied warning
776 * and error functions, while the png_rw_ptr type should match that of the
777 * user read/write data functions. Note that the 'write' function must not
778 * modify the buffer it is passed. The 'read' function, on the other hand, is
779 * expected to return the read data in the buffer.
780 */
781 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
782 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
783 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
784 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
785 int));
786 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
787 int));
788
789 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
790 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
791 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
792
793 /* The following callback receives png_uint_32 row_number, int pass for the
794 * png_bytep data of the row. When transforming an interlaced image the
795 * row number is the row number within the sub-image of the interlace pass, so
796 * the value will increase to the height of the sub-image (not the full image)
797 * then reset to 0 for the next pass.
798 *
799 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
800 * find the output pixel (x,y) given an interlaced sub-image pixel
801 * (row,col,pass). (See below for these macros.)
802 */
803 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
804 png_uint_32, int));
805 #endif
806
807 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
808 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
809 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
810 png_bytep));
811 #endif
812
813 #ifdef PNG_USER_CHUNKS_SUPPORTED
814 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
815 png_unknown_chunkp));
816 #endif
817 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
818 /* not used anywhere */
819 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
820 #endif
821
822 #ifdef PNG_SETJMP_SUPPORTED
823 /* This must match the function definition in <setjmp.h>, and the application
824 * must include this before png.h to obtain the definition of jmp_buf. The
825 * function is required to be PNG_NORETURN, but this is not checked. If the
826 * function does return the application will crash via an abort() or similar
827 * system level call.
828 *
829 * If you get a warning here while building the library you may need to make
830 * changes to ensure that pnglibconf.h records the calling convention used by
831 * your compiler. This may be very difficult - try using a different compiler
832 * to build the library!
833 */
834 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
835 #endif
836
837 /* Transform masks for the high-level interface */
838 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
839 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
840 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
841 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
842 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
843 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
844 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
845 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
846 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
847 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
848 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
849 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
850 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
851 /* Added to libpng-1.2.34 */
852 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
853 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
854 /* Added to libpng-1.4.0 */
855 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
856 /* Added to libpng-1.5.4 */
857 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
858 #if INT_MAX >= 0x8000 /* else this might break */
859 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
860 #endif
861
862 /* Flags for MNG supported features */
863 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
864 #define PNG_FLAG_MNG_FILTER_64 0x04
865 #define PNG_ALL_MNG_FEATURES 0x05
866
867 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
868 * this allowed the zlib default functions to be used on Windows
869 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
870 * ignores the first argument) should be completely compatible with the
871 * following.
872 */
873 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
874 png_alloc_size_t));
875 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
876
877 /* Section 4: exported functions
878 * Here are the function definitions most commonly used. This is not
879 * the place to find out how to use libpng. See libpng-manual.txt for the
880 * full explanation, see example.c for the summary. This just provides
881 * a simple one line description of the use of each function.
882 *
883 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
884 * pngconf.h and in the *.dfn files in the scripts directory.
885 *
886 * PNG_EXPORT(ordinal, type, name, (args));
887 *
888 * ordinal: ordinal that is used while building
889 * *.def files. The ordinal value is only
890 * relevant when preprocessing png.h with
891 * the *.dfn files for building symbol table
892 * entries, and are removed by pngconf.h.
893 * type: return type of the function
894 * name: function name
895 * args: function arguments, with types
896 *
897 * When we wish to append attributes to a function prototype we use
898 * the PNG_EXPORTA() macro instead.
899 *
900 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
901 *
902 * ordinal, type, name, and args: same as in PNG_EXPORT().
903 * attributes: function attributes
904 */
905
906 /* Returns the version number of the library */
907 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
908
909 /* Tell lib we have already handled the first <num_bytes> magic bytes.
910 * Handling more than 8 bytes from the beginning of the file is an error.
911 */
912 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
913
914 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
915 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
916 * signature, and non-zero otherwise. Having num_to_check == 0 or
917 * start > 7 will always fail (ie return non-zero).
918 */
919 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
920 png_size_t num_to_check));
921
922 /* Simple signature checking function. This is the same as calling
923 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
924 */
925 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
926
927 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
928 PNG_EXPORTA(4, png_structp, png_create_read_struct,
929 (png_const_charp user_png_ver, png_voidp error_ptr,
930 png_error_ptr error_fn, png_error_ptr warn_fn),
931 PNG_ALLOCATED);
932
933 /* Allocate and initialize png_ptr struct for writing, and any other memory */
934 PNG_EXPORTA(5, png_structp, png_create_write_struct,
935 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
936 png_error_ptr warn_fn),
937 PNG_ALLOCATED);
938
939 PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
940 (png_const_structrp png_ptr));
941
942 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
943 png_size_t size));
944
945 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
946 * match up.
947 */
948 #ifdef PNG_SETJMP_SUPPORTED
949 /* This function returns the jmp_buf built in to *png_ptr. It must be
950 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
951 * unless the default error function is overridden in which case NULL is
952 * acceptable. The size of the jmp_buf is checked against the actual size
953 * allocated by the library - the call will return NULL on a mismatch
954 * indicating an ABI mismatch.
955 */
956 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
957 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
958 # define png_jmpbuf(png_ptr) \
959 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
960 #else
961 # define png_jmpbuf(png_ptr) \
962 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
963 #endif
964 /* This function should be used by libpng applications in place of
965 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
966 * will use it; otherwise it will call PNG_ABORT(). This function was
967 * added in libpng-1.5.0.
968 */
969 PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
970 PNG_NORETURN);
971
972 #ifdef PNG_READ_SUPPORTED
973 /* Reset the compression stream */
974 PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
975 #endif
976
977 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
978 #ifdef PNG_USER_MEM_SUPPORTED
979 PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
980 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
981 png_error_ptr warn_fn,
982 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
983 PNG_ALLOCATED);
984 PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
985 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
986 png_error_ptr warn_fn,
987 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
988 PNG_ALLOCATED);
989 #endif
990
991 /* Write the PNG file signature. */
992 PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
993
994 /* Write a PNG chunk - size, type, (optional) data, CRC. */
995 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
996 chunk_name, png_const_bytep data, png_size_t length));
997
998 /* Write the start of a PNG chunk - length and chunk name. */
999 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1000 png_const_bytep chunk_name, png_uint_32 length));
1001
1002 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1003 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1004 png_const_bytep data, png_size_t length));
1005
1006 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1007 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1008
1009 /* Allocate and initialize the info structure */
1010 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1011 PNG_ALLOCATED);
1012
1013 /* DEPRECATED: this function allowed init structures to be created using the
1014 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1015 * the API will be removed in the future.
1016 */
1017 PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1018 png_size_t png_info_struct_size), PNG_DEPRECATED);
1019
1020 /* Writes all the PNG information before the image. */
1021 PNG_EXPORT(20, void, png_write_info_before_PLTE,
1022 (png_structrp png_ptr, png_const_inforp info_ptr));
1023 PNG_EXPORT(21, void, png_write_info,
1024 (png_structrp png_ptr, png_const_inforp info_ptr));
1025
1026 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1027 /* Read the information before the actual image data. */
1028 PNG_EXPORT(22, void, png_read_info,
1029 (png_structrp png_ptr, png_inforp info_ptr));
1030 #endif
1031
1032 #ifdef PNG_TIME_RFC1123_SUPPORTED
1033 /* Convert to a US string format: there is no localization support in this
1034 * routine. The original implementation used a 29 character buffer in
1035 * png_struct, this will be removed in future versions.
1036 */
1037 #if PNG_LIBPNG_VER < 10700
1038 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1039 PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1040 png_const_timep ptime),PNG_DEPRECATED);
1041 #endif
1042 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1043 png_const_timep ptime));
1044 #endif
1045
1046 #ifdef PNG_CONVERT_tIME_SUPPORTED
1047 /* Convert from a struct tm to png_time */
1048 PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1049 const struct tm * ttime));
1050
1051 /* Convert from time_t to png_time. Uses gmtime() */
1052 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1053 #endif /* CONVERT_tIME */
1054
1055 #ifdef PNG_READ_EXPAND_SUPPORTED
1056 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1057 PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1058 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1059 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1060 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1061 #endif
1062
1063 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1064 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1065 * of a tRNS chunk if present.
1066 */
1067 PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1068 #endif
1069
1070 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1071 /* Use blue, green, red order for pixels. */
1072 PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1073 #endif
1074
1075 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1076 /* Expand the grayscale to 24-bit RGB if necessary. */
1077 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1078 #endif
1079
1080 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1081 /* Reduce RGB to grayscale. */
1082 #define PNG_ERROR_ACTION_NONE 1
1083 #define PNG_ERROR_ACTION_WARN 2
1084 #define PNG_ERROR_ACTION_ERROR 3
1085 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1086
1087 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1088 int error_action, double red, double green))
1089 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1090 int error_action, png_fixed_point red, png_fixed_point green))
1091
1092 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1093 png_ptr));
1094 #endif
1095
1096 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1097 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1098 png_colorp palette));
1099 #endif
1100
1101 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1102 /* How the alpha channel is interpreted - this affects how the color channels
1103 * of a PNG file are returned to the calling application when an alpha channel,
1104 * or a tRNS chunk in a palette file, is present.
1105 *
1106 * This has no effect on the way pixels are written into a PNG output
1107 * datastream. The color samples in a PNG datastream are never premultiplied
1108 * with the alpha samples.
1109 *
1110 * The default is to return data according to the PNG specification: the alpha
1111 * channel is a linear measure of the contribution of the pixel to the
1112 * corresponding composited pixel, and the color channels are unassociated
1113 * (not premultiplied). The gamma encoded color channels must be scaled
1114 * according to the contribution and to do this it is necessary to undo
1115 * the encoding, scale the color values, perform the composition and reencode
1116 * the values. This is the 'PNG' mode.
1117 *
1118 * The alternative is to 'associate' the alpha with the color information by
1119 * storing color channel values that have been scaled by the alpha.
1120 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1121 * (the latter being the two common names for associated alpha color channels).
1122 *
1123 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1124 * value is equal to the maximum value.
1125 *
1126 * The final choice is to gamma encode the alpha channel as well. This is
1127 * broken because, in practice, no implementation that uses this choice
1128 * correctly undoes the encoding before handling alpha composition. Use this
1129 * choice only if other serious errors in the software or hardware you use
1130 * mandate it; the typical serious error is for dark halos to appear around
1131 * opaque areas of the composited PNG image because of arithmetic overflow.
1132 *
1133 * The API function png_set_alpha_mode specifies which of these choices to use
1134 * with an enumerated 'mode' value and the gamma of the required output:
1135 */
1136 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1137 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1138 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1139 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1140 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1141 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1142
1143 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1144 double output_gamma))
1145 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1146 int mode, png_fixed_point output_gamma))
1147 #endif
1148
1149 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1150 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1151 * how to decode the output values, not how they are encoded.
1152 */
1153 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1154 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1155 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1156 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1157 #endif
1158
1159 /* The following are examples of calls to png_set_alpha_mode to achieve the
1160 * required overall gamma correction and, where necessary, alpha
1161 * premultiplication.
1162 *
1163 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1164 * This is the default libpng handling of the alpha channel - it is not
1165 * pre-multiplied into the color components. In addition the call states
1166 * that the output is for a sRGB system and causes all PNG files without gAMA
1167 * chunks to be assumed to be encoded using sRGB.
1168 *
1169 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1170 * In this case the output is assumed to be something like an sRGB conformant
1171 * display preceeded by a power-law lookup table of power 1.45. This is how
1172 * early Mac systems behaved.
1173 *
1174 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1175 * This is the classic Jim Blinn approach and will work in academic
1176 * environments where everything is done by the book. It has the shortcoming
1177 * of assuming that input PNG data with no gamma information is linear - this
1178 * is unlikely to be correct unless the PNG files where generated locally.
1179 * Most of the time the output precision will be so low as to show
1180 * significant banding in dark areas of the image.
1181 *
1182 * png_set_expand_16(pp);
1183 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1184 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1185 * are assumed to have the sRGB encoding if not marked with a gamma value and
1186 * the output is always 16 bits per component. This permits accurate scaling
1187 * and processing of the data. If you know that your input PNG files were
1188 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1189 * correct value for your system.
1190 *
1191 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1192 * If you just need to composite the PNG image onto an existing background
1193 * and if you control the code that does this you can use the optimization
1194 * setting. In this case you just copy completely opaque pixels to the
1195 * output. For pixels that are not completely transparent (you just skip
1196 * those) you do the composition math using png_composite or png_composite_16
1197 * below then encode the resultant 8-bit or 16-bit values to match the output
1198 * encoding.
1199 *
1200 * Other cases
1201 * If neither the PNG nor the standard linear encoding work for you because
1202 * of the software or hardware you use then you have a big problem. The PNG
1203 * case will probably result in halos around the image. The linear encoding
1204 * will probably result in a washed out, too bright, image (it's actually too
1205 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1206 * substantially reduce the halos. Alternatively try:
1207 *
1208 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1209 * This option will also reduce the halos, but there will be slight dark
1210 * halos round the opaque parts of the image where the background is light.
1211 * In the OPTIMIZED mode the halos will be light halos where the background
1212 * is dark. Take your pick - the halos are unavoidable unless you can get
1213 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1214 * faster.)
1215 *
1216 * When the default gamma of PNG files doesn't match the output gamma.
1217 * If you have PNG files with no gamma information png_set_alpha_mode allows
1218 * you to provide a default gamma, but it also sets the ouput gamma to the
1219 * matching value. If you know your PNG files have a gamma that doesn't
1220 * match the output you can take advantage of the fact that
1221 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1222 * default if it is not already set:
1223 *
1224 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1225 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1226 * The first call sets both the default and the output gamma values, the
1227 * second call overrides the output gamma without changing the default. This
1228 * is easier than achieving the same effect with png_set_gamma. You must use
1229 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1230 * fire if more than one call to png_set_alpha_mode and png_set_background is
1231 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1232 * are ignored.
1233 */
1234
1235 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1236 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1237 #endif
1238
1239 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1240 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1241 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1242 #endif
1243
1244 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1245 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1246 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1247 #endif
1248
1249 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1250 /* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1251 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1252 int flags));
1253 /* The values of the PNG_FILLER_ defines should NOT be changed */
1254 # define PNG_FILLER_BEFORE 0
1255 # define PNG_FILLER_AFTER 1
1256 /* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1257 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1258 png_uint_32 filler, int flags));
1259 #endif /* READ_FILLER || WRITE_FILLER */
1260
1261 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1262 /* Swap bytes in 16-bit depth files. */
1263 PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1264 #endif
1265
1266 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1267 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1268 PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1269 #endif
1270
1271 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1272 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1273 /* Swap packing order of pixels in bytes. */
1274 PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1275 #endif
1276
1277 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1278 /* Converts files to legal bit depths. */
1279 PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1280 true_bits));
1281 #endif
1282
1283 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1284 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1285 /* Have the code handle the interlacing. Returns the number of passes.
1286 * MUST be called before png_read_update_info or png_start_read_image,
1287 * otherwise it will not have the desired effect. Note that it is still
1288 * necessary to call png_read_row or png_read_rows png_get_image_height
1289 * times for each pass.
1290 */
1291 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1292 #endif
1293
1294 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1295 /* Invert monochrome files */
1296 PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1297 #endif
1298
1299 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1300 /* Handle alpha and tRNS by replacing with a background color. Prior to
1301 * libpng-1.5.4 this API must not be called before the PNG file header has been
1302 * read. Doing so will result in unexpected behavior and possible warnings or
1303 * errors if the PNG file contains a bKGD chunk.
1304 */
1305 PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1306 png_const_color_16p background_color, int background_gamma_code,
1307 int need_expand, double background_gamma))
1308 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1309 png_const_color_16p background_color, int background_gamma_code,
1310 int need_expand, png_fixed_point background_gamma))
1311 #endif
1312 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1313 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1314 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1315 # define PNG_BACKGROUND_GAMMA_FILE 2
1316 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1317 #endif
1318
1319 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1320 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1321 PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1322 #endif
1323
1324 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1325 #define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
1326 /* Strip the second byte of information from a 16-bit depth file. */
1327 PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1328 #endif
1329
1330 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1331 /* Turn on quantizing, and reduce the palette to the number of colors
1332 * available.
1333 */
1334 PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1335 png_colorp palette, int num_palette, int maximum_colors,
1336 png_const_uint_16p histogram, int full_quantize));
1337 #endif
1338
1339 #ifdef PNG_READ_GAMMA_SUPPORTED
1340 /* The threshold on gamma processing is configurable but hard-wired into the
1341 * library. The following is the floating point variant.
1342 */
1343 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1344
1345 /* Handle gamma correction. Screen_gamma=(display_exponent).
1346 * NOTE: this API simply sets the screen and file gamma values. It will
1347 * therefore override the value for gamma in a PNG file if it is called after
1348 * the file header has been read - use with care - call before reading the PNG
1349 * file for best results!
1350 *
1351 * These routines accept the same gamma values as png_set_alpha_mode (described
1352 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1353 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1354 * is the inverse of a 'screen gamma' value.
1355 */
1356 PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1357 double screen_gamma, double override_file_gamma))
1358 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1359 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1360 #endif
1361
1362 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1363 /* Set how many lines between output flushes - 0 for no flushing */
1364 PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1365 /* Flush the current PNG output buffer */
1366 PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1367 #endif
1368
1369 /* Optional update palette with requested transformations */
1370 PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1371
1372 /* Optional call to update the users info structure */
1373 PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1374 png_inforp info_ptr));
1375
1376 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1377 /* Read one or more rows of image data. */
1378 PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1379 png_bytepp display_row, png_uint_32 num_rows));
1380 #endif
1381
1382 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1383 /* Read a row of data. */
1384 PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1385 png_bytep display_row));
1386 #endif
1387
1388 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1389 /* Read the whole image into memory at once. */
1390 PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1391 #endif
1392
1393 /* Write a row of image data */
1394 PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1395 png_const_bytep row));
1396
1397 /* Write a few rows of image data: (*row) is not written; however, the type
1398 * is declared as writeable to maintain compatibility with previous versions
1399 * of libpng and to allow the 'display_row' array from read_rows to be passed
1400 * unchanged to write_rows.
1401 */
1402 PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1403 png_uint_32 num_rows));
1404
1405 /* Write the image data */
1406 PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1407
1408 /* Write the end of the PNG file. */
1409 PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1410 png_inforp info_ptr));
1411
1412 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1413 /* Read the end of the PNG file. */
1414 PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1415 #endif
1416
1417 /* Free any memory associated with the png_info_struct */
1418 PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1419 png_infopp info_ptr_ptr));
1420
1421 /* Free any memory associated with the png_struct and the png_info_structs */
1422 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1423 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1424
1425 /* Free any memory associated with the png_struct and the png_info_structs */
1426 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1427 png_infopp info_ptr_ptr));
1428
1429 /* Set the libpng method of handling chunk CRC errors */
1430 PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1431 int ancil_action));
1432
1433 /* Values for png_set_crc_action() say how to handle CRC errors in
1434 * ancillary and critical chunks, and whether to use the data contained
1435 * therein. Note that it is impossible to "discard" data in a critical
1436 * chunk. For versions prior to 0.90, the action was always error/quit,
1437 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1438 * chunks is warn/discard. These values should NOT be changed.
1439 *
1440 * value action:critical action:ancillary
1441 */
1442 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1443 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1444 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1445 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1446 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1447 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1448
1449 #ifdef PNG_WRITE_SUPPORTED
1450 /* These functions give the user control over the scan-line filtering in
1451 * libpng and the compression methods used by zlib. These functions are
1452 * mainly useful for testing, as the defaults should work with most users.
1453 * Those users who are tight on memory or want faster performance at the
1454 * expense of compression can modify them. See the compression library
1455 * header file (zlib.h) for an explination of the compression functions.
1456 */
1457
1458 /* Set the filtering method(s) used by libpng. Currently, the only valid
1459 * value for "method" is 0.
1460 */
1461 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1462 int filters));
1463 #endif /* WRITE */
1464
1465 /* Flags for png_set_filter() to say which filters to use. The flags
1466 * are chosen so that they don't conflict with real filter types
1467 * below, in case they are supplied instead of the #defined constants.
1468 * These values should NOT be changed.
1469 */
1470 #define PNG_NO_FILTERS 0x00
1471 #define PNG_FILTER_NONE 0x08
1472 #define PNG_FILTER_SUB 0x10
1473 #define PNG_FILTER_UP 0x20
1474 #define PNG_FILTER_AVG 0x40
1475 #define PNG_FILTER_PAETH 0x80
1476 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
1477 PNG_FILTER_AVG | PNG_FILTER_PAETH)
1478
1479 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1480 * These defines should NOT be changed.
1481 */
1482 #define PNG_FILTER_VALUE_NONE 0
1483 #define PNG_FILTER_VALUE_SUB 1
1484 #define PNG_FILTER_VALUE_UP 2
1485 #define PNG_FILTER_VALUE_AVG 3
1486 #define PNG_FILTER_VALUE_PAETH 4
1487 #define PNG_FILTER_VALUE_LAST 5
1488
1489 #ifdef PNG_WRITE_SUPPORTED
1490 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1491 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1492 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1493 png_const_doublep filter_costs))
1494 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1495 (png_structrp png_ptr, int heuristic_method, int num_weights,
1496 png_const_fixed_point_p filter_weights,
1497 png_const_fixed_point_p filter_costs))
1498 #endif /* WRITE_WEIGHTED_FILTER */
1499
1500 /* The following are no longer used and will be removed from libpng-1.7: */
1501 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1502 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1503 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1504 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1505
1506 /* Set the library compression level. Currently, valid values range from
1507 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1508 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1509 * shown that zlib compression levels 3-6 usually perform as well as level 9
1510 * for PNG images, and do considerably fewer caclulations. In the future,
1511 * these values may not correspond directly to the zlib compression levels.
1512 */
1513 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1514 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1515 int level));
1516
1517 PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1518 int mem_level));
1519
1520 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1521 int strategy));
1522
1523 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1524 * smaller value of window_bits if it can do so safely.
1525 */
1526 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1527 int window_bits));
1528
1529 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1530 int method));
1531 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1532
1533 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1534 /* Also set zlib parameters for compressing non-IDAT chunks */
1535 PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1536 int level));
1537
1538 PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1539 int mem_level));
1540
1541 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1542 int strategy));
1543
1544 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1545 * smaller value of window_bits if it can do so safely.
1546 */
1547 PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1548 (png_structrp png_ptr, int window_bits));
1549
1550 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1551 int method));
1552 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1553 #endif /* WRITE */
1554
1555 /* These next functions are called for input/output, memory, and error
1556 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1557 * and call standard C I/O routines such as fread(), fwrite(), and
1558 * fprintf(). These functions can be made to use other I/O routines
1559 * at run time for those applications that need to handle I/O in a
1560 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1561 * more information.
1562 */
1563
1564 #ifdef PNG_STDIO_SUPPORTED
1565 /* Initialize the input/output for the PNG file to the default functions. */
1566 PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1567 #endif
1568
1569 /* Replace the (error and abort), and warning functions with user
1570 * supplied functions. If no messages are to be printed you must still
1571 * write and use replacement functions. The replacement error_fn should
1572 * still do a longjmp to the last setjmp location if you are using this
1573 * method of error handling. If error_fn or warning_fn is NULL, the
1574 * default function will be used.
1575 */
1576
1577 PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1578 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1579
1580 /* Return the user pointer associated with the error functions */
1581 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1582
1583 /* Replace the default data output functions with a user supplied one(s).
1584 * If buffered output is not used, then output_flush_fn can be set to NULL.
1585 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1586 * output_flush_fn will be ignored (and thus can be NULL).
1587 * It is probably a mistake to use NULL for output_flush_fn if
1588 * write_data_fn is not also NULL unless you have built libpng with
1589 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1590 * default flush function, which uses the standard *FILE structure, will
1591 * be used.
1592 */
1593 PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1594 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1595
1596 /* Replace the default data input function with a user supplied one. */
1597 PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1598 png_rw_ptr read_data_fn));
1599
1600 /* Return the user pointer associated with the I/O functions */
1601 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1602
1603 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1604 png_read_status_ptr read_row_fn));
1605
1606 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1607 png_write_status_ptr write_row_fn));
1608
1609 #ifdef PNG_USER_MEM_SUPPORTED
1610 /* Replace the default memory allocation functions with user supplied one(s). */
1611 PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1612 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1613 /* Return the user pointer associated with the memory functions */
1614 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1615 #endif
1616
1617 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1618 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1619 png_user_transform_ptr read_user_transform_fn));
1620 #endif
1621
1622 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1623 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1624 png_user_transform_ptr write_user_transform_fn));
1625 #endif
1626
1627 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1628 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1629 png_voidp user_transform_ptr, int user_transform_depth,
1630 int user_transform_channels));
1631 /* Return the user pointer associated with the user transform functions */
1632 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1633 (png_const_structrp png_ptr));
1634 #endif
1635
1636 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1637 /* Return information about the row currently being processed. Note that these
1638 * APIs do not fail but will return unexpected results if called outside a user
1639 * transform callback. Also note that when transforming an interlaced image the
1640 * row number is the row number within the sub-image of the interlace pass, so
1641 * the value will increase to the height of the sub-image (not the full image)
1642 * then reset to 0 for the next pass.
1643 *
1644 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1645 * find the output pixel (x,y) given an interlaced sub-image pixel
1646 * (row,col,pass). (See below for these macros.)
1647 */
1648 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1649 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1650 #endif
1651
1652 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1653 /* This callback is called only for *unknown* chunks. If
1654 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1655 * chunks to be treated as unknown, however in this case the callback must do
1656 * any processing required by the chunk (e.g. by calling the appropriate
1657 * png_set_ APIs.)
1658 *
1659 * There is no write support - on write, by default, all the chunks in the
1660 * 'unknown' list are written in the specified position.
1661 *
1662 * The integer return from the callback function is interpreted thus:
1663 *
1664 * negative: An error occurred; png_chunk_error will be called.
1665 * zero: The chunk was not handled, the chunk will be saved. A critical
1666 * chunk will cause an error at this point unless it is to be saved.
1667 * positive: The chunk was handled, libpng will ignore/discard it.
1668 *
1669 * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
1670 * how this behavior will change in libpng 1.7
1671 */
1672 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1673 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1674 #endif
1675
1676 #ifdef PNG_USER_CHUNKS_SUPPORTED
1677 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1678 #endif
1679
1680 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1681 /* Sets the function callbacks for the push reader, and a pointer to a
1682 * user-defined structure available to the callback functions.
1683 */
1684 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1685 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1686 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1687
1688 /* Returns the user pointer associated with the push read functions */
1689 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1690 (png_const_structrp png_ptr));
1691
1692 /* Function to be called when data becomes available */
1693 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1694 png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
1695
1696 /* A function which may be called *only* within png_process_data to stop the
1697 * processing of any more data. The function returns the number of bytes
1698 * remaining, excluding any that libpng has cached internally. A subsequent
1699 * call to png_process_data must supply these bytes again. If the argument
1700 * 'save' is set to true the routine will first save all the pending data and
1701 * will always return 0.
1702 */
1703 PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
1704
1705 /* A function which may be called *only* outside (after) a call to
1706 * png_process_data. It returns the number of bytes of data to skip in the
1707 * input. Normally it will return 0, but if it returns a non-zero value the
1708 * application must skip than number of bytes of input data and pass the
1709 * following data to the next call to png_process_data.
1710 */
1711 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1712
1713 /* Function that combines rows. 'new_row' is a flag that should come from
1714 * the callback and be non-NULL if anything needs to be done; the library
1715 * stores its own version of the new data internally and ignores the passed
1716 * in value.
1717 */
1718 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1719 png_bytep old_row, png_const_bytep new_row));
1720 #endif /* PROGRESSIVE_READ */
1721
1722 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1723 png_alloc_size_t size), PNG_ALLOCATED);
1724 /* Added at libpng version 1.4.0 */
1725 PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1726 png_alloc_size_t size), PNG_ALLOCATED);
1727
1728 /* Added at libpng version 1.2.4 */
1729 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1730 png_alloc_size_t size), PNG_ALLOCATED);
1731
1732 /* Frees a pointer allocated by png_malloc() */
1733 PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1734
1735 /* Free data that was allocated internally */
1736 PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1737 png_inforp info_ptr, png_uint_32 free_me, int num));
1738
1739 /* Reassign responsibility for freeing existing data, whether allocated
1740 * by libpng or by the application; this works on the png_info structure passed
1741 * in, it does not change the state for other png_info structures.
1742 *
1743 * It is unlikely that this function works correctly as of 1.6.0 and using it
1744 * may result either in memory leaks or double free of allocated data.
1745 */
1746 PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1747 png_inforp info_ptr, int freer, png_uint_32 mask));
1748
1749 /* Assignments for png_data_freer */
1750 #define PNG_DESTROY_WILL_FREE_DATA 1
1751 #define PNG_SET_WILL_FREE_DATA 1
1752 #define PNG_USER_WILL_FREE_DATA 2
1753 /* Flags for png_ptr->free_me and info_ptr->free_me */
1754 #define PNG_FREE_HIST 0x0008
1755 #define PNG_FREE_ICCP 0x0010
1756 #define PNG_FREE_SPLT 0x0020
1757 #define PNG_FREE_ROWS 0x0040
1758 #define PNG_FREE_PCAL 0x0080
1759 #define PNG_FREE_SCAL 0x0100
1760 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1761 # define PNG_FREE_UNKN 0x0200
1762 #endif
1763 /* PNG_FREE_LIST 0x0400 removed in 1.6.0 because it is ignored */
1764 #define PNG_FREE_PLTE 0x1000
1765 #define PNG_FREE_TRNS 0x2000
1766 #define PNG_FREE_TEXT 0x4000
1767 #define PNG_FREE_ALL 0x7fff
1768 #define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1769
1770 #ifdef PNG_USER_MEM_SUPPORTED
1771 PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1772 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1773 PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1774 png_voidp ptr), PNG_DEPRECATED);
1775 #endif
1776
1777 #ifdef PNG_ERROR_TEXT_SUPPORTED
1778 /* Fatal error in PNG image of libpng - can't continue */
1779 PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1780 png_const_charp error_message), PNG_NORETURN);
1781
1782 /* The same, but the chunk name is prepended to the error string. */
1783 PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1784 png_const_charp error_message), PNG_NORETURN);
1785
1786 #else
1787 /* Fatal error in PNG image of libpng - can't continue */
1788 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1789 # define png_error(s1,s2) png_err(s1)
1790 # define png_chunk_error(s1,s2) png_err(s1)
1791 #endif
1792
1793 #ifdef PNG_WARNINGS_SUPPORTED
1794 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1795 PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1796 png_const_charp warning_message));
1797
1798 /* Non-fatal error in libpng, chunk name is prepended to message. */
1799 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1800 png_const_charp warning_message));
1801 #else
1802 # define png_warning(s1,s2) ((void)(s1))
1803 # define png_chunk_warning(s1,s2) ((void)(s1))
1804 #endif
1805
1806 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1807 /* Benign error in libpng. Can continue, but may have a problem.
1808 * User can choose whether to handle as a fatal error or as a warning. */
1809 PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1810 png_const_charp warning_message));
1811
1812 #ifdef PNG_READ_SUPPORTED
1813 /* Same, chunk name is prepended to message (only during read) */
1814 PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1815 png_const_charp warning_message));
1816 #endif
1817
1818 PNG_EXPORT(109, void, png_set_benign_errors,
1819 (png_structrp png_ptr, int allowed));
1820 #else
1821 # ifdef PNG_ALLOW_BENIGN_ERRORS
1822 # define png_benign_error png_warning
1823 # define png_chunk_benign_error png_chunk_warning
1824 # else
1825 # define png_benign_error png_error
1826 # define png_chunk_benign_error png_chunk_error
1827 # endif
1828 #endif
1829
1830 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
1831 * Similarly, the png_get_<chunk> calls are used to read values from the
1832 * png_info_struct, either storing the parameters in the passed variables, or
1833 * setting pointers into the png_info_struct where the data is stored. The
1834 * png_get_<chunk> functions return a non-zero value if the data was available
1835 * in info_ptr, or return zero and do not change any of the parameters if the
1836 * data was not available.
1837 *
1838 * These functions should be used instead of directly accessing png_info
1839 * to avoid problems with future changes in the size and internal layout of
1840 * png_info_struct.
1841 */
1842 /* Returns "flag" if chunk data is valid in info_ptr. */
1843 PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1844 png_const_inforp info_ptr, png_uint_32 flag));
1845
1846 /* Returns number of bytes needed to hold a transformed row. */
1847 PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1848 png_const_inforp info_ptr));
1849
1850 #ifdef PNG_INFO_IMAGE_SUPPORTED
1851 /* Returns row_pointers, which is an array of pointers to scanlines that was
1852 * returned from png_read_png().
1853 */
1854 PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
1855 png_const_inforp info_ptr));
1856
1857 /* Set row_pointers, which is an array of pointers to scanlines for use
1858 * by png_write_png().
1859 */
1860 PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
1861 png_inforp info_ptr, png_bytepp row_pointers));
1862 #endif
1863
1864 /* Returns number of color channels in image. */
1865 PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
1866 png_const_inforp info_ptr));
1867
1868 #ifdef PNG_EASY_ACCESS_SUPPORTED
1869 /* Returns image width in pixels. */
1870 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
1871 png_const_inforp info_ptr));
1872
1873 /* Returns image height in pixels. */
1874 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
1875 png_const_inforp info_ptr));
1876
1877 /* Returns image bit_depth. */
1878 PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
1879 png_const_inforp info_ptr));
1880
1881 /* Returns image color_type. */
1882 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
1883 png_const_inforp info_ptr));
1884
1885 /* Returns image filter_type. */
1886 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
1887 png_const_inforp info_ptr));
1888
1889 /* Returns image interlace_type. */
1890 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
1891 png_const_inforp info_ptr));
1892
1893 /* Returns image compression_type. */
1894 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
1895 png_const_inforp info_ptr));
1896
1897 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
1898 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
1899 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1900 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
1901 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1902 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
1903 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1904
1905 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
1906 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
1907 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1908 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
1909 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1910
1911 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1912 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
1913 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1914 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
1915 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1916 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
1917 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1918 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
1919 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1920
1921 #endif /* EASY_ACCESS */
1922
1923 #ifdef PNG_READ_SUPPORTED
1924 /* Returns pointer to signature string read from PNG header */
1925 PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
1926 png_const_inforp info_ptr));
1927 #endif
1928
1929 #ifdef PNG_bKGD_SUPPORTED
1930 PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
1931 png_inforp info_ptr, png_color_16p *background));
1932 #endif
1933
1934 #ifdef PNG_bKGD_SUPPORTED
1935 PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
1936 png_inforp info_ptr, png_const_color_16p background));
1937 #endif
1938
1939 #ifdef PNG_cHRM_SUPPORTED
1940 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
1941 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
1942 double *red_y, double *green_x, double *green_y, double *blue_x,
1943 double *blue_y))
1944 PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
1945 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
1946 double *green_X, double *green_Y, double *green_Z, double *blue_X,
1947 double *blue_Y, double *blue_Z))
1948 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
1949 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1950 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
1951 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
1952 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
1953 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
1954 PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
1955 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1956 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
1957 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
1958 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
1959 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
1960 png_fixed_point *int_blue_Z))
1961 #endif
1962
1963 #ifdef PNG_cHRM_SUPPORTED
1964 PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
1965 png_inforp info_ptr,
1966 double white_x, double white_y, double red_x, double red_y, double green_x,
1967 double green_y, double blue_x, double blue_y))
1968 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
1969 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
1970 double green_X, double green_Y, double green_Z, double blue_X,
1971 double blue_Y, double blue_Z))
1972 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
1973 png_inforp info_ptr, png_fixed_point int_white_x,
1974 png_fixed_point int_white_y, png_fixed_point int_red_x,
1975 png_fixed_point int_red_y, png_fixed_point int_green_x,
1976 png_fixed_point int_green_y, png_fixed_point int_blue_x,
1977 png_fixed_point int_blue_y))
1978 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
1979 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
1980 png_fixed_point int_red_Z, png_fixed_point int_green_X,
1981 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
1982 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
1983 png_fixed_point int_blue_Z))
1984 #endif
1985
1986 #ifdef PNG_gAMA_SUPPORTED
1987 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
1988 png_const_inforp info_ptr, double *file_gamma))
1989 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
1990 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1991 png_fixed_point *int_file_gamma))
1992 #endif
1993
1994 #ifdef PNG_gAMA_SUPPORTED
1995 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
1996 png_inforp info_ptr, double file_gamma))
1997 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
1998 png_inforp info_ptr, png_fixed_point int_file_gamma))
1999 #endif
2000
2001 #ifdef PNG_hIST_SUPPORTED
2002 PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2003 png_inforp info_ptr, png_uint_16p *hist));
2004 #endif
2005
2006 #ifdef PNG_hIST_SUPPORTED
2007 PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2008 png_inforp info_ptr, png_const_uint_16p hist));
2009 #endif
2010
2011 PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2012 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2013 int *bit_depth, int *color_type, int *interlace_method,
2014 int *compression_method, int *filter_method));
2015
2016 PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2017 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2018 int color_type, int interlace_method, int compression_method,
2019 int filter_method));
2020
2021 #ifdef PNG_oFFs_SUPPORTED
2022 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2023 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2024 int *unit_type));
2025 #endif
2026
2027 #ifdef PNG_oFFs_SUPPORTED
2028 PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2029 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2030 int unit_type));
2031 #endif
2032
2033 #ifdef PNG_pCAL_SUPPORTED
2034 PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2035 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2036 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2037 png_charpp *params));
2038 #endif
2039
2040 #ifdef PNG_pCAL_SUPPORTED
2041 PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2042 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2043 int type, int nparams, png_const_charp units, png_charpp params));
2044 #endif
2045
2046 #ifdef PNG_pHYs_SUPPORTED
2047 PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2048 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2049 int *unit_type));
2050 #endif
2051
2052 #ifdef PNG_pHYs_SUPPORTED
2053 PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2054 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2055 #endif
2056
2057 PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2058 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2059
2060 PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2061 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2062
2063 #ifdef PNG_sBIT_SUPPORTED
2064 PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2065 png_inforp info_ptr, png_color_8p *sig_bit));
2066 #endif
2067
2068 #ifdef PNG_sBIT_SUPPORTED
2069 PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2070 png_inforp info_ptr, png_const_color_8p sig_bit));
2071 #endif
2072
2073 #ifdef PNG_sRGB_SUPPORTED
2074 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2075 png_const_inforp info_ptr, int *file_srgb_intent));
2076 #endif
2077
2078 #ifdef PNG_sRGB_SUPPORTED
2079 PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2080 png_inforp info_ptr, int srgb_intent));
2081 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2082 png_inforp info_ptr, int srgb_intent));
2083 #endif
2084
2085 #ifdef PNG_iCCP_SUPPORTED
2086 PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2087 png_inforp info_ptr, png_charpp name, int *compression_type,
2088 png_bytepp profile, png_uint_32 *proflen));
2089 #endif
2090
2091 #ifdef PNG_iCCP_SUPPORTED
2092 PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2093 png_inforp info_ptr, png_const_charp name, int compression_type,
2094 png_const_bytep profile, png_uint_32 proflen));
2095 #endif
2096
2097 #ifdef PNG_sPLT_SUPPORTED
2098 PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2099 png_inforp info_ptr, png_sPLT_tpp entries));
2100 #endif
2101
2102 #ifdef PNG_sPLT_SUPPORTED
2103 PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2104 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2105 #endif
2106
2107 #ifdef PNG_TEXT_SUPPORTED
2108 /* png_get_text also returns the number of text chunks in *num_text */
2109 PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2110 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2111 #endif
2112
2113 /* Note while png_set_text() will accept a structure whose text,
2114 * language, and translated keywords are NULL pointers, the structure
2115 * returned by png_get_text will always contain regular
2116 * zero-terminated C strings. They might be empty strings but
2117 * they will never be NULL pointers.
2118 */
2119
2120 #ifdef PNG_TEXT_SUPPORTED
2121 PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2122 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2123 #endif
2124
2125 #ifdef PNG_tIME_SUPPORTED
2126 PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2127 png_inforp info_ptr, png_timep *mod_time));
2128 #endif
2129
2130 #ifdef PNG_tIME_SUPPORTED
2131 PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2132 png_inforp info_ptr, png_const_timep mod_time));
2133 #endif
2134
2135 #ifdef PNG_tRNS_SUPPORTED
2136 PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2137 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2138 png_color_16p *trans_color));
2139 #endif
2140
2141 #ifdef PNG_tRNS_SUPPORTED
2142 PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2143 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2144 png_const_color_16p trans_color));
2145 #endif
2146
2147 #ifdef PNG_sCAL_SUPPORTED
2148 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2149 png_const_inforp info_ptr, int *unit, double *width, double *height))
2150 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2151 defined(PNG_FLOATING_POINT_SUPPORTED)
2152 /* NOTE: this API is currently implemented using floating point arithmetic,
2153 * consequently it can only be used on systems with floating point support.
2154 * In any case the range of values supported by png_fixed_point is small and it
2155 * is highly recommended that png_get_sCAL_s be used instead.
2156 */
2157 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2158 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2159 png_fixed_point *width, png_fixed_point *height))
2160 #endif
2161 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2162 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2163 png_charpp swidth, png_charpp sheight));
2164
2165 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2166 png_inforp info_ptr, int unit, double width, double height))
2167 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2168 png_inforp info_ptr, int unit, png_fixed_point width,
2169 png_fixed_point height))
2170 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2171 png_inforp info_ptr, int unit,
2172 png_const_charp swidth, png_const_charp sheight));
2173 #endif /* sCAL */
2174
2175 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2176 /* Provide the default handling for all unknown chunks or, optionally, for
2177 * specific unknown chunks.
2178 *
2179 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2180 * ignored and the default was used, the per-chunk setting only had an effect on
2181 * write. If you wish to have chunk-specific handling on read in code that must
2182 * work on earlier versions you must use a user chunk callback to specify the
2183 * desired handling (keep or discard.)
2184 *
2185 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2186 * parameter is interpreted as follows:
2187 *
2188 * READ:
2189 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2190 * Known chunks: do normal libpng processing, do not keep the chunk (but
2191 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2192 * Unknown chunks: for a specific chunk use the global default, when used
2193 * as the default discard the chunk data.
2194 * PNG_HANDLE_CHUNK_NEVER:
2195 * Discard the chunk data.
2196 * PNG_HANDLE_CHUNK_IF_SAFE:
2197 * Keep the chunk data if the chunk is not critical else raise a chunk
2198 * error.
2199 * PNG_HANDLE_CHUNK_ALWAYS:
2200 * Keep the chunk data.
2201 *
2202 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2203 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2204 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2205 * it simply resets the behavior to the libpng default.
2206 *
2207 * INTERACTION WTIH USER CHUNK CALLBACKS:
2208 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2209 * callback and the callback returns 0; the chunk is then always stored *unless*
2210 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2211 * the global default is *not* used in this case. (In effect the per-chunk
2212 * value is incremented to at least IF_SAFE.)
2213 *
2214 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2215 * per-chunk defaults will be honored. If you want to preserve the current
2216 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2217 * as the default - if you don't do this libpng 1.6 will issue a warning.
2218 *
2219 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2220 * earlier simply return '1' (handled).
2221 *
2222 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2223 * If this is *not* set known chunks will always be handled by libpng and
2224 * will never be stored in the unknown chunk list. Known chunks listed to
2225 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2226 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2227 * by libpng, in addition critical chunks must either be processed by the
2228 * callback or saved.
2229 *
2230 * The IHDR and IEND chunks must not be listed. Because this turns off the
2231 * default handling for chunks that would otherwise be recognized the
2232 * behavior of libpng transformations may well become incorrect!
2233 *
2234 * WRITE:
2235 * When writing chunks the options only apply to the chunks specified by
2236 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2237 * required by png_set_ calls and will always write the core critical chunks
2238 * (as required for PLTE).
2239 *
2240 * Each chunk in the png_set_unknown_chunks list is looked up in the
2241 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2242 * interpreted as follows:
2243 *
2244 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2245 * Write safe-to-copy chunks and write other chunks if the global
2246 * default is set to _ALWAYS, otherwise don't write this chunk.
2247 * PNG_HANDLE_CHUNK_NEVER:
2248 * Do not write the chunk.
2249 * PNG_HANDLE_CHUNK_IF_SAFE:
2250 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2251 * PNG_HANDLE_CHUNK_ALWAYS:
2252 * Write the chunk.
2253 *
2254 * Note that the default behavior is effectively the opposite of the read case -
2255 * in read unknown chunks are not stored by default, in write they are written
2256 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2257 * - on write the safe-to-copy bit is checked, on read the critical bit is
2258 * checked and on read if the chunk is critical an error will be raised.
2259 *
2260 * num_chunks:
2261 * ===========
2262 * If num_chunks is positive, then the "keep" parameter specifies the manner
2263 * for handling only those chunks appearing in the chunk_list array,
2264 * otherwise the chunk list array is ignored.
2265 *
2266 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2267 * unknown chunks, as described above.
2268 *
2269 * If num_chunks is negative, then the "keep" parameter specifies the manner
2270 * for handling all unknown chunks plus all chunks recognized by libpng
2271 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2272 * be processed by libpng.
2273 */
2274 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2275 int keep, png_const_bytep chunk_list, int num_chunks));
2276
2277 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2278 * the result is therefore true (non-zero) if special handling is required,
2279 * false for the default handling.
2280 */
2281 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2282 png_const_bytep chunk_name));
2283 #endif
2284
2285 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2286 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2287 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2288 int num_unknowns));
2289 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2290 * unknowns to the location currently stored in the png_struct. This is
2291 * invariably the wrong value on write. To fix this call the following API
2292 * for each chunk in the list with the correct location. If you know your
2293 * code won't be compiled on earlier versions you can rely on
2294 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2295 * the correct thing.
2296 */
2297
2298 PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2299 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2300
2301 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2302 png_inforp info_ptr, png_unknown_chunkpp entries));
2303 #endif
2304
2305 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2306 * If you need to turn it off for a chunk that your application has freed,
2307 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2308 */
2309 PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2310 png_inforp info_ptr, int mask));
2311
2312 #ifdef PNG_INFO_IMAGE_SUPPORTED
2313 /* The "params" pointer is currently not used and is for future expansion. */
2314 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2315 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2316 int transforms, png_voidp params));
2317 #endif
2318 #ifdef PNG_WRITE_SUPPORTED
2319 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2320 int transforms, png_voidp params));
2321 #endif
2322 #endif
2323
2324 PNG_EXPORT(180, png_const_charp, png_get_copyright,
2325 (png_const_structrp png_ptr));
2326 PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2327 (png_const_structrp png_ptr));
2328 PNG_EXPORT(182, png_const_charp, png_get_header_version,
2329 (png_const_structrp png_ptr));
2330 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2331 (png_const_structrp png_ptr));
2332
2333 #ifdef PNG_MNG_FEATURES_SUPPORTED
2334 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2335 png_uint_32 mng_features_permitted));
2336 #endif
2337
2338 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2339 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2340 #define PNG_HANDLE_CHUNK_NEVER 1
2341 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2342 #define PNG_HANDLE_CHUNK_ALWAYS 3
2343 #define PNG_HANDLE_CHUNK_LAST 4
2344
2345 /* Strip the prepended error numbers ("#nnn ") from error and warning
2346 * messages before passing them to the error or warning handler.
2347 */
2348 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2349 PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2350 png_uint_32 strip_mode));
2351 #endif
2352
2353 /* Added in libpng-1.2.6 */
2354 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2355 PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2356 png_uint_32 user_width_max, png_uint_32 user_height_max));
2357 PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2358 (png_const_structrp png_ptr));
2359 PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2360 (png_const_structrp png_ptr));
2361 /* Added in libpng-1.4.0 */
2362 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2363 png_uint_32 user_chunk_cache_max));
2364 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2365 (png_const_structrp png_ptr));
2366 /* Added in libpng-1.4.1 */
2367 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2368 png_alloc_size_t user_chunk_cache_max));
2369 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2370 (png_const_structrp png_ptr));
2371 #endif
2372
2373 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2374 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2375 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2376
2377 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2378 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2379
2380 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2381 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2382
2383 PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2384 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2385 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2386 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2387 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2388 #endif
2389
2390 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2391 png_const_inforp info_ptr))
2392 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2393 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2394 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2395 #endif
2396
2397 # ifdef PNG_pHYs_SUPPORTED
2398 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2399 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2400 int *unit_type));
2401 # endif /* pHYs */
2402 #endif /* INCH_CONVERSIONS */
2403
2404 /* Added in libpng-1.4.0 */
2405 #ifdef PNG_IO_STATE_SUPPORTED
2406 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2407
2408 /* Removed from libpng 1.6; use png_get_io_chunk_type. */
2409 PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2410 PNG_DEPRECATED)
2411
2412 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2413 (png_const_structrp png_ptr));
2414
2415 /* The flags returned by png_get_io_state() are the following: */
2416 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2417 # define PNG_IO_READING 0x0001 /* currently reading */
2418 # define PNG_IO_WRITING 0x0002 /* currently writing */
2419 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2420 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2421 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2422 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2423 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2424 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2425 #endif /* IO_STATE */
2426
2427 /* Interlace support. The following macros are always defined so that if
2428 * libpng interlace handling is turned off the macros may be used to handle
2429 * interlaced images within the application.
2430 */
2431 #define PNG_INTERLACE_ADAM7_PASSES 7
2432
2433 /* Two macros to return the first row and first column of the original,
2434 * full, image which appears in a given pass. 'pass' is in the range 0
2435 * to 6 and the result is in the range 0 to 7.
2436 */
2437 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2438 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2439
2440 /* A macro to return the offset between pixels in the output row for a pair of
2441 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2442 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2443 * COL_OFFSET is from one column to the next, within a row.
2444 */
2445 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2446 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2447
2448 /* Two macros to help evaluate the number of rows or columns in each
2449 * pass. This is expressed as a shift - effectively log2 of the number or
2450 * rows or columns in each 8x8 tile of the original image.
2451 */
2452 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2453 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2454
2455 /* Hence two macros to determine the number of rows or columns in a given
2456 * pass of an image given its height or width. In fact these macros may
2457 * return non-zero even though the sub-image is empty, because the other
2458 * dimension may be empty for a small image.
2459 */
2460 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2461 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2462 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2463 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2464
2465 /* For the reader row callbacks (both progressive and sequential) it is
2466 * necessary to find the row in the output image given a row in an interlaced
2467 * image, so two more macros:
2468 */
2469 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2470 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2471 #define PNG_COL_FROM_PASS_COL(x_in, pass) \
2472 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2473
2474 /* Two macros which return a boolean (0 or 1) saying whether the given row
2475 * or column is in a particular pass. These use a common utility macro that
2476 * returns a mask for a given pass - the offset 'off' selects the row or
2477 * column version. The mask has the appropriate bit set for each column in
2478 * the tile.
2479 */
2480 #define PNG_PASS_MASK(pass,off) ( \
2481 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2482 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2483
2484 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2485 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2486 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2487 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2488
2489 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2490 /* With these routines we avoid an integer divide, which will be slower on
2491 * most machines. However, it does take more operations than the corresponding
2492 * divide method, so it may be slower on a few RISC systems. There are two
2493 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2494 *
2495 * Note that the rounding factors are NOT supposed to be the same! 128 and
2496 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2497 * standard method.
2498 *
2499 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2500 */
2501
2502 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2503
2504 # define png_composite(composite, fg, alpha, bg) \
2505 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2506 * (png_uint_16)(alpha) \
2507 + (png_uint_16)(bg)*(png_uint_16)(255 \
2508 - (png_uint_16)(alpha)) + 128); \
2509 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); }
2510
2511 # define png_composite_16(composite, fg, alpha, bg) \
2512 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2513 * (png_uint_32)(alpha) \
2514 + (png_uint_32)(bg)*(65535 \
2515 - (png_uint_32)(alpha)) + 32768); \
2516 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); }
2517
2518 #else /* Standard method using integer division */
2519
2520 # define png_composite(composite, fg, alpha, bg) \
2521 (composite) = \
2522 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2523 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2524 127) / 255))
2525
2526 # define png_composite_16(composite, fg, alpha, bg) \
2527 (composite) = \
2528 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2529 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2530 32767) / 65535))
2531 #endif /* READ_COMPOSITE_NODIV */
2532
2533 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2534 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2535 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2536 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2537 #endif
2538
2539 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2540 png_const_bytep buf));
2541 /* No png_get_int_16 -- may be added if there's a real need for it. */
2542
2543 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2544 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2545 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2546 #endif
2547 #ifdef PNG_SAVE_INT_32_SUPPORTED
2548 PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2549 #endif
2550
2551 /* Place a 16-bit number into a buffer in PNG byte order.
2552 * The parameter is declared unsigned int, not png_uint_16,
2553 * just to avoid potential problems on pre-ANSI C compilers.
2554 */
2555 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2556 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2557 /* No png_save_int_16 -- may be added if there's a real need for it. */
2558 #endif
2559
2560 #ifdef PNG_USE_READ_MACROS
2561 /* Inline macros to do direct reads of bytes from the input buffer.
2562 * The png_get_int_32() routine assumes we are using two's complement
2563 * format for negative values, which is almost certainly true.
2564 */
2565 # define PNG_get_uint_32(buf) \
2566 (((png_uint_32)(*(buf)) << 24) + \
2567 ((png_uint_32)(*((buf) + 1)) << 16) + \
2568 ((png_uint_32)(*((buf) + 2)) << 8) + \
2569 ((png_uint_32)(*((buf) + 3))))
2570
2571 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2572 * function) incorrectly returned a value of type png_uint_32.
2573 */
2574 # define PNG_get_uint_16(buf) \
2575 ((png_uint_16) \
2576 (((unsigned int)(*(buf)) << 8) + \
2577 ((unsigned int)(*((buf) + 1)))))
2578
2579 # define PNG_get_int_32(buf) \
2580 ((png_int_32)((*(buf) & 0x80) \
2581 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2582 : (png_int_32)png_get_uint_32(buf)))
2583
2584 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2585 * but defining a macro name prefixed with PNG_PREFIX.
2586 */
2587 # ifndef PNG_PREFIX
2588 # define png_get_uint_32(buf) PNG_get_uint_32(buf)
2589 # define png_get_uint_16(buf) PNG_get_uint_16(buf)
2590 # define png_get_int_32(buf) PNG_get_int_32(buf)
2591 # endif
2592 #else
2593 # ifdef PNG_PREFIX
2594 /* No macros; revert to the (redefined) function */
2595 # define PNG_get_uint_32 (png_get_uint_32)
2596 # define PNG_get_uint_16 (png_get_uint_16)
2597 # define PNG_get_int_32 (png_get_int_32)
2598 # endif
2599 #endif
2600
2601 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2602 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
2603 (png_structrp png_ptr, int allowed));
2604 # ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2605 PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
2606 png_const_infop info_ptr));
2607 # endif
2608 #endif /* CHECK_FOR_INVALID_INDEX */
2609
2610 /*******************************************************************************
2611 * Section 5: SIMPLIFIED API
2612 *******************************************************************************
2613 *
2614 * Please read the documentation in libpng-manual.txt (TODO: write said
2615 * documentation) if you don't understand what follows.
2616 *
2617 * The simplified API hides the details of both libpng and the PNG file format
2618 * itself. It allows PNG files to be read into a very limited number of
2619 * in-memory bitmap formats or to be written from the same formats. If these
2620 * formats do not accomodate your needs then you can, and should, use the more
2621 * sophisticated APIs above - these support a wide variety of in-memory formats
2622 * and a wide variety of sophisticated transformations to those formats as well
2623 * as a wide variety of APIs to manipulate ancillary information.
2624 *
2625 * To read a PNG file using the simplified API:
2626 *
2627 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2628 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2629 * (this is REQUIRED, your program may crash if you don't do it.)
2630 * 2) Call the appropriate png_image_begin_read... function.
2631 * 3) Set the png_image 'format' member to the required sample format.
2632 * 4) Allocate a buffer for the image and, if required, the color-map.
2633 * 5) Call png_image_finish_read to read the image and, if required, the
2634 * color-map into your buffers.
2635 *
2636 * There are no restrictions on the format of the PNG input itself; all valid
2637 * color types, bit depths, and interlace methods are acceptable, and the
2638 * input image is transformed as necessary to the requested in-memory format
2639 * during the png_image_finish_read() step. The only caveat is that if you
2640 * request a color-mapped image from a PNG that is full-color or makes
2641 * complex use of an alpha channel the transformation is extremely lossy and the
2642 * result may look terrible.
2643 *
2644 * To write a PNG file using the simplified API:
2645 *
2646 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2647 * 2) Initialize the members of the structure that describe the image, setting
2648 * the 'format' member to the format of the image samples.
2649 * 3) Call the appropriate png_image_write... function with a pointer to the
2650 * image and, if necessary, the color-map to write the PNG data.
2651 *
2652 * png_image is a structure that describes the in-memory format of an image
2653 * when it is being read or defines the in-memory format of an image that you
2654 * need to write:
2655 */
2656 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2657 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2658
2659 #define PNG_IMAGE_VERSION 1
2660
2661 typedef struct png_control *png_controlp;
2662 typedef struct
2663 {
2664 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2665 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2666 png_uint_32 width; /* Image width in pixels (columns) */
2667 png_uint_32 height; /* Image height in pixels (rows) */
2668 png_uint_32 format; /* Image format as defined below */
2669 png_uint_32 flags; /* A bit mask containing informational flags */
2670 png_uint_32 colormap_entries;
2671 /* Number of entries in the color-map */
2672
2673 /* In the event of an error or warning the following field will be set to a
2674 * non-zero value and the 'message' field will contain a '\0' terminated
2675 * string with the libpng error or warning message. If both warnings and
2676 * an error were encountered, only the error is recorded. If there
2677 * are multiple warnings, only the first one is recorded.
2678 *
2679 * The upper 30 bits of this value are reserved, the low two bits contain
2680 * a value as follows:
2681 */
2682 # define PNG_IMAGE_WARNING 1
2683 # define PNG_IMAGE_ERROR 2
2684 /*
2685 * The result is a two-bit code such that a value more than 1 indicates
2686 * a failure in the API just called:
2687 *
2688 * 0 - no warning or error
2689 * 1 - warning
2690 * 2 - error
2691 * 3 - error preceded by warning
2692 */
2693 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2694
2695 png_uint_32 warning_or_error;
2696
2697 char message[64];
2698 } png_image, *png_imagep;
2699
2700 /* The samples of the image have one to four channels whose components have
2701 * original values in the range 0 to 1.0:
2702 *
2703 * 1: A single gray or luminance channel (G).
2704 * 2: A gray/luminance channel and an alpha channel (GA).
2705 * 3: Three red, green, blue color channels (RGB).
2706 * 4: Three color channels and an alpha channel (RGBA).
2707 *
2708 * The components are encoded in one of two ways:
2709 *
2710 * a) As a small integer, value 0..255, contained in a single byte. For the
2711 * alpha channel the original value is simply value/255. For the color or
2712 * luminance channels the value is encoded according to the sRGB specification
2713 * and matches the 8-bit format expected by typical display devices.
2714 *
2715 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2716 * channel and are suitable for passing to color management software.
2717 *
2718 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2719 * channels can be converted to the original value by dividing by 65535; all
2720 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2721 * the sRGB specification. This encoding is identified by the
2722 * PNG_FORMAT_FLAG_LINEAR flag below.
2723 *
2724 * When the simplified API needs to convert between sRGB and linear colorspaces,
2725 * the actual sRGB transfer curve defined in the sRGB specification (see the
2726 * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2727 * approximation used elsewhere in libpng.
2728 *
2729 * When an alpha channel is present it is expected to denote pixel coverage
2730 * of the color or luminance channels and is returned as an associated alpha
2731 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2732 * value.
2733 *
2734 * The samples are either contained directly in the image data, between 1 and 8
2735 * bytes per pixel according to the encoding, or are held in a color-map indexed
2736 * by bytes in the image data. In the case of a color-map the color-map entries
2737 * are individual samples, encoded as above, and the image data has one byte per
2738 * pixel to select the relevant sample from the color-map.
2739 */
2740
2741 /* PNG_FORMAT_*
2742 *
2743 * #defines to be used in png_image::format. Each #define identifies a
2744 * particular layout of sample data and, if present, alpha values. There are
2745 * separate defines for each of the two component encodings.
2746 *
2747 * A format is built up using single bit flag values. All combinations are
2748 * valid. Formats can be built up from the flag values or you can use one of
2749 * the predefined values below. When testing formats always use the FORMAT_FLAG
2750 * macros to test for individual features - future versions of the library may
2751 * add new flags.
2752 *
2753 * When reading or writing color-mapped images the format should be set to the
2754 * format of the entries in the color-map then png_image_{read,write}_colormap
2755 * called to read or write the color-map and set the format correctly for the
2756 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2757 *
2758 * NOTE: libpng can be built with particular features disabled. If you see
2759 * compiler errors because the definition of one of the following flags has been
2760 * compiled out it is because libpng does not have the required support. It is
2761 * possible, however, for the libpng configuration to enable the format on just
2762 * read or just write; in that case you may see an error at run time. You can
2763 * guard against this by checking for the definition of the appropriate
2764 * "_SUPPORTED" macro, one of:
2765 *
2766 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2767 */
2768 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2769 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2770 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2771 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2772
2773 #ifdef PNG_FORMAT_BGR_SUPPORTED
2774 # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2775 #endif
2776
2777 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
2778 # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2779 #endif
2780
2781 /* Commonly used formats have predefined macros.
2782 *
2783 * First the single byte (sRGB) formats:
2784 */
2785 #define PNG_FORMAT_GRAY 0
2786 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2787 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2788 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2789 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2790 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2791 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2792 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2793 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2794
2795 /* Then the linear 2-byte formats. When naming these "Y" is used to
2796 * indicate a luminance (gray) channel.
2797 */
2798 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2799 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2800 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2801 #define PNG_FORMAT_LINEAR_RGB_ALPHA \
2802 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2803
2804 /* With color-mapped formats the image data is one byte for each pixel, the byte
2805 * is an index into the color-map which is formatted as above. To obtain a
2806 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2807 * to one of the above definitions, or you can use one of the definitions below.
2808 */
2809 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2810 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2811 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2812 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2813 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2814 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2815
2816 /* PNG_IMAGE macros
2817 *
2818 * These are convenience macros to derive information from a png_image
2819 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2820 * actual image sample values - either the entries in the color-map or the
2821 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2822 * for the pixels and will always return 1 for color-mapped formats. The
2823 * remaining macros return information about the rows in the image and the
2824 * complete image.
2825 *
2826 * NOTE: All the macros that take a png_image::format parameter are compile time
2827 * constants if the format parameter is, itself, a constant. Therefore these
2828 * macros can be used in array declarations and case labels where required.
2829 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2830 * they can be used in #if tests.
2831 *
2832 * First the information about the samples.
2833 */
2834 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2835 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2836 /* Return the total number of channels in a given format: 1..4 */
2837
2838 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2839 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2840 /* Return the size in bytes of a single component of a pixel or color-map
2841 * entry (as appropriate) in the image: 1 or 2.
2842 */
2843
2844 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2845 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2846 /* This is the size of the sample data for one sample. If the image is
2847 * color-mapped it is the size of one color-map entry (and image pixels are
2848 * one byte in size), otherwise it is the size of one image pixel.
2849 */
2850
2851 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2852 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2853 /* The maximum size of the color-map required by the format expressed in a
2854 * count of components. This can be used to compile-time allocate a
2855 * color-map:
2856 *
2857 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2858 *
2859 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2860 *
2861 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2862 * information from one of the png_image_begin_read_ APIs and dynamically
2863 * allocate the required memory.
2864 */
2865
2866 /* Corresponding information about the pixels */
2867 #define PNG_IMAGE_PIXEL_(test,fmt)\
2868 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2869
2870 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2871 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2872 /* The number of separate channels (components) in a pixel; 1 for a
2873 * color-mapped image.
2874 */
2875
2876 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2877 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2878 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2879 * image.
2880 */
2881
2882 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2883 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2884
2885 /* Information about the whole row, or whole image */
2886 #define PNG_IMAGE_ROW_STRIDE(image)\
2887 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2888 /* Return the total number of components in a single row of the image; this
2889 * is the minimum 'row stride', the minimum count of components between each
2890 * row. For a color-mapped image this is the minimum number of bytes in a
2891 * row.
2892 */
2893
2894 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2895 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2896 /* Return the size, in bytes, of an image buffer given a png_image and a row
2897 * stride - the number of components to leave space for in each row.
2898 */
2899
2900 #define PNG_IMAGE_SIZE(image)\
2901 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2902 /* Return the size, in bytes, of the image in memory given just a png_image;
2903 * the row stride is the minimum stride required for the image.
2904 */
2905
2906 #define PNG_IMAGE_COLORMAP_SIZE(image)\
2907 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2908 /* Return the size, in bytes, of the color-map of this image. If the image
2909 * format is not a color-map format this will return a size sufficient for
2910 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2911 * you don't want to allocate a color-map in this case.
2912 */
2913
2914 /* PNG_IMAGE_FLAG_*
2915 *
2916 * Flags containing additional information about the image are held in the
2917 * 'flags' field of png_image.
2918 */
2919 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2920 /* This indicates the the RGB values of the in-memory bitmap do not
2921 * correspond to the red, green and blue end-points defined by sRGB.
2922 */
2923
2924 #define PNG_IMAGE_FLAG_FAST 0x02
2925 /* On write emphasise speed over compression; the resultant PNG file will be
2926 * larger but will be produced significantly faster, particular for large
2927 * images. Do not use this option for images which will be distributed, only
2928 * used it when producing intermediate files that will be read back in
2929 * repeatedly. For a typical 24-bit image the option will double the read
2930 * speed at the cost of increasing the image size by 25%, however for many
2931 * more compressible images the PNG file can be 10 times larger with only a
2932 * slight speed gain.
2933 */
2934
2935 #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
2936 /* On read if the image is a 16-bit per component image and there is no gAMA
2937 * or sRGB chunk assume that the components are sRGB encoded. Notice that
2938 * images output by the simplified API always have gamma information; setting
2939 * this flag only affects the interpretation of 16-bit images from an
2940 * external source. It is recommended that the application expose this flag
2941 * to the user; the user can normally easily recognize the difference between
2942 * linear and sRGB encoding. This flag has no effect on write - the data
2943 * passed to the write APIs must have the correct encoding (as defined
2944 * above.)
2945 *
2946 * If the flag is not set (the default) input 16-bit per component data is
2947 * assumed to be linear.
2948 *
2949 * NOTE: the flag can only be set after the png_image_begin_read_ call,
2950 * because that call initializes the 'flags' field.
2951 */
2952
2953 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
2954 /* READ APIs
2955 * ---------
2956 *
2957 * The png_image passed to the read APIs must have been initialized by setting
2958 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
2959 */
2960 #ifdef PNG_STDIO_SUPPORTED
2961 PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
2962 const char *file_name));
2963 /* The named file is opened for read and the image header is filled in
2964 * from the PNG header in the file.
2965 */
2966
2967 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
2968 FILE* file));
2969 /* The PNG header is read from the stdio FILE object. */
2970 #endif /* STDIO */
2971
2972 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
2973 png_const_voidp memory, png_size_t size));
2974 /* The PNG header is read from the given memory buffer. */
2975
2976 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
2977 png_const_colorp background, void *buffer, png_int_32 row_stride,
2978 void *colormap));
2979 /* Finish reading the image into the supplied buffer and clean up the
2980 * png_image structure.
2981 *
2982 * row_stride is the step, in byte or 2-byte units as appropriate,
2983 * between adjacent rows. A positive stride indicates that the top-most row
2984 * is first in the buffer - the normal top-down arrangement. A negative
2985 * stride indicates that the bottom-most row is first in the buffer.
2986 *
2987 * background need only be supplied if an alpha channel must be removed from
2988 * a png_byte format and the removal is to be done by compositing on a solid
2989 * color; otherwise it may be NULL and any composition will be done directly
2990 * onto the buffer. The value is an sRGB color to use for the background,
2991 * for grayscale output the green channel is used.
2992 *
2993 * background must be supplied when an alpha channel must be removed from a
2994 * single byte color-mapped output format, in other words if:
2995 *
2996 * 1) The original format from png_image_begin_read_from_* had
2997 * PNG_FORMAT_FLAG_ALPHA set.
2998 * 2) The format set by the application does not.
2999 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3000 * PNG_FORMAT_FLAG_LINEAR *not* set.
3001 *
3002 * For linear output removing the alpha channel is always done by compositing
3003 * on black and background is ignored.
3004 *
3005 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3006 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3007 * image->colormap_entries will be updated to the actual number of entries
3008 * written to the colormap; this may be less than the original value.
3009 */
3010
3011 PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3012 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3013 * NULL. May be called at any time after the structure is initialized.
3014 */
3015 #endif /* SIMPLIFIED_READ */
3016
3017 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3018 #ifdef PNG_STDIO_SUPPORTED
3019 /* WRITE APIS
3020 * ----------
3021 * For write you must initialize a png_image structure to describe the image to
3022 * be written. To do this use memset to set the whole structure to 0 then
3023 * initialize fields describing your image.
3024 *
3025 * version: must be set to PNG_IMAGE_VERSION
3026 * opaque: must be initialized to NULL
3027 * width: image width in pixels
3028 * height: image height in rows
3029 * format: the format of the data (image and color-map) you wish to write
3030 * flags: set to 0 unless one of the defined flags applies; set
3031 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3032 * values do not correspond to the colors in sRGB.
3033 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3034 */
3035 PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3036 const char *file, int convert_to_8bit, const void *buffer,
3037 png_int_32 row_stride, const void *colormap));
3038 /* Write the image to the named file. */
3039
3040 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3041 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3042 const void *colormap));
3043 /* Write the image to the given (FILE*). */
3044
3045 /* With both write APIs if image is in one of the linear formats with 16-bit
3046 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3047 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3048 * encoded PNG file is written.
3049 *
3050 * With color-mapped data formats the colormap parameter point to a color-map
3051 * with at least image->colormap_entries encoded in the specified format. If
3052 * the format is linear the written PNG color-map will be converted to sRGB
3053 * regardless of the convert_to_8_bit flag.
3054 *
3055 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3056 * from one row to the next in component sized units (1 or 2 bytes) and if
3057 * negative indicates a bottom-up row layout in the buffer. If row_stride is zero,
3058 * libpng will calculate it for you from the image width and number of channels.
3059 *
3060 * Note that the write API does not support interlacing, sub-8-bit pixels, indexed
3061 * PNG (color_type 3) or most ancillary chunks.
3062 */
3063 #endif /* STDIO */
3064 #endif /* SIMPLIFIED_WRITE */
3065 /*******************************************************************************
3066 * END OF SIMPLIFIED API
3067 ******************************************************************************/
3068 #endif /* SIMPLIFIED_{READ|WRITE} */
3069
3070 /*******************************************************************************
3071 * Section 6: IMPLEMENTATION OPTIONS
3072 *******************************************************************************
3073 *
3074 * Support for arbitrary implementation-specific optimizations. The API allows
3075 * particular options to be turned on or off. 'Option' is the number of the
3076 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3077 * by the PNG_OPTION_ defines below.
3078 *
3079 * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
3080 * are detected at run time, however sometimes it may be impossible
3081 * to do this in user mode, in which case it is necessary to discover
3082 * the capabilities in an OS specific way. Such capabilities are
3083 * listed here when libpng has support for them and must be turned
3084 * ON by the application if present.
3085 *
3086 * SOFTWARE: sometimes software optimizations actually result in performance
3087 * decrease on some architectures or systems, or with some sets of
3088 * PNG images. 'Software' options allow such optimizations to be
3089 * selected at run time.
3090 */
3091 #ifdef PNG_SET_OPTION_SUPPORTED
3092 #ifdef PNG_ARM_NEON_API_SUPPORTED
3093 # define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3094 #endif
3095 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3096 #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3097 #define PNG_OPTION_NEXT 6 /* Next option - numbers must be even */
3098
3099 /* Return values: NOTE: there are four values and 'off' is *not* zero */
3100 #define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3101 #define PNG_OPTION_INVALID 1 /* Option number out of range */
3102 #define PNG_OPTION_OFF 2
3103 #define PNG_OPTION_ON 3
3104
3105 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3106 int onoff));
3107 #endif /* SET_OPTION */
3108
3109 /*******************************************************************************
3110 * END OF HARDWARE AND SOFTWARE OPTIONS
3111 ******************************************************************************/
3112
3113 /* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3114 * defs, and in scripts/symbols.def.
3115 */
3116
3117 /* The last ordinal number (this is the *last* one already used; the next
3118 * one to use is one more than this.)
3119 */
3120 #ifdef PNG_EXPORT_LAST_ORDINAL
3121 PNG_EXPORT_LAST_ORDINAL(244);
3122 #endif
3123
3124 #ifdef __cplusplus
3125 }
3126 #endif
3127
3128 #endif /* PNG_VERSION_INFO_ONLY */
3129 /* Do not put anything past this line */
3130 #endif /* PNG_H */