2 /* png.h - header file for PNG reference library
4 * libpng version 1.6.32, August 24, 2017
6 * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
10 * This code is released under the libpng license (See LICENSE, below)
12 * Authors and maintainers:
13 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
14 * libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
15 * libpng versions 0.97, January 1998, through 1.6.32, August 24, 2017:
16 * Glenn Randers-Pehrson.
17 * See also "Contributing Authors", below.
21 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
23 * If you modify libpng you may insert additional notices immediately following
26 * This code is released under the libpng license.
28 * libpng versions 1.0.7, July 1, 2000 through 1.6.32, August 24, 2017 are
29 * Copyright (c) 2000-2002, 2004, 2006-2017 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:
34 * Simon-Pierre Cadieux
40 * Mandar Sahastrabuddhe
44 * and with the following additions to the disclaimer:
46 * There is no warranty against interference with your enjoyment of the
47 * library or against infringement. There is no warranty that our
48 * efforts or the library will fulfill any of your particular purposes
49 * or needs. This library is provided with all faults, and the entire
50 * risk of satisfactory quality, performance, accuracy, and effort is with
53 * Some files in the "contrib" directory and some configure-generated
54 * files that are distributed with libpng have other copyright owners and
55 * are released under other open source licenses.
57 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
58 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
59 * libpng-0.96, and are distributed according to the same disclaimer and
60 * license as libpng-0.96, with the following individuals added to the list
61 * of Contributing Authors:
64 * Glenn Randers-Pehrson
67 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
68 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
69 * and are distributed according to the same disclaimer and license as
70 * libpng-0.88, with the following individuals added to the list of
71 * Contributing Authors:
80 * Some files in the "scripts" directory have other copyright owners
81 * but are released under this license.
83 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
84 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
86 * For the purposes of this copyright and license, "Contributing Authors"
87 * is defined as the following set of individuals:
95 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
96 * and Group 42, Inc. disclaim all warranties, expressed or implied,
97 * including, without limitation, the warranties of merchantability and of
98 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
99 * assume no liability for direct, indirect, incidental, special, exemplary,
100 * or consequential damages, which may result from the use of the PNG
101 * Reference Library, even if advised of the possibility of such damage.
103 * Permission is hereby granted to use, copy, modify, and distribute this
104 * source code, or portions hereof, for any purpose, without fee, subject
105 * to the following restrictions:
107 * 1. The origin of this source code must not be misrepresented.
109 * 2. Altered versions must be plainly marked as such and must not
110 * be misrepresented as being the original source.
112 * 3. This Copyright notice may not be removed or altered from any
113 * source or altered source distribution.
115 * The Contributing Authors and Group 42, Inc. specifically permit, without
116 * fee, and encourage the use of this source code as a component to
117 * supporting the PNG file format in commercial products. If you use this
118 * source code in a product, acknowledgment is not required but would be
121 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
125 * The name "libpng" has not been registered by the Copyright owner
126 * as a trademark in any jurisdiction. However, because libpng has
127 * been distributed and maintained world-wide, continually since 1995,
128 * the Copyright owner claims "common-law trademark protection" in any
129 * jurisdiction where common-law trademark is recognized.
133 * Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
134 * a certification mark of the Open Source Initiative. OSI has not addressed
135 * the additional disclaimers inserted at version 1.0.7.
139 * The Copyright owner believes that the Export Control Classification
140 * Number (ECCN) for libpng is EAR99, which means not subject to export
141 * controls or International Traffic in Arms Regulations (ITAR) because
142 * it is open source, publicly available software, that does not contain
143 * any encryption software. See the EAR, paragraphs 734.3(b)(3) and
148 * A "png_get_copyright" function is available, for convenient use in "about"
149 * boxes and the like:
151 * printf("%s", png_get_copyright(NULL));
153 * Also, the PNG logo (in PNG format, of course) is supplied in the
154 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
158 * The contributing authors would like to thank all those who helped
159 * with testing, bug fixes, and patience. This wouldn't have been
160 * possible without all of you.
162 * Thanks to Frank J. T. Wojcik for helping with the documentation.
165 /* Note about libpng version numbers:
167 * Due to various miscommunications, unforeseen code incompatibilities
168 * and occasional factors outside the authors' control, version numbering
169 * on the library has not always been consistent and straightforward.
170 * The following table summarizes matters since version 0.89c, which was
171 * the first widely used release:
173 * source png.h png.h shared-lib
174 * version string int version
175 * ------- ------ ----- ----------
176 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
177 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
178 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
179 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
180 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
181 * 0.97c 0.97 97 2.0.97
182 * 0.98 0.98 98 2.0.98
183 * 0.99 0.99 98 2.0.99
184 * 0.99a-m 0.99 99 2.0.99
185 * 1.00 1.00 100 2.1.0 [100 should be 10000]
186 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
187 * 1.0.1 png.h string is 10001 2.1.0
188 * 1.0.1a-e identical to the 10002 from here on, the shared library
189 * 1.0.2 source version) 10002 is 2.V where V is the source code
190 * 1.0.2a-b 10003 version, except as noted.
195 * 1.0.5 (+ 2 patches) 10005
197 * 1.0.5e-r 10100 (not source compatible)
198 * 1.0.5s-v 10006 (not binary compatible)
199 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
200 * 1.0.6d-f 10007 (still binary incompatible)
202 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
204 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
205 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
206 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
207 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
208 * 1.0.7 1 10007 (still compatible)
210 * 1.0.19 10 10019 10.so.0.19[.0]
212 * 1.2.57 13 10257 12.so.0.57[.0]
214 * 1.5.28 15 10527 15.so.15.28[.0]
216 * 1.6.32 16 10632 16.so.16.32[.0]
218 * Henceforth the source version will match the shared-library major
219 * and minor numbers; the shared-library major version number will be
220 * used for changes in backward compatibility, as it is intended. The
221 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
222 * for applications, is an unsigned integer of the form xyyzz corresponding
223 * to the source version x.y.z (leading zeros in y and z). Beta versions
224 * were given the previous public release number plus a letter, until
225 * version 1.0.6j; from then on they were given the upcoming public
226 * release number plus "betaNN" or "rcNN".
228 * Binary incompatibility exists only when applications make direct access
229 * to the info_ptr or png_ptr members through png.h, and the compiled
230 * application is loaded with a different version of the library.
232 * DLLNUM will change each time there are forward or backward changes
233 * in binary compatibility (e.g., when a new feature is added).
235 * See libpng.txt or libpng.3 for more information. The PNG specification
236 * is available as a W3C Recommendation and as an ISO Specification,
237 * <https://www.w3.org/TR/2003/REC-PNG-20031110/
241 * Y2K compliance in libpng:
242 * =========================
246 * Since the PNG Development group is an ad-hoc body, we can't make
247 * an official declaration.
249 * This is your unofficial assurance that libpng from version 0.71 and
250 * upward through 1.6.32 are Y2K compliant. It is my belief that
251 * earlier versions were also Y2K compliant.
253 * Libpng only has two year fields. One is a 2-byte unsigned integer
254 * that will hold years up to 65535. The other, which is deprecated,
255 * holds the date in text format, and will hold years up to 9999.
258 * "png_uint_16 year" in png_time_struct.
261 * "char time_buffer[29]" in png_struct. This is no longer used
262 * in libpng-1.6.x and will be removed from libpng-1.7.0.
264 * There are seven time-related functions:
265 * png.c: png_convert_to_rfc_1123_buffer() in png.c
266 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
267 * png_convert_to_rfc_1152() in error prior to libpng-0.98)
268 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
269 * png_convert_from_time_t() in pngwrite.c
270 * png_get_tIME() in pngget.c
271 * png_handle_tIME() in pngrutil.c, called in pngread.c
272 * png_set_tIME() in pngset.c
273 * png_write_tIME() in pngwutil.c, called in pngwrite.c
275 * All handle dates properly in a Y2K environment. The
276 * png_convert_from_time_t() function calls gmtime() to convert from system
277 * clock time, which returns (year - 1900), which we properly convert to
278 * the full 4-digit year. There is a possibility that libpng applications
279 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
280 * function, or that they are incorrectly passing only a 2-digit year
281 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
282 * but this is not under our control. The libpng documentation has always
283 * stated that it works with 4-digit years, and the APIs have been
284 * documented as such.
286 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
287 * integer to hold the year, and can hold years as large as 65535.
289 * zlib, upon which libpng depends, is also Y2K compliant. It contains
290 * no date-related code.
292 * Glenn Randers-Pehrson
294 * PNG Development Group
300 /* This is not the place to learn how to use libpng. The file libpng-manual.txt
301 * describes how to use libpng, and the file example.c summarizes it
302 * with some code on which to build. This file is useful for looking
303 * at the actual function definitions and structure components. If that
304 * file has been stripped from your copy of libpng, you can find it at
305 * <http://www.libpng.org/pub/png/libpng-manual.txt>
307 * If you just need to read a PNG file and don't want to read the documentation
308 * skip to the end of this file and read the section entitled 'simplified API'.
311 /* Version information for png.h - this should match the version in png.c */
312 #define PNG_LIBPNG_VER_STRING "1.6.32"
313 #define PNG_HEADER_VERSION_STRING " libpng version 1.6.32 - August 24, 2017\n"
315 #define PNG_LIBPNG_VER_SONUM 16
316 #define PNG_LIBPNG_VER_DLLNUM 16
318 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
319 #define PNG_LIBPNG_VER_MAJOR 1
320 #define PNG_LIBPNG_VER_MINOR 6
321 #define PNG_LIBPNG_VER_RELEASE 32
323 /* This should match the numeric part of the final component of
324 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
327 #define PNG_LIBPNG_VER_BUILD 0
330 #define PNG_LIBPNG_BUILD_ALPHA 1
331 #define PNG_LIBPNG_BUILD_BETA 2
332 #define PNG_LIBPNG_BUILD_RC 3
333 #define PNG_LIBPNG_BUILD_STABLE 4
334 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
336 /* Release-Specific Flags */
337 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
338 PNG_LIBPNG_BUILD_STABLE only */
339 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
340 PNG_LIBPNG_BUILD_SPECIAL */
341 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
342 PNG_LIBPNG_BUILD_PRIVATE */
344 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
346 /* Careful here. At one time, Guy wanted to use 082, but that would be octal.
347 * We must not include leading zeros.
348 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
349 * version 1.0.0 was mis-numbered 100 instead of 10000). From
350 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
352 #define PNG_LIBPNG_VER 10632 /* 1.6.32 */
354 /* Library configuration: these options cannot be changed after
355 * the library has been built.
358 /* If pnglibconf.h is missing, you can
359 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
361 # include "pnglibconf.h"
364 #ifndef PNG_VERSION_INFO_ONLY
365 /* Machine specific configuration. */
366 # include "pngconf.h"
370 * Added at libpng-1.2.8
372 * Ref MSDN: Private as priority over Special
373 * VS_FF_PRIVATEBUILD File *was not* built using standard release
374 * procedures. If this value is given, the StringFileInfo block must
375 * contain a PrivateBuild string.
377 * VS_FF_SPECIALBUILD File *was* built by the original company using
378 * standard release procedures but is a variation of the standard
379 * file of the same version number. If this value is given, the
380 * StringFileInfo block must contain a SpecialBuild string.
383 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
384 # define PNG_LIBPNG_BUILD_TYPE \
385 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
387 # ifdef PNG_LIBPNG_SPECIALBUILD
388 # define PNG_LIBPNG_BUILD_TYPE \
389 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
391 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
395 #ifndef PNG_VERSION_INFO_ONLY
397 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
400 #endif /* __cplusplus */
402 /* Version information for C files, stored in png.c. This had better match
405 #define png_libpng_ver png_get_header_ver(NULL)
407 /* This file is arranged in several sections:
410 * 2. Any configuration options that can be specified by for the application
411 * code when it is built. (Build time configuration is in pnglibconf.h)
412 * 3. Type definitions (base types are defined in pngconf.h), structure
414 * 4. Exported library functions.
416 * 6. Implementation options.
418 * The library source code has additional files (principally pngpriv.h) that
419 * allow configuration of the library.
422 /* Section 1: [omitted] */
424 /* Section 2: run time configuration
425 * See pnglibconf.h for build time configuration
427 * Run time configuration allows the application to choose between
428 * implementations of certain arithmetic APIs. The default is set
429 * at build time and recorded in pnglibconf.h, but it is safe to
430 * override these (and only these) settings. Note that this won't
431 * change what the library does, only application code, and the
432 * settings can (and probably should) be made on a per-file basis
433 * by setting the #defines before including png.h
435 * Use macros to read integers from PNG data or use the exported
437 * PNG_USE_READ_MACROS: use the macros (see below) Note that
438 * the macros evaluate their argument multiple times.
439 * PNG_NO_USE_READ_MACROS: call the relevant library function.
441 * Use the alternative algorithm for compositing alpha samples that
442 * does not use division?
443 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
445 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
447 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
449 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
450 * APIs to png_warning.
451 * Otherwise the calls are mapped to png_error.
454 /* Section 3: type definitions, including structures and compile time
456 * See pngconf.h for base types that vary by machine/system
459 /* This triggers a compiler error in png.c, if png.c and png.h
460 * do not agree upon the version number.
462 typedef char* png_libpng_version_1_6_32
;
464 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
466 * png_struct is the cache of information used while reading or writing a single
467 * PNG file. One of these is always required, although the simplified API
468 * (below) hides the creation and destruction of it.
470 typedef struct png_struct_def png_struct
;
471 typedef const png_struct
* png_const_structp
;
472 typedef png_struct
* png_structp
;
473 typedef png_struct
* * png_structpp
;
475 /* png_info contains information read from or to be written to a PNG file. One
476 * or more of these must exist while reading or creating a PNG file. The
477 * information is not used by libpng during read but is used to control what
478 * gets written when a PNG file is created. "png_get_" function calls read
479 * information during read and "png_set_" functions calls write information
480 * when creating a PNG.
481 * been moved into a separate header file that is not accessible to
482 * applications. Read libpng-manual.txt or libpng.3 for more info.
484 typedef struct png_info_def png_info
;
485 typedef png_info
* png_infop
;
486 typedef const png_info
* png_const_infop
;
487 typedef png_info
* * png_infopp
;
489 /* Types with names ending 'p' are pointer types. The corresponding types with
490 * names ending 'rp' are identical pointer types except that the pointer is
491 * marked 'restrict', which means that it is the only pointer to the object
492 * passed to the function. Applications should not use the 'restrict' types;
493 * it is always valid to pass 'p' to a pointer with a function argument of the
494 * corresponding 'rp' type. Different compilers have different rules with
495 * regard to type matching in the presence of 'restrict'. For backward
496 * compatibility libpng callbacks never have 'restrict' in their parameters and,
497 * consequentially, writing portable application code is extremely difficult if
498 * an attempt is made to use 'restrict'.
500 typedef png_struct
* PNG_RESTRICT png_structrp
;
501 typedef const png_struct
* PNG_RESTRICT png_const_structrp
;
502 typedef png_info
* PNG_RESTRICT png_inforp
;
503 typedef const png_info
* PNG_RESTRICT png_const_inforp
;
505 /* Three color definitions. The order of the red, green, and blue, (and the
506 * exact size) is not important, although the size of the fields need to
507 * be png_byte or png_uint_16 (as defined below).
509 typedef struct png_color_struct
515 typedef png_color
* png_colorp
;
516 typedef const png_color
* png_const_colorp
;
517 typedef png_color
* * png_colorpp
;
519 typedef struct png_color_16_struct
521 png_byte index
; /* used for palette files */
522 png_uint_16 red
; /* for use in red green blue files */
525 png_uint_16 gray
; /* for use in grayscale files */
527 typedef png_color_16
* png_color_16p
;
528 typedef const png_color_16
* png_const_color_16p
;
529 typedef png_color_16
* * png_color_16pp
;
531 typedef struct png_color_8_struct
533 png_byte red
; /* for use in red green blue files */
536 png_byte gray
; /* for use in grayscale files */
537 png_byte alpha
; /* for alpha channel files */
539 typedef png_color_8
* png_color_8p
;
540 typedef const png_color_8
* png_const_color_8p
;
541 typedef png_color_8
* * png_color_8pp
;
544 * The following two structures are used for the in-core representation
547 typedef struct png_sPLT_entry_struct
553 png_uint_16 frequency
;
555 typedef png_sPLT_entry
* png_sPLT_entryp
;
556 typedef const png_sPLT_entry
* png_const_sPLT_entryp
;
557 typedef png_sPLT_entry
* * png_sPLT_entrypp
;
559 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples
560 * occupy the LSB of their respective members, and the MSB of each member
561 * is zero-filled. The frequency member always occupies the full 16 bits.
564 typedef struct png_sPLT_struct
566 png_charp name
; /* palette name */
567 png_byte depth
; /* depth of palette samples */
568 png_sPLT_entryp entries
; /* palette entries */
569 png_int_32 nentries
; /* number of palette entries */
571 typedef png_sPLT_t
* png_sPLT_tp
;
572 typedef const png_sPLT_t
* png_const_sPLT_tp
;
573 typedef png_sPLT_t
* * png_sPLT_tpp
;
575 #ifdef PNG_TEXT_SUPPORTED
576 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
577 * and whether that contents is compressed or not. The "key" field
578 * points to a regular zero-terminated C string. The "text" fields can be a
579 * regular C string, an empty string, or a NULL pointer.
580 * However, the structure returned by png_get_text() will always contain
581 * the "text" field as a regular zero-terminated C string (possibly
582 * empty), never a NULL pointer, so it can be safely used in printf() and
583 * other string-handling functions. Note that the "itxt_length", "lang", and
584 * "lang_key" members of the structure only exist when the library is built
585 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
586 * default without iTXt support. Also note that when iTXt *is* supported,
587 * the "lang" and "lang_key" fields contain NULL pointers when the
588 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
589 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
590 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
591 * which is always 0 or 1, or its "compression method" which is always 0.
593 typedef struct png_text_struct
595 int compression
; /* compression value:
600 png_charp key
; /* keyword, 1-79 character description of "text" */
601 png_charp text
; /* comment, may be an empty string (ie "")
603 png_size_t text_length
; /* length of the text string */
604 png_size_t itxt_length
; /* length of the itxt string */
605 png_charp lang
; /* language code, 0-79 characters
607 png_charp lang_key
; /* keyword translated UTF-8 string, 0 or more
608 chars or a NULL pointer */
610 typedef png_text
* png_textp
;
611 typedef const png_text
* png_const_textp
;
612 typedef png_text
* * png_textpp
;
615 /* Supported compression types for text in PNG files (tEXt, and zTXt).
616 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
617 #define PNG_TEXT_COMPRESSION_NONE_WR -3
618 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
619 #define PNG_TEXT_COMPRESSION_NONE -1
620 #define PNG_TEXT_COMPRESSION_zTXt 0
621 #define PNG_ITXT_COMPRESSION_NONE 1
622 #define PNG_ITXT_COMPRESSION_zTXt 2
623 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
625 /* png_time is a way to hold the time in an machine independent way.
626 * Two conversions are provided, both from time_t and struct tm. There
627 * is no portable way to convert to either of these structures, as far
628 * as I know. If you know of a portable way, send it to me. As a side
629 * note - PNG has always been Year 2000 compliant!
631 typedef struct png_time_struct
633 png_uint_16 year
; /* full year, as in, 1995 */
634 png_byte month
; /* month of year, 1 - 12 */
635 png_byte day
; /* day of month, 1 - 31 */
636 png_byte hour
; /* hour of day, 0 - 23 */
637 png_byte minute
; /* minute of hour, 0 - 59 */
638 png_byte second
; /* second of minute, 0 - 60 (for leap seconds) */
640 typedef png_time
* png_timep
;
641 typedef const png_time
* png_const_timep
;
642 typedef png_time
* * png_timepp
;
644 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
645 defined(PNG_USER_CHUNKS_SUPPORTED)
646 /* png_unknown_chunk is a structure to hold queued chunks for which there is
647 * no specific support. The idea is that we can use this to queue
648 * up private chunks for output even though the library doesn't actually
649 * know about their semantics.
651 * The data in the structure is set by libpng on read and used on write.
653 typedef struct png_unknown_chunk_t
655 png_byte name
[5]; /* Textual chunk name with '\0' terminator */
656 png_byte
*data
; /* Data, should not be modified on read! */
659 /* On write 'location' must be set using the flag values listed below.
660 * Notice that on read it is set by libpng however the values stored have
661 * more bits set than are listed below. Always treat the value as a
662 * bitmask. On write set only one bit - setting multiple bits may cause the
663 * chunk to be written in multiple places.
665 png_byte location
; /* mode of operation at read time */
669 typedef png_unknown_chunk
* png_unknown_chunkp
;
670 typedef const png_unknown_chunk
* png_const_unknown_chunkp
;
671 typedef png_unknown_chunk
* * png_unknown_chunkpp
;
674 /* Flag values for the unknown chunk location byte. */
675 #define PNG_HAVE_IHDR 0x01
676 #define PNG_HAVE_PLTE 0x02
677 #define PNG_AFTER_IDAT 0x08
679 /* Maximum positive integer used in PNG is (2^31)-1 */
680 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
681 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
682 #define PNG_SIZE_MAX ((png_size_t)(-1))
684 /* These are constants for fixed point values encoded in the
685 * PNG specification manner (x100000)
687 #define PNG_FP_1 100000
688 #define PNG_FP_HALF 50000
689 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
690 #define PNG_FP_MIN (-PNG_FP_MAX)
692 /* These describe the color_type field in png_info. */
693 /* color type masks */
694 #define PNG_COLOR_MASK_PALETTE 1
695 #define PNG_COLOR_MASK_COLOR 2
696 #define PNG_COLOR_MASK_ALPHA 4
698 /* color types. Note that not all combinations are legal */
699 #define PNG_COLOR_TYPE_GRAY 0
700 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
701 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
702 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
703 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
705 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
706 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
708 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
709 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
710 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
712 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
713 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
714 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
715 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
717 /* These are for the interlacing type. These values should NOT be changed. */
718 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
719 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
720 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
722 /* These are for the oFFs chunk. These values should NOT be changed. */
723 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
724 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
725 #define PNG_OFFSET_LAST 2 /* Not a valid value */
727 /* These are for the pCAL chunk. These values should NOT be changed. */
728 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
729 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
730 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
731 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
732 #define PNG_EQUATION_LAST 4 /* Not a valid value */
734 /* These are for the sCAL chunk. These values should NOT be changed. */
735 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
736 #define PNG_SCALE_METER 1 /* meters per pixel */
737 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
738 #define PNG_SCALE_LAST 3 /* Not a valid value */
740 /* These are for the pHYs chunk. These values should NOT be changed. */
741 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
742 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
743 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
745 /* These are for the sRGB chunk. These values should NOT be changed. */
746 #define PNG_sRGB_INTENT_PERCEPTUAL 0
747 #define PNG_sRGB_INTENT_RELATIVE 1
748 #define PNG_sRGB_INTENT_SATURATION 2
749 #define PNG_sRGB_INTENT_ABSOLUTE 3
750 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
752 /* This is for text chunks */
753 #define PNG_KEYWORD_MAX_LENGTH 79
755 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
756 #define PNG_MAX_PALETTE_LENGTH 256
758 /* These determine if an ancillary chunk's data has been successfully read
759 * from the PNG header, or if the application has filled in the corresponding
760 * data in the info_struct to be written into the output file. The values
761 * of the PNG_INFO_<chunk> defines should NOT be changed.
763 #define PNG_INFO_gAMA 0x0001U
764 #define PNG_INFO_sBIT 0x0002U
765 #define PNG_INFO_cHRM 0x0004U
766 #define PNG_INFO_PLTE 0x0008U
767 #define PNG_INFO_tRNS 0x0010U
768 #define PNG_INFO_bKGD 0x0020U
769 #define PNG_INFO_hIST 0x0040U
770 #define PNG_INFO_pHYs 0x0080U
771 #define PNG_INFO_oFFs 0x0100U
772 #define PNG_INFO_tIME 0x0200U
773 #define PNG_INFO_pCAL 0x0400U
774 #define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
775 #define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
776 #define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
777 #define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
778 #define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
779 #define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
781 /* This is used for the transformation routines, as some of them
782 * change these values for the row. It also should enable using
783 * the routines for other purposes.
785 typedef struct png_row_info_struct
787 png_uint_32 width
; /* width of row */
788 png_size_t rowbytes
; /* number of bytes in row */
789 png_byte color_type
; /* color type of row */
790 png_byte bit_depth
; /* bit depth of row */
791 png_byte channels
; /* number of channels (1, 2, 3, or 4) */
792 png_byte pixel_depth
; /* bits per pixel (depth * channels) */
795 typedef png_row_info
* png_row_infop
;
796 typedef png_row_info
* * png_row_infopp
;
798 /* These are the function types for the I/O functions and for the functions
799 * that allow the user to override the default I/O functions with his or her
800 * own. The png_error_ptr type should match that of user-supplied warning
801 * and error functions, while the png_rw_ptr type should match that of the
802 * user read/write data functions. Note that the 'write' function must not
803 * modify the buffer it is passed. The 'read' function, on the other hand, is
804 * expected to return the read data in the buffer.
806 typedef PNG_CALLBACK(void, *png_error_ptr
, (png_structp
, png_const_charp
));
807 typedef PNG_CALLBACK(void, *png_rw_ptr
, (png_structp
, png_bytep
, png_size_t
));
808 typedef PNG_CALLBACK(void, *png_flush_ptr
, (png_structp
));
809 typedef PNG_CALLBACK(void, *png_read_status_ptr
, (png_structp
, png_uint_32
,
811 typedef PNG_CALLBACK(void, *png_write_status_ptr
, (png_structp
, png_uint_32
,
814 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
815 typedef PNG_CALLBACK(void, *png_progressive_info_ptr
, (png_structp
, png_infop
));
816 typedef PNG_CALLBACK(void, *png_progressive_end_ptr
, (png_structp
, png_infop
));
818 /* The following callback receives png_uint_32 row_number, int pass for the
819 * png_bytep data of the row. When transforming an interlaced image the
820 * row number is the row number within the sub-image of the interlace pass, so
821 * the value will increase to the height of the sub-image (not the full image)
822 * then reset to 0 for the next pass.
824 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
825 * find the output pixel (x,y) given an interlaced sub-image pixel
826 * (row,col,pass). (See below for these macros.)
828 typedef PNG_CALLBACK(void, *png_progressive_row_ptr
, (png_structp
, png_bytep
,
832 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
833 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
834 typedef PNG_CALLBACK(void, *png_user_transform_ptr
, (png_structp
, png_row_infop
,
838 #ifdef PNG_USER_CHUNKS_SUPPORTED
839 typedef PNG_CALLBACK(int, *png_user_chunk_ptr
, (png_structp
,
840 png_unknown_chunkp
));
842 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
843 /* not used anywhere */
844 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
847 #ifdef PNG_SETJMP_SUPPORTED
848 /* This must match the function definition in <setjmp.h>, and the application
849 * must include this before png.h to obtain the definition of jmp_buf. The
850 * function is required to be PNG_NORETURN, but this is not checked. If the
851 * function does return the application will crash via an abort() or similar
854 * If you get a warning here while building the library you may need to make
855 * changes to ensure that pnglibconf.h records the calling convention used by
856 * your compiler. This may be very difficult - try using a different compiler
857 * to build the library!
859 PNG_FUNCTION(void, (PNGCAPI
*png_longjmp_ptr
), PNGARG((jmp_buf, int)), typedef);
862 /* Transform masks for the high-level interface */
863 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
864 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
865 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
866 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
867 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
868 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
869 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
870 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
871 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
872 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
873 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
874 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
875 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
876 /* Added to libpng-1.2.34 */
877 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
878 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
879 /* Added to libpng-1.4.0 */
880 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
881 /* Added to libpng-1.5.4 */
882 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
883 #if INT_MAX >= 0x8000 /* else this might break */
884 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
887 /* Flags for MNG supported features */
888 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
889 #define PNG_FLAG_MNG_FILTER_64 0x04
890 #define PNG_ALL_MNG_FEATURES 0x05
892 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
893 * this allowed the zlib default functions to be used on Windows
894 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
895 * ignores the first argument) should be completely compatible with the
898 typedef PNG_CALLBACK(png_voidp
, *png_malloc_ptr
, (png_structp
,
900 typedef PNG_CALLBACK(void, *png_free_ptr
, (png_structp
, png_voidp
));
902 /* Section 4: exported functions
903 * Here are the function definitions most commonly used. This is not
904 * the place to find out how to use libpng. See libpng-manual.txt for the
905 * full explanation, see example.c for the summary. This just provides
906 * a simple one line description of the use of each function.
908 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
909 * pngconf.h and in the *.dfn files in the scripts directory.
911 * PNG_EXPORT(ordinal, type, name, (args));
913 * ordinal: ordinal that is used while building
914 * *.def files. The ordinal value is only
915 * relevant when preprocessing png.h with
916 * the *.dfn files for building symbol table
917 * entries, and are removed by pngconf.h.
918 * type: return type of the function
919 * name: function name
920 * args: function arguments, with types
922 * When we wish to append attributes to a function prototype we use
923 * the PNG_EXPORTA() macro instead.
925 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
927 * ordinal, type, name, and args: same as in PNG_EXPORT().
928 * attributes: function attributes
931 /* Returns the version number of the library */
932 PNG_EXPORT(1, png_uint_32
, png_access_version_number
, (void));
934 /* Tell lib we have already handled the first <num_bytes> magic bytes.
935 * Handling more than 8 bytes from the beginning of the file is an error.
937 PNG_EXPORT(2, void, png_set_sig_bytes
, (png_structrp png_ptr
, int num_bytes
));
939 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
940 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
941 * signature, and non-zero otherwise. Having num_to_check == 0 or
942 * start > 7 will always fail (ie return non-zero).
944 PNG_EXPORT(3, int, png_sig_cmp
, (png_const_bytep sig
, png_size_t start
,
945 png_size_t num_to_check
));
947 /* Simple signature checking function. This is the same as calling
948 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
950 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
952 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
953 PNG_EXPORTA(4, png_structp
, png_create_read_struct
,
954 (png_const_charp user_png_ver
, png_voidp error_ptr
,
955 png_error_ptr error_fn
, png_error_ptr warn_fn
),
958 /* Allocate and initialize png_ptr struct for writing, and any other memory */
959 PNG_EXPORTA(5, png_structp
, png_create_write_struct
,
960 (png_const_charp user_png_ver
, png_voidp error_ptr
, png_error_ptr error_fn
,
961 png_error_ptr warn_fn
),
964 PNG_EXPORT(6, png_size_t
, png_get_compression_buffer_size
,
965 (png_const_structrp png_ptr
));
967 PNG_EXPORT(7, void, png_set_compression_buffer_size
, (png_structrp png_ptr
,
970 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
973 #ifdef PNG_SETJMP_SUPPORTED
974 /* This function returns the jmp_buf built in to *png_ptr. It must be
975 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
976 * unless the default error function is overridden in which case NULL is
977 * acceptable. The size of the jmp_buf is checked against the actual size
978 * allocated by the library - the call will return NULL on a mismatch
979 * indicating an ABI mismatch.
981 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn
, (png_structrp png_ptr
,
982 png_longjmp_ptr longjmp_fn
, size_t jmp_buf_size
));
983 # define png_jmpbuf(png_ptr) \
984 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
986 # define png_jmpbuf(png_ptr) \
987 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
989 /* This function should be used by libpng applications in place of
990 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
991 * will use it; otherwise it will call PNG_ABORT(). This function was
992 * added in libpng-1.5.0.
994 PNG_EXPORTA(9, void, png_longjmp
, (png_const_structrp png_ptr
, int val
),
997 #ifdef PNG_READ_SUPPORTED
998 /* Reset the compression stream */
999 PNG_EXPORTA(10, int, png_reset_zstream
, (png_structrp png_ptr
), PNG_DEPRECATED
);
1002 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1003 #ifdef PNG_USER_MEM_SUPPORTED
1004 PNG_EXPORTA(11, png_structp
, png_create_read_struct_2
,
1005 (png_const_charp user_png_ver
, png_voidp error_ptr
, png_error_ptr error_fn
,
1006 png_error_ptr warn_fn
,
1007 png_voidp mem_ptr
, png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),
1009 PNG_EXPORTA(12, png_structp
, png_create_write_struct_2
,
1010 (png_const_charp user_png_ver
, png_voidp error_ptr
, png_error_ptr error_fn
,
1011 png_error_ptr warn_fn
,
1012 png_voidp mem_ptr
, png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),
1016 /* Write the PNG file signature. */
1017 PNG_EXPORT(13, void, png_write_sig
, (png_structrp png_ptr
));
1019 /* Write a PNG chunk - size, type, (optional) data, CRC. */
1020 PNG_EXPORT(14, void, png_write_chunk
, (png_structrp png_ptr
, png_const_bytep
1021 chunk_name
, png_const_bytep data
, png_size_t length
));
1023 /* Write the start of a PNG chunk - length and chunk name. */
1024 PNG_EXPORT(15, void, png_write_chunk_start
, (png_structrp png_ptr
,
1025 png_const_bytep chunk_name
, png_uint_32 length
));
1027 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1028 PNG_EXPORT(16, void, png_write_chunk_data
, (png_structrp png_ptr
,
1029 png_const_bytep data
, png_size_t length
));
1031 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1032 PNG_EXPORT(17, void, png_write_chunk_end
, (png_structrp png_ptr
));
1034 /* Allocate and initialize the info structure */
1035 PNG_EXPORTA(18, png_infop
, png_create_info_struct
, (png_const_structrp png_ptr
),
1038 /* DEPRECATED: this function allowed init structures to be created using the
1039 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1040 * the API will be removed in the future.
1042 PNG_EXPORTA(19, void, png_info_init_3
, (png_infopp info_ptr
,
1043 png_size_t png_info_struct_size
), PNG_DEPRECATED
);
1045 /* Writes all the PNG information before the image. */
1046 PNG_EXPORT(20, void, png_write_info_before_PLTE
,
1047 (png_structrp png_ptr
, png_const_inforp info_ptr
));
1048 PNG_EXPORT(21, void, png_write_info
,
1049 (png_structrp png_ptr
, png_const_inforp info_ptr
));
1051 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1052 /* Read the information before the actual image data. */
1053 PNG_EXPORT(22, void, png_read_info
,
1054 (png_structrp png_ptr
, png_inforp info_ptr
));
1057 #ifdef PNG_TIME_RFC1123_SUPPORTED
1058 /* Convert to a US string format: there is no localization support in this
1059 * routine. The original implementation used a 29 character buffer in
1060 * png_struct, this will be removed in future versions.
1062 #if PNG_LIBPNG_VER < 10700
1063 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1064 PNG_EXPORTA(23, png_const_charp
, png_convert_to_rfc1123
, (png_structrp png_ptr
,
1065 png_const_timep ptime
),PNG_DEPRECATED
);
1067 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer
, (char out
[29],
1068 png_const_timep ptime
));
1071 #ifdef PNG_CONVERT_tIME_SUPPORTED
1072 /* Convert from a struct tm to png_time */
1073 PNG_EXPORT(24, void, png_convert_from_struct_tm
, (png_timep ptime
,
1074 const struct tm
* ttime
));
1076 /* Convert from time_t to png_time. Uses gmtime() */
1077 PNG_EXPORT(25, void, png_convert_from_time_t
, (png_timep ptime
, time_t ttime
));
1078 #endif /* CONVERT_tIME */
1080 #ifdef PNG_READ_EXPAND_SUPPORTED
1081 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1082 PNG_EXPORT(26, void, png_set_expand
, (png_structrp png_ptr
));
1083 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8
, (png_structrp png_ptr
));
1084 PNG_EXPORT(28, void, png_set_palette_to_rgb
, (png_structrp png_ptr
));
1085 PNG_EXPORT(29, void, png_set_tRNS_to_alpha
, (png_structrp png_ptr
));
1088 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1089 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1090 * of a tRNS chunk if present.
1092 PNG_EXPORT(221, void, png_set_expand_16
, (png_structrp png_ptr
));
1095 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1096 /* Use blue, green, red order for pixels. */
1097 PNG_EXPORT(30, void, png_set_bgr
, (png_structrp png_ptr
));
1100 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1101 /* Expand the grayscale to 24-bit RGB if necessary. */
1102 PNG_EXPORT(31, void, png_set_gray_to_rgb
, (png_structrp png_ptr
));
1105 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1106 /* Reduce RGB to grayscale. */
1107 #define PNG_ERROR_ACTION_NONE 1
1108 #define PNG_ERROR_ACTION_WARN 2
1109 #define PNG_ERROR_ACTION_ERROR 3
1110 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1112 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray
, (png_structrp png_ptr
,
1113 int error_action
, double red
, double green
))
1114 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed
, (png_structrp png_ptr
,
1115 int error_action
, png_fixed_point red
, png_fixed_point green
))
1117 PNG_EXPORT(34, png_byte
, png_get_rgb_to_gray_status
, (png_const_structrp
1121 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1122 PNG_EXPORT(35, void, png_build_grayscale_palette
, (int bit_depth
,
1123 png_colorp palette
));
1126 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1127 /* How the alpha channel is interpreted - this affects how the color channels
1128 * of a PNG file are returned to the calling application when an alpha channel,
1129 * or a tRNS chunk in a palette file, is present.
1131 * This has no effect on the way pixels are written into a PNG output
1132 * datastream. The color samples in a PNG datastream are never premultiplied
1133 * with the alpha samples.
1135 * The default is to return data according to the PNG specification: the alpha
1136 * channel is a linear measure of the contribution of the pixel to the
1137 * corresponding composited pixel, and the color channels are unassociated
1138 * (not premultiplied). The gamma encoded color channels must be scaled
1139 * according to the contribution and to do this it is necessary to undo
1140 * the encoding, scale the color values, perform the composition and reencode
1141 * the values. This is the 'PNG' mode.
1143 * The alternative is to 'associate' the alpha with the color information by
1144 * storing color channel values that have been scaled by the alpha.
1145 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1146 * (the latter being the two common names for associated alpha color channels).
1148 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1149 * value is equal to the maximum value.
1151 * The final choice is to gamma encode the alpha channel as well. This is
1152 * broken because, in practice, no implementation that uses this choice
1153 * correctly undoes the encoding before handling alpha composition. Use this
1154 * choice only if other serious errors in the software or hardware you use
1155 * mandate it; the typical serious error is for dark halos to appear around
1156 * opaque areas of the composited PNG image because of arithmetic overflow.
1158 * The API function png_set_alpha_mode specifies which of these choices to use
1159 * with an enumerated 'mode' value and the gamma of the required output:
1161 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1162 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1163 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1164 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1165 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1166 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1168 PNG_FP_EXPORT(227, void, png_set_alpha_mode
, (png_structrp png_ptr
, int mode
,
1169 double output_gamma
))
1170 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed
, (png_structrp png_ptr
,
1171 int mode
, png_fixed_point output_gamma
))
1174 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1175 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1176 * how to decode the output values, not how they are encoded.
1178 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1179 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1180 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1181 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1184 /* The following are examples of calls to png_set_alpha_mode to achieve the
1185 * required overall gamma correction and, where necessary, alpha
1186 * premultiplication.
1188 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1189 * This is the default libpng handling of the alpha channel - it is not
1190 * pre-multiplied into the color components. In addition the call states
1191 * that the output is for a sRGB system and causes all PNG files without gAMA
1192 * chunks to be assumed to be encoded using sRGB.
1194 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1195 * In this case the output is assumed to be something like an sRGB conformant
1196 * display preceeded by a power-law lookup table of power 1.45. This is how
1197 * early Mac systems behaved.
1199 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1200 * This is the classic Jim Blinn approach and will work in academic
1201 * environments where everything is done by the book. It has the shortcoming
1202 * of assuming that input PNG data with no gamma information is linear - this
1203 * is unlikely to be correct unless the PNG files where generated locally.
1204 * Most of the time the output precision will be so low as to show
1205 * significant banding in dark areas of the image.
1207 * png_set_expand_16(pp);
1208 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1209 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1210 * are assumed to have the sRGB encoding if not marked with a gamma value and
1211 * the output is always 16 bits per component. This permits accurate scaling
1212 * and processing of the data. If you know that your input PNG files were
1213 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1214 * correct value for your system.
1216 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1217 * If you just need to composite the PNG image onto an existing background
1218 * and if you control the code that does this you can use the optimization
1219 * setting. In this case you just copy completely opaque pixels to the
1220 * output. For pixels that are not completely transparent (you just skip
1221 * those) you do the composition math using png_composite or png_composite_16
1222 * below then encode the resultant 8-bit or 16-bit values to match the output
1226 * If neither the PNG nor the standard linear encoding work for you because
1227 * of the software or hardware you use then you have a big problem. The PNG
1228 * case will probably result in halos around the image. The linear encoding
1229 * will probably result in a washed out, too bright, image (it's actually too
1230 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1231 * substantially reduce the halos. Alternatively try:
1233 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1234 * This option will also reduce the halos, but there will be slight dark
1235 * halos round the opaque parts of the image where the background is light.
1236 * In the OPTIMIZED mode the halos will be light halos where the background
1237 * is dark. Take your pick - the halos are unavoidable unless you can get
1238 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1241 * When the default gamma of PNG files doesn't match the output gamma.
1242 * If you have PNG files with no gamma information png_set_alpha_mode allows
1243 * you to provide a default gamma, but it also sets the ouput gamma to the
1244 * matching value. If you know your PNG files have a gamma that doesn't
1245 * match the output you can take advantage of the fact that
1246 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1247 * default if it is not already set:
1249 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1250 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1251 * The first call sets both the default and the output gamma values, the
1252 * second call overrides the output gamma without changing the default. This
1253 * is easier than achieving the same effect with png_set_gamma. You must use
1254 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1255 * fire if more than one call to png_set_alpha_mode and png_set_background is
1256 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1260 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1261 PNG_EXPORT(36, void, png_set_strip_alpha
, (png_structrp png_ptr
));
1264 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1265 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1266 PNG_EXPORT(37, void, png_set_swap_alpha
, (png_structrp png_ptr
));
1269 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1270 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1271 PNG_EXPORT(38, void, png_set_invert_alpha
, (png_structrp png_ptr
));
1274 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1275 /* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1276 PNG_EXPORT(39, void, png_set_filler
, (png_structrp png_ptr
, png_uint_32 filler
,
1278 /* The values of the PNG_FILLER_ defines should NOT be changed */
1279 # define PNG_FILLER_BEFORE 0
1280 # define PNG_FILLER_AFTER 1
1281 /* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1282 PNG_EXPORT(40, void, png_set_add_alpha
, (png_structrp png_ptr
,
1283 png_uint_32 filler
, int flags
));
1284 #endif /* READ_FILLER || WRITE_FILLER */
1286 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1287 /* Swap bytes in 16-bit depth files. */
1288 PNG_EXPORT(41, void, png_set_swap
, (png_structrp png_ptr
));
1291 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1292 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1293 PNG_EXPORT(42, void, png_set_packing
, (png_structrp png_ptr
));
1296 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1297 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1298 /* Swap packing order of pixels in bytes. */
1299 PNG_EXPORT(43, void, png_set_packswap
, (png_structrp png_ptr
));
1302 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1303 /* Converts files to legal bit depths. */
1304 PNG_EXPORT(44, void, png_set_shift
, (png_structrp png_ptr
, png_const_color_8p
1308 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1309 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1310 /* Have the code handle the interlacing. Returns the number of passes.
1311 * MUST be called before png_read_update_info or png_start_read_image,
1312 * otherwise it will not have the desired effect. Note that it is still
1313 * necessary to call png_read_row or png_read_rows png_get_image_height
1314 * times for each pass.
1316 PNG_EXPORT(45, int, png_set_interlace_handling
, (png_structrp png_ptr
));
1319 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1320 /* Invert monochrome files */
1321 PNG_EXPORT(46, void, png_set_invert_mono
, (png_structrp png_ptr
));
1324 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1325 /* Handle alpha and tRNS by replacing with a background color. Prior to
1326 * libpng-1.5.4 this API must not be called before the PNG file header has been
1327 * read. Doing so will result in unexpected behavior and possible warnings or
1328 * errors if the PNG file contains a bKGD chunk.
1330 PNG_FP_EXPORT(47, void, png_set_background
, (png_structrp png_ptr
,
1331 png_const_color_16p background_color
, int background_gamma_code
,
1332 int need_expand
, double background_gamma
))
1333 PNG_FIXED_EXPORT(215, void, png_set_background_fixed
, (png_structrp png_ptr
,
1334 png_const_color_16p background_color
, int background_gamma_code
,
1335 int need_expand
, png_fixed_point background_gamma
))
1337 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1338 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1339 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1340 # define PNG_BACKGROUND_GAMMA_FILE 2
1341 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1344 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1345 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1346 PNG_EXPORT(229, void, png_set_scale_16
, (png_structrp png_ptr
));
1349 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1350 #define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
1351 /* Strip the second byte of information from a 16-bit depth file. */
1352 PNG_EXPORT(48, void, png_set_strip_16
, (png_structrp png_ptr
));
1355 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1356 /* Turn on quantizing, and reduce the palette to the number of colors
1359 PNG_EXPORT(49, void, png_set_quantize
, (png_structrp png_ptr
,
1360 png_colorp palette
, int num_palette
, int maximum_colors
,
1361 png_const_uint_16p histogram
, int full_quantize
));
1364 #ifdef PNG_READ_GAMMA_SUPPORTED
1365 /* The threshold on gamma processing is configurable but hard-wired into the
1366 * library. The following is the floating point variant.
1368 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1370 /* Handle gamma correction. Screen_gamma=(display_exponent).
1371 * NOTE: this API simply sets the screen and file gamma values. It will
1372 * therefore override the value for gamma in a PNG file if it is called after
1373 * the file header has been read - use with care - call before reading the PNG
1374 * file for best results!
1376 * These routines accept the same gamma values as png_set_alpha_mode (described
1377 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1378 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1379 * is the inverse of a 'screen gamma' value.
1381 PNG_FP_EXPORT(50, void, png_set_gamma
, (png_structrp png_ptr
,
1382 double screen_gamma
, double override_file_gamma
))
1383 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed
, (png_structrp png_ptr
,
1384 png_fixed_point screen_gamma
, png_fixed_point override_file_gamma
))
1387 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1388 /* Set how many lines between output flushes - 0 for no flushing */
1389 PNG_EXPORT(51, void, png_set_flush
, (png_structrp png_ptr
, int nrows
));
1390 /* Flush the current PNG output buffer */
1391 PNG_EXPORT(52, void, png_write_flush
, (png_structrp png_ptr
));
1394 /* Optional update palette with requested transformations */
1395 PNG_EXPORT(53, void, png_start_read_image
, (png_structrp png_ptr
));
1397 /* Optional call to update the users info structure */
1398 PNG_EXPORT(54, void, png_read_update_info
, (png_structrp png_ptr
,
1399 png_inforp info_ptr
));
1401 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1402 /* Read one or more rows of image data. */
1403 PNG_EXPORT(55, void, png_read_rows
, (png_structrp png_ptr
, png_bytepp row
,
1404 png_bytepp display_row
, png_uint_32 num_rows
));
1407 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1408 /* Read a row of data. */
1409 PNG_EXPORT(56, void, png_read_row
, (png_structrp png_ptr
, png_bytep row
,
1410 png_bytep display_row
));
1413 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1414 /* Read the whole image into memory at once. */
1415 PNG_EXPORT(57, void, png_read_image
, (png_structrp png_ptr
, png_bytepp image
));
1418 /* Write a row of image data */
1419 PNG_EXPORT(58, void, png_write_row
, (png_structrp png_ptr
,
1420 png_const_bytep row
));
1422 /* Write a few rows of image data: (*row) is not written; however, the type
1423 * is declared as writeable to maintain compatibility with previous versions
1424 * of libpng and to allow the 'display_row' array from read_rows to be passed
1425 * unchanged to write_rows.
1427 PNG_EXPORT(59, void, png_write_rows
, (png_structrp png_ptr
, png_bytepp row
,
1428 png_uint_32 num_rows
));
1430 /* Write the image data */
1431 PNG_EXPORT(60, void, png_write_image
, (png_structrp png_ptr
, png_bytepp image
));
1433 /* Write the end of the PNG file. */
1434 PNG_EXPORT(61, void, png_write_end
, (png_structrp png_ptr
,
1435 png_inforp info_ptr
));
1437 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1438 /* Read the end of the PNG file. */
1439 PNG_EXPORT(62, void, png_read_end
, (png_structrp png_ptr
, png_inforp info_ptr
));
1442 /* Free any memory associated with the png_info_struct */
1443 PNG_EXPORT(63, void, png_destroy_info_struct
, (png_const_structrp png_ptr
,
1444 png_infopp info_ptr_ptr
));
1446 /* Free any memory associated with the png_struct and the png_info_structs */
1447 PNG_EXPORT(64, void, png_destroy_read_struct
, (png_structpp png_ptr_ptr
,
1448 png_infopp info_ptr_ptr
, png_infopp end_info_ptr_ptr
));
1450 /* Free any memory associated with the png_struct and the png_info_structs */
1451 PNG_EXPORT(65, void, png_destroy_write_struct
, (png_structpp png_ptr_ptr
,
1452 png_infopp info_ptr_ptr
));
1454 /* Set the libpng method of handling chunk CRC errors */
1455 PNG_EXPORT(66, void, png_set_crc_action
, (png_structrp png_ptr
, int crit_action
,
1458 /* Values for png_set_crc_action() say how to handle CRC errors in
1459 * ancillary and critical chunks, and whether to use the data contained
1460 * therein. Note that it is impossible to "discard" data in a critical
1461 * chunk. For versions prior to 0.90, the action was always error/quit,
1462 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1463 * chunks is warn/discard. These values should NOT be changed.
1465 * value action:critical action:ancillary
1467 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1468 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1469 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1470 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1471 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1472 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1474 #ifdef PNG_WRITE_SUPPORTED
1475 /* These functions give the user control over the scan-line filtering in
1476 * libpng and the compression methods used by zlib. These functions are
1477 * mainly useful for testing, as the defaults should work with most users.
1478 * Those users who are tight on memory or want faster performance at the
1479 * expense of compression can modify them. See the compression library
1480 * header file (zlib.h) for an explination of the compression functions.
1483 /* Set the filtering method(s) used by libpng. Currently, the only valid
1484 * value for "method" is 0.
1486 PNG_EXPORT(67, void, png_set_filter
, (png_structrp png_ptr
, int method
,
1490 /* Flags for png_set_filter() to say which filters to use. The flags
1491 * are chosen so that they don't conflict with real filter types
1492 * below, in case they are supplied instead of the #defined constants.
1493 * These values should NOT be changed.
1495 #define PNG_NO_FILTERS 0x00
1496 #define PNG_FILTER_NONE 0x08
1497 #define PNG_FILTER_SUB 0x10
1498 #define PNG_FILTER_UP 0x20
1499 #define PNG_FILTER_AVG 0x40
1500 #define PNG_FILTER_PAETH 0x80
1501 #define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
1502 #define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
1504 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1505 * These defines should NOT be changed.
1507 #define PNG_FILTER_VALUE_NONE 0
1508 #define PNG_FILTER_VALUE_SUB 1
1509 #define PNG_FILTER_VALUE_UP 2
1510 #define PNG_FILTER_VALUE_AVG 3
1511 #define PNG_FILTER_VALUE_PAETH 4
1512 #define PNG_FILTER_VALUE_LAST 5
1514 #ifdef PNG_WRITE_SUPPORTED
1515 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1516 PNG_FP_EXPORT(68, void, png_set_filter_heuristics
, (png_structrp png_ptr
,
1517 int heuristic_method
, int num_weights
, png_const_doublep filter_weights
,
1518 png_const_doublep filter_costs
))
1519 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed
,
1520 (png_structrp png_ptr
, int heuristic_method
, int num_weights
,
1521 png_const_fixed_point_p filter_weights
,
1522 png_const_fixed_point_p filter_costs
))
1523 #endif /* WRITE_WEIGHTED_FILTER */
1525 /* The following are no longer used and will be removed from libpng-1.7: */
1526 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1527 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1528 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1529 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1531 /* Set the library compression level. Currently, valid values range from
1532 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1533 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1534 * shown that zlib compression levels 3-6 usually perform as well as level 9
1535 * for PNG images, and do considerably fewer caclulations. In the future,
1536 * these values may not correspond directly to the zlib compression levels.
1538 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1539 PNG_EXPORT(69, void, png_set_compression_level
, (png_structrp png_ptr
,
1542 PNG_EXPORT(70, void, png_set_compression_mem_level
, (png_structrp png_ptr
,
1545 PNG_EXPORT(71, void, png_set_compression_strategy
, (png_structrp png_ptr
,
1548 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1549 * smaller value of window_bits if it can do so safely.
1551 PNG_EXPORT(72, void, png_set_compression_window_bits
, (png_structrp png_ptr
,
1554 PNG_EXPORT(73, void, png_set_compression_method
, (png_structrp png_ptr
,
1556 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1558 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1559 /* Also set zlib parameters for compressing non-IDAT chunks */
1560 PNG_EXPORT(222, void, png_set_text_compression_level
, (png_structrp png_ptr
,
1563 PNG_EXPORT(223, void, png_set_text_compression_mem_level
, (png_structrp png_ptr
,
1566 PNG_EXPORT(224, void, png_set_text_compression_strategy
, (png_structrp png_ptr
,
1569 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1570 * smaller value of window_bits if it can do so safely.
1572 PNG_EXPORT(225, void, png_set_text_compression_window_bits
,
1573 (png_structrp png_ptr
, int window_bits
));
1575 PNG_EXPORT(226, void, png_set_text_compression_method
, (png_structrp png_ptr
,
1577 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1580 /* These next functions are called for input/output, memory, and error
1581 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1582 * and call standard C I/O routines such as fread(), fwrite(), and
1583 * fprintf(). These functions can be made to use other I/O routines
1584 * at run time for those applications that need to handle I/O in a
1585 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1589 #ifdef PNG_STDIO_SUPPORTED
1590 /* Initialize the input/output for the PNG file to the default functions. */
1591 PNG_EXPORT(74, void, png_init_io
, (png_structrp png_ptr
, png_FILE_p fp
));
1594 /* Replace the (error and abort), and warning functions with user
1595 * supplied functions. If no messages are to be printed you must still
1596 * write and use replacement functions. The replacement error_fn should
1597 * still do a longjmp to the last setjmp location if you are using this
1598 * method of error handling. If error_fn or warning_fn is NULL, the
1599 * default function will be used.
1602 PNG_EXPORT(75, void, png_set_error_fn
, (png_structrp png_ptr
,
1603 png_voidp error_ptr
, png_error_ptr error_fn
, png_error_ptr warning_fn
));
1605 /* Return the user pointer associated with the error functions */
1606 PNG_EXPORT(76, png_voidp
, png_get_error_ptr
, (png_const_structrp png_ptr
));
1608 /* Replace the default data output functions with a user supplied one(s).
1609 * If buffered output is not used, then output_flush_fn can be set to NULL.
1610 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1611 * output_flush_fn will be ignored (and thus can be NULL).
1612 * It is probably a mistake to use NULL for output_flush_fn if
1613 * write_data_fn is not also NULL unless you have built libpng with
1614 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1615 * default flush function, which uses the standard *FILE structure, will
1618 PNG_EXPORT(77, void, png_set_write_fn
, (png_structrp png_ptr
, png_voidp io_ptr
,
1619 png_rw_ptr write_data_fn
, png_flush_ptr output_flush_fn
));
1621 /* Replace the default data input function with a user supplied one. */
1622 PNG_EXPORT(78, void, png_set_read_fn
, (png_structrp png_ptr
, png_voidp io_ptr
,
1623 png_rw_ptr read_data_fn
));
1625 /* Return the user pointer associated with the I/O functions */
1626 PNG_EXPORT(79, png_voidp
, png_get_io_ptr
, (png_const_structrp png_ptr
));
1628 PNG_EXPORT(80, void, png_set_read_status_fn
, (png_structrp png_ptr
,
1629 png_read_status_ptr read_row_fn
));
1631 PNG_EXPORT(81, void, png_set_write_status_fn
, (png_structrp png_ptr
,
1632 png_write_status_ptr write_row_fn
));
1634 #ifdef PNG_USER_MEM_SUPPORTED
1635 /* Replace the default memory allocation functions with user supplied one(s). */
1636 PNG_EXPORT(82, void, png_set_mem_fn
, (png_structrp png_ptr
, png_voidp mem_ptr
,
1637 png_malloc_ptr malloc_fn
, png_free_ptr free_fn
));
1638 /* Return the user pointer associated with the memory functions */
1639 PNG_EXPORT(83, png_voidp
, png_get_mem_ptr
, (png_const_structrp png_ptr
));
1642 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1643 PNG_EXPORT(84, void, png_set_read_user_transform_fn
, (png_structrp png_ptr
,
1644 png_user_transform_ptr read_user_transform_fn
));
1647 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1648 PNG_EXPORT(85, void, png_set_write_user_transform_fn
, (png_structrp png_ptr
,
1649 png_user_transform_ptr write_user_transform_fn
));
1652 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1653 PNG_EXPORT(86, void, png_set_user_transform_info
, (png_structrp png_ptr
,
1654 png_voidp user_transform_ptr
, int user_transform_depth
,
1655 int user_transform_channels
));
1656 /* Return the user pointer associated with the user transform functions */
1657 PNG_EXPORT(87, png_voidp
, png_get_user_transform_ptr
,
1658 (png_const_structrp png_ptr
));
1661 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1662 /* Return information about the row currently being processed. Note that these
1663 * APIs do not fail but will return unexpected results if called outside a user
1664 * transform callback. Also note that when transforming an interlaced image the
1665 * row number is the row number within the sub-image of the interlace pass, so
1666 * the value will increase to the height of the sub-image (not the full image)
1667 * then reset to 0 for the next pass.
1669 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1670 * find the output pixel (x,y) given an interlaced sub-image pixel
1671 * (row,col,pass). (See below for these macros.)
1673 PNG_EXPORT(217, png_uint_32
, png_get_current_row_number
, (png_const_structrp
));
1674 PNG_EXPORT(218, png_byte
, png_get_current_pass_number
, (png_const_structrp
));
1677 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1678 /* This callback is called only for *unknown* chunks. If
1679 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1680 * chunks to be treated as unknown, however in this case the callback must do
1681 * any processing required by the chunk (e.g. by calling the appropriate
1684 * There is no write support - on write, by default, all the chunks in the
1685 * 'unknown' list are written in the specified position.
1687 * The integer return from the callback function is interpreted thus:
1689 * negative: An error occurred; png_chunk_error will be called.
1690 * zero: The chunk was not handled, the chunk will be saved. A critical
1691 * chunk will cause an error at this point unless it is to be saved.
1692 * positive: The chunk was handled, libpng will ignore/discard it.
1694 * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
1695 * how this behavior will change in libpng 1.7
1697 PNG_EXPORT(88, void, png_set_read_user_chunk_fn
, (png_structrp png_ptr
,
1698 png_voidp user_chunk_ptr
, png_user_chunk_ptr read_user_chunk_fn
));
1701 #ifdef PNG_USER_CHUNKS_SUPPORTED
1702 PNG_EXPORT(89, png_voidp
, png_get_user_chunk_ptr
, (png_const_structrp png_ptr
));
1705 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1706 /* Sets the function callbacks for the push reader, and a pointer to a
1707 * user-defined structure available to the callback functions.
1709 PNG_EXPORT(90, void, png_set_progressive_read_fn
, (png_structrp png_ptr
,
1710 png_voidp progressive_ptr
, png_progressive_info_ptr info_fn
,
1711 png_progressive_row_ptr row_fn
, png_progressive_end_ptr end_fn
));
1713 /* Returns the user pointer associated with the push read functions */
1714 PNG_EXPORT(91, png_voidp
, png_get_progressive_ptr
,
1715 (png_const_structrp png_ptr
));
1717 /* Function to be called when data becomes available */
1718 PNG_EXPORT(92, void, png_process_data
, (png_structrp png_ptr
,
1719 png_inforp info_ptr
, png_bytep buffer
, png_size_t buffer_size
));
1721 /* A function which may be called *only* within png_process_data to stop the
1722 * processing of any more data. The function returns the number of bytes
1723 * remaining, excluding any that libpng has cached internally. A subsequent
1724 * call to png_process_data must supply these bytes again. If the argument
1725 * 'save' is set to true the routine will first save all the pending data and
1726 * will always return 0.
1728 PNG_EXPORT(219, png_size_t
, png_process_data_pause
, (png_structrp
, int save
));
1730 /* A function which may be called *only* outside (after) a call to
1731 * png_process_data. It returns the number of bytes of data to skip in the
1732 * input. Normally it will return 0, but if it returns a non-zero value the
1733 * application must skip than number of bytes of input data and pass the
1734 * following data to the next call to png_process_data.
1736 PNG_EXPORT(220, png_uint_32
, png_process_data_skip
, (png_structrp
));
1738 /* Function that combines rows. 'new_row' is a flag that should come from
1739 * the callback and be non-NULL if anything needs to be done; the library
1740 * stores its own version of the new data internally and ignores the passed
1743 PNG_EXPORT(93, void, png_progressive_combine_row
, (png_const_structrp png_ptr
,
1744 png_bytep old_row
, png_const_bytep new_row
));
1745 #endif /* PROGRESSIVE_READ */
1747 PNG_EXPORTA(94, png_voidp
, png_malloc
, (png_const_structrp png_ptr
,
1748 png_alloc_size_t size
), PNG_ALLOCATED
);
1749 /* Added at libpng version 1.4.0 */
1750 PNG_EXPORTA(95, png_voidp
, png_calloc
, (png_const_structrp png_ptr
,
1751 png_alloc_size_t size
), PNG_ALLOCATED
);
1753 /* Added at libpng version 1.2.4 */
1754 PNG_EXPORTA(96, png_voidp
, png_malloc_warn
, (png_const_structrp png_ptr
,
1755 png_alloc_size_t size
), PNG_ALLOCATED
);
1757 /* Frees a pointer allocated by png_malloc() */
1758 PNG_EXPORT(97, void, png_free
, (png_const_structrp png_ptr
, png_voidp ptr
));
1760 /* Free data that was allocated internally */
1761 PNG_EXPORT(98, void, png_free_data
, (png_const_structrp png_ptr
,
1762 png_inforp info_ptr
, png_uint_32 free_me
, int num
));
1764 /* Reassign responsibility for freeing existing data, whether allocated
1765 * by libpng or by the application; this works on the png_info structure passed
1766 * in, it does not change the state for other png_info structures.
1768 * It is unlikely that this function works correctly as of 1.6.0 and using it
1769 * may result either in memory leaks or double free of allocated data.
1771 PNG_EXPORT(99, void, png_data_freer
, (png_const_structrp png_ptr
,
1772 png_inforp info_ptr
, int freer
, png_uint_32 mask
));
1774 /* Assignments for png_data_freer */
1775 #define PNG_DESTROY_WILL_FREE_DATA 1
1776 #define PNG_SET_WILL_FREE_DATA 1
1777 #define PNG_USER_WILL_FREE_DATA 2
1778 /* Flags for png_ptr->free_me and info_ptr->free_me */
1779 #define PNG_FREE_HIST 0x0008U
1780 #define PNG_FREE_ICCP 0x0010U
1781 #define PNG_FREE_SPLT 0x0020U
1782 #define PNG_FREE_ROWS 0x0040U
1783 #define PNG_FREE_PCAL 0x0080U
1784 #define PNG_FREE_SCAL 0x0100U
1785 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1786 # define PNG_FREE_UNKN 0x0200U
1788 /* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */
1789 #define PNG_FREE_PLTE 0x1000U
1790 #define PNG_FREE_TRNS 0x2000U
1791 #define PNG_FREE_TEXT 0x4000U
1792 #define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
1793 #define PNG_FREE_ALL 0xffffU
1794 #define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1796 #ifdef PNG_USER_MEM_SUPPORTED
1797 PNG_EXPORTA(100, png_voidp
, png_malloc_default
, (png_const_structrp png_ptr
,
1798 png_alloc_size_t size
), PNG_ALLOCATED PNG_DEPRECATED
);
1799 PNG_EXPORTA(101, void, png_free_default
, (png_const_structrp png_ptr
,
1800 png_voidp ptr
), PNG_DEPRECATED
);
1803 #ifdef PNG_ERROR_TEXT_SUPPORTED
1804 /* Fatal error in PNG image of libpng - can't continue */
1805 PNG_EXPORTA(102, void, png_error
, (png_const_structrp png_ptr
,
1806 png_const_charp error_message
), PNG_NORETURN
);
1808 /* The same, but the chunk name is prepended to the error string. */
1809 PNG_EXPORTA(103, void, png_chunk_error
, (png_const_structrp png_ptr
,
1810 png_const_charp error_message
), PNG_NORETURN
);
1813 /* Fatal error in PNG image of libpng - can't continue */
1814 PNG_EXPORTA(104, void, png_err
, (png_const_structrp png_ptr
), PNG_NORETURN
);
1815 # define png_error(s1,s2) png_err(s1)
1816 # define png_chunk_error(s1,s2) png_err(s1)
1819 #ifdef PNG_WARNINGS_SUPPORTED
1820 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1821 PNG_EXPORT(105, void, png_warning
, (png_const_structrp png_ptr
,
1822 png_const_charp warning_message
));
1824 /* Non-fatal error in libpng, chunk name is prepended to message. */
1825 PNG_EXPORT(106, void, png_chunk_warning
, (png_const_structrp png_ptr
,
1826 png_const_charp warning_message
));
1828 # define png_warning(s1,s2) ((void)(s1))
1829 # define png_chunk_warning(s1,s2) ((void)(s1))
1832 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1833 /* Benign error in libpng. Can continue, but may have a problem.
1834 * User can choose whether to handle as a fatal error or as a warning. */
1835 PNG_EXPORT(107, void, png_benign_error
, (png_const_structrp png_ptr
,
1836 png_const_charp warning_message
));
1838 #ifdef PNG_READ_SUPPORTED
1839 /* Same, chunk name is prepended to message (only during read) */
1840 PNG_EXPORT(108, void, png_chunk_benign_error
, (png_const_structrp png_ptr
,
1841 png_const_charp warning_message
));
1844 PNG_EXPORT(109, void, png_set_benign_errors
,
1845 (png_structrp png_ptr
, int allowed
));
1847 # ifdef PNG_ALLOW_BENIGN_ERRORS
1848 # define png_benign_error png_warning
1849 # define png_chunk_benign_error png_chunk_warning
1851 # define png_benign_error png_error
1852 # define png_chunk_benign_error png_chunk_error
1856 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
1857 * Similarly, the png_get_<chunk> calls are used to read values from the
1858 * png_info_struct, either storing the parameters in the passed variables, or
1859 * setting pointers into the png_info_struct where the data is stored. The
1860 * png_get_<chunk> functions return a non-zero value if the data was available
1861 * in info_ptr, or return zero and do not change any of the parameters if the
1862 * data was not available.
1864 * These functions should be used instead of directly accessing png_info
1865 * to avoid problems with future changes in the size and internal layout of
1868 /* Returns "flag" if chunk data is valid in info_ptr. */
1869 PNG_EXPORT(110, png_uint_32
, png_get_valid
, (png_const_structrp png_ptr
,
1870 png_const_inforp info_ptr
, png_uint_32 flag
));
1872 /* Returns number of bytes needed to hold a transformed row. */
1873 PNG_EXPORT(111, png_size_t
, png_get_rowbytes
, (png_const_structrp png_ptr
,
1874 png_const_inforp info_ptr
));
1876 #ifdef PNG_INFO_IMAGE_SUPPORTED
1877 /* Returns row_pointers, which is an array of pointers to scanlines that was
1878 * returned from png_read_png().
1880 PNG_EXPORT(112, png_bytepp
, png_get_rows
, (png_const_structrp png_ptr
,
1881 png_const_inforp info_ptr
));
1883 /* Set row_pointers, which is an array of pointers to scanlines for use
1884 * by png_write_png().
1886 PNG_EXPORT(113, void, png_set_rows
, (png_const_structrp png_ptr
,
1887 png_inforp info_ptr
, png_bytepp row_pointers
));
1890 /* Returns number of color channels in image. */
1891 PNG_EXPORT(114, png_byte
, png_get_channels
, (png_const_structrp png_ptr
,
1892 png_const_inforp info_ptr
));
1894 #ifdef PNG_EASY_ACCESS_SUPPORTED
1895 /* Returns image width in pixels. */
1896 PNG_EXPORT(115, png_uint_32
, png_get_image_width
, (png_const_structrp png_ptr
,
1897 png_const_inforp info_ptr
));
1899 /* Returns image height in pixels. */
1900 PNG_EXPORT(116, png_uint_32
, png_get_image_height
, (png_const_structrp png_ptr
,
1901 png_const_inforp info_ptr
));
1903 /* Returns image bit_depth. */
1904 PNG_EXPORT(117, png_byte
, png_get_bit_depth
, (png_const_structrp png_ptr
,
1905 png_const_inforp info_ptr
));
1907 /* Returns image color_type. */
1908 PNG_EXPORT(118, png_byte
, png_get_color_type
, (png_const_structrp png_ptr
,
1909 png_const_inforp info_ptr
));
1911 /* Returns image filter_type. */
1912 PNG_EXPORT(119, png_byte
, png_get_filter_type
, (png_const_structrp png_ptr
,
1913 png_const_inforp info_ptr
));
1915 /* Returns image interlace_type. */
1916 PNG_EXPORT(120, png_byte
, png_get_interlace_type
, (png_const_structrp png_ptr
,
1917 png_const_inforp info_ptr
));
1919 /* Returns image compression_type. */
1920 PNG_EXPORT(121, png_byte
, png_get_compression_type
, (png_const_structrp png_ptr
,
1921 png_const_inforp info_ptr
));
1923 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
1924 PNG_EXPORT(122, png_uint_32
, png_get_pixels_per_meter
,
1925 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1926 PNG_EXPORT(123, png_uint_32
, png_get_x_pixels_per_meter
,
1927 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1928 PNG_EXPORT(124, png_uint_32
, png_get_y_pixels_per_meter
,
1929 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1931 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
1932 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio
,
1933 (png_const_structrp png_ptr
, png_const_inforp info_ptr
))
1934 PNG_FIXED_EXPORT(210, png_fixed_point
, png_get_pixel_aspect_ratio_fixed
,
1935 (png_const_structrp png_ptr
, png_const_inforp info_ptr
))
1937 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1938 PNG_EXPORT(126, png_int_32
, png_get_x_offset_pixels
,
1939 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1940 PNG_EXPORT(127, png_int_32
, png_get_y_offset_pixels
,
1941 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1942 PNG_EXPORT(128, png_int_32
, png_get_x_offset_microns
,
1943 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1944 PNG_EXPORT(129, png_int_32
, png_get_y_offset_microns
,
1945 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
1947 #endif /* EASY_ACCESS */
1949 #ifdef PNG_READ_SUPPORTED
1950 /* Returns pointer to signature string read from PNG header */
1951 PNG_EXPORT(130, png_const_bytep
, png_get_signature
, (png_const_structrp png_ptr
,
1952 png_const_inforp info_ptr
));
1955 #ifdef PNG_bKGD_SUPPORTED
1956 PNG_EXPORT(131, png_uint_32
, png_get_bKGD
, (png_const_structrp png_ptr
,
1957 png_inforp info_ptr
, png_color_16p
*background
));
1960 #ifdef PNG_bKGD_SUPPORTED
1961 PNG_EXPORT(132, void, png_set_bKGD
, (png_const_structrp png_ptr
,
1962 png_inforp info_ptr
, png_const_color_16p background
));
1965 #ifdef PNG_cHRM_SUPPORTED
1966 PNG_FP_EXPORT(133, png_uint_32
, png_get_cHRM
, (png_const_structrp png_ptr
,
1967 png_const_inforp info_ptr
, double *white_x
, double *white_y
, double *red_x
,
1968 double *red_y
, double *green_x
, double *green_y
, double *blue_x
,
1970 PNG_FP_EXPORT(230, png_uint_32
, png_get_cHRM_XYZ
, (png_const_structrp png_ptr
,
1971 png_const_inforp info_ptr
, double *red_X
, double *red_Y
, double *red_Z
,
1972 double *green_X
, double *green_Y
, double *green_Z
, double *blue_X
,
1973 double *blue_Y
, double *blue_Z
))
1974 PNG_FIXED_EXPORT(134, png_uint_32
, png_get_cHRM_fixed
,
1975 (png_const_structrp png_ptr
, png_const_inforp info_ptr
,
1976 png_fixed_point
*int_white_x
, png_fixed_point
*int_white_y
,
1977 png_fixed_point
*int_red_x
, png_fixed_point
*int_red_y
,
1978 png_fixed_point
*int_green_x
, png_fixed_point
*int_green_y
,
1979 png_fixed_point
*int_blue_x
, png_fixed_point
*int_blue_y
))
1980 PNG_FIXED_EXPORT(231, png_uint_32
, png_get_cHRM_XYZ_fixed
,
1981 (png_const_structrp png_ptr
, png_const_inforp info_ptr
,
1982 png_fixed_point
*int_red_X
, png_fixed_point
*int_red_Y
,
1983 png_fixed_point
*int_red_Z
, png_fixed_point
*int_green_X
,
1984 png_fixed_point
*int_green_Y
, png_fixed_point
*int_green_Z
,
1985 png_fixed_point
*int_blue_X
, png_fixed_point
*int_blue_Y
,
1986 png_fixed_point
*int_blue_Z
))
1989 #ifdef PNG_cHRM_SUPPORTED
1990 PNG_FP_EXPORT(135, void, png_set_cHRM
, (png_const_structrp png_ptr
,
1991 png_inforp info_ptr
,
1992 double white_x
, double white_y
, double red_x
, double red_y
, double green_x
,
1993 double green_y
, double blue_x
, double blue_y
))
1994 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ
, (png_const_structrp png_ptr
,
1995 png_inforp info_ptr
, double red_X
, double red_Y
, double red_Z
,
1996 double green_X
, double green_Y
, double green_Z
, double blue_X
,
1997 double blue_Y
, double blue_Z
))
1998 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed
, (png_const_structrp png_ptr
,
1999 png_inforp info_ptr
, png_fixed_point int_white_x
,
2000 png_fixed_point int_white_y
, png_fixed_point int_red_x
,
2001 png_fixed_point int_red_y
, png_fixed_point int_green_x
,
2002 png_fixed_point int_green_y
, png_fixed_point int_blue_x
,
2003 png_fixed_point int_blue_y
))
2004 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed
, (png_const_structrp png_ptr
,
2005 png_inforp info_ptr
, png_fixed_point int_red_X
, png_fixed_point int_red_Y
,
2006 png_fixed_point int_red_Z
, png_fixed_point int_green_X
,
2007 png_fixed_point int_green_Y
, png_fixed_point int_green_Z
,
2008 png_fixed_point int_blue_X
, png_fixed_point int_blue_Y
,
2009 png_fixed_point int_blue_Z
))
2012 #ifdef PNG_eXIf_SUPPORTED
2013 PNG_EXPORT(246, png_uint_32
, png_get_eXIf
, (png_const_structrp png_ptr
,
2014 png_inforp info_ptr
, png_bytep
*exif
));
2015 PNG_EXPORT(247, void, png_set_eXIf
, (png_const_structrp png_ptr
,
2016 png_inforp info_ptr
, const png_bytep exif
));
2018 PNG_EXPORT(248, png_uint_32
, png_get_eXIf_1
, (png_const_structrp png_ptr
,
2019 png_const_inforp info_ptr
, png_uint_32
*num_exif
, png_bytep
*exif
));
2020 PNG_EXPORT(249, void, png_set_eXIf_1
, (png_const_structrp png_ptr
,
2021 png_inforp info_ptr
, const png_uint_32 num_exif
, const png_bytep exif
));
2024 #ifdef PNG_gAMA_SUPPORTED
2025 PNG_FP_EXPORT(137, png_uint_32
, png_get_gAMA
, (png_const_structrp png_ptr
,
2026 png_const_inforp info_ptr
, double *file_gamma
))
2027 PNG_FIXED_EXPORT(138, png_uint_32
, png_get_gAMA_fixed
,
2028 (png_const_structrp png_ptr
, png_const_inforp info_ptr
,
2029 png_fixed_point
*int_file_gamma
))
2032 #ifdef PNG_gAMA_SUPPORTED
2033 PNG_FP_EXPORT(139, void, png_set_gAMA
, (png_const_structrp png_ptr
,
2034 png_inforp info_ptr
, double file_gamma
))
2035 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed
, (png_const_structrp png_ptr
,
2036 png_inforp info_ptr
, png_fixed_point int_file_gamma
))
2039 #ifdef PNG_hIST_SUPPORTED
2040 PNG_EXPORT(141, png_uint_32
, png_get_hIST
, (png_const_structrp png_ptr
,
2041 png_inforp info_ptr
, png_uint_16p
*hist
));
2042 PNG_EXPORT(142, void, png_set_hIST
, (png_const_structrp png_ptr
,
2043 png_inforp info_ptr
, png_const_uint_16p hist
));
2046 PNG_EXPORT(143, png_uint_32
, png_get_IHDR
, (png_const_structrp png_ptr
,
2047 png_const_inforp info_ptr
, png_uint_32
*width
, png_uint_32
*height
,
2048 int *bit_depth
, int *color_type
, int *interlace_method
,
2049 int *compression_method
, int *filter_method
));
2051 PNG_EXPORT(144, void, png_set_IHDR
, (png_const_structrp png_ptr
,
2052 png_inforp info_ptr
, png_uint_32 width
, png_uint_32 height
, int bit_depth
,
2053 int color_type
, int interlace_method
, int compression_method
,
2054 int filter_method
));
2056 #ifdef PNG_oFFs_SUPPORTED
2057 PNG_EXPORT(145, png_uint_32
, png_get_oFFs
, (png_const_structrp png_ptr
,
2058 png_const_inforp info_ptr
, png_int_32
*offset_x
, png_int_32
*offset_y
,
2062 #ifdef PNG_oFFs_SUPPORTED
2063 PNG_EXPORT(146, void, png_set_oFFs
, (png_const_structrp png_ptr
,
2064 png_inforp info_ptr
, png_int_32 offset_x
, png_int_32 offset_y
,
2068 #ifdef PNG_pCAL_SUPPORTED
2069 PNG_EXPORT(147, png_uint_32
, png_get_pCAL
, (png_const_structrp png_ptr
,
2070 png_inforp info_ptr
, png_charp
*purpose
, png_int_32
*X0
,
2071 png_int_32
*X1
, int *type
, int *nparams
, png_charp
*units
,
2072 png_charpp
*params
));
2075 #ifdef PNG_pCAL_SUPPORTED
2076 PNG_EXPORT(148, void, png_set_pCAL
, (png_const_structrp png_ptr
,
2077 png_inforp info_ptr
, png_const_charp purpose
, png_int_32 X0
, png_int_32 X1
,
2078 int type
, int nparams
, png_const_charp units
, png_charpp params
));
2081 #ifdef PNG_pHYs_SUPPORTED
2082 PNG_EXPORT(149, png_uint_32
, png_get_pHYs
, (png_const_structrp png_ptr
,
2083 png_const_inforp info_ptr
, png_uint_32
*res_x
, png_uint_32
*res_y
,
2087 #ifdef PNG_pHYs_SUPPORTED
2088 PNG_EXPORT(150, void, png_set_pHYs
, (png_const_structrp png_ptr
,
2089 png_inforp info_ptr
, png_uint_32 res_x
, png_uint_32 res_y
, int unit_type
));
2092 PNG_EXPORT(151, png_uint_32
, png_get_PLTE
, (png_const_structrp png_ptr
,
2093 png_inforp info_ptr
, png_colorp
*palette
, int *num_palette
));
2095 PNG_EXPORT(152, void, png_set_PLTE
, (png_structrp png_ptr
,
2096 png_inforp info_ptr
, png_const_colorp palette
, int num_palette
));
2098 #ifdef PNG_sBIT_SUPPORTED
2099 PNG_EXPORT(153, png_uint_32
, png_get_sBIT
, (png_const_structrp png_ptr
,
2100 png_inforp info_ptr
, png_color_8p
*sig_bit
));
2103 #ifdef PNG_sBIT_SUPPORTED
2104 PNG_EXPORT(154, void, png_set_sBIT
, (png_const_structrp png_ptr
,
2105 png_inforp info_ptr
, png_const_color_8p sig_bit
));
2108 #ifdef PNG_sRGB_SUPPORTED
2109 PNG_EXPORT(155, png_uint_32
, png_get_sRGB
, (png_const_structrp png_ptr
,
2110 png_const_inforp info_ptr
, int *file_srgb_intent
));
2113 #ifdef PNG_sRGB_SUPPORTED
2114 PNG_EXPORT(156, void, png_set_sRGB
, (png_const_structrp png_ptr
,
2115 png_inforp info_ptr
, int srgb_intent
));
2116 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM
, (png_const_structrp png_ptr
,
2117 png_inforp info_ptr
, int srgb_intent
));
2120 #ifdef PNG_iCCP_SUPPORTED
2121 PNG_EXPORT(158, png_uint_32
, png_get_iCCP
, (png_const_structrp png_ptr
,
2122 png_inforp info_ptr
, png_charpp name
, int *compression_type
,
2123 png_bytepp profile
, png_uint_32
*proflen
));
2126 #ifdef PNG_iCCP_SUPPORTED
2127 PNG_EXPORT(159, void, png_set_iCCP
, (png_const_structrp png_ptr
,
2128 png_inforp info_ptr
, png_const_charp name
, int compression_type
,
2129 png_const_bytep profile
, png_uint_32 proflen
));
2132 #ifdef PNG_sPLT_SUPPORTED
2133 PNG_EXPORT(160, int, png_get_sPLT
, (png_const_structrp png_ptr
,
2134 png_inforp info_ptr
, png_sPLT_tpp entries
));
2137 #ifdef PNG_sPLT_SUPPORTED
2138 PNG_EXPORT(161, void, png_set_sPLT
, (png_const_structrp png_ptr
,
2139 png_inforp info_ptr
, png_const_sPLT_tp entries
, int nentries
));
2142 #ifdef PNG_TEXT_SUPPORTED
2143 /* png_get_text also returns the number of text chunks in *num_text */
2144 PNG_EXPORT(162, int, png_get_text
, (png_const_structrp png_ptr
,
2145 png_inforp info_ptr
, png_textp
*text_ptr
, int *num_text
));
2148 /* Note while png_set_text() will accept a structure whose text,
2149 * language, and translated keywords are NULL pointers, the structure
2150 * returned by png_get_text will always contain regular
2151 * zero-terminated C strings. They might be empty strings but
2152 * they will never be NULL pointers.
2155 #ifdef PNG_TEXT_SUPPORTED
2156 PNG_EXPORT(163, void, png_set_text
, (png_const_structrp png_ptr
,
2157 png_inforp info_ptr
, png_const_textp text_ptr
, int num_text
));
2160 #ifdef PNG_tIME_SUPPORTED
2161 PNG_EXPORT(164, png_uint_32
, png_get_tIME
, (png_const_structrp png_ptr
,
2162 png_inforp info_ptr
, png_timep
*mod_time
));
2165 #ifdef PNG_tIME_SUPPORTED
2166 PNG_EXPORT(165, void, png_set_tIME
, (png_const_structrp png_ptr
,
2167 png_inforp info_ptr
, png_const_timep mod_time
));
2170 #ifdef PNG_tRNS_SUPPORTED
2171 PNG_EXPORT(166, png_uint_32
, png_get_tRNS
, (png_const_structrp png_ptr
,
2172 png_inforp info_ptr
, png_bytep
*trans_alpha
, int *num_trans
,
2173 png_color_16p
*trans_color
));
2176 #ifdef PNG_tRNS_SUPPORTED
2177 PNG_EXPORT(167, void, png_set_tRNS
, (png_structrp png_ptr
,
2178 png_inforp info_ptr
, png_const_bytep trans_alpha
, int num_trans
,
2179 png_const_color_16p trans_color
));
2182 #ifdef PNG_sCAL_SUPPORTED
2183 PNG_FP_EXPORT(168, png_uint_32
, png_get_sCAL
, (png_const_structrp png_ptr
,
2184 png_const_inforp info_ptr
, int *unit
, double *width
, double *height
))
2185 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2186 defined(PNG_FLOATING_POINT_SUPPORTED)
2187 /* NOTE: this API is currently implemented using floating point arithmetic,
2188 * consequently it can only be used on systems with floating point support.
2189 * In any case the range of values supported by png_fixed_point is small and it
2190 * is highly recommended that png_get_sCAL_s be used instead.
2192 PNG_FIXED_EXPORT(214, png_uint_32
, png_get_sCAL_fixed
,
2193 (png_const_structrp png_ptr
, png_const_inforp info_ptr
, int *unit
,
2194 png_fixed_point
*width
, png_fixed_point
*height
))
2196 PNG_EXPORT(169, png_uint_32
, png_get_sCAL_s
,
2197 (png_const_structrp png_ptr
, png_const_inforp info_ptr
, int *unit
,
2198 png_charpp swidth
, png_charpp sheight
));
2200 PNG_FP_EXPORT(170, void, png_set_sCAL
, (png_const_structrp png_ptr
,
2201 png_inforp info_ptr
, int unit
, double width
, double height
))
2202 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed
, (png_const_structrp png_ptr
,
2203 png_inforp info_ptr
, int unit
, png_fixed_point width
,
2204 png_fixed_point height
))
2205 PNG_EXPORT(171, void, png_set_sCAL_s
, (png_const_structrp png_ptr
,
2206 png_inforp info_ptr
, int unit
,
2207 png_const_charp swidth
, png_const_charp sheight
));
2210 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2211 /* Provide the default handling for all unknown chunks or, optionally, for
2212 * specific unknown chunks.
2214 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2215 * ignored and the default was used, the per-chunk setting only had an effect on
2216 * write. If you wish to have chunk-specific handling on read in code that must
2217 * work on earlier versions you must use a user chunk callback to specify the
2218 * desired handling (keep or discard.)
2220 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2221 * parameter is interpreted as follows:
2224 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2225 * Known chunks: do normal libpng processing, do not keep the chunk (but
2226 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2227 * Unknown chunks: for a specific chunk use the global default, when used
2228 * as the default discard the chunk data.
2229 * PNG_HANDLE_CHUNK_NEVER:
2230 * Discard the chunk data.
2231 * PNG_HANDLE_CHUNK_IF_SAFE:
2232 * Keep the chunk data if the chunk is not critical else raise a chunk
2234 * PNG_HANDLE_CHUNK_ALWAYS:
2235 * Keep the chunk data.
2237 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2238 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2239 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2240 * it simply resets the behavior to the libpng default.
2242 * INTERACTION WTIH USER CHUNK CALLBACKS:
2243 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2244 * callback and the callback returns 0; the chunk is then always stored *unless*
2245 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2246 * the global default is *not* used in this case. (In effect the per-chunk
2247 * value is incremented to at least IF_SAFE.)
2249 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2250 * per-chunk defaults will be honored. If you want to preserve the current
2251 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2252 * as the default - if you don't do this libpng 1.6 will issue a warning.
2254 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2255 * earlier simply return '1' (handled).
2257 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2258 * If this is *not* set known chunks will always be handled by libpng and
2259 * will never be stored in the unknown chunk list. Known chunks listed to
2260 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2261 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2262 * by libpng, in addition critical chunks must either be processed by the
2263 * callback or saved.
2265 * The IHDR and IEND chunks must not be listed. Because this turns off the
2266 * default handling for chunks that would otherwise be recognized the
2267 * behavior of libpng transformations may well become incorrect!
2270 * When writing chunks the options only apply to the chunks specified by
2271 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2272 * required by png_set_ calls and will always write the core critical chunks
2273 * (as required for PLTE).
2275 * Each chunk in the png_set_unknown_chunks list is looked up in the
2276 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2277 * interpreted as follows:
2279 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2280 * Write safe-to-copy chunks and write other chunks if the global
2281 * default is set to _ALWAYS, otherwise don't write this chunk.
2282 * PNG_HANDLE_CHUNK_NEVER:
2283 * Do not write the chunk.
2284 * PNG_HANDLE_CHUNK_IF_SAFE:
2285 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2286 * PNG_HANDLE_CHUNK_ALWAYS:
2289 * Note that the default behavior is effectively the opposite of the read case -
2290 * in read unknown chunks are not stored by default, in write they are written
2291 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2292 * - on write the safe-to-copy bit is checked, on read the critical bit is
2293 * checked and on read if the chunk is critical an error will be raised.
2297 * If num_chunks is positive, then the "keep" parameter specifies the manner
2298 * for handling only those chunks appearing in the chunk_list array,
2299 * otherwise the chunk list array is ignored.
2301 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2302 * unknown chunks, as described above.
2304 * If num_chunks is negative, then the "keep" parameter specifies the manner
2305 * for handling all unknown chunks plus all chunks recognized by libpng
2306 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2307 * be processed by libpng.
2309 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2310 PNG_EXPORT(172, void, png_set_keep_unknown_chunks
, (png_structrp png_ptr
,
2311 int keep
, png_const_bytep chunk_list
, int num_chunks
));
2312 #endif /* HANDLE_AS_UNKNOWN */
2314 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2315 * the result is therefore true (non-zero) if special handling is required,
2316 * false for the default handling.
2318 PNG_EXPORT(173, int, png_handle_as_unknown
, (png_const_structrp png_ptr
,
2319 png_const_bytep chunk_name
));
2320 #endif /* SET_UNKNOWN_CHUNKS */
2322 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2323 PNG_EXPORT(174, void, png_set_unknown_chunks
, (png_const_structrp png_ptr
,
2324 png_inforp info_ptr
, png_const_unknown_chunkp unknowns
,
2326 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2327 * unknowns to the location currently stored in the png_struct. This is
2328 * invariably the wrong value on write. To fix this call the following API
2329 * for each chunk in the list with the correct location. If you know your
2330 * code won't be compiled on earlier versions you can rely on
2331 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2332 * the correct thing.
2335 PNG_EXPORT(175, void, png_set_unknown_chunk_location
,
2336 (png_const_structrp png_ptr
, png_inforp info_ptr
, int chunk
, int location
));
2338 PNG_EXPORT(176, int, png_get_unknown_chunks
, (png_const_structrp png_ptr
,
2339 png_inforp info_ptr
, png_unknown_chunkpp entries
));
2342 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2343 * If you need to turn it off for a chunk that your application has freed,
2344 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2346 PNG_EXPORT(177, void, png_set_invalid
, (png_const_structrp png_ptr
,
2347 png_inforp info_ptr
, int mask
));
2349 #ifdef PNG_INFO_IMAGE_SUPPORTED
2350 /* The "params" pointer is currently not used and is for future expansion. */
2351 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2352 PNG_EXPORT(178, void, png_read_png
, (png_structrp png_ptr
, png_inforp info_ptr
,
2353 int transforms
, png_voidp params
));
2355 #ifdef PNG_WRITE_SUPPORTED
2356 PNG_EXPORT(179, void, png_write_png
, (png_structrp png_ptr
, png_inforp info_ptr
,
2357 int transforms
, png_voidp params
));
2361 PNG_EXPORT(180, png_const_charp
, png_get_copyright
,
2362 (png_const_structrp png_ptr
));
2363 PNG_EXPORT(181, png_const_charp
, png_get_header_ver
,
2364 (png_const_structrp png_ptr
));
2365 PNG_EXPORT(182, png_const_charp
, png_get_header_version
,
2366 (png_const_structrp png_ptr
));
2367 PNG_EXPORT(183, png_const_charp
, png_get_libpng_ver
,
2368 (png_const_structrp png_ptr
));
2370 #ifdef PNG_MNG_FEATURES_SUPPORTED
2371 PNG_EXPORT(184, png_uint_32
, png_permit_mng_features
, (png_structrp png_ptr
,
2372 png_uint_32 mng_features_permitted
));
2375 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2376 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2377 #define PNG_HANDLE_CHUNK_NEVER 1
2378 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2379 #define PNG_HANDLE_CHUNK_ALWAYS 3
2380 #define PNG_HANDLE_CHUNK_LAST 4
2382 /* Strip the prepended error numbers ("#nnn ") from error and warning
2383 * messages before passing them to the error or warning handler.
2385 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2386 PNG_EXPORT(185, void, png_set_strip_error_numbers
, (png_structrp png_ptr
,
2387 png_uint_32 strip_mode
));
2390 /* Added in libpng-1.2.6 */
2391 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2392 PNG_EXPORT(186, void, png_set_user_limits
, (png_structrp png_ptr
,
2393 png_uint_32 user_width_max
, png_uint_32 user_height_max
));
2394 PNG_EXPORT(187, png_uint_32
, png_get_user_width_max
,
2395 (png_const_structrp png_ptr
));
2396 PNG_EXPORT(188, png_uint_32
, png_get_user_height_max
,
2397 (png_const_structrp png_ptr
));
2398 /* Added in libpng-1.4.0 */
2399 PNG_EXPORT(189, void, png_set_chunk_cache_max
, (png_structrp png_ptr
,
2400 png_uint_32 user_chunk_cache_max
));
2401 PNG_EXPORT(190, png_uint_32
, png_get_chunk_cache_max
,
2402 (png_const_structrp png_ptr
));
2403 /* Added in libpng-1.4.1 */
2404 PNG_EXPORT(191, void, png_set_chunk_malloc_max
, (png_structrp png_ptr
,
2405 png_alloc_size_t user_chunk_cache_max
));
2406 PNG_EXPORT(192, png_alloc_size_t
, png_get_chunk_malloc_max
,
2407 (png_const_structrp png_ptr
));
2410 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2411 PNG_EXPORT(193, png_uint_32
, png_get_pixels_per_inch
,
2412 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
2414 PNG_EXPORT(194, png_uint_32
, png_get_x_pixels_per_inch
,
2415 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
2417 PNG_EXPORT(195, png_uint_32
, png_get_y_pixels_per_inch
,
2418 (png_const_structrp png_ptr
, png_const_inforp info_ptr
));
2420 PNG_FP_EXPORT(196, float, png_get_x_offset_inches
,
2421 (png_const_structrp png_ptr
, png_const_inforp info_ptr
))
2422 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2423 PNG_FIXED_EXPORT(211, png_fixed_point
, png_get_x_offset_inches_fixed
,
2424 (png_const_structrp png_ptr
, png_const_inforp info_ptr
))
2427 PNG_FP_EXPORT(197, float, png_get_y_offset_inches
, (png_const_structrp png_ptr
,
2428 png_const_inforp info_ptr
))
2429 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2430 PNG_FIXED_EXPORT(212, png_fixed_point
, png_get_y_offset_inches_fixed
,
2431 (png_const_structrp png_ptr
, png_const_inforp info_ptr
))
2434 # ifdef PNG_pHYs_SUPPORTED
2435 PNG_EXPORT(198, png_uint_32
, png_get_pHYs_dpi
, (png_const_structrp png_ptr
,
2436 png_const_inforp info_ptr
, png_uint_32
*res_x
, png_uint_32
*res_y
,
2439 #endif /* INCH_CONVERSIONS */
2441 /* Added in libpng-1.4.0 */
2442 #ifdef PNG_IO_STATE_SUPPORTED
2443 PNG_EXPORT(199, png_uint_32
, png_get_io_state
, (png_const_structrp png_ptr
));
2445 /* Removed from libpng 1.6; use png_get_io_chunk_type. */
2446 PNG_REMOVED(200, png_const_bytep
, png_get_io_chunk_name
, (png_structrp png_ptr
),
2449 PNG_EXPORT(216, png_uint_32
, png_get_io_chunk_type
,
2450 (png_const_structrp png_ptr
));
2452 /* The flags returned by png_get_io_state() are the following: */
2453 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2454 # define PNG_IO_READING 0x0001 /* currently reading */
2455 # define PNG_IO_WRITING 0x0002 /* currently writing */
2456 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2457 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2458 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2459 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2460 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2461 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2462 #endif /* IO_STATE */
2464 /* Interlace support. The following macros are always defined so that if
2465 * libpng interlace handling is turned off the macros may be used to handle
2466 * interlaced images within the application.
2468 #define PNG_INTERLACE_ADAM7_PASSES 7
2470 /* Two macros to return the first row and first column of the original,
2471 * full, image which appears in a given pass. 'pass' is in the range 0
2472 * to 6 and the result is in the range 0 to 7.
2474 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2475 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2477 /* A macro to return the offset between pixels in the output row for a pair of
2478 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2479 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2480 * COL_OFFSET is from one column to the next, within a row.
2482 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2483 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2485 /* Two macros to help evaluate the number of rows or columns in each
2486 * pass. This is expressed as a shift - effectively log2 of the number or
2487 * rows or columns in each 8x8 tile of the original image.
2489 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2490 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2492 /* Hence two macros to determine the number of rows or columns in a given
2493 * pass of an image given its height or width. In fact these macros may
2494 * return non-zero even though the sub-image is empty, because the other
2495 * dimension may be empty for a small image.
2497 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2498 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2499 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2500 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2502 /* For the reader row callbacks (both progressive and sequential) it is
2503 * necessary to find the row in the output image given a row in an interlaced
2504 * image, so two more macros:
2506 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2507 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2508 #define PNG_COL_FROM_PASS_COL(x_in, pass) \
2509 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2511 /* Two macros which return a boolean (0 or 1) saying whether the given row
2512 * or column is in a particular pass. These use a common utility macro that
2513 * returns a mask for a given pass - the offset 'off' selects the row or
2514 * column version. The mask has the appropriate bit set for each column in
2517 #define PNG_PASS_MASK(pass,off) ( \
2518 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2519 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2521 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2522 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2523 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2524 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2526 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2527 /* With these routines we avoid an integer divide, which will be slower on
2528 * most machines. However, it does take more operations than the corresponding
2529 * divide method, so it may be slower on a few RISC systems. There are two
2530 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2532 * Note that the rounding factors are NOT supposed to be the same! 128 and
2533 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2536 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2539 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2541 # define png_composite(composite, fg, alpha, bg) \
2543 png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2544 * (png_uint_16)(alpha) \
2545 + (png_uint_16)(bg)*(png_uint_16)(255 \
2546 - (png_uint_16)(alpha)) + 128); \
2547 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
2550 # define png_composite_16(composite, fg, alpha, bg) \
2552 png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2553 * (png_uint_32)(alpha) \
2554 + (png_uint_32)(bg)*(65535 \
2555 - (png_uint_32)(alpha)) + 32768); \
2556 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
2559 #else /* Standard method using integer division */
2561 # define png_composite(composite, fg, alpha, bg) \
2563 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2564 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2567 # define png_composite_16(composite, fg, alpha, bg) \
2569 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2570 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2572 #endif /* READ_COMPOSITE_NODIV */
2574 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2575 PNG_EXPORT(201, png_uint_32
, png_get_uint_32
, (png_const_bytep buf
));
2576 PNG_EXPORT(202, png_uint_16
, png_get_uint_16
, (png_const_bytep buf
));
2577 PNG_EXPORT(203, png_int_32
, png_get_int_32
, (png_const_bytep buf
));
2580 PNG_EXPORT(204, png_uint_32
, png_get_uint_31
, (png_const_structrp png_ptr
,
2581 png_const_bytep buf
));
2582 /* No png_get_int_16 -- may be added if there's a real need for it. */
2584 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2585 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2586 PNG_EXPORT(205, void, png_save_uint_32
, (png_bytep buf
, png_uint_32 i
));
2588 #ifdef PNG_SAVE_INT_32_SUPPORTED
2589 PNG_EXPORT(206, void, png_save_int_32
, (png_bytep buf
, png_int_32 i
));
2592 /* Place a 16-bit number into a buffer in PNG byte order.
2593 * The parameter is declared unsigned int, not png_uint_16,
2594 * just to avoid potential problems on pre-ANSI C compilers.
2596 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2597 PNG_EXPORT(207, void, png_save_uint_16
, (png_bytep buf
, unsigned int i
));
2598 /* No png_save_int_16 -- may be added if there's a real need for it. */
2601 #ifdef PNG_USE_READ_MACROS
2602 /* Inline macros to do direct reads of bytes from the input buffer.
2603 * The png_get_int_32() routine assumes we are using two's complement
2604 * format for negative values, which is almost certainly true.
2606 # define PNG_get_uint_32(buf) \
2607 (((png_uint_32)(*(buf)) << 24) + \
2608 ((png_uint_32)(*((buf) + 1)) << 16) + \
2609 ((png_uint_32)(*((buf) + 2)) << 8) + \
2610 ((png_uint_32)(*((buf) + 3))))
2612 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2613 * function) incorrectly returned a value of type png_uint_32.
2615 # define PNG_get_uint_16(buf) \
2617 (((unsigned int)(*(buf)) << 8) + \
2618 ((unsigned int)(*((buf) + 1)))))
2620 # define PNG_get_int_32(buf) \
2621 ((png_int_32)((*(buf) & 0x80) \
2622 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2623 : (png_int_32)png_get_uint_32(buf)))
2625 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2626 * but defining a macro name prefixed with PNG_PREFIX.
2629 # define png_get_uint_32(buf) PNG_get_uint_32(buf)
2630 # define png_get_uint_16(buf) PNG_get_uint_16(buf)
2631 # define png_get_int_32(buf) PNG_get_int_32(buf)
2635 /* No macros; revert to the (redefined) function */
2636 # define PNG_get_uint_32 (png_get_uint_32)
2637 # define PNG_get_uint_16 (png_get_uint_16)
2638 # define PNG_get_int_32 (png_get_int_32)
2642 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2643 PNG_EXPORT(242, void, png_set_check_for_invalid_index
,
2644 (png_structrp png_ptr
, int allowed
));
2645 # ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2646 PNG_EXPORT(243, int, png_get_palette_max
, (png_const_structp png_ptr
,
2647 png_const_infop info_ptr
));
2649 #endif /* CHECK_FOR_INVALID_INDEX */
2651 /*******************************************************************************
2652 * Section 5: SIMPLIFIED API
2653 *******************************************************************************
2655 * Please read the documentation in libpng-manual.txt (TODO: write said
2656 * documentation) if you don't understand what follows.
2658 * The simplified API hides the details of both libpng and the PNG file format
2659 * itself. It allows PNG files to be read into a very limited number of
2660 * in-memory bitmap formats or to be written from the same formats. If these
2661 * formats do not accomodate your needs then you can, and should, use the more
2662 * sophisticated APIs above - these support a wide variety of in-memory formats
2663 * and a wide variety of sophisticated transformations to those formats as well
2664 * as a wide variety of APIs to manipulate ancillary information.
2666 * To read a PNG file using the simplified API:
2668 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2669 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2670 * (this is REQUIRED, your program may crash if you don't do it.)
2671 * 2) Call the appropriate png_image_begin_read... function.
2672 * 3) Set the png_image 'format' member to the required sample format.
2673 * 4) Allocate a buffer for the image and, if required, the color-map.
2674 * 5) Call png_image_finish_read to read the image and, if required, the
2675 * color-map into your buffers.
2677 * There are no restrictions on the format of the PNG input itself; all valid
2678 * color types, bit depths, and interlace methods are acceptable, and the
2679 * input image is transformed as necessary to the requested in-memory format
2680 * during the png_image_finish_read() step. The only caveat is that if you
2681 * request a color-mapped image from a PNG that is full-color or makes
2682 * complex use of an alpha channel the transformation is extremely lossy and the
2683 * result may look terrible.
2685 * To write a PNG file using the simplified API:
2687 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2688 * 2) Initialize the members of the structure that describe the image, setting
2689 * the 'format' member to the format of the image samples.
2690 * 3) Call the appropriate png_image_write... function with a pointer to the
2691 * image and, if necessary, the color-map to write the PNG data.
2693 * png_image is a structure that describes the in-memory format of an image
2694 * when it is being read or defines the in-memory format of an image that you
2697 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2698 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2700 #define PNG_IMAGE_VERSION 1
2702 typedef struct png_control
*png_controlp
;
2705 png_controlp opaque
; /* Initialize to NULL, free with png_image_free */
2706 png_uint_32 version
; /* Set to PNG_IMAGE_VERSION */
2707 png_uint_32 width
; /* Image width in pixels (columns) */
2708 png_uint_32 height
; /* Image height in pixels (rows) */
2709 png_uint_32 format
; /* Image format as defined below */
2710 png_uint_32 flags
; /* A bit mask containing informational flags */
2711 png_uint_32 colormap_entries
;
2712 /* Number of entries in the color-map */
2714 /* In the event of an error or warning the following field will be set to a
2715 * non-zero value and the 'message' field will contain a '\0' terminated
2716 * string with the libpng error or warning message. If both warnings and
2717 * an error were encountered, only the error is recorded. If there
2718 * are multiple warnings, only the first one is recorded.
2720 * The upper 30 bits of this value are reserved, the low two bits contain
2721 * a value as follows:
2723 # define PNG_IMAGE_WARNING 1
2724 # define PNG_IMAGE_ERROR 2
2726 * The result is a two-bit code such that a value more than 1 indicates
2727 * a failure in the API just called:
2729 * 0 - no warning or error
2732 * 3 - error preceded by warning
2734 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2736 png_uint_32 warning_or_error
;
2739 } png_image
, *png_imagep
;
2741 /* The samples of the image have one to four channels whose components have
2742 * original values in the range 0 to 1.0:
2744 * 1: A single gray or luminance channel (G).
2745 * 2: A gray/luminance channel and an alpha channel (GA).
2746 * 3: Three red, green, blue color channels (RGB).
2747 * 4: Three color channels and an alpha channel (RGBA).
2749 * The components are encoded in one of two ways:
2751 * a) As a small integer, value 0..255, contained in a single byte. For the
2752 * alpha channel the original value is simply value/255. For the color or
2753 * luminance channels the value is encoded according to the sRGB specification
2754 * and matches the 8-bit format expected by typical display devices.
2756 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2757 * channel and are suitable for passing to color management software.
2759 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2760 * channels can be converted to the original value by dividing by 65535; all
2761 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2762 * the sRGB specification. This encoding is identified by the
2763 * PNG_FORMAT_FLAG_LINEAR flag below.
2765 * When the simplified API needs to convert between sRGB and linear colorspaces,
2766 * the actual sRGB transfer curve defined in the sRGB specification (see the
2767 * article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2768 * approximation used elsewhere in libpng.
2770 * When an alpha channel is present it is expected to denote pixel coverage
2771 * of the color or luminance channels and is returned as an associated alpha
2772 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2775 * The samples are either contained directly in the image data, between 1 and 8
2776 * bytes per pixel according to the encoding, or are held in a color-map indexed
2777 * by bytes in the image data. In the case of a color-map the color-map entries
2778 * are individual samples, encoded as above, and the image data has one byte per
2779 * pixel to select the relevant sample from the color-map.
2784 * #defines to be used in png_image::format. Each #define identifies a
2785 * particular layout of sample data and, if present, alpha values. There are
2786 * separate defines for each of the two component encodings.
2788 * A format is built up using single bit flag values. All combinations are
2789 * valid. Formats can be built up from the flag values or you can use one of
2790 * the predefined values below. When testing formats always use the FORMAT_FLAG
2791 * macros to test for individual features - future versions of the library may
2794 * When reading or writing color-mapped images the format should be set to the
2795 * format of the entries in the color-map then png_image_{read,write}_colormap
2796 * called to read or write the color-map and set the format correctly for the
2797 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2799 * NOTE: libpng can be built with particular features disabled. If you see
2800 * compiler errors because the definition of one of the following flags has been
2801 * compiled out it is because libpng does not have the required support. It is
2802 * possible, however, for the libpng configuration to enable the format on just
2803 * read or just write; in that case you may see an error at run time. You can
2804 * guard against this by checking for the definition of the appropriate
2805 * "_SUPPORTED" macro, one of:
2807 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2809 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2810 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2811 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2812 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2814 #ifdef PNG_FORMAT_BGR_SUPPORTED
2815 # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2818 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
2819 # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2822 /* Commonly used formats have predefined macros.
2824 * First the single byte (sRGB) formats:
2826 #define PNG_FORMAT_GRAY 0
2827 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2828 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2829 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2830 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2831 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2832 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2833 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2834 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2836 /* Then the linear 2-byte formats. When naming these "Y" is used to
2837 * indicate a luminance (gray) channel.
2839 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2840 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2841 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2842 #define PNG_FORMAT_LINEAR_RGB_ALPHA \
2843 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2845 /* With color-mapped formats the image data is one byte for each pixel, the byte
2846 * is an index into the color-map which is formatted as above. To obtain a
2847 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2848 * to one of the above definitions, or you can use one of the definitions below.
2850 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2851 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2852 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2853 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2854 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2855 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2859 * These are convenience macros to derive information from a png_image
2860 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2861 * actual image sample values - either the entries in the color-map or the
2862 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2863 * for the pixels and will always return 1 for color-mapped formats. The
2864 * remaining macros return information about the rows in the image and the
2867 * NOTE: All the macros that take a png_image::format parameter are compile time
2868 * constants if the format parameter is, itself, a constant. Therefore these
2869 * macros can be used in array declarations and case labels where required.
2870 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2871 * they can be used in #if tests.
2873 * First the information about the samples.
2875 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2876 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2877 /* Return the total number of channels in a given format: 1..4 */
2879 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2880 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2881 /* Return the size in bytes of a single component of a pixel or color-map
2882 * entry (as appropriate) in the image: 1 or 2.
2885 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2886 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2887 /* This is the size of the sample data for one sample. If the image is
2888 * color-mapped it is the size of one color-map entry (and image pixels are
2889 * one byte in size), otherwise it is the size of one image pixel.
2892 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2893 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2894 /* The maximum size of the color-map required by the format expressed in a
2895 * count of components. This can be used to compile-time allocate a
2898 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2900 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2902 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2903 * information from one of the png_image_begin_read_ APIs and dynamically
2904 * allocate the required memory.
2907 /* Corresponding information about the pixels */
2908 #define PNG_IMAGE_PIXEL_(test,fmt)\
2909 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2911 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2912 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2913 /* The number of separate channels (components) in a pixel; 1 for a
2914 * color-mapped image.
2917 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2918 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2919 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2923 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2924 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2926 /* Information about the whole row, or whole image */
2927 #define PNG_IMAGE_ROW_STRIDE(image)\
2928 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2929 /* Return the total number of components in a single row of the image; this
2930 * is the minimum 'row stride', the minimum count of components between each
2931 * row. For a color-mapped image this is the minimum number of bytes in a
2934 * WARNING: this macro overflows for some images with more than one component
2935 * and very large image widths. libpng will refuse to process an image where
2936 * this macro would overflow.
2939 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2940 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2941 /* Return the size, in bytes, of an image buffer given a png_image and a row
2942 * stride - the number of components to leave space for in each row.
2944 * WARNING: this macro overflows a 32-bit integer for some large PNG images,
2945 * libpng will refuse to process an image where such an overflow would occur.
2948 #define PNG_IMAGE_SIZE(image)\
2949 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2950 /* Return the size, in bytes, of the image in memory given just a png_image;
2951 * the row stride is the minimum stride required for the image.
2954 #define PNG_IMAGE_COLORMAP_SIZE(image)\
2955 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2956 /* Return the size, in bytes, of the color-map of this image. If the image
2957 * format is not a color-map format this will return a size sufficient for
2958 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2959 * you don't want to allocate a color-map in this case.
2964 * Flags containing additional information about the image are held in the
2965 * 'flags' field of png_image.
2967 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2968 /* This indicates the the RGB values of the in-memory bitmap do not
2969 * correspond to the red, green and blue end-points defined by sRGB.
2972 #define PNG_IMAGE_FLAG_FAST 0x02
2973 /* On write emphasise speed over compression; the resultant PNG file will be
2974 * larger but will be produced significantly faster, particular for large
2975 * images. Do not use this option for images which will be distributed, only
2976 * used it when producing intermediate files that will be read back in
2977 * repeatedly. For a typical 24-bit image the option will double the read
2978 * speed at the cost of increasing the image size by 25%, however for many
2979 * more compressible images the PNG file can be 10 times larger with only a
2980 * slight speed gain.
2983 #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
2984 /* On read if the image is a 16-bit per component image and there is no gAMA
2985 * or sRGB chunk assume that the components are sRGB encoded. Notice that
2986 * images output by the simplified API always have gamma information; setting
2987 * this flag only affects the interpretation of 16-bit images from an
2988 * external source. It is recommended that the application expose this flag
2989 * to the user; the user can normally easily recognize the difference between
2990 * linear and sRGB encoding. This flag has no effect on write - the data
2991 * passed to the write APIs must have the correct encoding (as defined
2994 * If the flag is not set (the default) input 16-bit per component data is
2995 * assumed to be linear.
2997 * NOTE: the flag can only be set after the png_image_begin_read_ call,
2998 * because that call initializes the 'flags' field.
3001 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
3005 * The png_image passed to the read APIs must have been initialized by setting
3006 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
3008 #ifdef PNG_STDIO_SUPPORTED
3009 PNG_EXPORT(234, int, png_image_begin_read_from_file
, (png_imagep image
,
3010 const char *file_name
));
3011 /* The named file is opened for read and the image header is filled in
3012 * from the PNG header in the file.
3015 PNG_EXPORT(235, int, png_image_begin_read_from_stdio
, (png_imagep image
,
3017 /* The PNG header is read from the stdio FILE object. */
3020 PNG_EXPORT(236, int, png_image_begin_read_from_memory
, (png_imagep image
,
3021 png_const_voidp memory
, png_size_t size
));
3022 /* The PNG header is read from the given memory buffer. */
3024 PNG_EXPORT(237, int, png_image_finish_read
, (png_imagep image
,
3025 png_const_colorp background
, void *buffer
, png_int_32 row_stride
,
3027 /* Finish reading the image into the supplied buffer and clean up the
3028 * png_image structure.
3030 * row_stride is the step, in byte or 2-byte units as appropriate,
3031 * between adjacent rows. A positive stride indicates that the top-most row
3032 * is first in the buffer - the normal top-down arrangement. A negative
3033 * stride indicates that the bottom-most row is first in the buffer.
3035 * background need only be supplied if an alpha channel must be removed from
3036 * a png_byte format and the removal is to be done by compositing on a solid
3037 * color; otherwise it may be NULL and any composition will be done directly
3038 * onto the buffer. The value is an sRGB color to use for the background,
3039 * for grayscale output the green channel is used.
3041 * background must be supplied when an alpha channel must be removed from a
3042 * single byte color-mapped output format, in other words if:
3044 * 1) The original format from png_image_begin_read_from_* had
3045 * PNG_FORMAT_FLAG_ALPHA set.
3046 * 2) The format set by the application does not.
3047 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3048 * PNG_FORMAT_FLAG_LINEAR *not* set.
3050 * For linear output removing the alpha channel is always done by compositing
3051 * on black and background is ignored.
3053 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3054 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3055 * image->colormap_entries will be updated to the actual number of entries
3056 * written to the colormap; this may be less than the original value.
3059 PNG_EXPORT(238, void, png_image_free
, (png_imagep image
));
3060 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3061 * NULL. May be called at any time after the structure is initialized.
3063 #endif /* SIMPLIFIED_READ */
3065 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3068 * For write you must initialize a png_image structure to describe the image to
3069 * be written. To do this use memset to set the whole structure to 0 then
3070 * initialize fields describing your image.
3072 * version: must be set to PNG_IMAGE_VERSION
3073 * opaque: must be initialized to NULL
3074 * width: image width in pixels
3075 * height: image height in rows
3076 * format: the format of the data (image and color-map) you wish to write
3077 * flags: set to 0 unless one of the defined flags applies; set
3078 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3079 * values do not correspond to the colors in sRGB.
3080 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3082 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3083 PNG_EXPORT(239, int, png_image_write_to_file
, (png_imagep image
,
3084 const char *file
, int convert_to_8bit
, const void *buffer
,
3085 png_int_32 row_stride
, const void *colormap
));
3086 /* Write the image to the named file. */
3088 PNG_EXPORT(240, int, png_image_write_to_stdio
, (png_imagep image
, FILE *file
,
3089 int convert_to_8_bit
, const void *buffer
, png_int_32 row_stride
,
3090 const void *colormap
));
3091 /* Write the image to the given (FILE*). */
3092 #endif /* SIMPLIFIED_WRITE_STDIO */
3094 /* With all write APIs if image is in one of the linear formats with 16-bit
3095 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3096 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3097 * encoded PNG file is written.
3099 * With color-mapped data formats the colormap parameter point to a color-map
3100 * with at least image->colormap_entries encoded in the specified format. If
3101 * the format is linear the written PNG color-map will be converted to sRGB
3102 * regardless of the convert_to_8_bit flag.
3104 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3105 * from one row to the next in component sized units (1 or 2 bytes) and if
3106 * negative indicates a bottom-up row layout in the buffer. If row_stride is
3107 * zero, libpng will calculate it for you from the image width and number of
3110 * Note that the write API does not support interlacing, sub-8-bit pixels or
3111 * most ancillary chunks. If you need to write text chunks (e.g. for copyright
3112 * notices) you need to use one of the other APIs.
3115 PNG_EXPORT(245, int, png_image_write_to_memory
, (png_imagep image
, void *memory
,
3116 png_alloc_size_t
* PNG_RESTRICT memory_bytes
, int convert_to_8_bit
,
3117 const void *buffer
, png_int_32 row_stride
, const void *colormap
));
3118 /* Write the image to the given memory buffer. The function both writes the
3119 * whole PNG data stream to *memory and updates *memory_bytes with the count
3122 * 'memory' may be NULL. In this case *memory_bytes is not read however on
3123 * success the number of bytes which would have been written will still be
3124 * stored in *memory_bytes. On failure *memory_bytes will contain 0.
3126 * If 'memory' is not NULL it must point to memory[*memory_bytes] of
3129 * If the function returns success memory[*memory_bytes] (if 'memory' is not
3130 * NULL) contains the written PNG data. *memory_bytes will always be less
3131 * than or equal to the original value.
3133 * If the function returns false and *memory_bytes was not changed an error
3134 * occured during write. If *memory_bytes was changed, or is not 0 if
3135 * 'memory' was NULL, the write would have succeeded but for the memory
3136 * buffer being too small. *memory_bytes contains the required number of
3137 * bytes and will be bigger that the original value.
3140 #define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
3141 row_stride, colormap)\
3142 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
3143 row_stride, colormap)
3144 /* Return the amount of memory in 'size' required to compress this image.
3145 * The png_image structure 'image' must be filled in as in the above
3146 * function and must not be changed before the actual write call, the buffer
3147 * and all other parameters must also be identical to that in the final
3148 * write call. The 'size' variable need not be initialized.
3150 * NOTE: the macro returns true/false, if false is returned 'size' will be
3151 * set to zero and the write failed and probably will fail if tried again.
3154 /* You can pre-allocate the buffer by making sure it is of sufficient size
3155 * regardless of the amount of compression achieved. The buffer size will
3156 * always be bigger than the original image and it will never be filled. The
3157 * following macros are provided to assist in allocating the buffer.
3159 #define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
3160 /* The number of uncompressed bytes in the PNG byte encoding of the image;
3161 * uncompressing the PNG IDAT data will give this number of bytes.
3163 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
3164 * macro can because of the extra bytes used in the PNG byte encoding. You
3165 * need to avoid this macro if your image size approaches 2^30 in width or
3166 * height. The same goes for the remainder of these macros; they all produce
3167 * bigger numbers than the actual in-memory image size.
3169 #ifndef PNG_ZLIB_MAX_SIZE
3170 # define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
3171 /* An upper bound on the number of compressed bytes given 'b' uncompressed
3172 * bytes. This is based on deflateBounds() in zlib; different
3173 * implementations of zlib compression may conceivably produce more data so
3174 * if your zlib implementation is not zlib itself redefine this macro
3179 #define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
3180 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
3181 /* An upper bound on the size of the data in the PNG IDAT chunks. */
3183 #define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
3184 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
3185 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
3186 12U+3U*(image).colormap_entries/*PLTE data*/+\
3187 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
3188 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
3189 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
3190 /* A helper for the following macro; if your compiler cannot handle the
3191 * following macro use this one with the result of
3192 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
3193 * compilers should handle this just fine.)
3196 #define PNG_IMAGE_PNG_SIZE_MAX(image)\
3197 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
3198 /* An upper bound on the total length of the PNG data stream for 'image'.
3199 * The result is of type png_alloc_size_t, on 32-bit systems this may
3200 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
3201 * run out of buffer space but return a corrected size which should work.
3203 #endif /* SIMPLIFIED_WRITE */
3204 /*******************************************************************************
3205 * END OF SIMPLIFIED API
3206 ******************************************************************************/
3207 #endif /* SIMPLIFIED_{READ|WRITE} */
3209 /*******************************************************************************
3210 * Section 6: IMPLEMENTATION OPTIONS
3211 *******************************************************************************
3213 * Support for arbitrary implementation-specific optimizations. The API allows
3214 * particular options to be turned on or off. 'Option' is the number of the
3215 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3216 * by the PNG_OPTION_ defines below.
3218 * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
3219 * are detected at run time, however sometimes it may be impossible
3220 * to do this in user mode, in which case it is necessary to discover
3221 * the capabilities in an OS specific way. Such capabilities are
3222 * listed here when libpng has support for them and must be turned
3223 * ON by the application if present.
3225 * SOFTWARE: sometimes software optimizations actually result in performance
3226 * decrease on some architectures or systems, or with some sets of
3227 * PNG images. 'Software' options allow such optimizations to be
3228 * selected at run time.
3230 #ifdef PNG_SET_OPTION_SUPPORTED
3231 #ifdef PNG_ARM_NEON_API_SUPPORTED
3232 # define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3234 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3235 #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3236 #ifdef PNG_MIPS_MSA_API_SUPPORTED
3237 # define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */
3239 #define PNG_IGNORE_ADLER32 8
3240 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
3241 # define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions supported */
3243 #define PNG_OPTION_NEXT 12 /* Next option - numbers must be even */
3245 /* Return values: NOTE: there are four values and 'off' is *not* zero */
3246 #define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3247 #define PNG_OPTION_INVALID 1 /* Option number out of range */
3248 #define PNG_OPTION_OFF 2
3249 #define PNG_OPTION_ON 3
3251 PNG_EXPORT(244, int, png_set_option
, (png_structrp png_ptr
, int option
,
3253 #endif /* SET_OPTION */
3255 /*******************************************************************************
3256 * END OF HARDWARE AND SOFTWARE OPTIONS
3257 ******************************************************************************/
3259 /* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3260 * defs, and in scripts/symbols.def.
3263 /* The last ordinal number (this is the *last* one already used; the next
3264 * one to use is one more than this.)
3266 #ifdef PNG_EXPORT_LAST_ORDINAL
3267 PNG_EXPORT_LAST_ORDINAL(249);
3274 #endif /* PNG_VERSION_INFO_ONLY */
3275 /* Do not put anything past this line */