1
2 /* pngwrite.c - general routines to write a PNG file
3 *
4 * Copyright (c) 2018-2022 Cosmin Truta
5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6 * Copyright (c) 1996-1997 Andreas Dilger
7 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
8 *
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
12 */
13
14 #include "pngpriv.h"
15 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
16 # include <errno.h>
17 #endif /* SIMPLIFIED_WRITE_STDIO */
18
19 #ifdef PNG_WRITE_SUPPORTED
20
21 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
22 /* Write out all the unknown chunks for the current given location */
23 static void
write_unknown_chunks(png_structrp png_ptr,png_const_inforp info_ptr,unsigned int where)24 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
25 unsigned int where)
26 {
27 if (info_ptr->unknown_chunks_num != 0)
28 {
29 png_const_unknown_chunkp up;
30
31 png_debug(5, "writing extra chunks");
32
33 for (up = info_ptr->unknown_chunks;
34 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
35 ++up)
36 if ((up->location & where) != 0)
37 {
38 /* If per-chunk unknown chunk handling is enabled use it, otherwise
39 * just write the chunks the application has set.
40 */
41 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
42 int keep = png_handle_as_unknown(png_ptr, up->name);
43
44 /* NOTE: this code is radically different from the read side in the
45 * matter of handling an ancillary unknown chunk. In the read side
46 * the default behavior is to discard it, in the code below the default
47 * behavior is to write it. Critical chunks are, however, only
48 * written if explicitly listed or if the default is set to write all
49 * unknown chunks.
50 *
51 * The default handling is also slightly weird - it is not possible to
52 * stop the writing of all unsafe-to-copy chunks!
53 *
54 * TODO: REVIEW: this would seem to be a bug.
55 */
56 if (keep != PNG_HANDLE_CHUNK_NEVER &&
57 ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
58 keep == PNG_HANDLE_CHUNK_ALWAYS ||
59 (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
60 png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
61 #endif
62 {
63 /* TODO: review, what is wrong with a zero length unknown chunk? */
64 if (up->size == 0)
65 png_warning(png_ptr, "Writing zero-length unknown chunk");
66
67 png_write_chunk(png_ptr, up->name, up->data, up->size);
68 }
69 }
70 }
71 }
72 #endif /* WRITE_UNKNOWN_CHUNKS */
73
74 /* Writes all the PNG information. This is the suggested way to use the
75 * library. If you have a new chunk to add, make a function to write it,
76 * and put it in the correct location here. If you want the chunk written
77 * after the image data, put it in png_write_end(). I strongly encourage
78 * you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before
79 * writing the chunk, as that will keep the code from breaking if you want
80 * to just write a plain PNG file. If you have long comments, I suggest
81 * writing them in png_write_end(), and compressing them.
82 */
83 void PNGAPI
png_write_info_before_PLTE(png_structrp png_ptr,png_const_inforp info_ptr)84 png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
85 {
86 png_debug(1, "in png_write_info_before_PLTE");
87
88 if (png_ptr == NULL || info_ptr == NULL)
89 return;
90
91 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
92 {
93 /* Write PNG signature */
94 png_write_sig(png_ptr);
95
96 #ifdef PNG_MNG_FEATURES_SUPPORTED
97 if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
98 png_ptr->mng_features_permitted != 0)
99 {
100 png_warning(png_ptr,
101 "MNG features are not allowed in a PNG datastream");
102 png_ptr->mng_features_permitted = 0;
103 }
104 #endif
105
106 /* Write IHDR information. */
107 png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
108 info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
109 info_ptr->filter_type,
110 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
111 info_ptr->interlace_type
112 #else
113 0
114 #endif
115 );
116
117 /* The rest of these check to see if the valid field has the appropriate
118 * flag set, and if it does, writes the chunk.
119 *
120 * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
121 * the chunks will be written if the WRITE routine is there and
122 * information * is available in the COLORSPACE. (See
123 * png_colorspace_sync_info in png.c for where the valid flags get set.)
124 *
125 * Under certain circumstances the colorspace can be invalidated without
126 * syncing the info_struct 'valid' flags; this happens if libpng detects
127 * an error and calls png_error while the color space is being set, yet
128 * the application continues writing the PNG. So check the 'invalid'
129 * flag here too.
130 */
131 #ifdef PNG_GAMMA_SUPPORTED
132 # ifdef PNG_WRITE_gAMA_SUPPORTED
133 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
134 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
135 (info_ptr->valid & PNG_INFO_gAMA) != 0)
136 png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
137 # endif
138 #endif
139
140 #ifdef PNG_COLORSPACE_SUPPORTED
141 /* Write only one of sRGB or an ICC profile. If a profile was supplied
142 * and it matches one of the known sRGB ones issue a warning.
143 */
144 # ifdef PNG_WRITE_iCCP_SUPPORTED
145 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
146 (info_ptr->valid & PNG_INFO_iCCP) != 0)
147 {
148 # ifdef PNG_WRITE_sRGB_SUPPORTED
149 if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
150 png_app_warning(png_ptr,
151 "profile matches sRGB but writing iCCP instead");
152 # endif
153
154 png_write_iCCP(png_ptr, info_ptr->iccp_name,
155 info_ptr->iccp_profile);
156 }
157 # ifdef PNG_WRITE_sRGB_SUPPORTED
158 else
159 # endif
160 # endif
161
162 # ifdef PNG_WRITE_sRGB_SUPPORTED
163 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
164 (info_ptr->valid & PNG_INFO_sRGB) != 0)
165 png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
166 # endif /* WRITE_sRGB */
167 #endif /* COLORSPACE */
168
169 #ifdef PNG_WRITE_sBIT_SUPPORTED
170 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
171 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
172 #endif
173
174 #ifdef PNG_COLORSPACE_SUPPORTED
175 # ifdef PNG_WRITE_cHRM_SUPPORTED
176 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
177 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
178 (info_ptr->valid & PNG_INFO_cHRM) != 0)
179 png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
180 # endif
181 #endif
182
183 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
184 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
185 #endif
186
187 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
188 }
189 }
190
191 void PNGAPI
png_write_info(png_structrp png_ptr,png_const_inforp info_ptr)192 png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
193 {
194 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
195 int i;
196 #endif
197
198 png_debug(1, "in png_write_info");
199
200 if (png_ptr == NULL || info_ptr == NULL)
201 return;
202
203 png_write_info_before_PLTE(png_ptr, info_ptr);
204
205 if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
206 png_write_PLTE(png_ptr, info_ptr->palette,
207 (png_uint_32)info_ptr->num_palette);
208
209 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
210 png_error(png_ptr, "Valid palette required for paletted images");
211
212 #ifdef PNG_WRITE_tRNS_SUPPORTED
213 if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
214 {
215 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
216 /* Invert the alpha channel (in tRNS) */
217 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
218 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
219 {
220 int j, jend;
221
222 jend = info_ptr->num_trans;
223 if (jend > PNG_MAX_PALETTE_LENGTH)
224 jend = PNG_MAX_PALETTE_LENGTH;
225
226 for (j = 0; j<jend; ++j)
227 info_ptr->trans_alpha[j] =
228 (png_byte)(255 - info_ptr->trans_alpha[j]);
229 }
230 #endif
231 png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
232 info_ptr->num_trans, info_ptr->color_type);
233 }
234 #endif
235 #ifdef PNG_WRITE_bKGD_SUPPORTED
236 if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
237 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
238 #endif
239
240 #ifdef PNG_WRITE_eXIf_SUPPORTED
241 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
242 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
243 #endif
244
245 #ifdef PNG_WRITE_hIST_SUPPORTED
246 if ((info_ptr->valid & PNG_INFO_hIST) != 0)
247 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
248 #endif
249
250 #ifdef PNG_WRITE_oFFs_SUPPORTED
251 if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
252 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
253 info_ptr->offset_unit_type);
254 #endif
255
256 #ifdef PNG_WRITE_pCAL_SUPPORTED
257 if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
258 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
259 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
260 info_ptr->pcal_units, info_ptr->pcal_params);
261 #endif
262
263 #ifdef PNG_WRITE_sCAL_SUPPORTED
264 if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
265 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
266 info_ptr->scal_s_width, info_ptr->scal_s_height);
267 #endif /* sCAL */
268
269 #ifdef PNG_WRITE_pHYs_SUPPORTED
270 if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
271 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
272 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
273 #endif /* pHYs */
274
275 #ifdef PNG_WRITE_tIME_SUPPORTED
276 if ((info_ptr->valid & PNG_INFO_tIME) != 0)
277 {
278 png_write_tIME(png_ptr, &(info_ptr->mod_time));
279 png_ptr->mode |= PNG_WROTE_tIME;
280 }
281 #endif /* tIME */
282
283 #ifdef PNG_WRITE_sPLT_SUPPORTED
284 if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
285 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
286 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
287 #endif /* sPLT */
288
289 #ifdef PNG_WRITE_TEXT_SUPPORTED
290 /* Check to see if we need to write text chunks */
291 for (i = 0; i < info_ptr->num_text; i++)
292 {
293 png_debug2(2, "Writing header text chunk %d, type %d", i,
294 info_ptr->text[i].compression);
295 /* An internationalized chunk? */
296 if (info_ptr->text[i].compression > 0)
297 {
298 #ifdef PNG_WRITE_iTXt_SUPPORTED
299 /* Write international chunk */
300 png_write_iTXt(png_ptr,
301 info_ptr->text[i].compression,
302 info_ptr->text[i].key,
303 info_ptr->text[i].lang,
304 info_ptr->text[i].lang_key,
305 info_ptr->text[i].text);
306 /* Mark this chunk as written */
307 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
308 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
309 else
310 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
311 #else
312 png_warning(png_ptr, "Unable to write international text");
313 #endif
314 }
315
316 /* If we want a compressed text chunk */
317 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
318 {
319 #ifdef PNG_WRITE_zTXt_SUPPORTED
320 /* Write compressed chunk */
321 png_write_zTXt(png_ptr, info_ptr->text[i].key,
322 info_ptr->text[i].text, info_ptr->text[i].compression);
323 /* Mark this chunk as written */
324 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
325 #else
326 png_warning(png_ptr, "Unable to write compressed text");
327 #endif
328 }
329
330 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
331 {
332 #ifdef PNG_WRITE_tEXt_SUPPORTED
333 /* Write uncompressed chunk */
334 png_write_tEXt(png_ptr, info_ptr->text[i].key,
335 info_ptr->text[i].text,
336 0);
337 /* Mark this chunk as written */
338 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
339 #else
340 /* Can't get here */
341 png_warning(png_ptr, "Unable to write uncompressed text");
342 #endif
343 }
344 }
345 #endif /* tEXt */
346
347 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
348 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
349 #endif
350 }
351
352 /* Writes the end of the PNG file. If you don't want to write comments or
353 * time information, you can pass NULL for info. If you already wrote these
354 * in png_write_info(), do not write them again here. If you have long
355 * comments, I suggest writing them here, and compressing them.
356 */
357 void PNGAPI
png_write_end(png_structrp png_ptr,png_inforp info_ptr)358 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
359 {
360 png_debug(1, "in png_write_end");
361
362 if (png_ptr == NULL)
363 return;
364
365 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
366 png_error(png_ptr, "No IDATs written into file");
367
368 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
369 if (png_ptr->num_palette_max > png_ptr->num_palette)
370 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
371 #endif
372
373 /* See if user wants us to write information chunks */
374 if (info_ptr != NULL)
375 {
376 #ifdef PNG_WRITE_TEXT_SUPPORTED
377 int i; /* local index variable */
378 #endif
379 #ifdef PNG_WRITE_tIME_SUPPORTED
380 /* Check to see if user has supplied a time chunk */
381 if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
382 (png_ptr->mode & PNG_WROTE_tIME) == 0)
383 png_write_tIME(png_ptr, &(info_ptr->mod_time));
384
385 #endif
386 #ifdef PNG_WRITE_TEXT_SUPPORTED
387 /* Loop through comment chunks */
388 for (i = 0; i < info_ptr->num_text; i++)
389 {
390 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
391 info_ptr->text[i].compression);
392 /* An internationalized chunk? */
393 if (info_ptr->text[i].compression > 0)
394 {
395 #ifdef PNG_WRITE_iTXt_SUPPORTED
396 /* Write international chunk */
397 png_write_iTXt(png_ptr,
398 info_ptr->text[i].compression,
399 info_ptr->text[i].key,
400 info_ptr->text[i].lang,
401 info_ptr->text[i].lang_key,
402 info_ptr->text[i].text);
403 /* Mark this chunk as written */
404 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
405 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
406 else
407 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
408 #else
409 png_warning(png_ptr, "Unable to write international text");
410 #endif
411 }
412
413 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
414 {
415 #ifdef PNG_WRITE_zTXt_SUPPORTED
416 /* Write compressed chunk */
417 png_write_zTXt(png_ptr, info_ptr->text[i].key,
418 info_ptr->text[i].text, info_ptr->text[i].compression);
419 /* Mark this chunk as written */
420 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
421 #else
422 png_warning(png_ptr, "Unable to write compressed text");
423 #endif
424 }
425
426 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
427 {
428 #ifdef PNG_WRITE_tEXt_SUPPORTED
429 /* Write uncompressed chunk */
430 png_write_tEXt(png_ptr, info_ptr->text[i].key,
431 info_ptr->text[i].text, 0);
432 /* Mark this chunk as written */
433 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
434 #else
435 png_warning(png_ptr, "Unable to write uncompressed text");
436 #endif
437 }
438 }
439 #endif
440
441 #ifdef PNG_WRITE_eXIf_SUPPORTED
442 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
443 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
444 #endif
445
446 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
447 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
448 #endif
449 }
450
451 png_ptr->mode |= PNG_AFTER_IDAT;
452
453 /* Write end of PNG file */
454 png_write_IEND(png_ptr);
455
456 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
457 * and restored again in libpng-1.2.30, may cause some applications that
458 * do not set png_ptr->output_flush_fn to crash. If your application
459 * experiences a problem, please try building libpng with
460 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
461 * png-mng-implement at lists.sf.net .
462 */
463 #ifdef PNG_WRITE_FLUSH_SUPPORTED
464 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
465 png_flush(png_ptr);
466 # endif
467 #endif
468 }
469
470 #ifdef PNG_CONVERT_tIME_SUPPORTED
471 void PNGAPI
png_convert_from_struct_tm(png_timep ptime,const struct tm * ttime)472 png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
473 {
474 png_debug(1, "in png_convert_from_struct_tm");
475
476 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
477 ptime->month = (png_byte)(ttime->tm_mon + 1);
478 ptime->day = (png_byte)ttime->tm_mday;
479 ptime->hour = (png_byte)ttime->tm_hour;
480 ptime->minute = (png_byte)ttime->tm_min;
481 ptime->second = (png_byte)ttime->tm_sec;
482 }
483
484 void PNGAPI
png_convert_from_time_t(png_timep ptime,time_t ttime)485 png_convert_from_time_t(png_timep ptime, time_t ttime)
486 {
487 struct tm *tbuf;
488
489 png_debug(1, "in png_convert_from_time_t");
490
491 tbuf = gmtime(&ttime);
492 if (tbuf == NULL)
493 {
494 /* TODO: add a safe function which takes a png_ptr argument and raises
495 * a png_error if the ttime argument is invalid and the call to gmtime
496 * fails as a consequence.
497 */
498 memset(ptime, 0, sizeof(*ptime));
499 return;
500 }
501
502 png_convert_from_struct_tm(ptime, tbuf);
503 }
504 #endif
505
506 /* Initialize png_ptr structure, and allocate any memory needed */
507 PNG_FUNCTION(png_structp,PNGAPI
508 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
509 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
510 {
511 #ifndef PNG_USER_MEM_SUPPORTED
512 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
513 error_fn, warn_fn, NULL, NULL, NULL);
514 #else
515 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
516 warn_fn, NULL, NULL, NULL);
517 }
518
519 /* Alternate initialize png_ptr structure, and allocate any memory needed */
520 PNG_FUNCTION(png_structp,PNGAPI
521 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
522 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
523 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
524 {
525 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
526 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
527 #endif /* USER_MEM */
528 if (png_ptr != NULL)
529 {
530 /* Set the zlib control values to defaults; they can be overridden by the
531 * application after the struct has been created.
532 */
533 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
534
535 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
536 * pngwutil.c defaults it according to whether or not filters will be
537 * used, and ignores this setting.
538 */
539 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
540 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
541 png_ptr->zlib_mem_level = 8;
542 png_ptr->zlib_window_bits = 15;
543 png_ptr->zlib_method = 8;
544
545 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
546 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
547 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
548 png_ptr->zlib_text_mem_level = 8;
549 png_ptr->zlib_text_window_bits = 15;
550 png_ptr->zlib_text_method = 8;
551 #endif /* WRITE_COMPRESSED_TEXT */
552
553 /* This is a highly dubious configuration option; by default it is off,
554 * but it may be appropriate for private builds that are testing
555 * extensions not conformant to the current specification, or of
556 * applications that must not fail to write at all costs!
557 */
558 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
559 /* In stable builds only warn if an application error can be completely
560 * handled.
561 */
562 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
563 #endif
564
565 /* App warnings are warnings in release (or release candidate) builds but
566 * are errors during development.
567 */
568 #if PNG_RELEASE_BUILD
569 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
570 #endif
571
572 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
573 * do it itself) avoiding setting the default function if it is not
574 * required.
575 */
576 png_set_write_fn(png_ptr, NULL, NULL, NULL);
577 }
578
579 return png_ptr;
580 }
581
582
583 /* Write a few rows of image data. If the image is interlaced,
584 * either you will have to write the 7 sub images, or, if you
585 * have called png_set_interlace_handling(), you will have to
586 * "write" the image seven times.
587 */
588 void PNGAPI
png_write_rows(png_structrp png_ptr,png_bytepp row,png_uint_32 num_rows)589 png_write_rows(png_structrp png_ptr, png_bytepp row,
590 png_uint_32 num_rows)
591 {
592 png_uint_32 i; /* row counter */
593 png_bytepp rp; /* row pointer */
594
595 png_debug(1, "in png_write_rows");
596
597 if (png_ptr == NULL)
598 return;
599
600 /* Loop through the rows */
601 for (i = 0, rp = row; i < num_rows; i++, rp++)
602 {
603 png_write_row(png_ptr, *rp);
604 }
605 }
606
607 /* Write the image. You only need to call this function once, even
608 * if you are writing an interlaced image.
609 */
610 void PNGAPI
png_write_image(png_structrp png_ptr,png_bytepp image)611 png_write_image(png_structrp png_ptr, png_bytepp image)
612 {
613 png_uint_32 i; /* row index */
614 int pass, num_pass; /* pass variables */
615 png_bytepp rp; /* points to current row */
616
617 if (png_ptr == NULL)
618 return;
619
620 png_debug(1, "in png_write_image");
621
622 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
623 /* Initialize interlace handling. If image is not interlaced,
624 * this will set pass to 1
625 */
626 num_pass = png_set_interlace_handling(png_ptr);
627 #else
628 num_pass = 1;
629 #endif
630 /* Loop through passes */
631 for (pass = 0; pass < num_pass; pass++)
632 {
633 /* Loop through image */
634 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
635 {
636 png_write_row(png_ptr, *rp);
637 }
638 }
639 }
640
641 #ifdef PNG_MNG_FEATURES_SUPPORTED
642 /* Performs intrapixel differencing */
643 static void
png_do_write_intrapixel(png_row_infop row_info,png_bytep row)644 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
645 {
646 png_debug(1, "in png_do_write_intrapixel");
647
648 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
649 {
650 int bytes_per_pixel;
651 png_uint_32 row_width = row_info->width;
652 if (row_info->bit_depth == 8)
653 {
654 png_bytep rp;
655 png_uint_32 i;
656
657 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
658 bytes_per_pixel = 3;
659
660 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
661 bytes_per_pixel = 4;
662
663 else
664 return;
665
666 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
667 {
668 *(rp) = (png_byte)(*rp - *(rp + 1));
669 *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
670 }
671 }
672
673 #ifdef PNG_WRITE_16BIT_SUPPORTED
674 else if (row_info->bit_depth == 16)
675 {
676 png_bytep rp;
677 png_uint_32 i;
678
679 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
680 bytes_per_pixel = 6;
681
682 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
683 bytes_per_pixel = 8;
684
685 else
686 return;
687
688 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
689 {
690 png_uint_32 s0 = (png_uint_32)(*(rp ) << 8) | *(rp + 1);
691 png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
692 png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
693 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
694 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
695 *(rp ) = (png_byte)(red >> 8);
696 *(rp + 1) = (png_byte)red;
697 *(rp + 4) = (png_byte)(blue >> 8);
698 *(rp + 5) = (png_byte)blue;
699 }
700 }
701 #endif /* WRITE_16BIT */
702 }
703 }
704 #endif /* MNG_FEATURES */
705
706 /* Called by user to write a row of image data */
707 void PNGAPI
png_write_row(png_structrp png_ptr,png_const_bytep row)708 png_write_row(png_structrp png_ptr, png_const_bytep row)
709 {
710 /* 1.5.6: moved from png_struct to be a local structure: */
711 png_row_info row_info;
712
713 if (png_ptr == NULL)
714 return;
715
716 png_debug2(1, "in png_write_row (row %u, pass %d)",
717 png_ptr->row_number, png_ptr->pass);
718
719 /* Initialize transformations and other stuff if first time */
720 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
721 {
722 /* Make sure we wrote the header info */
723 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
724 png_error(png_ptr,
725 "png_write_info was never called before png_write_row");
726
727 /* Check for transforms that have been set but were defined out */
728 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
729 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
730 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
731 #endif
732
733 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
734 if ((png_ptr->transformations & PNG_FILLER) != 0)
735 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
736 #endif
737 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
738 defined(PNG_READ_PACKSWAP_SUPPORTED)
739 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
740 png_warning(png_ptr,
741 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
742 #endif
743
744 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
745 if ((png_ptr->transformations & PNG_PACK) != 0)
746 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
747 #endif
748
749 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
750 if ((png_ptr->transformations & PNG_SHIFT) != 0)
751 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
752 #endif
753
754 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
755 if ((png_ptr->transformations & PNG_BGR) != 0)
756 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
757 #endif
758
759 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
760 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
761 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
762 #endif
763
764 png_write_start_row(png_ptr);
765 }
766
767 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
768 /* If interlaced and not interested in row, return */
769 if (png_ptr->interlaced != 0 &&
770 (png_ptr->transformations & PNG_INTERLACE) != 0)
771 {
772 switch (png_ptr->pass)
773 {
774 case 0:
775 if ((png_ptr->row_number & 0x07) != 0)
776 {
777 png_write_finish_row(png_ptr);
778 return;
779 }
780 break;
781
782 case 1:
783 if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
784 {
785 png_write_finish_row(png_ptr);
786 return;
787 }
788 break;
789
790 case 2:
791 if ((png_ptr->row_number & 0x07) != 4)
792 {
793 png_write_finish_row(png_ptr);
794 return;
795 }
796 break;
797
798 case 3:
799 if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
800 {
801 png_write_finish_row(png_ptr);
802 return;
803 }
804 break;
805
806 case 4:
807 if ((png_ptr->row_number & 0x03) != 2)
808 {
809 png_write_finish_row(png_ptr);
810 return;
811 }
812 break;
813
814 case 5:
815 if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
816 {
817 png_write_finish_row(png_ptr);
818 return;
819 }
820 break;
821
822 case 6:
823 if ((png_ptr->row_number & 0x01) == 0)
824 {
825 png_write_finish_row(png_ptr);
826 return;
827 }
828 break;
829
830 default: /* error: ignore it */
831 break;
832 }
833 }
834 #endif
835
836 /* Set up row info for transformations */
837 row_info.color_type = png_ptr->color_type;
838 row_info.width = png_ptr->usr_width;
839 row_info.channels = png_ptr->usr_channels;
840 row_info.bit_depth = png_ptr->usr_bit_depth;
841 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
842 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
843
844 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
845 png_debug1(3, "row_info->width = %u", row_info.width);
846 png_debug1(3, "row_info->channels = %d", row_info.channels);
847 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
848 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
849 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
850
851 /* Copy user's row into buffer, leaving room for filter byte. */
852 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
853
854 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
855 /* Handle interlacing */
856 if (png_ptr->interlaced && png_ptr->pass < 6 &&
857 (png_ptr->transformations & PNG_INTERLACE) != 0)
858 {
859 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
860 /* This should always get caught above, but still ... */
861 if (row_info.width == 0)
862 {
863 png_write_finish_row(png_ptr);
864 return;
865 }
866 }
867 #endif
868
869 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
870 /* Handle other transformations */
871 if (png_ptr->transformations != 0)
872 png_do_write_transformations(png_ptr, &row_info);
873 #endif
874
875 /* At this point the row_info pixel depth must match the 'transformed' depth,
876 * which is also the output depth.
877 */
878 if (row_info.pixel_depth != png_ptr->pixel_depth ||
879 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
880 png_error(png_ptr, "internal write transform logic error");
881
882 #ifdef PNG_MNG_FEATURES_SUPPORTED
883 /* Write filter_method 64 (intrapixel differencing) only if
884 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
885 * 2. Libpng did not write a PNG signature (this filter_method is only
886 * used in PNG datastreams that are embedded in MNG datastreams) and
887 * 3. The application called png_permit_mng_features with a mask that
888 * included PNG_FLAG_MNG_FILTER_64 and
889 * 4. The filter_method is 64 and
890 * 5. The color_type is RGB or RGBA
891 */
892 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
893 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
894 {
895 /* Intrapixel differencing */
896 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
897 }
898 #endif
899
900 /* Added at libpng-1.5.10 */
901 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
902 /* Check for out-of-range palette index */
903 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
904 png_ptr->num_palette_max >= 0)
905 png_do_check_palette_indexes(png_ptr, &row_info);
906 #endif
907
908 /* Find a filter if necessary, filter the row and write it out. */
909 png_write_find_filter(png_ptr, &row_info);
910
911 if (png_ptr->write_row_fn != NULL)
912 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
913 }
914
915 #ifdef PNG_WRITE_FLUSH_SUPPORTED
916 /* Set the automatic flush interval or 0 to turn flushing off */
917 void PNGAPI
png_set_flush(png_structrp png_ptr,int nrows)918 png_set_flush(png_structrp png_ptr, int nrows)
919 {
920 png_debug(1, "in png_set_flush");
921
922 if (png_ptr == NULL)
923 return;
924
925 png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
926 }
927
928 /* Flush the current output buffers now */
929 void PNGAPI
png_write_flush(png_structrp png_ptr)930 png_write_flush(png_structrp png_ptr)
931 {
932 png_debug(1, "in png_write_flush");
933
934 if (png_ptr == NULL)
935 return;
936
937 /* We have already written out all of the data */
938 if (png_ptr->row_number >= png_ptr->num_rows)
939 return;
940
941 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
942 png_ptr->flush_rows = 0;
943 png_flush(png_ptr);
944 }
945 #endif /* WRITE_FLUSH */
946
947 /* Free any memory used in png_ptr struct without freeing the struct itself. */
948 static void
png_write_destroy(png_structrp png_ptr)949 png_write_destroy(png_structrp png_ptr)
950 {
951 png_debug(1, "in png_write_destroy");
952
953 /* Free any memory zlib uses */
954 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
955 deflateEnd(&png_ptr->zstream);
956
957 /* Free our memory. png_free checks NULL for us. */
958 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
959 png_free(png_ptr, png_ptr->row_buf);
960 png_ptr->row_buf = NULL;
961 #ifdef PNG_WRITE_FILTER_SUPPORTED
962 png_free(png_ptr, png_ptr->prev_row);
963 png_free(png_ptr, png_ptr->try_row);
964 png_free(png_ptr, png_ptr->tst_row);
965 png_ptr->prev_row = NULL;
966 png_ptr->try_row = NULL;
967 png_ptr->tst_row = NULL;
968 #endif
969
970 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
971 png_free(png_ptr, png_ptr->chunk_list);
972 png_ptr->chunk_list = NULL;
973 #endif
974
975 /* The error handling and memory handling information is left intact at this
976 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
977 * for how this happens.
978 */
979 }
980
981 /* Free all memory used by the write.
982 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
983 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
984 * the passed in info_structs but it would quietly fail to free any of the data
985 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
986 * has no png_ptr.)
987 */
988 void PNGAPI
png_destroy_write_struct(png_structpp png_ptr_ptr,png_infopp info_ptr_ptr)989 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
990 {
991 png_debug(1, "in png_destroy_write_struct");
992
993 if (png_ptr_ptr != NULL)
994 {
995 png_structrp png_ptr = *png_ptr_ptr;
996
997 if (png_ptr != NULL) /* added in libpng 1.6.0 */
998 {
999 png_destroy_info_struct(png_ptr, info_ptr_ptr);
1000
1001 *png_ptr_ptr = NULL;
1002 png_write_destroy(png_ptr);
1003 png_destroy_png_struct(png_ptr);
1004 }
1005 }
1006 }
1007
1008 /* Allow the application to select one or more row filters to use. */
1009 void PNGAPI
png_set_filter(png_structrp png_ptr,int method,int filters)1010 png_set_filter(png_structrp png_ptr, int method, int filters)
1011 {
1012 png_debug(1, "in png_set_filter");
1013
1014 if (png_ptr == NULL)
1015 return;
1016
1017 #ifdef PNG_MNG_FEATURES_SUPPORTED
1018 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
1019 (method == PNG_INTRAPIXEL_DIFFERENCING))
1020 method = PNG_FILTER_TYPE_BASE;
1021
1022 #endif
1023 if (method == PNG_FILTER_TYPE_BASE)
1024 {
1025 switch (filters & (PNG_ALL_FILTERS | 0x07))
1026 {
1027 #ifdef PNG_WRITE_FILTER_SUPPORTED
1028 case 5:
1029 case 6:
1030 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1031 #endif /* WRITE_FILTER */
1032 /* FALLTHROUGH */
1033 case PNG_FILTER_VALUE_NONE:
1034 png_ptr->do_filter = PNG_FILTER_NONE; break;
1035
1036 #ifdef PNG_WRITE_FILTER_SUPPORTED
1037 case PNG_FILTER_VALUE_SUB:
1038 png_ptr->do_filter = PNG_FILTER_SUB; break;
1039
1040 case PNG_FILTER_VALUE_UP:
1041 png_ptr->do_filter = PNG_FILTER_UP; break;
1042
1043 case PNG_FILTER_VALUE_AVG:
1044 png_ptr->do_filter = PNG_FILTER_AVG; break;
1045
1046 case PNG_FILTER_VALUE_PAETH:
1047 png_ptr->do_filter = PNG_FILTER_PAETH; break;
1048
1049 default:
1050 png_ptr->do_filter = (png_byte)filters; break;
1051 #else
1052 default:
1053 png_app_error(png_ptr, "Unknown row filter for method 0");
1054 #endif /* WRITE_FILTER */
1055 }
1056
1057 #ifdef PNG_WRITE_FILTER_SUPPORTED
1058 /* If we have allocated the row_buf, this means we have already started
1059 * with the image and we should have allocated all of the filter buffers
1060 * that have been selected. If prev_row isn't already allocated, then
1061 * it is too late to start using the filters that need it, since we
1062 * will be missing the data in the previous row. If an application
1063 * wants to start and stop using particular filters during compression,
1064 * it should start out with all of the filters, and then remove them
1065 * or add them back after the start of compression.
1066 *
1067 * NOTE: this is a nasty constraint on the code, because it means that the
1068 * prev_row buffer must be maintained even if there are currently no
1069 * 'prev_row' requiring filters active.
1070 */
1071 if (png_ptr->row_buf != NULL)
1072 {
1073 int num_filters;
1074 png_alloc_size_t buf_size;
1075
1076 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1077 * images cannot benefit from certain filters. If this isn't done here
1078 * the check below will fire on 1 pixel high images.
1079 */
1080 if (png_ptr->height == 1)
1081 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1082
1083 if (png_ptr->width == 1)
1084 filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1085
1086 if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
1087 && png_ptr->prev_row == NULL)
1088 {
1089 /* This is the error case, however it is benign - the previous row
1090 * is not available so the filter can't be used. Just warn here.
1091 */
1092 png_app_warning(png_ptr,
1093 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1094 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1095 }
1096
1097 num_filters = 0;
1098
1099 if (filters & PNG_FILTER_SUB)
1100 num_filters++;
1101
1102 if (filters & PNG_FILTER_UP)
1103 num_filters++;
1104
1105 if (filters & PNG_FILTER_AVG)
1106 num_filters++;
1107
1108 if (filters & PNG_FILTER_PAETH)
1109 num_filters++;
1110
1111 /* Allocate needed row buffers if they have not already been
1112 * allocated.
1113 */
1114 buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1115 png_ptr->width) + 1;
1116
1117 if (png_ptr->try_row == NULL)
1118 png_ptr->try_row = png_voidcast(png_bytep,
1119 png_malloc(png_ptr, buf_size));
1120
1121 if (num_filters > 1)
1122 {
1123 if (png_ptr->tst_row == NULL)
1124 png_ptr->tst_row = png_voidcast(png_bytep,
1125 png_malloc(png_ptr, buf_size));
1126 }
1127 }
1128 png_ptr->do_filter = (png_byte)filters;
1129 #endif
1130 }
1131 else
1132 png_error(png_ptr, "Unknown custom filter method");
1133 }
1134
1135 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1136 /* Provide floating and fixed point APIs */
1137 #ifdef PNG_FLOATING_POINT_SUPPORTED
1138 void PNGAPI
png_set_filter_heuristics(png_structrp png_ptr,int heuristic_method,int num_weights,png_const_doublep filter_weights,png_const_doublep filter_costs)1139 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1140 int num_weights, png_const_doublep filter_weights,
1141 png_const_doublep filter_costs)
1142 {
1143 PNG_UNUSED(png_ptr)
1144 PNG_UNUSED(heuristic_method)
1145 PNG_UNUSED(num_weights)
1146 PNG_UNUSED(filter_weights)
1147 PNG_UNUSED(filter_costs)
1148 }
1149 #endif /* FLOATING_POINT */
1150
1151 #ifdef PNG_FIXED_POINT_SUPPORTED
1152 void PNGAPI
png_set_filter_heuristics_fixed(png_structrp png_ptr,int heuristic_method,int num_weights,png_const_fixed_point_p filter_weights,png_const_fixed_point_p filter_costs)1153 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1154 int num_weights, png_const_fixed_point_p filter_weights,
1155 png_const_fixed_point_p filter_costs)
1156 {
1157 PNG_UNUSED(png_ptr)
1158 PNG_UNUSED(heuristic_method)
1159 PNG_UNUSED(num_weights)
1160 PNG_UNUSED(filter_weights)
1161 PNG_UNUSED(filter_costs)
1162 }
1163 #endif /* FIXED_POINT */
1164 #endif /* WRITE_WEIGHTED_FILTER */
1165
1166 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1167 void PNGAPI
png_set_compression_level(png_structrp png_ptr,int level)1168 png_set_compression_level(png_structrp png_ptr, int level)
1169 {
1170 png_debug(1, "in png_set_compression_level");
1171
1172 if (png_ptr == NULL)
1173 return;
1174
1175 png_ptr->zlib_level = level;
1176 }
1177
1178 void PNGAPI
png_set_compression_mem_level(png_structrp png_ptr,int mem_level)1179 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1180 {
1181 png_debug(1, "in png_set_compression_mem_level");
1182
1183 if (png_ptr == NULL)
1184 return;
1185
1186 png_ptr->zlib_mem_level = mem_level;
1187 }
1188
1189 void PNGAPI
png_set_compression_strategy(png_structrp png_ptr,int strategy)1190 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1191 {
1192 png_debug(1, "in png_set_compression_strategy");
1193
1194 if (png_ptr == NULL)
1195 return;
1196
1197 /* The flag setting here prevents the libpng dynamic selection of strategy.
1198 */
1199 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1200 png_ptr->zlib_strategy = strategy;
1201 }
1202
1203 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1204 * smaller value of window_bits if it can do so safely.
1205 */
1206 void PNGAPI
png_set_compression_window_bits(png_structrp png_ptr,int window_bits)1207 png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1208 {
1209 if (png_ptr == NULL)
1210 return;
1211
1212 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1213 * meant that negative window bits values could be selected that would cause
1214 * libpng to write a non-standard PNG file with raw deflate or gzip
1215 * compressed IDAT or ancillary chunks. Such files can be read and there is
1216 * no warning on read, so this seems like a very bad idea.
1217 */
1218 if (window_bits > 15)
1219 {
1220 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1221 window_bits = 15;
1222 }
1223
1224 else if (window_bits < 8)
1225 {
1226 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1227 window_bits = 8;
1228 }
1229
1230 png_ptr->zlib_window_bits = window_bits;
1231 }
1232
1233 void PNGAPI
png_set_compression_method(png_structrp png_ptr,int method)1234 png_set_compression_method(png_structrp png_ptr, int method)
1235 {
1236 png_debug(1, "in png_set_compression_method");
1237
1238 if (png_ptr == NULL)
1239 return;
1240
1241 /* This would produce an invalid PNG file if it worked, but it doesn't and
1242 * deflate will fault it, so it is harmless to just warn here.
1243 */
1244 if (method != 8)
1245 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1246
1247 png_ptr->zlib_method = method;
1248 }
1249 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1250
1251 /* The following were added to libpng-1.5.4 */
1252 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1253 void PNGAPI
png_set_text_compression_level(png_structrp png_ptr,int level)1254 png_set_text_compression_level(png_structrp png_ptr, int level)
1255 {
1256 png_debug(1, "in png_set_text_compression_level");
1257
1258 if (png_ptr == NULL)
1259 return;
1260
1261 png_ptr->zlib_text_level = level;
1262 }
1263
1264 void PNGAPI
png_set_text_compression_mem_level(png_structrp png_ptr,int mem_level)1265 png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1266 {
1267 png_debug(1, "in png_set_text_compression_mem_level");
1268
1269 if (png_ptr == NULL)
1270 return;
1271
1272 png_ptr->zlib_text_mem_level = mem_level;
1273 }
1274
1275 void PNGAPI
png_set_text_compression_strategy(png_structrp png_ptr,int strategy)1276 png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1277 {
1278 png_debug(1, "in png_set_text_compression_strategy");
1279
1280 if (png_ptr == NULL)
1281 return;
1282
1283 png_ptr->zlib_text_strategy = strategy;
1284 }
1285
1286 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1287 * smaller value of window_bits if it can do so safely.
1288 */
1289 void PNGAPI
png_set_text_compression_window_bits(png_structrp png_ptr,int window_bits)1290 png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1291 {
1292 if (png_ptr == NULL)
1293 return;
1294
1295 if (window_bits > 15)
1296 {
1297 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1298 window_bits = 15;
1299 }
1300
1301 else if (window_bits < 8)
1302 {
1303 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1304 window_bits = 8;
1305 }
1306
1307 png_ptr->zlib_text_window_bits = window_bits;
1308 }
1309
1310 void PNGAPI
png_set_text_compression_method(png_structrp png_ptr,int method)1311 png_set_text_compression_method(png_structrp png_ptr, int method)
1312 {
1313 png_debug(1, "in png_set_text_compression_method");
1314
1315 if (png_ptr == NULL)
1316 return;
1317
1318 if (method != 8)
1319 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1320
1321 png_ptr->zlib_text_method = method;
1322 }
1323 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1324 /* end of API added to libpng-1.5.4 */
1325
1326 void PNGAPI
png_set_write_status_fn(png_structrp png_ptr,png_write_status_ptr write_row_fn)1327 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1328 {
1329 if (png_ptr == NULL)
1330 return;
1331
1332 png_ptr->write_row_fn = write_row_fn;
1333 }
1334
1335 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1336 void PNGAPI
png_set_write_user_transform_fn(png_structrp png_ptr,png_user_transform_ptr write_user_transform_fn)1337 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1338 write_user_transform_fn)
1339 {
1340 png_debug(1, "in png_set_write_user_transform_fn");
1341
1342 if (png_ptr == NULL)
1343 return;
1344
1345 png_ptr->transformations |= PNG_USER_TRANSFORM;
1346 png_ptr->write_user_transform_fn = write_user_transform_fn;
1347 }
1348 #endif
1349
1350
1351 #ifdef PNG_INFO_IMAGE_SUPPORTED
1352 void PNGAPI
png_write_png(png_structrp png_ptr,png_inforp info_ptr,int transforms,voidp params)1353 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1354 int transforms, voidp params)
1355 {
1356 if (png_ptr == NULL || info_ptr == NULL)
1357 return;
1358
1359 if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1360 {
1361 png_app_error(png_ptr, "no rows for png_write_image to write");
1362 return;
1363 }
1364
1365 /* Write the file header information. */
1366 png_write_info(png_ptr, info_ptr);
1367
1368 /* ------ these transformations don't touch the info structure ------- */
1369
1370 /* Invert monochrome pixels */
1371 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1372 #ifdef PNG_WRITE_INVERT_SUPPORTED
1373 png_set_invert_mono(png_ptr);
1374 #else
1375 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1376 #endif
1377
1378 /* Shift the pixels up to a legal bit depth and fill in
1379 * as appropriate to correctly scale the image.
1380 */
1381 if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1382 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1383 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1384 png_set_shift(png_ptr, &info_ptr->sig_bit);
1385 #else
1386 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1387 #endif
1388
1389 /* Pack pixels into bytes */
1390 if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1391 #ifdef PNG_WRITE_PACK_SUPPORTED
1392 png_set_packing(png_ptr);
1393 #else
1394 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1395 #endif
1396
1397 /* Swap location of alpha bytes from ARGB to RGBA */
1398 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1399 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1400 png_set_swap_alpha(png_ptr);
1401 #else
1402 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1403 #endif
1404
1405 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1406 * RGB, note that the code expects the input color type to be G or RGB; no
1407 * alpha channel.
1408 */
1409 if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
1410 PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1411 {
1412 #ifdef PNG_WRITE_FILLER_SUPPORTED
1413 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1414 {
1415 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1416 png_app_error(png_ptr,
1417 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1418
1419 /* Continue if ignored - this is the pre-1.6.10 behavior */
1420 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1421 }
1422
1423 else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1424 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1425 #else
1426 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1427 #endif
1428 }
1429
1430 /* Flip BGR pixels to RGB */
1431 if ((transforms & PNG_TRANSFORM_BGR) != 0)
1432 #ifdef PNG_WRITE_BGR_SUPPORTED
1433 png_set_bgr(png_ptr);
1434 #else
1435 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1436 #endif
1437
1438 /* Swap bytes of 16-bit files to most significant byte first */
1439 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1440 #ifdef PNG_WRITE_SWAP_SUPPORTED
1441 png_set_swap(png_ptr);
1442 #else
1443 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1444 #endif
1445
1446 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1447 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1448 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1449 png_set_packswap(png_ptr);
1450 #else
1451 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1452 #endif
1453
1454 /* Invert the alpha channel from opacity to transparency */
1455 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1456 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1457 png_set_invert_alpha(png_ptr);
1458 #else
1459 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1460 #endif
1461
1462 /* ----------------------- end of transformations ------------------- */
1463
1464 /* Write the bits */
1465 png_write_image(png_ptr, info_ptr->row_pointers);
1466
1467 /* It is REQUIRED to call this to finish writing the rest of the file */
1468 png_write_end(png_ptr, info_ptr);
1469
1470 PNG_UNUSED(params)
1471 }
1472 #endif
1473
1474
1475 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1476 /* Initialize the write structure - general purpose utility. */
1477 static int
png_image_write_init(png_imagep image)1478 png_image_write_init(png_imagep image)
1479 {
1480 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1481 png_safe_error, png_safe_warning);
1482
1483 if (png_ptr != NULL)
1484 {
1485 png_infop info_ptr = png_create_info_struct(png_ptr);
1486
1487 if (info_ptr != NULL)
1488 {
1489 png_controlp control = png_voidcast(png_controlp,
1490 png_malloc_warn(png_ptr, (sizeof *control)));
1491
1492 if (control != NULL)
1493 {
1494 memset(control, 0, (sizeof *control));
1495
1496 control->png_ptr = png_ptr;
1497 control->info_ptr = info_ptr;
1498 control->for_write = 1;
1499
1500 image->opaque = control;
1501 return 1;
1502 }
1503
1504 /* Error clean up */
1505 png_destroy_info_struct(png_ptr, &info_ptr);
1506 }
1507
1508 png_destroy_write_struct(&png_ptr, NULL);
1509 }
1510
1511 return png_image_error(image, "png_image_write_: out of memory");
1512 }
1513
1514 /* Arguments to png_image_write_main: */
1515 typedef struct
1516 {
1517 /* Arguments: */
1518 png_imagep image;
1519 png_const_voidp buffer;
1520 png_int_32 row_stride;
1521 png_const_voidp colormap;
1522 int convert_to_8bit;
1523 /* Local variables: */
1524 png_const_voidp first_row;
1525 ptrdiff_t row_bytes;
1526 png_voidp local_row;
1527 /* Byte count for memory writing */
1528 png_bytep memory;
1529 png_alloc_size_t memory_bytes; /* not used for STDIO */
1530 png_alloc_size_t output_bytes; /* running total */
1531 } png_image_write_control;
1532
1533 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1534 * do any necessary byte swapping. The component order is defined by the
1535 * png_image format value.
1536 */
1537 static int
png_write_image_16bit(png_voidp argument)1538 png_write_image_16bit(png_voidp argument)
1539 {
1540 png_image_write_control *display = png_voidcast(png_image_write_control*,
1541 argument);
1542 png_imagep image = display->image;
1543 png_structrp png_ptr = image->opaque->png_ptr;
1544
1545 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1546 display->first_row);
1547 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1548 png_uint_16p row_end;
1549 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1550 3 : 1;
1551 int aindex = 0;
1552 png_uint_32 y = image->height;
1553
1554 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1555 {
1556 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1557 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1558 {
1559 aindex = -1;
1560 ++input_row; /* To point to the first component */
1561 ++output_row;
1562 }
1563 else
1564 aindex = (int)channels;
1565 # else
1566 aindex = (int)channels;
1567 # endif
1568 }
1569
1570 else
1571 png_error(png_ptr, "png_write_image: internal call error");
1572
1573 /* Work out the output row end and count over this, note that the increment
1574 * above to 'row' means that row_end can actually be beyond the end of the
1575 * row; this is correct.
1576 */
1577 row_end = output_row + image->width * (channels+1);
1578
1579 for (; y > 0; --y)
1580 {
1581 png_const_uint_16p in_ptr = input_row;
1582 png_uint_16p out_ptr = output_row;
1583
1584 while (out_ptr < row_end)
1585 {
1586 png_uint_16 alpha = in_ptr[aindex];
1587 png_uint_32 reciprocal = 0;
1588 int c;
1589
1590 out_ptr[aindex] = alpha;
1591
1592 /* Calculate a reciprocal. The correct calculation is simply
1593 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1594 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1595 * is only initialized when required.
1596 */
1597 if (alpha > 0 && alpha < 65535)
1598 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1599
1600 c = (int)channels;
1601 do /* always at least one channel */
1602 {
1603 png_uint_16 component = *in_ptr++;
1604
1605 /* The following gives 65535 for an alpha of 0, which is fine,
1606 * otherwise if 0/0 is represented as some other value there is more
1607 * likely to be a discontinuity which will probably damage
1608 * compression when moving from a fully transparent area to a
1609 * nearly transparent one. (The assumption here is that opaque
1610 * areas tend not to be 0 intensity.)
1611 */
1612 if (component >= alpha)
1613 component = 65535;
1614
1615 /* component<alpha, so component/alpha is less than one and
1616 * component*reciprocal is less than 2^31.
1617 */
1618 else if (component > 0 && alpha < 65535)
1619 {
1620 png_uint_32 calc = component * reciprocal;
1621 calc += 16384; /* round to nearest */
1622 component = (png_uint_16)(calc >> 15);
1623 }
1624
1625 *out_ptr++ = component;
1626 }
1627 while (--c > 0);
1628
1629 /* Skip to next component (skip the intervening alpha channel) */
1630 ++in_ptr;
1631 ++out_ptr;
1632 }
1633
1634 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1635 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1636 }
1637
1638 return 1;
1639 }
1640
1641 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1642 * is present it must be removed from the components, the components are then
1643 * written in sRGB encoding. No components are added or removed.
1644 *
1645 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1646 * calculation can be done to 15 bits of accuracy; however, the output needs to
1647 * be scaled in the range 0..255*65535, so include that scaling here.
1648 */
1649 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1650
1651 static png_byte
png_unpremultiply(png_uint_32 component,png_uint_32 alpha,png_uint_32 reciprocal)1652 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1653 png_uint_32 reciprocal/*from the above macro*/)
1654 {
1655 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1656 * is represented as some other value there is more likely to be a
1657 * discontinuity which will probably damage compression when moving from a
1658 * fully transparent area to a nearly transparent one. (The assumption here
1659 * is that opaque areas tend not to be 0 intensity.)
1660 *
1661 * There is a rounding problem here; if alpha is less than 128 it will end up
1662 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1663 * output change for this too.
1664 */
1665 if (component >= alpha || alpha < 128)
1666 return 255;
1667
1668 /* component<alpha, so component/alpha is less than one and
1669 * component*reciprocal is less than 2^31.
1670 */
1671 else if (component > 0)
1672 {
1673 /* The test is that alpha/257 (rounded) is less than 255, the first value
1674 * that becomes 255 is 65407.
1675 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1676 * be exact!) [Could also test reciprocal != 0]
1677 */
1678 if (alpha < 65407)
1679 {
1680 component *= reciprocal;
1681 component += 64; /* round to nearest */
1682 component >>= 7;
1683 }
1684
1685 else
1686 component *= 255;
1687
1688 /* Convert the component to sRGB. */
1689 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1690 }
1691
1692 else
1693 return 0;
1694 }
1695
1696 static int
png_write_image_8bit(png_voidp argument)1697 png_write_image_8bit(png_voidp argument)
1698 {
1699 png_image_write_control *display = png_voidcast(png_image_write_control*,
1700 argument);
1701 png_imagep image = display->image;
1702 png_structrp png_ptr = image->opaque->png_ptr;
1703
1704 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1705 display->first_row);
1706 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1707 png_uint_32 y = image->height;
1708 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1709 3 : 1;
1710
1711 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1712 {
1713 png_bytep row_end;
1714 int aindex;
1715
1716 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1717 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1718 {
1719 aindex = -1;
1720 ++input_row; /* To point to the first component */
1721 ++output_row;
1722 }
1723
1724 else
1725 # endif
1726 aindex = (int)channels;
1727
1728 /* Use row_end in place of a loop counter: */
1729 row_end = output_row + image->width * (channels+1);
1730
1731 for (; y > 0; --y)
1732 {
1733 png_const_uint_16p in_ptr = input_row;
1734 png_bytep out_ptr = output_row;
1735
1736 while (out_ptr < row_end)
1737 {
1738 png_uint_16 alpha = in_ptr[aindex];
1739 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1740 png_uint_32 reciprocal = 0;
1741 int c;
1742
1743 /* Scale and write the alpha channel. */
1744 out_ptr[aindex] = alphabyte;
1745
1746 if (alphabyte > 0 && alphabyte < 255)
1747 reciprocal = UNP_RECIPROCAL(alpha);
1748
1749 c = (int)channels;
1750 do /* always at least one channel */
1751 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1752 while (--c > 0);
1753
1754 /* Skip to next component (skip the intervening alpha channel) */
1755 ++in_ptr;
1756 ++out_ptr;
1757 } /* while out_ptr < row_end */
1758
1759 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1760 display->local_row));
1761 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1762 } /* while y */
1763 }
1764
1765 else
1766 {
1767 /* No alpha channel, so the row_end really is the end of the row and it
1768 * is sufficient to loop over the components one by one.
1769 */
1770 png_bytep row_end = output_row + image->width * channels;
1771
1772 for (; y > 0; --y)
1773 {
1774 png_const_uint_16p in_ptr = input_row;
1775 png_bytep out_ptr = output_row;
1776
1777 while (out_ptr < row_end)
1778 {
1779 png_uint_32 component = *in_ptr++;
1780
1781 component *= 255;
1782 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1783 }
1784
1785 png_write_row(png_ptr, output_row);
1786 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1787 }
1788 }
1789
1790 return 1;
1791 }
1792
1793 static void
png_image_set_PLTE(png_image_write_control * display)1794 png_image_set_PLTE(png_image_write_control *display)
1795 {
1796 png_imagep image = display->image;
1797 const void *cmap = display->colormap;
1798 int entries = image->colormap_entries > 256 ? 256 :
1799 (int)image->colormap_entries;
1800
1801 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1802 png_uint_32 format = image->format;
1803 unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1804
1805 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1806 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1807 int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1808 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1809 # else
1810 # define afirst 0
1811 # endif
1812
1813 # ifdef PNG_FORMAT_BGR_SUPPORTED
1814 int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1815 # else
1816 # define bgr 0
1817 # endif
1818
1819 int i, num_trans;
1820 png_color palette[256];
1821 png_byte tRNS[256];
1822
1823 memset(tRNS, 255, (sizeof tRNS));
1824 memset(palette, 0, (sizeof palette));
1825
1826 for (i=num_trans=0; i<entries; ++i)
1827 {
1828 /* This gets automatically converted to sRGB with reversal of the
1829 * pre-multiplication if the color-map has an alpha channel.
1830 */
1831 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1832 {
1833 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1834
1835 entry += (unsigned int)i * channels;
1836
1837 if ((channels & 1) != 0) /* no alpha */
1838 {
1839 if (channels >= 3) /* RGB */
1840 {
1841 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1842 entry[(2 ^ bgr)]);
1843 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1844 entry[1]);
1845 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1846 entry[bgr]);
1847 }
1848
1849 else /* Gray */
1850 palette[i].blue = palette[i].red = palette[i].green =
1851 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1852 }
1853
1854 else /* alpha */
1855 {
1856 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1857 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1858 png_uint_32 reciprocal = 0;
1859
1860 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1861 * this is designed to produce a value scaled to 255*65535 when
1862 * divided by 128 (i.e. asr 7).
1863 */
1864 if (alphabyte > 0 && alphabyte < 255)
1865 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1866
1867 tRNS[i] = alphabyte;
1868 if (alphabyte < 255)
1869 num_trans = i+1;
1870
1871 if (channels >= 3) /* RGB */
1872 {
1873 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1874 alpha, reciprocal);
1875 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1876 reciprocal);
1877 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1878 reciprocal);
1879 }
1880
1881 else /* gray */
1882 palette[i].blue = palette[i].red = palette[i].green =
1883 png_unpremultiply(entry[afirst], alpha, reciprocal);
1884 }
1885 }
1886
1887 else /* Color-map has sRGB values */
1888 {
1889 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1890
1891 entry += (unsigned int)i * channels;
1892
1893 switch (channels)
1894 {
1895 case 4:
1896 tRNS[i] = entry[afirst ? 0 : 3];
1897 if (tRNS[i] < 255)
1898 num_trans = i+1;
1899 /* FALLTHROUGH */
1900 case 3:
1901 palette[i].blue = entry[afirst + (2 ^ bgr)];
1902 palette[i].green = entry[afirst + 1];
1903 palette[i].red = entry[afirst + bgr];
1904 break;
1905
1906 case 2:
1907 tRNS[i] = entry[1 ^ afirst];
1908 if (tRNS[i] < 255)
1909 num_trans = i+1;
1910 /* FALLTHROUGH */
1911 case 1:
1912 palette[i].blue = palette[i].red = palette[i].green =
1913 entry[afirst];
1914 break;
1915
1916 default:
1917 break;
1918 }
1919 }
1920 }
1921
1922 # ifdef afirst
1923 # undef afirst
1924 # endif
1925 # ifdef bgr
1926 # undef bgr
1927 # endif
1928
1929 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
1930 entries);
1931
1932 if (num_trans > 0)
1933 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
1934 num_trans, NULL);
1935
1936 image->colormap_entries = (png_uint_32)entries;
1937 }
1938
1939 static int
png_image_write_main(png_voidp argument)1940 png_image_write_main(png_voidp argument)
1941 {
1942 png_image_write_control *display = png_voidcast(png_image_write_control*,
1943 argument);
1944 png_imagep image = display->image;
1945 png_structrp png_ptr = image->opaque->png_ptr;
1946 png_inforp info_ptr = image->opaque->info_ptr;
1947 png_uint_32 format = image->format;
1948
1949 /* The following four ints are actually booleans */
1950 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
1951 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
1952 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
1953 int write_16bit = linear && (display->convert_to_8bit == 0);
1954
1955 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
1956 /* Make sure we error out on any bad situation */
1957 png_set_benign_errors(png_ptr, 0/*error*/);
1958 # endif
1959
1960 /* Default the 'row_stride' parameter if required, also check the row stride
1961 * and total image size to ensure that they are within the system limits.
1962 */
1963 {
1964 unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
1965
1966 if (image->width <= 0x7fffffffU/channels) /* no overflow */
1967 {
1968 png_uint_32 check;
1969 png_uint_32 png_row_stride = image->width * channels;
1970
1971 if (display->row_stride == 0)
1972 display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
1973
1974 if (display->row_stride < 0)
1975 check = (png_uint_32)(-display->row_stride);
1976
1977 else
1978 check = (png_uint_32)display->row_stride;
1979
1980 if (check >= png_row_stride)
1981 {
1982 /* Now check for overflow of the image buffer calculation; this
1983 * limits the whole image size to 32 bits for API compatibility with
1984 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
1985 */
1986 if (image->height > 0xffffffffU/png_row_stride)
1987 png_error(image->opaque->png_ptr, "memory image too large");
1988 }
1989
1990 else
1991 png_error(image->opaque->png_ptr, "supplied row stride too small");
1992 }
1993
1994 else
1995 png_error(image->opaque->png_ptr, "image row stride too large");
1996 }
1997
1998 /* Set the required transforms then write the rows in the correct order. */
1999 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
2000 {
2001 if (display->colormap != NULL && image->colormap_entries > 0)
2002 {
2003 png_uint_32 entries = image->colormap_entries;
2004
2005 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2006 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
2007 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
2008 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2009
2010 png_image_set_PLTE(display);
2011 }
2012
2013 else
2014 png_error(image->opaque->png_ptr,
2015 "no color-map for color-mapped image");
2016 }
2017
2018 else
2019 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2020 write_16bit ? 16 : 8,
2021 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2022 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2023 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2024
2025 /* Counter-intuitively the data transformations must be called *after*
2026 * png_write_info, not before as in the read code, but the 'set' functions
2027 * must still be called before. Just set the color space information, never
2028 * write an interlaced image.
2029 */
2030
2031 if (write_16bit != 0)
2032 {
2033 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2034 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2035
2036 if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2037 png_set_cHRM_fixed(png_ptr, info_ptr,
2038 /* color x y */
2039 /* white */ 31270, 32900,
2040 /* red */ 64000, 33000,
2041 /* green */ 30000, 60000,
2042 /* blue */ 15000, 6000
2043 );
2044 }
2045
2046 else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2047 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2048
2049 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2050 * space must still be gamma encoded.
2051 */
2052 else
2053 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2054
2055 /* Write the file header. */
2056 png_write_info(png_ptr, info_ptr);
2057
2058 /* Now set up the data transformations (*after* the header is written),
2059 * remove the handled transformations from the 'format' flags for checking.
2060 *
2061 * First check for a little endian system if writing 16-bit files.
2062 */
2063 if (write_16bit != 0)
2064 {
2065 png_uint_16 le = 0x0001;
2066
2067 if ((*(png_const_bytep) & le) != 0)
2068 png_set_swap(png_ptr);
2069 }
2070
2071 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2072 if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2073 {
2074 if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2075 png_set_bgr(png_ptr);
2076 format &= ~PNG_FORMAT_FLAG_BGR;
2077 }
2078 # endif
2079
2080 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2081 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2082 {
2083 if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2084 png_set_swap_alpha(png_ptr);
2085 format &= ~PNG_FORMAT_FLAG_AFIRST;
2086 }
2087 # endif
2088
2089 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2090 * above, but the application data is still byte packed.
2091 */
2092 if (colormap != 0 && image->colormap_entries <= 16)
2093 png_set_packing(png_ptr);
2094
2095 /* That should have handled all (both) the transforms. */
2096 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2097 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2098 png_error(png_ptr, "png_write_image: unsupported transformation");
2099
2100 {
2101 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2102 ptrdiff_t row_bytes = display->row_stride;
2103
2104 if (linear != 0)
2105 row_bytes *= (sizeof (png_uint_16));
2106
2107 if (row_bytes < 0)
2108 row += (image->height-1) * (-row_bytes);
2109
2110 display->first_row = row;
2111 display->row_bytes = row_bytes;
2112 }
2113
2114 /* Apply 'fast' options if the flag is set. */
2115 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2116 {
2117 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2118 /* NOTE: determined by experiment using pngstest, this reflects some
2119 * balance between the time to write the image once and the time to read
2120 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2121 * total (user) time on a heavily loaded system.
2122 */
2123 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2124 png_set_compression_level(png_ptr, 3);
2125 # endif
2126 }
2127
2128 /* Check for the cases that currently require a pre-transform on the row
2129 * before it is written. This only applies when the input is 16-bit and
2130 * either there is an alpha channel or it is converted to 8-bit.
2131 */
2132 if ((linear != 0 && alpha != 0 ) ||
2133 (colormap == 0 && display->convert_to_8bit != 0))
2134 {
2135 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2136 png_get_rowbytes(png_ptr, info_ptr)));
2137 int result;
2138
2139 display->local_row = row;
2140 if (write_16bit != 0)
2141 result = png_safe_execute(image, png_write_image_16bit, display);
2142 else
2143 result = png_safe_execute(image, png_write_image_8bit, display);
2144 display->local_row = NULL;
2145
2146 png_free(png_ptr, row);
2147
2148 /* Skip the 'write_end' on error: */
2149 if (result == 0)
2150 return 0;
2151 }
2152
2153 /* Otherwise this is the case where the input is in a format currently
2154 * supported by the rest of the libpng write code; call it directly.
2155 */
2156 else
2157 {
2158 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2159 ptrdiff_t row_bytes = display->row_bytes;
2160 png_uint_32 y = image->height;
2161
2162 for (; y > 0; --y)
2163 {
2164 png_write_row(png_ptr, row);
2165 row += row_bytes;
2166 }
2167 }
2168
2169 png_write_end(png_ptr, info_ptr);
2170 return 1;
2171 }
2172
2173
2174 static void (PNGCBAPI
2175 image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
2176 {
2177 png_image_write_control *display = png_voidcast(png_image_write_control*,
2178 png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
2179 png_alloc_size_t ob = display->output_bytes;
2180
2181 /* Check for overflow; this should never happen: */
2182 if (size <= ((png_alloc_size_t)-1) - ob)
2183 {
2184 /* I don't think libpng ever does this, but just in case: */
2185 if (size > 0)
2186 {
2187 if (display->memory_bytes >= ob+size) /* writing */
2188 memcpy(display->memory+ob, data, size);
2189
2190 /* Always update the size: */
2191 display->output_bytes = ob+size;
2192 }
2193 }
2194
2195 else
2196 png_error(png_ptr, "png_image_write_to_memory: PNG too big");
2197 }
2198
2199 static void (PNGCBAPI
2200 image_memory_flush)(png_structp png_ptr)
2201 {
2202 PNG_UNUSED(png_ptr)
2203 }
2204
2205 static int
png_image_write_memory(png_voidp argument)2206 png_image_write_memory(png_voidp argument)
2207 {
2208 png_image_write_control *display = png_voidcast(png_image_write_control*,
2209 argument);
2210
2211 /* The rest of the memory-specific init and write_main in an error protected
2212 * environment. This case needs to use callbacks for the write operations
2213 * since libpng has no built in support for writing to memory.
2214 */
2215 png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
2216 image_memory_write, image_memory_flush);
2217
2218 return png_image_write_main(display);
2219 }
2220
2221 int PNGAPI
png_image_write_to_memory(png_imagep image,void * memory,png_alloc_size_t * PNG_RESTRICT memory_bytes,int convert_to_8bit,const void * buffer,png_int_32 row_stride,const void * colormap)2222 png_image_write_to_memory(png_imagep image, void *memory,
2223 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
2224 const void *buffer, png_int_32 row_stride, const void *colormap)
2225 {
2226 /* Write the image to the given buffer, or count the bytes if it is NULL */
2227 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2228 {
2229 if (memory_bytes != NULL && buffer != NULL)
2230 {
2231 /* This is to give the caller an easier error detection in the NULL
2232 * case and guard against uninitialized variable problems:
2233 */
2234 if (memory == NULL)
2235 *memory_bytes = 0;
2236
2237 if (png_image_write_init(image) != 0)
2238 {
2239 png_image_write_control display;
2240 int result;
2241
2242 memset(&display, 0, (sizeof display));
2243 display.image = image;
2244 display.buffer = buffer;
2245 display.row_stride = row_stride;
2246 display.colormap = colormap;
2247 display.convert_to_8bit = convert_to_8bit;
2248 display.memory = png_voidcast(png_bytep, memory);
2249 display.memory_bytes = *memory_bytes;
2250 display.output_bytes = 0;
2251
2252 result = png_safe_execute(image, png_image_write_memory, &display);
2253 png_image_free(image);
2254
2255 /* write_memory returns true even if we ran out of buffer. */
2256 if (result)
2257 {
2258 /* On out-of-buffer this function returns '0' but still updates
2259 * memory_bytes:
2260 */
2261 if (memory != NULL && display.output_bytes > *memory_bytes)
2262 result = 0;
2263
2264 *memory_bytes = display.output_bytes;
2265 }
2266
2267 return result;
2268 }
2269
2270 else
2271 return 0;
2272 }
2273
2274 else
2275 return png_image_error(image,
2276 "png_image_write_to_memory: invalid argument");
2277 }
2278
2279 else if (image != NULL)
2280 return png_image_error(image,
2281 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2282
2283 else
2284 return 0;
2285 }
2286
2287 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2288 int PNGAPI
png_image_write_to_stdio(png_imagep image,FILE * file,int convert_to_8bit,const void * buffer,png_int_32 row_stride,const void * colormap)2289 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2290 const void *buffer, png_int_32 row_stride, const void *colormap)
2291 {
2292 /* Write the image to the given (FILE*). */
2293 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2294 {
2295 if (file != NULL && buffer != NULL)
2296 {
2297 if (png_image_write_init(image) != 0)
2298 {
2299 png_image_write_control display;
2300 int result;
2301
2302 /* This is slightly evil, but png_init_io doesn't do anything other
2303 * than this and we haven't changed the standard IO functions so
2304 * this saves a 'safe' function.
2305 */
2306 image->opaque->png_ptr->io_ptr = file;
2307
2308 memset(&display, 0, (sizeof display));
2309 display.image = image;
2310 display.buffer = buffer;
2311 display.row_stride = row_stride;
2312 display.colormap = colormap;
2313 display.convert_to_8bit = convert_to_8bit;
2314
2315 result = png_safe_execute(image, png_image_write_main, &display);
2316 png_image_free(image);
2317 return result;
2318 }
2319
2320 else
2321 return 0;
2322 }
2323
2324 else
2325 return png_image_error(image,
2326 "png_image_write_to_stdio: invalid argument");
2327 }
2328
2329 else if (image != NULL)
2330 return png_image_error(image,
2331 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2332
2333 else
2334 return 0;
2335 }
2336
2337 int PNGAPI
png_image_write_to_file(png_imagep image,const char * file_name,int convert_to_8bit,const void * buffer,png_int_32 row_stride,const void * colormap)2338 png_image_write_to_file(png_imagep image, const char *file_name,
2339 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2340 const void *colormap)
2341 {
2342 /* Write the image to the named file. */
2343 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2344 {
2345 if (file_name != NULL && buffer != NULL)
2346 {
2347 FILE *fp = fopen(file_name, "wb");
2348
2349 if (fp != NULL)
2350 {
2351 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2352 row_stride, colormap) != 0)
2353 {
2354 int error; /* from fflush/fclose */
2355
2356 /* Make sure the file is flushed correctly. */
2357 if (fflush(fp) == 0 && ferror(fp) == 0)
2358 {
2359 if (fclose(fp) == 0)
2360 return 1;
2361
2362 error = errno; /* from fclose */
2363 }
2364
2365 else
2366 {
2367 error = errno; /* from fflush or ferror */
2368 (void)fclose(fp);
2369 }
2370
2371 (void)remove(file_name);
2372 /* The image has already been cleaned up; this is just used to
2373 * set the error (because the original write succeeded).
2374 */
2375 return png_image_error(image, strerror(error));
2376 }
2377
2378 else
2379 {
2380 /* Clean up: just the opened file. */
2381 (void)fclose(fp);
2382 (void)remove(file_name);
2383 return 0;
2384 }
2385 }
2386
2387 else
2388 return png_image_error(image, strerror(errno));
2389 }
2390
2391 else
2392 return png_image_error(image,
2393 "png_image_write_to_file: invalid argument");
2394 }
2395
2396 else if (image != NULL)
2397 return png_image_error(image,
2398 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2399
2400 else
2401 return 0;
2402 }
2403 #endif /* SIMPLIFIED_WRITE_STDIO */
2404 #endif /* SIMPLIFIED_WRITE */
2405 #endif /* WRITE */
2406