1
2 /* pngwrite.c - general routines to write a PNG file
3 *
4 * Copyright (c) 2018-2019 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_ flag, and check info_ptr->valid before writing
79 * the chunk, as that will keep the code from breaking if you want to just
80 * write a plain PNG file. If you have long comments, I suggest writing
81 * 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_WRITE_APNG_SUPPORTED
132 if (info_ptr->valid & PNG_INFO_acTL)
133 png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
134 #endif
135 #ifdef PNG_GAMMA_SUPPORTED
136 # ifdef PNG_WRITE_gAMA_SUPPORTED
137 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
138 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
139 (info_ptr->valid & PNG_INFO_gAMA) != 0)
140 png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
141 # endif
142 #endif
143
144 #ifdef PNG_COLORSPACE_SUPPORTED
145 /* Write only one of sRGB or an ICC profile. If a profile was supplied
146 * and it matches one of the known sRGB ones issue a warning.
147 */
148 # ifdef PNG_WRITE_iCCP_SUPPORTED
149 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
150 (info_ptr->valid & PNG_INFO_iCCP) != 0)
151 {
152 # ifdef PNG_WRITE_sRGB_SUPPORTED
153 if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
154 png_app_warning(png_ptr,
155 "profile matches sRGB but writing iCCP instead");
156 # endif
157
158 png_write_iCCP(png_ptr, info_ptr->iccp_name,
159 info_ptr->iccp_profile);
160 }
161 # ifdef PNG_WRITE_sRGB_SUPPORTED
162 else
163 # endif
164 # endif
165
166 # ifdef PNG_WRITE_sRGB_SUPPORTED
167 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
168 (info_ptr->valid & PNG_INFO_sRGB) != 0)
169 png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
170 # endif /* WRITE_sRGB */
171 #endif /* COLORSPACE */
172
173 #ifdef PNG_WRITE_sBIT_SUPPORTED
174 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
175 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
176 #endif
177
178 #ifdef PNG_COLORSPACE_SUPPORTED
179 # ifdef PNG_WRITE_cHRM_SUPPORTED
180 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
181 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
182 (info_ptr->valid & PNG_INFO_cHRM) != 0)
183 png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
184 # endif
185 #endif
186
187 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
188 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
189 #endif
190
191 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
192 }
193 }
194
195 void PNGAPI
png_write_info(png_structrp png_ptr,png_const_inforp info_ptr)196 png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
197 {
198 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
199 int i;
200 #endif
201
202 png_debug(1, "in png_write_info");
203
204 if (png_ptr == NULL || info_ptr == NULL)
205 return;
206
207 png_write_info_before_PLTE(png_ptr, info_ptr);
208
209 if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
210 png_write_PLTE(png_ptr, info_ptr->palette,
211 (png_uint_32)info_ptr->num_palette);
212
213 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
214 png_error(png_ptr, "Valid palette required for paletted images");
215
216 #ifdef PNG_WRITE_tRNS_SUPPORTED
217 if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
218 {
219 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
220 /* Invert the alpha channel (in tRNS) */
221 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
222 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
223 {
224 int j, jend;
225
226 jend = info_ptr->num_trans;
227 if (jend > PNG_MAX_PALETTE_LENGTH)
228 jend = PNG_MAX_PALETTE_LENGTH;
229
230 for (j = 0; j<jend; ++j)
231 info_ptr->trans_alpha[j] =
232 (png_byte)(255 - info_ptr->trans_alpha[j]);
233 }
234 #endif
235 png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
236 info_ptr->num_trans, info_ptr->color_type);
237 }
238 #endif
239 #ifdef PNG_WRITE_bKGD_SUPPORTED
240 if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
241 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
242 #endif
243
244 #ifdef PNG_WRITE_eXIf_SUPPORTED
245 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
246 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
247 #endif
248
249 #ifdef PNG_WRITE_hIST_SUPPORTED
250 if ((info_ptr->valid & PNG_INFO_hIST) != 0)
251 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
252 #endif
253
254 #ifdef PNG_WRITE_oFFs_SUPPORTED
255 if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
256 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
257 info_ptr->offset_unit_type);
258 #endif
259
260 #ifdef PNG_WRITE_pCAL_SUPPORTED
261 if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
262 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
263 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
264 info_ptr->pcal_units, info_ptr->pcal_params);
265 #endif
266
267 #ifdef PNG_WRITE_sCAL_SUPPORTED
268 if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
269 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
270 info_ptr->scal_s_width, info_ptr->scal_s_height);
271 #endif /* sCAL */
272
273 #ifdef PNG_WRITE_pHYs_SUPPORTED
274 if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
275 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
276 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
277 #endif /* pHYs */
278
279 #ifdef PNG_WRITE_tIME_SUPPORTED
280 if ((info_ptr->valid & PNG_INFO_tIME) != 0)
281 {
282 png_write_tIME(png_ptr, &(info_ptr->mod_time));
283 png_ptr->mode |= PNG_WROTE_tIME;
284 }
285 #endif /* tIME */
286
287 #ifdef PNG_WRITE_sPLT_SUPPORTED
288 if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
289 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
290 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
291 #endif /* sPLT */
292
293 #ifdef PNG_WRITE_TEXT_SUPPORTED
294 /* Check to see if we need to write text chunks */
295 for (i = 0; i < info_ptr->num_text; i++)
296 {
297 png_debug2(2, "Writing header text chunk %d, type %d", i,
298 info_ptr->text[i].compression);
299 /* An internationalized chunk? */
300 if (info_ptr->text[i].compression > 0)
301 {
302 #ifdef PNG_WRITE_iTXt_SUPPORTED
303 /* Write international chunk */
304 png_write_iTXt(png_ptr,
305 info_ptr->text[i].compression,
306 info_ptr->text[i].key,
307 info_ptr->text[i].lang,
308 info_ptr->text[i].lang_key,
309 info_ptr->text[i].text);
310 /* Mark this chunk as written */
311 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
312 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
313 else
314 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
315 #else
316 png_warning(png_ptr, "Unable to write international text");
317 #endif
318 }
319
320 /* If we want a compressed text chunk */
321 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
322 {
323 #ifdef PNG_WRITE_zTXt_SUPPORTED
324 /* Write compressed chunk */
325 png_write_zTXt(png_ptr, info_ptr->text[i].key,
326 info_ptr->text[i].text, info_ptr->text[i].compression);
327 /* Mark this chunk as written */
328 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
329 #else
330 png_warning(png_ptr, "Unable to write compressed text");
331 #endif
332 }
333
334 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
335 {
336 #ifdef PNG_WRITE_tEXt_SUPPORTED
337 /* Write uncompressed chunk */
338 png_write_tEXt(png_ptr, info_ptr->text[i].key,
339 info_ptr->text[i].text,
340 0);
341 /* Mark this chunk as written */
342 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
343 #else
344 /* Can't get here */
345 png_warning(png_ptr, "Unable to write uncompressed text");
346 #endif
347 }
348 }
349 #endif /* tEXt */
350
351 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
352 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
353 #endif
354 }
355
356 /* Writes the end of the PNG file. If you don't want to write comments or
357 * time information, you can pass NULL for info. If you already wrote these
358 * in png_write_info(), do not write them again here. If you have long
359 * comments, I suggest writing them here, and compressing them.
360 */
361 void PNGAPI
png_write_end(png_structrp png_ptr,png_inforp info_ptr)362 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
363 {
364 png_debug(1, "in png_write_end");
365
366 if (png_ptr == NULL)
367 return;
368
369 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
370 png_error(png_ptr, "No IDATs written into file");
371
372 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
373 if (png_ptr->num_palette_max > png_ptr->num_palette)
374 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
375 #endif
376
377 #ifdef PNG_WRITE_APNG_SUPPORTED
378 if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
379 png_error(png_ptr, "Not enough frames written");
380 #endif
381
382 /* See if user wants us to write information chunks */
383 if (info_ptr != NULL)
384 {
385 #ifdef PNG_WRITE_TEXT_SUPPORTED
386 int i; /* local index variable */
387 #endif
388 #ifdef PNG_WRITE_tIME_SUPPORTED
389 /* Check to see if user has supplied a time chunk */
390 if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
391 (png_ptr->mode & PNG_WROTE_tIME) == 0)
392 png_write_tIME(png_ptr, &(info_ptr->mod_time));
393
394 #endif
395 #ifdef PNG_WRITE_TEXT_SUPPORTED
396 /* Loop through comment chunks */
397 for (i = 0; i < info_ptr->num_text; i++)
398 {
399 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
400 info_ptr->text[i].compression);
401 /* An internationalized chunk? */
402 if (info_ptr->text[i].compression > 0)
403 {
404 #ifdef PNG_WRITE_iTXt_SUPPORTED
405 /* Write international chunk */
406 png_write_iTXt(png_ptr,
407 info_ptr->text[i].compression,
408 info_ptr->text[i].key,
409 info_ptr->text[i].lang,
410 info_ptr->text[i].lang_key,
411 info_ptr->text[i].text);
412 /* Mark this chunk as written */
413 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
414 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
415 else
416 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
417 #else
418 png_warning(png_ptr, "Unable to write international text");
419 #endif
420 }
421
422 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
423 {
424 #ifdef PNG_WRITE_zTXt_SUPPORTED
425 /* Write compressed chunk */
426 png_write_zTXt(png_ptr, info_ptr->text[i].key,
427 info_ptr->text[i].text, info_ptr->text[i].compression);
428 /* Mark this chunk as written */
429 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
430 #else
431 png_warning(png_ptr, "Unable to write compressed text");
432 #endif
433 }
434
435 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
436 {
437 #ifdef PNG_WRITE_tEXt_SUPPORTED
438 /* Write uncompressed chunk */
439 png_write_tEXt(png_ptr, info_ptr->text[i].key,
440 info_ptr->text[i].text, 0);
441 /* Mark this chunk as written */
442 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
443 #else
444 png_warning(png_ptr, "Unable to write uncompressed text");
445 #endif
446 }
447 }
448 #endif
449
450 #ifdef PNG_WRITE_eXIf_SUPPORTED
451 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
452 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
453 #endif
454
455 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
456 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
457 #endif
458 }
459
460 png_ptr->mode |= PNG_AFTER_IDAT;
461
462 /* Write end of PNG file */
463 png_write_IEND(png_ptr);
464
465 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
466 * and restored again in libpng-1.2.30, may cause some applications that
467 * do not set png_ptr->output_flush_fn to crash. If your application
468 * experiences a problem, please try building libpng with
469 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
470 * png-mng-implement at lists.sf.net .
471 */
472 #ifdef PNG_WRITE_FLUSH_SUPPORTED
473 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
474 png_flush(png_ptr);
475 # endif
476 #endif
477 }
478
479 #ifdef PNG_CONVERT_tIME_SUPPORTED
480 void PNGAPI
png_convert_from_struct_tm(png_timep ptime,const struct tm * ttime)481 png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
482 {
483 png_debug(1, "in png_convert_from_struct_tm");
484
485 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
486 ptime->month = (png_byte)(ttime->tm_mon + 1);
487 ptime->day = (png_byte)ttime->tm_mday;
488 ptime->hour = (png_byte)ttime->tm_hour;
489 ptime->minute = (png_byte)ttime->tm_min;
490 ptime->second = (png_byte)ttime->tm_sec;
491 }
492
493 void PNGAPI
png_convert_from_time_t(png_timep ptime,time_t ttime)494 png_convert_from_time_t(png_timep ptime, time_t ttime)
495 {
496 struct tm *tbuf;
497
498 png_debug(1, "in png_convert_from_time_t");
499
500 tbuf = gmtime(&ttime);
501 png_convert_from_struct_tm(ptime, tbuf);
502 }
503 #endif
504
505 /* Initialize png_ptr structure, and allocate any memory needed */
506 PNG_FUNCTION(png_structp,PNGAPI
507 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
508 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
509 {
510 #ifndef PNG_USER_MEM_SUPPORTED
511 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
512 error_fn, warn_fn, NULL, NULL, NULL);
513 #else
514 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
515 warn_fn, NULL, NULL, NULL);
516 }
517
518 /* Alternate initialize png_ptr structure, and allocate any memory needed */
519 PNG_FUNCTION(png_structp,PNGAPI
520 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
521 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
522 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
523 {
524 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
525 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
526 #endif /* USER_MEM */
527 if (png_ptr != NULL)
528 {
529 /* Set the zlib control values to defaults; they can be overridden by the
530 * application after the struct has been created.
531 */
532 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
533
534 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
535 * pngwutil.c defaults it according to whether or not filters will be
536 * used, and ignores this setting.
537 */
538 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
539 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
540 png_ptr->zlib_mem_level = 8;
541 png_ptr->zlib_window_bits = 15;
542 png_ptr->zlib_method = 8;
543
544 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
545 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
546 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
547 png_ptr->zlib_text_mem_level = 8;
548 png_ptr->zlib_text_window_bits = 15;
549 png_ptr->zlib_text_method = 8;
550 #endif /* WRITE_COMPRESSED_TEXT */
551
552 /* This is a highly dubious configuration option; by default it is off,
553 * but it may be appropriate for private builds that are testing
554 * extensions not conformant to the current specification, or of
555 * applications that must not fail to write at all costs!
556 */
557 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
558 /* In stable builds only warn if an application error can be completely
559 * handled.
560 */
561 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
562 #endif
563
564 /* App warnings are warnings in release (or release candidate) builds but
565 * are errors during development.
566 */
567 #if PNG_RELEASE_BUILD
568 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
569 #endif
570
571 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
572 * do it itself) avoiding setting the default function if it is not
573 * required.
574 */
575 png_set_write_fn(png_ptr, NULL, NULL, NULL);
576 }
577
578 return png_ptr;
579 }
580
581
582 /* Write a few rows of image data. If the image is interlaced,
583 * either you will have to write the 7 sub images, or, if you
584 * have called png_set_interlace_handling(), you will have to
585 * "write" the image seven times.
586 */
587 void PNGAPI
png_write_rows(png_structrp png_ptr,png_bytepp row,png_uint_32 num_rows)588 png_write_rows(png_structrp png_ptr, png_bytepp row,
589 png_uint_32 num_rows)
590 {
591 png_uint_32 i; /* row counter */
592 png_bytepp rp; /* row pointer */
593
594 png_debug(1, "in png_write_rows");
595
596 if (png_ptr == NULL)
597 return;
598
599 /* Loop through the rows */
600 for (i = 0, rp = row; i < num_rows; i++, rp++)
601 {
602 png_write_row(png_ptr, *rp);
603 }
604 }
605
606 /* Write the image. You only need to call this function once, even
607 * if you are writing an interlaced image.
608 */
609 void PNGAPI
png_write_image(png_structrp png_ptr,png_bytepp image)610 png_write_image(png_structrp png_ptr, png_bytepp image)
611 {
612 png_uint_32 i; /* row index */
613 int pass, num_pass; /* pass variables */
614 png_bytepp rp; /* points to current row */
615
616 if (png_ptr == NULL)
617 return;
618
619 png_debug(1, "in png_write_image");
620
621 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
622 /* Initialize interlace handling. If image is not interlaced,
623 * this will set pass to 1
624 */
625 num_pass = png_set_interlace_handling(png_ptr);
626 #else
627 num_pass = 1;
628 #endif
629 /* Loop through passes */
630 for (pass = 0; pass < num_pass; pass++)
631 {
632 /* Loop through image */
633 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
634 {
635 png_write_row(png_ptr, *rp);
636 }
637 }
638 }
639
640 #ifdef PNG_MNG_FEATURES_SUPPORTED
641 /* Performs intrapixel differencing */
642 static void
png_do_write_intrapixel(png_row_infop row_info,png_bytep row)643 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
644 {
645 png_debug(1, "in png_do_write_intrapixel");
646
647 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
648 {
649 int bytes_per_pixel;
650 png_uint_32 row_width = row_info->width;
651 if (row_info->bit_depth == 8)
652 {
653 png_bytep rp;
654 png_uint_32 i;
655
656 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
657 bytes_per_pixel = 3;
658
659 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
660 bytes_per_pixel = 4;
661
662 else
663 return;
664
665 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
666 {
667 *(rp) = (png_byte)(*rp - *(rp + 1));
668 *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
669 }
670 }
671
672 #ifdef PNG_WRITE_16BIT_SUPPORTED
673 else if (row_info->bit_depth == 16)
674 {
675 png_bytep rp;
676 png_uint_32 i;
677
678 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
679 bytes_per_pixel = 6;
680
681 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
682 bytes_per_pixel = 8;
683
684 else
685 return;
686
687 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
688 {
689 png_uint_32 s0 = (png_uint_32)(*(rp ) << 8) | *(rp + 1);
690 png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
691 png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
692 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
693 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
694 *(rp ) = (png_byte)(red >> 8);
695 *(rp + 1) = (png_byte)red;
696 *(rp + 4) = (png_byte)(blue >> 8);
697 *(rp + 5) = (png_byte)blue;
698 }
699 }
700 #endif /* WRITE_16BIT */
701 }
702 }
703 #endif /* MNG_FEATURES */
704
705 /* Called by user to write a row of image data */
706 void PNGAPI
png_write_row(png_structrp png_ptr,png_const_bytep row)707 png_write_row(png_structrp png_ptr, png_const_bytep row)
708 {
709 /* 1.5.6: moved from png_struct to be a local structure: */
710 png_row_info row_info;
711
712 if (png_ptr == NULL)
713 return;
714
715 png_debug2(1, "in png_write_row (row %u, pass %d)",
716 png_ptr->row_number, png_ptr->pass);
717
718 /* Initialize transformations and other stuff if first time */
719 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
720 {
721 /* Make sure we wrote the header info */
722 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
723 png_error(png_ptr,
724 "png_write_info was never called before png_write_row");
725
726 /* Check for transforms that have been set but were defined out */
727 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
728 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
729 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
730 #endif
731
732 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
733 if ((png_ptr->transformations & PNG_FILLER) != 0)
734 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
735 #endif
736 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
737 defined(PNG_READ_PACKSWAP_SUPPORTED)
738 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
739 png_warning(png_ptr,
740 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
741 #endif
742
743 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
744 if ((png_ptr->transformations & PNG_PACK) != 0)
745 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
746 #endif
747
748 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
749 if ((png_ptr->transformations & PNG_SHIFT) != 0)
750 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
751 #endif
752
753 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
754 if ((png_ptr->transformations & PNG_BGR) != 0)
755 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
756 #endif
757
758 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
759 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
760 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
761 #endif
762
763 png_write_start_row(png_ptr);
764 }
765
766 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
767 /* If interlaced and not interested in row, return */
768 if (png_ptr->interlaced != 0 &&
769 (png_ptr->transformations & PNG_INTERLACE) != 0)
770 {
771 switch (png_ptr->pass)
772 {
773 case 0:
774 if ((png_ptr->row_number & 0x07) != 0)
775 {
776 png_write_finish_row(png_ptr);
777 return;
778 }
779 break;
780
781 case 1:
782 if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
783 {
784 png_write_finish_row(png_ptr);
785 return;
786 }
787 break;
788
789 case 2:
790 if ((png_ptr->row_number & 0x07) != 4)
791 {
792 png_write_finish_row(png_ptr);
793 return;
794 }
795 break;
796
797 case 3:
798 if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
799 {
800 png_write_finish_row(png_ptr);
801 return;
802 }
803 break;
804
805 case 4:
806 if ((png_ptr->row_number & 0x03) != 2)
807 {
808 png_write_finish_row(png_ptr);
809 return;
810 }
811 break;
812
813 case 5:
814 if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
815 {
816 png_write_finish_row(png_ptr);
817 return;
818 }
819 break;
820
821 case 6:
822 if ((png_ptr->row_number & 0x01) == 0)
823 {
824 png_write_finish_row(png_ptr);
825 return;
826 }
827 break;
828
829 default: /* error: ignore it */
830 break;
831 }
832 }
833 #endif
834
835 /* Set up row info for transformations */
836 row_info.color_type = png_ptr->color_type;
837 row_info.width = png_ptr->usr_width;
838 row_info.channels = png_ptr->usr_channels;
839 row_info.bit_depth = png_ptr->usr_bit_depth;
840 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
841 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
842
843 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
844 png_debug1(3, "row_info->width = %u", row_info.width);
845 png_debug1(3, "row_info->channels = %d", row_info.channels);
846 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
847 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
848 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
849
850 /* Copy user's row into buffer, leaving room for filter byte. */
851 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
852
853 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
854 /* Handle interlacing */
855 if (png_ptr->interlaced && png_ptr->pass < 6 &&
856 (png_ptr->transformations & PNG_INTERLACE) != 0)
857 {
858 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
859 /* This should always get caught above, but still ... */
860 if (row_info.width == 0)
861 {
862 png_write_finish_row(png_ptr);
863 return;
864 }
865 }
866 #endif
867
868 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
869 /* Handle other transformations */
870 if (png_ptr->transformations != 0)
871 png_do_write_transformations(png_ptr, &row_info);
872 #endif
873
874 /* At this point the row_info pixel depth must match the 'transformed' depth,
875 * which is also the output depth.
876 */
877 if (row_info.pixel_depth != png_ptr->pixel_depth ||
878 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
879 png_error(png_ptr, "internal write transform logic error");
880
881 #ifdef PNG_MNG_FEATURES_SUPPORTED
882 /* Write filter_method 64 (intrapixel differencing) only if
883 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
884 * 2. Libpng did not write a PNG signature (this filter_method is only
885 * used in PNG datastreams that are embedded in MNG datastreams) and
886 * 3. The application called png_permit_mng_features with a mask that
887 * included PNG_FLAG_MNG_FILTER_64 and
888 * 4. The filter_method is 64 and
889 * 5. The color_type is RGB or RGBA
890 */
891 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
892 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
893 {
894 /* Intrapixel differencing */
895 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
896 }
897 #endif
898
899 /* Added at libpng-1.5.10 */
900 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
901 /* Check for out-of-range palette index */
902 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
903 png_ptr->num_palette_max >= 0)
904 png_do_check_palette_indexes(png_ptr, &row_info);
905 #endif
906
907 /* Find a filter if necessary, filter the row and write it out. */
908 png_write_find_filter(png_ptr, &row_info);
909
910 if (png_ptr->write_row_fn != NULL)
911 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
912 }
913
914 #ifdef PNG_WRITE_FLUSH_SUPPORTED
915 /* Set the automatic flush interval or 0 to turn flushing off */
916 void PNGAPI
png_set_flush(png_structrp png_ptr,int nrows)917 png_set_flush(png_structrp png_ptr, int nrows)
918 {
919 png_debug(1, "in png_set_flush");
920
921 if (png_ptr == NULL)
922 return;
923
924 png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
925 }
926
927 /* Flush the current output buffers now */
928 void PNGAPI
png_write_flush(png_structrp png_ptr)929 png_write_flush(png_structrp png_ptr)
930 {
931 png_debug(1, "in png_write_flush");
932
933 if (png_ptr == NULL)
934 return;
935
936 /* We have already written out all of the data */
937 if (png_ptr->row_number >= png_ptr->num_rows)
938 return;
939
940 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
941 png_ptr->flush_rows = 0;
942 png_flush(png_ptr);
943 }
944 #endif /* WRITE_FLUSH */
945
946 /* Free any memory used in png_ptr struct without freeing the struct itself. */
947 static void
png_write_destroy(png_structrp png_ptr)948 png_write_destroy(png_structrp png_ptr)
949 {
950 png_debug(1, "in png_write_destroy");
951
952 /* Free any memory zlib uses */
953 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
954 deflateEnd(&png_ptr->zstream);
955
956 /* Free our memory. png_free checks NULL for us. */
957 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
958 png_free(png_ptr, png_ptr->row_buf);
959 png_ptr->row_buf = NULL;
960 #ifdef PNG_WRITE_FILTER_SUPPORTED
961 png_free(png_ptr, png_ptr->prev_row);
962 png_free(png_ptr, png_ptr->try_row);
963 png_free(png_ptr, png_ptr->tst_row);
964 png_ptr->prev_row = NULL;
965 png_ptr->try_row = NULL;
966 png_ptr->tst_row = NULL;
967 #endif
968
969 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
970 png_free(png_ptr, png_ptr->chunk_list);
971 png_ptr->chunk_list = NULL;
972 #endif
973
974 /* The error handling and memory handling information is left intact at this
975 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
976 * for how this happens.
977 */
978 }
979
980 /* Free all memory used by the write.
981 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
982 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
983 * the passed in info_structs but it would quietly fail to free any of the data
984 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
985 * has no png_ptr.)
986 */
987 void PNGAPI
png_destroy_write_struct(png_structpp png_ptr_ptr,png_infopp info_ptr_ptr)988 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
989 {
990 png_debug(1, "in png_destroy_write_struct");
991
992 if (png_ptr_ptr != NULL)
993 {
994 png_structrp png_ptr = *png_ptr_ptr;
995
996 if (png_ptr != NULL) /* added in libpng 1.6.0 */
997 {
998 png_destroy_info_struct(png_ptr, info_ptr_ptr);
999
1000 *png_ptr_ptr = NULL;
1001 png_write_destroy(png_ptr);
1002 png_destroy_png_struct(png_ptr);
1003 }
1004 }
1005 }
1006
1007 /* Allow the application to select one or more row filters to use. */
1008 void PNGAPI
png_set_filter(png_structrp png_ptr,int method,int filters)1009 png_set_filter(png_structrp png_ptr, int method, int filters)
1010 {
1011 png_debug(1, "in png_set_filter");
1012
1013 if (png_ptr == NULL)
1014 return;
1015
1016 #ifdef PNG_MNG_FEATURES_SUPPORTED
1017 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
1018 (method == PNG_INTRAPIXEL_DIFFERENCING))
1019 method = PNG_FILTER_TYPE_BASE;
1020
1021 #endif
1022 if (method == PNG_FILTER_TYPE_BASE)
1023 {
1024 switch (filters & (PNG_ALL_FILTERS | 0x07))
1025 {
1026 #ifdef PNG_WRITE_FILTER_SUPPORTED
1027 case 5:
1028 case 6:
1029 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1030 #endif /* WRITE_FILTER */
1031 /* FALLTHROUGH */
1032 case PNG_FILTER_VALUE_NONE:
1033 png_ptr->do_filter = PNG_FILTER_NONE; break;
1034
1035 #ifdef PNG_WRITE_FILTER_SUPPORTED
1036 case PNG_FILTER_VALUE_SUB:
1037 png_ptr->do_filter = PNG_FILTER_SUB; break;
1038
1039 case PNG_FILTER_VALUE_UP:
1040 png_ptr->do_filter = PNG_FILTER_UP; break;
1041
1042 case PNG_FILTER_VALUE_AVG:
1043 png_ptr->do_filter = PNG_FILTER_AVG; break;
1044
1045 case PNG_FILTER_VALUE_PAETH:
1046 png_ptr->do_filter = PNG_FILTER_PAETH; break;
1047
1048 default:
1049 png_ptr->do_filter = (png_byte)filters; break;
1050 #else
1051 default:
1052 png_app_error(png_ptr, "Unknown row filter for method 0");
1053 #endif /* WRITE_FILTER */
1054 }
1055
1056 #ifdef PNG_WRITE_FILTER_SUPPORTED
1057 /* If we have allocated the row_buf, this means we have already started
1058 * with the image and we should have allocated all of the filter buffers
1059 * that have been selected. If prev_row isn't already allocated, then
1060 * it is too late to start using the filters that need it, since we
1061 * will be missing the data in the previous row. If an application
1062 * wants to start and stop using particular filters during compression,
1063 * it should start out with all of the filters, and then remove them
1064 * or add them back after the start of compression.
1065 *
1066 * NOTE: this is a nasty constraint on the code, because it means that the
1067 * prev_row buffer must be maintained even if there are currently no
1068 * 'prev_row' requiring filters active.
1069 */
1070 if (png_ptr->row_buf != NULL)
1071 {
1072 int num_filters;
1073 png_alloc_size_t buf_size;
1074
1075 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1076 * images cannot benefit from certain filters. If this isn't done here
1077 * the check below will fire on 1 pixel high images.
1078 */
1079 if (png_ptr->height == 1)
1080 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1081
1082 if (png_ptr->width == 1)
1083 filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1084
1085 if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
1086 && png_ptr->prev_row == NULL)
1087 {
1088 /* This is the error case, however it is benign - the previous row
1089 * is not available so the filter can't be used. Just warn here.
1090 */
1091 png_app_warning(png_ptr,
1092 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1093 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1094 }
1095
1096 num_filters = 0;
1097
1098 if (filters & PNG_FILTER_SUB)
1099 num_filters++;
1100
1101 if (filters & PNG_FILTER_UP)
1102 num_filters++;
1103
1104 if (filters & PNG_FILTER_AVG)
1105 num_filters++;
1106
1107 if (filters & PNG_FILTER_PAETH)
1108 num_filters++;
1109
1110 /* Allocate needed row buffers if they have not already been
1111 * allocated.
1112 */
1113 buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1114 png_ptr->width) + 1;
1115
1116 if (png_ptr->try_row == NULL)
1117 png_ptr->try_row = png_voidcast(png_bytep,
1118 png_malloc(png_ptr, buf_size));
1119
1120 if (num_filters > 1)
1121 {
1122 if (png_ptr->tst_row == NULL)
1123 png_ptr->tst_row = png_voidcast(png_bytep,
1124 png_malloc(png_ptr, buf_size));
1125 }
1126 }
1127 png_ptr->do_filter = (png_byte)filters;
1128 #endif
1129 }
1130 else
1131 png_error(png_ptr, "Unknown custom filter method");
1132 }
1133
1134 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1135 /* Provide floating and fixed point APIs */
1136 #ifdef PNG_FLOATING_POINT_SUPPORTED
1137 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)1138 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1139 int num_weights, png_const_doublep filter_weights,
1140 png_const_doublep filter_costs)
1141 {
1142 PNG_UNUSED(png_ptr)
1143 PNG_UNUSED(heuristic_method)
1144 PNG_UNUSED(num_weights)
1145 PNG_UNUSED(filter_weights)
1146 PNG_UNUSED(filter_costs)
1147 }
1148 #endif /* FLOATING_POINT */
1149
1150 #ifdef PNG_FIXED_POINT_SUPPORTED
1151 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)1152 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1153 int num_weights, png_const_fixed_point_p filter_weights,
1154 png_const_fixed_point_p filter_costs)
1155 {
1156 PNG_UNUSED(png_ptr)
1157 PNG_UNUSED(heuristic_method)
1158 PNG_UNUSED(num_weights)
1159 PNG_UNUSED(filter_weights)
1160 PNG_UNUSED(filter_costs)
1161 }
1162 #endif /* FIXED_POINT */
1163 #endif /* WRITE_WEIGHTED_FILTER */
1164
1165 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1166 void PNGAPI
png_set_compression_level(png_structrp png_ptr,int level)1167 png_set_compression_level(png_structrp png_ptr, int level)
1168 {
1169 png_debug(1, "in png_set_compression_level");
1170
1171 if (png_ptr == NULL)
1172 return;
1173
1174 png_ptr->zlib_level = level;
1175 }
1176
1177 void PNGAPI
png_set_compression_mem_level(png_structrp png_ptr,int mem_level)1178 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1179 {
1180 png_debug(1, "in png_set_compression_mem_level");
1181
1182 if (png_ptr == NULL)
1183 return;
1184
1185 png_ptr->zlib_mem_level = mem_level;
1186 }
1187
1188 void PNGAPI
png_set_compression_strategy(png_structrp png_ptr,int strategy)1189 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1190 {
1191 png_debug(1, "in png_set_compression_strategy");
1192
1193 if (png_ptr == NULL)
1194 return;
1195
1196 /* The flag setting here prevents the libpng dynamic selection of strategy.
1197 */
1198 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1199 png_ptr->zlib_strategy = strategy;
1200 }
1201
1202 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1203 * smaller value of window_bits if it can do so safely.
1204 */
1205 void PNGAPI
png_set_compression_window_bits(png_structrp png_ptr,int window_bits)1206 png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1207 {
1208 if (png_ptr == NULL)
1209 return;
1210
1211 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1212 * meant that negative window bits values could be selected that would cause
1213 * libpng to write a non-standard PNG file with raw deflate or gzip
1214 * compressed IDAT or ancillary chunks. Such files can be read and there is
1215 * no warning on read, so this seems like a very bad idea.
1216 */
1217 if (window_bits > 15)
1218 {
1219 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1220 window_bits = 15;
1221 }
1222
1223 else if (window_bits < 8)
1224 {
1225 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1226 window_bits = 8;
1227 }
1228
1229 png_ptr->zlib_window_bits = window_bits;
1230 }
1231
1232 void PNGAPI
png_set_compression_method(png_structrp png_ptr,int method)1233 png_set_compression_method(png_structrp png_ptr, int method)
1234 {
1235 png_debug(1, "in png_set_compression_method");
1236
1237 if (png_ptr == NULL)
1238 return;
1239
1240 /* This would produce an invalid PNG file if it worked, but it doesn't and
1241 * deflate will fault it, so it is harmless to just warn here.
1242 */
1243 if (method != 8)
1244 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1245
1246 png_ptr->zlib_method = method;
1247 }
1248 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1249
1250 /* The following were added to libpng-1.5.4 */
1251 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1252 void PNGAPI
png_set_text_compression_level(png_structrp png_ptr,int level)1253 png_set_text_compression_level(png_structrp png_ptr, int level)
1254 {
1255 png_debug(1, "in png_set_text_compression_level");
1256
1257 if (png_ptr == NULL)
1258 return;
1259
1260 png_ptr->zlib_text_level = level;
1261 }
1262
1263 void PNGAPI
png_set_text_compression_mem_level(png_structrp png_ptr,int mem_level)1264 png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1265 {
1266 png_debug(1, "in png_set_text_compression_mem_level");
1267
1268 if (png_ptr == NULL)
1269 return;
1270
1271 png_ptr->zlib_text_mem_level = mem_level;
1272 }
1273
1274 void PNGAPI
png_set_text_compression_strategy(png_structrp png_ptr,int strategy)1275 png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1276 {
1277 png_debug(1, "in png_set_text_compression_strategy");
1278
1279 if (png_ptr == NULL)
1280 return;
1281
1282 png_ptr->zlib_text_strategy = strategy;
1283 }
1284
1285 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1286 * smaller value of window_bits if it can do so safely.
1287 */
1288 void PNGAPI
png_set_text_compression_window_bits(png_structrp png_ptr,int window_bits)1289 png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1290 {
1291 if (png_ptr == NULL)
1292 return;
1293
1294 if (window_bits > 15)
1295 {
1296 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1297 window_bits = 15;
1298 }
1299
1300 else if (window_bits < 8)
1301 {
1302 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1303 window_bits = 8;
1304 }
1305
1306 png_ptr->zlib_text_window_bits = window_bits;
1307 }
1308
1309 void PNGAPI
png_set_text_compression_method(png_structrp png_ptr,int method)1310 png_set_text_compression_method(png_structrp png_ptr, int method)
1311 {
1312 png_debug(1, "in png_set_text_compression_method");
1313
1314 if (png_ptr == NULL)
1315 return;
1316
1317 if (method != 8)
1318 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1319
1320 png_ptr->zlib_text_method = method;
1321 }
1322 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1323 /* end of API added to libpng-1.5.4 */
1324
1325 void PNGAPI
png_set_write_status_fn(png_structrp png_ptr,png_write_status_ptr write_row_fn)1326 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1327 {
1328 if (png_ptr == NULL)
1329 return;
1330
1331 png_ptr->write_row_fn = write_row_fn;
1332 }
1333
1334 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1335 void PNGAPI
png_set_write_user_transform_fn(png_structrp png_ptr,png_user_transform_ptr write_user_transform_fn)1336 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1337 write_user_transform_fn)
1338 {
1339 png_debug(1, "in png_set_write_user_transform_fn");
1340
1341 if (png_ptr == NULL)
1342 return;
1343
1344 png_ptr->transformations |= PNG_USER_TRANSFORM;
1345 png_ptr->write_user_transform_fn = write_user_transform_fn;
1346 }
1347 #endif
1348
1349
1350 #ifdef PNG_INFO_IMAGE_SUPPORTED
1351 void PNGAPI
png_write_png(png_structrp png_ptr,png_inforp info_ptr,int transforms,voidp params)1352 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1353 int transforms, voidp params)
1354 {
1355 if (png_ptr == NULL || info_ptr == NULL)
1356 return;
1357
1358 if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1359 {
1360 png_app_error(png_ptr, "no rows for png_write_image to write");
1361 return;
1362 }
1363
1364 /* Write the file header information. */
1365 png_write_info(png_ptr, info_ptr);
1366
1367 /* ------ these transformations don't touch the info structure ------- */
1368
1369 /* Invert monochrome pixels */
1370 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1371 #ifdef PNG_WRITE_INVERT_SUPPORTED
1372 png_set_invert_mono(png_ptr);
1373 #else
1374 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1375 #endif
1376
1377 /* Shift the pixels up to a legal bit depth and fill in
1378 * as appropriate to correctly scale the image.
1379 */
1380 if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1381 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1382 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1383 png_set_shift(png_ptr, &info_ptr->sig_bit);
1384 #else
1385 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1386 #endif
1387
1388 /* Pack pixels into bytes */
1389 if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1390 #ifdef PNG_WRITE_PACK_SUPPORTED
1391 png_set_packing(png_ptr);
1392 #else
1393 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1394 #endif
1395
1396 /* Swap location of alpha bytes from ARGB to RGBA */
1397 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1398 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1399 png_set_swap_alpha(png_ptr);
1400 #else
1401 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1402 #endif
1403
1404 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1405 * RGB, note that the code expects the input color type to be G or RGB; no
1406 * alpha channel.
1407 */
1408 if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
1409 PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1410 {
1411 #ifdef PNG_WRITE_FILLER_SUPPORTED
1412 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1413 {
1414 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1415 png_app_error(png_ptr,
1416 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1417
1418 /* Continue if ignored - this is the pre-1.6.10 behavior */
1419 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1420 }
1421
1422 else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1423 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1424 #else
1425 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1426 #endif
1427 }
1428
1429 /* Flip BGR pixels to RGB */
1430 if ((transforms & PNG_TRANSFORM_BGR) != 0)
1431 #ifdef PNG_WRITE_BGR_SUPPORTED
1432 png_set_bgr(png_ptr);
1433 #else
1434 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1435 #endif
1436
1437 /* Swap bytes of 16-bit files to most significant byte first */
1438 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1439 #ifdef PNG_WRITE_SWAP_SUPPORTED
1440 png_set_swap(png_ptr);
1441 #else
1442 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1443 #endif
1444
1445 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1446 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1447 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1448 png_set_packswap(png_ptr);
1449 #else
1450 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1451 #endif
1452
1453 /* Invert the alpha channel from opacity to transparency */
1454 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1455 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1456 png_set_invert_alpha(png_ptr);
1457 #else
1458 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1459 #endif
1460
1461 /* ----------------------- end of transformations ------------------- */
1462
1463 /* Write the bits */
1464 png_write_image(png_ptr, info_ptr->row_pointers);
1465
1466 /* It is REQUIRED to call this to finish writing the rest of the file */
1467 png_write_end(png_ptr, info_ptr);
1468
1469 PNG_UNUSED(params)
1470 }
1471 #endif
1472
1473 #ifdef PNG_WRITE_APNG_SUPPORTED
1474 void PNGAPI
png_write_frame_head(png_structp png_ptr,png_infop info_ptr,png_bytepp row_pointers,png_uint_32 width,png_uint_32 height,png_uint_32 x_offset,png_uint_32 y_offset,png_uint_16 delay_num,png_uint_16 delay_den,png_byte dispose_op,png_byte blend_op)1475 png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
1476 png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
1477 png_uint_32 x_offset, png_uint_32 y_offset,
1478 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
1479 png_byte blend_op)
1480 {
1481 png_debug(1, "in png_write_frame_head");
1482
1483 /* there is a chance this has been set after png_write_info was called,
1484 * so it would be set but not written. is there a way to be sure? */
1485 if (!(info_ptr->valid & PNG_INFO_acTL))
1486 png_error(png_ptr, "png_write_frame_head(): acTL not set");
1487
1488 png_write_reset(png_ptr);
1489
1490 png_write_reinit(png_ptr, info_ptr, width, height);
1491
1492 if ( !(png_ptr->num_frames_written == 0 &&
1493 (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) ) )
1494 png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
1495 delay_num, delay_den, dispose_op, blend_op);
1496
1497 PNG_UNUSED(row_pointers)
1498 }
1499
1500 void PNGAPI
png_write_frame_tail(png_structp png_ptr,png_infop info_ptr)1501 png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
1502 {
1503 png_debug(1, "in png_write_frame_tail");
1504
1505 png_ptr->num_frames_written++;
1506
1507 PNG_UNUSED(info_ptr)
1508 }
1509 #endif /* PNG_WRITE_APNG_SUPPORTED */
1510
1511 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1512 /* Initialize the write structure - general purpose utility. */
1513 static int
png_image_write_init(png_imagep image)1514 png_image_write_init(png_imagep image)
1515 {
1516 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1517 png_safe_error, png_safe_warning);
1518
1519 if (png_ptr != NULL)
1520 {
1521 png_infop info_ptr = png_create_info_struct(png_ptr);
1522
1523 if (info_ptr != NULL)
1524 {
1525 png_controlp control = png_voidcast(png_controlp,
1526 png_malloc_warn(png_ptr, (sizeof *control)));
1527
1528 if (control != NULL)
1529 {
1530 memset(control, 0, (sizeof *control));
1531
1532 control->png_ptr = png_ptr;
1533 control->info_ptr = info_ptr;
1534 control->for_write = 1;
1535
1536 image->opaque = control;
1537 return 1;
1538 }
1539
1540 /* Error clean up */
1541 png_destroy_info_struct(png_ptr, &info_ptr);
1542 }
1543
1544 png_destroy_write_struct(&png_ptr, NULL);
1545 }
1546
1547 return png_image_error(image, "png_image_write_: out of memory");
1548 }
1549
1550 /* Arguments to png_image_write_main: */
1551 typedef struct
1552 {
1553 /* Arguments: */
1554 png_imagep image;
1555 png_const_voidp buffer;
1556 png_int_32 row_stride;
1557 png_const_voidp colormap;
1558 int convert_to_8bit;
1559 /* Local variables: */
1560 png_const_voidp first_row;
1561 ptrdiff_t row_bytes;
1562 png_voidp local_row;
1563 /* Byte count for memory writing */
1564 png_bytep memory;
1565 png_alloc_size_t memory_bytes; /* not used for STDIO */
1566 png_alloc_size_t output_bytes; /* running total */
1567 } png_image_write_control;
1568
1569 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1570 * do any necessary byte swapping. The component order is defined by the
1571 * png_image format value.
1572 */
1573 static int
png_write_image_16bit(png_voidp argument)1574 png_write_image_16bit(png_voidp argument)
1575 {
1576 png_image_write_control *display = png_voidcast(png_image_write_control*,
1577 argument);
1578 png_imagep image = display->image;
1579 png_structrp png_ptr = image->opaque->png_ptr;
1580
1581 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1582 display->first_row);
1583 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1584 png_uint_16p row_end;
1585 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1586 3 : 1;
1587 int aindex = 0;
1588 png_uint_32 y = image->height;
1589
1590 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1591 {
1592 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1593 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1594 {
1595 aindex = -1;
1596 ++input_row; /* To point to the first component */
1597 ++output_row;
1598 }
1599 else
1600 aindex = (int)channels;
1601 # else
1602 aindex = (int)channels;
1603 # endif
1604 }
1605
1606 else
1607 png_error(png_ptr, "png_write_image: internal call error");
1608
1609 /* Work out the output row end and count over this, note that the increment
1610 * above to 'row' means that row_end can actually be beyond the end of the
1611 * row; this is correct.
1612 */
1613 row_end = output_row + image->width * (channels+1);
1614
1615 for (; y > 0; --y)
1616 {
1617 png_const_uint_16p in_ptr = input_row;
1618 png_uint_16p out_ptr = output_row;
1619
1620 while (out_ptr < row_end)
1621 {
1622 png_uint_16 alpha = in_ptr[aindex];
1623 png_uint_32 reciprocal = 0;
1624 int c;
1625
1626 out_ptr[aindex] = alpha;
1627
1628 /* Calculate a reciprocal. The correct calculation is simply
1629 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1630 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1631 * is only initialized when required.
1632 */
1633 if (alpha > 0 && alpha < 65535)
1634 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1635
1636 c = (int)channels;
1637 do /* always at least one channel */
1638 {
1639 png_uint_16 component = *in_ptr++;
1640
1641 /* The following gives 65535 for an alpha of 0, which is fine,
1642 * otherwise if 0/0 is represented as some other value there is more
1643 * likely to be a discontinuity which will probably damage
1644 * compression when moving from a fully transparent area to a
1645 * nearly transparent one. (The assumption here is that opaque
1646 * areas tend not to be 0 intensity.)
1647 */
1648 if (component >= alpha)
1649 component = 65535;
1650
1651 /* component<alpha, so component/alpha is less than one and
1652 * component*reciprocal is less than 2^31.
1653 */
1654 else if (component > 0 && alpha < 65535)
1655 {
1656 png_uint_32 calc = component * reciprocal;
1657 calc += 16384; /* round to nearest */
1658 component = (png_uint_16)(calc >> 15);
1659 }
1660
1661 *out_ptr++ = component;
1662 }
1663 while (--c > 0);
1664
1665 /* Skip to next component (skip the intervening alpha channel) */
1666 ++in_ptr;
1667 ++out_ptr;
1668 }
1669
1670 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1671 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1672 }
1673
1674 return 1;
1675 }
1676
1677 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1678 * is present it must be removed from the components, the components are then
1679 * written in sRGB encoding. No components are added or removed.
1680 *
1681 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1682 * calculation can be done to 15 bits of accuracy; however, the output needs to
1683 * be scaled in the range 0..255*65535, so include that scaling here.
1684 */
1685 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1686
1687 static png_byte
png_unpremultiply(png_uint_32 component,png_uint_32 alpha,png_uint_32 reciprocal)1688 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1689 png_uint_32 reciprocal/*from the above macro*/)
1690 {
1691 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1692 * is represented as some other value there is more likely to be a
1693 * discontinuity which will probably damage compression when moving from a
1694 * fully transparent area to a nearly transparent one. (The assumption here
1695 * is that opaque areas tend not to be 0 intensity.)
1696 *
1697 * There is a rounding problem here; if alpha is less than 128 it will end up
1698 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1699 * output change for this too.
1700 */
1701 if (component >= alpha || alpha < 128)
1702 return 255;
1703
1704 /* component<alpha, so component/alpha is less than one and
1705 * component*reciprocal is less than 2^31.
1706 */
1707 else if (component > 0)
1708 {
1709 /* The test is that alpha/257 (rounded) is less than 255, the first value
1710 * that becomes 255 is 65407.
1711 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1712 * be exact!) [Could also test reciprocal != 0]
1713 */
1714 if (alpha < 65407)
1715 {
1716 component *= reciprocal;
1717 component += 64; /* round to nearest */
1718 component >>= 7;
1719 }
1720
1721 else
1722 component *= 255;
1723
1724 /* Convert the component to sRGB. */
1725 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1726 }
1727
1728 else
1729 return 0;
1730 }
1731
1732 static int
png_write_image_8bit(png_voidp argument)1733 png_write_image_8bit(png_voidp argument)
1734 {
1735 png_image_write_control *display = png_voidcast(png_image_write_control*,
1736 argument);
1737 png_imagep image = display->image;
1738 png_structrp png_ptr = image->opaque->png_ptr;
1739
1740 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1741 display->first_row);
1742 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1743 png_uint_32 y = image->height;
1744 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1745 3 : 1;
1746
1747 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1748 {
1749 png_bytep row_end;
1750 int aindex;
1751
1752 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1753 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1754 {
1755 aindex = -1;
1756 ++input_row; /* To point to the first component */
1757 ++output_row;
1758 }
1759
1760 else
1761 # endif
1762 aindex = (int)channels;
1763
1764 /* Use row_end in place of a loop counter: */
1765 row_end = output_row + image->width * (channels+1);
1766
1767 for (; y > 0; --y)
1768 {
1769 png_const_uint_16p in_ptr = input_row;
1770 png_bytep out_ptr = output_row;
1771
1772 while (out_ptr < row_end)
1773 {
1774 png_uint_16 alpha = in_ptr[aindex];
1775 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1776 png_uint_32 reciprocal = 0;
1777 int c;
1778
1779 /* Scale and write the alpha channel. */
1780 out_ptr[aindex] = alphabyte;
1781
1782 if (alphabyte > 0 && alphabyte < 255)
1783 reciprocal = UNP_RECIPROCAL(alpha);
1784
1785 c = (int)channels;
1786 do /* always at least one channel */
1787 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1788 while (--c > 0);
1789
1790 /* Skip to next component (skip the intervening alpha channel) */
1791 ++in_ptr;
1792 ++out_ptr;
1793 } /* while out_ptr < row_end */
1794
1795 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1796 display->local_row));
1797 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1798 } /* while y */
1799 }
1800
1801 else
1802 {
1803 /* No alpha channel, so the row_end really is the end of the row and it
1804 * is sufficient to loop over the components one by one.
1805 */
1806 png_bytep row_end = output_row + image->width * channels;
1807
1808 for (; y > 0; --y)
1809 {
1810 png_const_uint_16p in_ptr = input_row;
1811 png_bytep out_ptr = output_row;
1812
1813 while (out_ptr < row_end)
1814 {
1815 png_uint_32 component = *in_ptr++;
1816
1817 component *= 255;
1818 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1819 }
1820
1821 png_write_row(png_ptr, output_row);
1822 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1823 }
1824 }
1825
1826 return 1;
1827 }
1828
1829 static void
png_image_set_PLTE(png_image_write_control * display)1830 png_image_set_PLTE(png_image_write_control *display)
1831 {
1832 png_imagep image = display->image;
1833 const void *cmap = display->colormap;
1834 int entries = image->colormap_entries > 256 ? 256 :
1835 (int)image->colormap_entries;
1836
1837 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1838 png_uint_32 format = image->format;
1839 unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1840
1841 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1842 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1843 int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1844 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1845 # else
1846 # define afirst 0
1847 # endif
1848
1849 # ifdef PNG_FORMAT_BGR_SUPPORTED
1850 int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1851 # else
1852 # define bgr 0
1853 # endif
1854
1855 int i, num_trans;
1856 png_color palette[256];
1857 png_byte tRNS[256];
1858
1859 memset(tRNS, 255, (sizeof tRNS));
1860 memset(palette, 0, (sizeof palette));
1861
1862 for (i=num_trans=0; i<entries; ++i)
1863 {
1864 /* This gets automatically converted to sRGB with reversal of the
1865 * pre-multiplication if the color-map has an alpha channel.
1866 */
1867 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1868 {
1869 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1870
1871 entry += (unsigned int)i * channels;
1872
1873 if ((channels & 1) != 0) /* no alpha */
1874 {
1875 if (channels >= 3) /* RGB */
1876 {
1877 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1878 entry[(2 ^ bgr)]);
1879 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1880 entry[1]);
1881 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1882 entry[bgr]);
1883 }
1884
1885 else /* Gray */
1886 palette[i].blue = palette[i].red = palette[i].green =
1887 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1888 }
1889
1890 else /* alpha */
1891 {
1892 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1893 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1894 png_uint_32 reciprocal = 0;
1895
1896 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1897 * this is designed to produce a value scaled to 255*65535 when
1898 * divided by 128 (i.e. asr 7).
1899 */
1900 if (alphabyte > 0 && alphabyte < 255)
1901 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1902
1903 tRNS[i] = alphabyte;
1904 if (alphabyte < 255)
1905 num_trans = i+1;
1906
1907 if (channels >= 3) /* RGB */
1908 {
1909 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1910 alpha, reciprocal);
1911 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1912 reciprocal);
1913 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1914 reciprocal);
1915 }
1916
1917 else /* gray */
1918 palette[i].blue = palette[i].red = palette[i].green =
1919 png_unpremultiply(entry[afirst], alpha, reciprocal);
1920 }
1921 }
1922
1923 else /* Color-map has sRGB values */
1924 {
1925 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1926
1927 entry += (unsigned int)i * channels;
1928
1929 switch (channels)
1930 {
1931 case 4:
1932 tRNS[i] = entry[afirst ? 0 : 3];
1933 if (tRNS[i] < 255)
1934 num_trans = i+1;
1935 /* FALLTHROUGH */
1936 case 3:
1937 palette[i].blue = entry[afirst + (2 ^ bgr)];
1938 palette[i].green = entry[afirst + 1];
1939 palette[i].red = entry[afirst + bgr];
1940 break;
1941
1942 case 2:
1943 tRNS[i] = entry[1 ^ afirst];
1944 if (tRNS[i] < 255)
1945 num_trans = i+1;
1946 /* FALLTHROUGH */
1947 case 1:
1948 palette[i].blue = palette[i].red = palette[i].green =
1949 entry[afirst];
1950 break;
1951
1952 default:
1953 break;
1954 }
1955 }
1956 }
1957
1958 # ifdef afirst
1959 # undef afirst
1960 # endif
1961 # ifdef bgr
1962 # undef bgr
1963 # endif
1964
1965 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
1966 entries);
1967
1968 if (num_trans > 0)
1969 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
1970 num_trans, NULL);
1971
1972 image->colormap_entries = (png_uint_32)entries;
1973 }
1974
1975 static int
png_image_write_main(png_voidp argument)1976 png_image_write_main(png_voidp argument)
1977 {
1978 png_image_write_control *display = png_voidcast(png_image_write_control*,
1979 argument);
1980 png_imagep image = display->image;
1981 png_structrp png_ptr = image->opaque->png_ptr;
1982 png_inforp info_ptr = image->opaque->info_ptr;
1983 png_uint_32 format = image->format;
1984
1985 /* The following four ints are actually booleans */
1986 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
1987 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
1988 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
1989 int write_16bit = linear && (display->convert_to_8bit == 0);
1990
1991 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
1992 /* Make sure we error out on any bad situation */
1993 png_set_benign_errors(png_ptr, 0/*error*/);
1994 # endif
1995
1996 /* Default the 'row_stride' parameter if required, also check the row stride
1997 * and total image size to ensure that they are within the system limits.
1998 */
1999 {
2000 unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
2001
2002 if (image->width <= 0x7fffffffU/channels) /* no overflow */
2003 {
2004 png_uint_32 check;
2005 png_uint_32 png_row_stride = image->width * channels;
2006
2007 if (display->row_stride == 0)
2008 display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
2009
2010 if (display->row_stride < 0)
2011 check = (png_uint_32)(-display->row_stride);
2012
2013 else
2014 check = (png_uint_32)display->row_stride;
2015
2016 if (check >= png_row_stride)
2017 {
2018 /* Now check for overflow of the image buffer calculation; this
2019 * limits the whole image size to 32 bits for API compatibility with
2020 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
2021 */
2022 if (image->height > 0xffffffffU/png_row_stride)
2023 png_error(image->opaque->png_ptr, "memory image too large");
2024 }
2025
2026 else
2027 png_error(image->opaque->png_ptr, "supplied row stride too small");
2028 }
2029
2030 else
2031 png_error(image->opaque->png_ptr, "image row stride too large");
2032 }
2033
2034 /* Set the required transforms then write the rows in the correct order. */
2035 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
2036 {
2037 if (display->colormap != NULL && image->colormap_entries > 0)
2038 {
2039 png_uint_32 entries = image->colormap_entries;
2040
2041 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2042 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
2043 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
2044 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2045
2046 png_image_set_PLTE(display);
2047 }
2048
2049 else
2050 png_error(image->opaque->png_ptr,
2051 "no color-map for color-mapped image");
2052 }
2053
2054 else
2055 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2056 write_16bit ? 16 : 8,
2057 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2058 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2059 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2060
2061 /* Counter-intuitively the data transformations must be called *after*
2062 * png_write_info, not before as in the read code, but the 'set' functions
2063 * must still be called before. Just set the color space information, never
2064 * write an interlaced image.
2065 */
2066
2067 if (write_16bit != 0)
2068 {
2069 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2070 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2071
2072 if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2073 png_set_cHRM_fixed(png_ptr, info_ptr,
2074 /* color x y */
2075 /* white */ 31270, 32900,
2076 /* red */ 64000, 33000,
2077 /* green */ 30000, 60000,
2078 /* blue */ 15000, 6000
2079 );
2080 }
2081
2082 else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2083 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2084
2085 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2086 * space must still be gamma encoded.
2087 */
2088 else
2089 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2090
2091 /* Write the file header. */
2092 png_write_info(png_ptr, info_ptr);
2093
2094 /* Now set up the data transformations (*after* the header is written),
2095 * remove the handled transformations from the 'format' flags for checking.
2096 *
2097 * First check for a little endian system if writing 16-bit files.
2098 */
2099 if (write_16bit != 0)
2100 {
2101 png_uint_16 le = 0x0001;
2102
2103 if ((*(png_const_bytep) & le) != 0)
2104 png_set_swap(png_ptr);
2105 }
2106
2107 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2108 if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2109 {
2110 if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2111 png_set_bgr(png_ptr);
2112 format &= ~PNG_FORMAT_FLAG_BGR;
2113 }
2114 # endif
2115
2116 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2117 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2118 {
2119 if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2120 png_set_swap_alpha(png_ptr);
2121 format &= ~PNG_FORMAT_FLAG_AFIRST;
2122 }
2123 # endif
2124
2125 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2126 * above, but the application data is still byte packed.
2127 */
2128 if (colormap != 0 && image->colormap_entries <= 16)
2129 png_set_packing(png_ptr);
2130
2131 /* That should have handled all (both) the transforms. */
2132 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2133 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2134 png_error(png_ptr, "png_write_image: unsupported transformation");
2135
2136 {
2137 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2138 ptrdiff_t row_bytes = display->row_stride;
2139
2140 if (linear != 0)
2141 row_bytes *= (sizeof (png_uint_16));
2142
2143 if (row_bytes < 0)
2144 row += (image->height-1) * (-row_bytes);
2145
2146 display->first_row = row;
2147 display->row_bytes = row_bytes;
2148 }
2149
2150 /* Apply 'fast' options if the flag is set. */
2151 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2152 {
2153 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2154 /* NOTE: determined by experiment using pngstest, this reflects some
2155 * balance between the time to write the image once and the time to read
2156 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2157 * total (user) time on a heavily loaded system.
2158 */
2159 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2160 png_set_compression_level(png_ptr, 3);
2161 # endif
2162 }
2163
2164 /* Check for the cases that currently require a pre-transform on the row
2165 * before it is written. This only applies when the input is 16-bit and
2166 * either there is an alpha channel or it is converted to 8-bit.
2167 */
2168 if ((linear != 0 && alpha != 0 ) ||
2169 (colormap == 0 && display->convert_to_8bit != 0))
2170 {
2171 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2172 png_get_rowbytes(png_ptr, info_ptr)));
2173 int result;
2174
2175 display->local_row = row;
2176 if (write_16bit != 0)
2177 result = png_safe_execute(image, png_write_image_16bit, display);
2178 else
2179 result = png_safe_execute(image, png_write_image_8bit, display);
2180 display->local_row = NULL;
2181
2182 png_free(png_ptr, row);
2183
2184 /* Skip the 'write_end' on error: */
2185 if (result == 0)
2186 return 0;
2187 }
2188
2189 /* Otherwise this is the case where the input is in a format currently
2190 * supported by the rest of the libpng write code; call it directly.
2191 */
2192 else
2193 {
2194 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2195 ptrdiff_t row_bytes = display->row_bytes;
2196 png_uint_32 y = image->height;
2197
2198 for (; y > 0; --y)
2199 {
2200 png_write_row(png_ptr, row);
2201 row += row_bytes;
2202 }
2203 }
2204
2205 png_write_end(png_ptr, info_ptr);
2206 return 1;
2207 }
2208
2209
2210 static void (PNGCBAPI
2211 image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
2212 {
2213 png_image_write_control *display = png_voidcast(png_image_write_control*,
2214 png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
2215 png_alloc_size_t ob = display->output_bytes;
2216
2217 /* Check for overflow; this should never happen: */
2218 if (size <= ((png_alloc_size_t)-1) - ob)
2219 {
2220 /* I don't think libpng ever does this, but just in case: */
2221 if (size > 0)
2222 {
2223 if (display->memory_bytes >= ob+size) /* writing */
2224 memcpy(display->memory+ob, data, size);
2225
2226 /* Always update the size: */
2227 display->output_bytes = ob+size;
2228 }
2229 }
2230
2231 else
2232 png_error(png_ptr, "png_image_write_to_memory: PNG too big");
2233 }
2234
2235 static void (PNGCBAPI
2236 image_memory_flush)(png_structp png_ptr)
2237 {
2238 PNG_UNUSED(png_ptr)
2239 }
2240
2241 static int
png_image_write_memory(png_voidp argument)2242 png_image_write_memory(png_voidp argument)
2243 {
2244 png_image_write_control *display = png_voidcast(png_image_write_control*,
2245 argument);
2246
2247 /* The rest of the memory-specific init and write_main in an error protected
2248 * environment. This case needs to use callbacks for the write operations
2249 * since libpng has no built in support for writing to memory.
2250 */
2251 png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
2252 image_memory_write, image_memory_flush);
2253
2254 return png_image_write_main(display);
2255 }
2256
2257 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)2258 png_image_write_to_memory(png_imagep image, void *memory,
2259 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
2260 const void *buffer, png_int_32 row_stride, const void *colormap)
2261 {
2262 /* Write the image to the given buffer, or count the bytes if it is NULL */
2263 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2264 {
2265 if (memory_bytes != NULL && buffer != NULL)
2266 {
2267 /* This is to give the caller an easier error detection in the NULL
2268 * case and guard against uninitialized variable problems:
2269 */
2270 if (memory == NULL)
2271 *memory_bytes = 0;
2272
2273 if (png_image_write_init(image) != 0)
2274 {
2275 png_image_write_control display;
2276 int result;
2277
2278 memset(&display, 0, (sizeof display));
2279 display.image = image;
2280 display.buffer = buffer;
2281 display.row_stride = row_stride;
2282 display.colormap = colormap;
2283 display.convert_to_8bit = convert_to_8bit;
2284 display.memory = png_voidcast(png_bytep, memory);
2285 display.memory_bytes = *memory_bytes;
2286 display.output_bytes = 0;
2287
2288 result = png_safe_execute(image, png_image_write_memory, &display);
2289 png_image_free(image);
2290
2291 /* write_memory returns true even if we ran out of buffer. */
2292 if (result)
2293 {
2294 /* On out-of-buffer this function returns '0' but still updates
2295 * memory_bytes:
2296 */
2297 if (memory != NULL && display.output_bytes > *memory_bytes)
2298 result = 0;
2299
2300 *memory_bytes = display.output_bytes;
2301 }
2302
2303 return result;
2304 }
2305
2306 else
2307 return 0;
2308 }
2309
2310 else
2311 return png_image_error(image,
2312 "png_image_write_to_memory: invalid argument");
2313 }
2314
2315 else if (image != NULL)
2316 return png_image_error(image,
2317 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2318
2319 else
2320 return 0;
2321 }
2322
2323 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2324 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)2325 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2326 const void *buffer, png_int_32 row_stride, const void *colormap)
2327 {
2328 /* Write the image to the given (FILE*). */
2329 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2330 {
2331 if (file != NULL && buffer != NULL)
2332 {
2333 if (png_image_write_init(image) != 0)
2334 {
2335 png_image_write_control display;
2336 int result;
2337
2338 /* This is slightly evil, but png_init_io doesn't do anything other
2339 * than this and we haven't changed the standard IO functions so
2340 * this saves a 'safe' function.
2341 */
2342 image->opaque->png_ptr->io_ptr = file;
2343
2344 memset(&display, 0, (sizeof display));
2345 display.image = image;
2346 display.buffer = buffer;
2347 display.row_stride = row_stride;
2348 display.colormap = colormap;
2349 display.convert_to_8bit = convert_to_8bit;
2350
2351 result = png_safe_execute(image, png_image_write_main, &display);
2352 png_image_free(image);
2353 return result;
2354 }
2355
2356 else
2357 return 0;
2358 }
2359
2360 else
2361 return png_image_error(image,
2362 "png_image_write_to_stdio: invalid argument");
2363 }
2364
2365 else if (image != NULL)
2366 return png_image_error(image,
2367 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2368
2369 else
2370 return 0;
2371 }
2372
2373 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)2374 png_image_write_to_file(png_imagep image, const char *file_name,
2375 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2376 const void *colormap)
2377 {
2378 /* Write the image to the named file. */
2379 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2380 {
2381 if (file_name != NULL && buffer != NULL)
2382 {
2383 FILE *fp = fopen(file_name, "wb");
2384
2385 if (fp != NULL)
2386 {
2387 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2388 row_stride, colormap) != 0)
2389 {
2390 int error; /* from fflush/fclose */
2391
2392 /* Make sure the file is flushed correctly. */
2393 if (fflush(fp) == 0 && ferror(fp) == 0)
2394 {
2395 if (fclose(fp) == 0)
2396 return 1;
2397
2398 error = errno; /* from fclose */
2399 }
2400
2401 else
2402 {
2403 error = errno; /* from fflush or ferror */
2404 (void)fclose(fp);
2405 }
2406
2407 (void)remove(file_name);
2408 /* The image has already been cleaned up; this is just used to
2409 * set the error (because the original write succeeded).
2410 */
2411 return png_image_error(image, strerror(error));
2412 }
2413
2414 else
2415 {
2416 /* Clean up: just the opened file. */
2417 (void)fclose(fp);
2418 (void)remove(file_name);
2419 return 0;
2420 }
2421 }
2422
2423 else
2424 return png_image_error(image, strerror(errno));
2425 }
2426
2427 else
2428 return png_image_error(image,
2429 "png_image_write_to_file: invalid argument");
2430 }
2431
2432 else if (image != NULL)
2433 return png_image_error(image,
2434 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2435
2436 else
2437 return 0;
2438 }
2439 #endif /* SIMPLIFIED_WRITE_STDIO */
2440 #endif /* SIMPLIFIED_WRITE */
2441 #endif /* WRITE */
2442