1
2 /* pngwrite.c - general routines to write a PNG file
3 *
4 * Last changed in libpng 1.6.26 [October 20, 2016]
5 * Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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_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_hIST_SUPPORTED
241 if ((info_ptr->valid & PNG_INFO_hIST) != 0)
242 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
243 #endif
244
245 #ifdef PNG_WRITE_oFFs_SUPPORTED
246 if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
247 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
248 info_ptr->offset_unit_type);
249 #endif
250
251 #ifdef PNG_WRITE_pCAL_SUPPORTED
252 if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
253 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
254 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
255 info_ptr->pcal_units, info_ptr->pcal_params);
256 #endif
257
258 #ifdef PNG_WRITE_sCAL_SUPPORTED
259 if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
260 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
261 info_ptr->scal_s_width, info_ptr->scal_s_height);
262 #endif /* sCAL */
263
264 #ifdef PNG_WRITE_pHYs_SUPPORTED
265 if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
266 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
267 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
268 #endif /* pHYs */
269
270 #ifdef PNG_WRITE_tIME_SUPPORTED
271 if ((info_ptr->valid & PNG_INFO_tIME) != 0)
272 {
273 png_write_tIME(png_ptr, &(info_ptr->mod_time));
274 png_ptr->mode |= PNG_WROTE_tIME;
275 }
276 #endif /* tIME */
277
278 #ifdef PNG_WRITE_sPLT_SUPPORTED
279 if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
280 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
281 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
282 #endif /* sPLT */
283
284 #ifdef PNG_WRITE_TEXT_SUPPORTED
285 /* Check to see if we need to write text chunks */
286 for (i = 0; i < info_ptr->num_text; i++)
287 {
288 png_debug2(2, "Writing header text chunk %d, type %d", i,
289 info_ptr->text[i].compression);
290 /* An internationalized chunk? */
291 if (info_ptr->text[i].compression > 0)
292 {
293 #ifdef PNG_WRITE_iTXt_SUPPORTED
294 /* Write international chunk */
295 png_write_iTXt(png_ptr,
296 info_ptr->text[i].compression,
297 info_ptr->text[i].key,
298 info_ptr->text[i].lang,
299 info_ptr->text[i].lang_key,
300 info_ptr->text[i].text);
301 /* Mark this chunk as written */
302 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
303 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
304 else
305 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
306 #else
307 png_warning(png_ptr, "Unable to write international text");
308 #endif
309 }
310
311 /* If we want a compressed text chunk */
312 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
313 {
314 #ifdef PNG_WRITE_zTXt_SUPPORTED
315 /* Write compressed chunk */
316 png_write_zTXt(png_ptr, info_ptr->text[i].key,
317 info_ptr->text[i].text, info_ptr->text[i].compression);
318 /* Mark this chunk as written */
319 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
320 #else
321 png_warning(png_ptr, "Unable to write compressed text");
322 #endif
323 }
324
325 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
326 {
327 #ifdef PNG_WRITE_tEXt_SUPPORTED
328 /* Write uncompressed chunk */
329 png_write_tEXt(png_ptr, info_ptr->text[i].key,
330 info_ptr->text[i].text,
331 0);
332 /* Mark this chunk as written */
333 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
334 #else
335 /* Can't get here */
336 png_warning(png_ptr, "Unable to write uncompressed text");
337 #endif
338 }
339 }
340 #endif /* tEXt */
341
342 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
343 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
344 #endif
345 }
346
347 /* Writes the end of the PNG file. If you don't want to write comments or
348 * time information, you can pass NULL for info. If you already wrote these
349 * in png_write_info(), do not write them again here. If you have long
350 * comments, I suggest writing them here, and compressing them.
351 */
352 void PNGAPI
png_write_end(png_structrp png_ptr,png_inforp info_ptr)353 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
354 {
355 png_debug(1, "in png_write_end");
356
357 if (png_ptr == NULL)
358 return;
359
360 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
361 png_error(png_ptr, "No IDATs written into file");
362
363 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
364 if (png_ptr->num_palette_max > png_ptr->num_palette)
365 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
366 #endif
367
368 /* See if user wants us to write information chunks */
369 if (info_ptr != NULL)
370 {
371 #ifdef PNG_WRITE_TEXT_SUPPORTED
372 int i; /* local index variable */
373 #endif
374 #ifdef PNG_WRITE_tIME_SUPPORTED
375 /* Check to see if user has supplied a time chunk */
376 if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
377 (png_ptr->mode & PNG_WROTE_tIME) == 0)
378 png_write_tIME(png_ptr, &(info_ptr->mod_time));
379
380 #endif
381 #ifdef PNG_WRITE_TEXT_SUPPORTED
382 /* Loop through comment chunks */
383 for (i = 0; i < info_ptr->num_text; i++)
384 {
385 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
386 info_ptr->text[i].compression);
387 /* An internationalized chunk? */
388 if (info_ptr->text[i].compression > 0)
389 {
390 #ifdef PNG_WRITE_iTXt_SUPPORTED
391 /* Write international chunk */
392 png_write_iTXt(png_ptr,
393 info_ptr->text[i].compression,
394 info_ptr->text[i].key,
395 info_ptr->text[i].lang,
396 info_ptr->text[i].lang_key,
397 info_ptr->text[i].text);
398 /* Mark this chunk as written */
399 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
400 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
401 else
402 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
403 #else
404 png_warning(png_ptr, "Unable to write international text");
405 #endif
406 }
407
408 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
409 {
410 #ifdef PNG_WRITE_zTXt_SUPPORTED
411 /* Write compressed chunk */
412 png_write_zTXt(png_ptr, info_ptr->text[i].key,
413 info_ptr->text[i].text, info_ptr->text[i].compression);
414 /* Mark this chunk as written */
415 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
416 #else
417 png_warning(png_ptr, "Unable to write compressed text");
418 #endif
419 }
420
421 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
422 {
423 #ifdef PNG_WRITE_tEXt_SUPPORTED
424 /* Write uncompressed chunk */
425 png_write_tEXt(png_ptr, info_ptr->text[i].key,
426 info_ptr->text[i].text, 0);
427 /* Mark this chunk as written */
428 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
429 #else
430 png_warning(png_ptr, "Unable to write uncompressed text");
431 #endif
432 }
433 }
434 #endif
435 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
436 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
437 #endif
438 }
439
440 png_ptr->mode |= PNG_AFTER_IDAT;
441
442 /* Write end of PNG file */
443 png_write_IEND(png_ptr);
444
445 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
446 * and restored again in libpng-1.2.30, may cause some applications that
447 * do not set png_ptr->output_flush_fn to crash. If your application
448 * experiences a problem, please try building libpng with
449 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
450 * png-mng-implement at lists.sf.net .
451 */
452 #ifdef PNG_WRITE_FLUSH_SUPPORTED
453 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
454 png_flush(png_ptr);
455 # endif
456 #endif
457 }
458
459 #ifdef PNG_CONVERT_tIME_SUPPORTED
460 void PNGAPI
png_convert_from_struct_tm(png_timep ptime,PNG_CONST struct tm * ttime)461 png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)
462 {
463 png_debug(1, "in png_convert_from_struct_tm");
464
465 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
466 ptime->month = (png_byte)(ttime->tm_mon + 1);
467 ptime->day = (png_byte)ttime->tm_mday;
468 ptime->hour = (png_byte)ttime->tm_hour;
469 ptime->minute = (png_byte)ttime->tm_min;
470 ptime->second = (png_byte)ttime->tm_sec;
471 }
472
473 void PNGAPI
png_convert_from_time_t(png_timep ptime,time_t ttime)474 png_convert_from_time_t(png_timep ptime, time_t ttime)
475 {
476 struct tm *tbuf;
477
478 png_debug(1, "in png_convert_from_time_t");
479
480 tbuf = gmtime(&ttime);
481 png_convert_from_struct_tm(ptime, tbuf);
482 }
483 #endif
484
485 /* Initialize png_ptr structure, and allocate any memory needed */
486 PNG_FUNCTION(png_structp,PNGAPI
487 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
488 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
489 {
490 #ifndef PNG_USER_MEM_SUPPORTED
491 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
492 error_fn, warn_fn, NULL, NULL, NULL);
493 #else
494 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
495 warn_fn, NULL, NULL, NULL);
496 }
497
498 /* Alternate initialize png_ptr structure, and allocate any memory needed */
499 PNG_FUNCTION(png_structp,PNGAPI
500 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
501 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
502 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
503 {
504 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
505 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
506 #endif /* USER_MEM */
507 if (png_ptr != NULL)
508 {
509 /* Set the zlib control values to defaults; they can be overridden by the
510 * application after the struct has been created.
511 */
512 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
513
514 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
515 * pngwutil.c defaults it according to whether or not filters will be
516 * used, and ignores this setting.
517 */
518 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
519 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
520 png_ptr->zlib_mem_level = 8;
521 png_ptr->zlib_window_bits = 15;
522 png_ptr->zlib_method = 8;
523
524 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
525 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
526 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
527 png_ptr->zlib_text_mem_level = 8;
528 png_ptr->zlib_text_window_bits = 15;
529 png_ptr->zlib_text_method = 8;
530 #endif /* WRITE_COMPRESSED_TEXT */
531
532 /* This is a highly dubious configuration option; by default it is off,
533 * but it may be appropriate for private builds that are testing
534 * extensions not conformant to the current specification, or of
535 * applications that must not fail to write at all costs!
536 */
537 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
538 /* In stable builds only warn if an application error can be completely
539 * handled.
540 */
541 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
542 #endif
543
544 /* App warnings are warnings in release (or release candidate) builds but
545 * are errors during development.
546 */
547 #if PNG_RELEASE_BUILD
548 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
549 #endif
550
551 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
552 * do it itself) avoiding setting the default function if it is not
553 * required.
554 */
555 png_set_write_fn(png_ptr, NULL, NULL, NULL);
556 }
557
558 return png_ptr;
559 }
560
561
562 /* Write a few rows of image data. If the image is interlaced,
563 * either you will have to write the 7 sub images, or, if you
564 * have called png_set_interlace_handling(), you will have to
565 * "write" the image seven times.
566 */
567 void PNGAPI
png_write_rows(png_structrp png_ptr,png_bytepp row,png_uint_32 num_rows)568 png_write_rows(png_structrp png_ptr, png_bytepp row,
569 png_uint_32 num_rows)
570 {
571 png_uint_32 i; /* row counter */
572 png_bytepp rp; /* row pointer */
573
574 png_debug(1, "in png_write_rows");
575
576 if (png_ptr == NULL)
577 return;
578
579 /* Loop through the rows */
580 for (i = 0, rp = row; i < num_rows; i++, rp++)
581 {
582 png_write_row(png_ptr, *rp);
583 }
584 }
585
586 /* Write the image. You only need to call this function once, even
587 * if you are writing an interlaced image.
588 */
589 void PNGAPI
png_write_image(png_structrp png_ptr,png_bytepp image)590 png_write_image(png_structrp png_ptr, png_bytepp image)
591 {
592 png_uint_32 i; /* row index */
593 int pass, num_pass; /* pass variables */
594 png_bytepp rp; /* points to current row */
595
596 if (png_ptr == NULL)
597 return;
598
599 png_debug(1, "in png_write_image");
600
601 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
602 /* Initialize interlace handling. If image is not interlaced,
603 * this will set pass to 1
604 */
605 num_pass = png_set_interlace_handling(png_ptr);
606 #else
607 num_pass = 1;
608 #endif
609 /* Loop through passes */
610 for (pass = 0; pass < num_pass; pass++)
611 {
612 /* Loop through image */
613 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
614 {
615 png_write_row(png_ptr, *rp);
616 }
617 }
618 }
619
620 #ifdef PNG_MNG_FEATURES_SUPPORTED
621 /* Performs intrapixel differencing */
622 static void
png_do_write_intrapixel(png_row_infop row_info,png_bytep row)623 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
624 {
625 png_debug(1, "in png_do_write_intrapixel");
626
627 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
628 {
629 int bytes_per_pixel;
630 png_uint_32 row_width = row_info->width;
631 if (row_info->bit_depth == 8)
632 {
633 png_bytep rp;
634 png_uint_32 i;
635
636 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
637 bytes_per_pixel = 3;
638
639 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
640 bytes_per_pixel = 4;
641
642 else
643 return;
644
645 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
646 {
647 *(rp) = (png_byte)(*rp - *(rp + 1));
648 *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
649 }
650 }
651
652 #ifdef PNG_WRITE_16BIT_SUPPORTED
653 else if (row_info->bit_depth == 16)
654 {
655 png_bytep rp;
656 png_uint_32 i;
657
658 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
659 bytes_per_pixel = 6;
660
661 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
662 bytes_per_pixel = 8;
663
664 else
665 return;
666
667 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
668 {
669 png_uint_32 s0 = (png_uint_32)(*(rp ) << 8) | *(rp + 1);
670 png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
671 png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
672 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
673 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
674 *(rp ) = (png_byte)(red >> 8);
675 *(rp + 1) = (png_byte)red;
676 *(rp + 4) = (png_byte)(blue >> 8);
677 *(rp + 5) = (png_byte)blue;
678 }
679 }
680 #endif /* WRITE_16BIT */
681 }
682 }
683 #endif /* MNG_FEATURES */
684
685 /* Called by user to write a row of image data */
686 void PNGAPI
png_write_row(png_structrp png_ptr,png_const_bytep row)687 png_write_row(png_structrp png_ptr, png_const_bytep row)
688 {
689 /* 1.5.6: moved from png_struct to be a local structure: */
690 png_row_info row_info;
691
692 if (png_ptr == NULL)
693 return;
694
695 png_debug2(1, "in png_write_row (row %u, pass %d)",
696 png_ptr->row_number, png_ptr->pass);
697
698 /* Initialize transformations and other stuff if first time */
699 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
700 {
701 /* Make sure we wrote the header info */
702 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
703 png_error(png_ptr,
704 "png_write_info was never called before png_write_row");
705
706 /* Check for transforms that have been set but were defined out */
707 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
708 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
709 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
710 #endif
711
712 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
713 if ((png_ptr->transformations & PNG_FILLER) != 0)
714 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
715 #endif
716 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
717 defined(PNG_READ_PACKSWAP_SUPPORTED)
718 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
719 png_warning(png_ptr,
720 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
721 #endif
722
723 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
724 if ((png_ptr->transformations & PNG_PACK) != 0)
725 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
726 #endif
727
728 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
729 if ((png_ptr->transformations & PNG_SHIFT) != 0)
730 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
731 #endif
732
733 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
734 if ((png_ptr->transformations & PNG_BGR) != 0)
735 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
736 #endif
737
738 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
739 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
740 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
741 #endif
742
743 png_write_start_row(png_ptr);
744 }
745
746 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
747 /* If interlaced and not interested in row, return */
748 if (png_ptr->interlaced != 0 &&
749 (png_ptr->transformations & PNG_INTERLACE) != 0)
750 {
751 switch (png_ptr->pass)
752 {
753 case 0:
754 if ((png_ptr->row_number & 0x07) != 0)
755 {
756 png_write_finish_row(png_ptr);
757 return;
758 }
759 break;
760
761 case 1:
762 if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
763 {
764 png_write_finish_row(png_ptr);
765 return;
766 }
767 break;
768
769 case 2:
770 if ((png_ptr->row_number & 0x07) != 4)
771 {
772 png_write_finish_row(png_ptr);
773 return;
774 }
775 break;
776
777 case 3:
778 if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
779 {
780 png_write_finish_row(png_ptr);
781 return;
782 }
783 break;
784
785 case 4:
786 if ((png_ptr->row_number & 0x03) != 2)
787 {
788 png_write_finish_row(png_ptr);
789 return;
790 }
791 break;
792
793 case 5:
794 if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
795 {
796 png_write_finish_row(png_ptr);
797 return;
798 }
799 break;
800
801 case 6:
802 if ((png_ptr->row_number & 0x01) == 0)
803 {
804 png_write_finish_row(png_ptr);
805 return;
806 }
807 break;
808
809 default: /* error: ignore it */
810 break;
811 }
812 }
813 #endif
814
815 /* Set up row info for transformations */
816 row_info.color_type = png_ptr->color_type;
817 row_info.width = png_ptr->usr_width;
818 row_info.channels = png_ptr->usr_channels;
819 row_info.bit_depth = png_ptr->usr_bit_depth;
820 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
821 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
822
823 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
824 png_debug1(3, "row_info->width = %u", row_info.width);
825 png_debug1(3, "row_info->channels = %d", row_info.channels);
826 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
827 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
828 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
829
830 /* Copy user's row into buffer, leaving room for filter byte. */
831 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
832
833 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
834 /* Handle interlacing */
835 if (png_ptr->interlaced && png_ptr->pass < 6 &&
836 (png_ptr->transformations & PNG_INTERLACE) != 0)
837 {
838 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
839 /* This should always get caught above, but still ... */
840 if (row_info.width == 0)
841 {
842 png_write_finish_row(png_ptr);
843 return;
844 }
845 }
846 #endif
847
848 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
849 /* Handle other transformations */
850 if (png_ptr->transformations != 0)
851 png_do_write_transformations(png_ptr, &row_info);
852 #endif
853
854 /* At this point the row_info pixel depth must match the 'transformed' depth,
855 * which is also the output depth.
856 */
857 if (row_info.pixel_depth != png_ptr->pixel_depth ||
858 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
859 png_error(png_ptr, "internal write transform logic error");
860
861 #ifdef PNG_MNG_FEATURES_SUPPORTED
862 /* Write filter_method 64 (intrapixel differencing) only if
863 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
864 * 2. Libpng did not write a PNG signature (this filter_method is only
865 * used in PNG datastreams that are embedded in MNG datastreams) and
866 * 3. The application called png_permit_mng_features with a mask that
867 * included PNG_FLAG_MNG_FILTER_64 and
868 * 4. The filter_method is 64 and
869 * 5. The color_type is RGB or RGBA
870 */
871 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
872 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
873 {
874 /* Intrapixel differencing */
875 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
876 }
877 #endif
878
879 /* Added at libpng-1.5.10 */
880 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
881 /* Check for out-of-range palette index */
882 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
883 png_ptr->num_palette_max >= 0)
884 png_do_check_palette_indexes(png_ptr, &row_info);
885 #endif
886
887 /* Find a filter if necessary, filter the row and write it out. */
888 png_write_find_filter(png_ptr, &row_info);
889
890 if (png_ptr->write_row_fn != NULL)
891 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
892 }
893
894 #ifdef PNG_WRITE_FLUSH_SUPPORTED
895 /* Set the automatic flush interval or 0 to turn flushing off */
896 void PNGAPI
png_set_flush(png_structrp png_ptr,int nrows)897 png_set_flush(png_structrp png_ptr, int nrows)
898 {
899 png_debug(1, "in png_set_flush");
900
901 if (png_ptr == NULL)
902 return;
903
904 png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
905 }
906
907 /* Flush the current output buffers now */
908 void PNGAPI
png_write_flush(png_structrp png_ptr)909 png_write_flush(png_structrp png_ptr)
910 {
911 png_debug(1, "in png_write_flush");
912
913 if (png_ptr == NULL)
914 return;
915
916 /* We have already written out all of the data */
917 if (png_ptr->row_number >= png_ptr->num_rows)
918 return;
919
920 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
921 png_ptr->flush_rows = 0;
922 png_flush(png_ptr);
923 }
924 #endif /* WRITE_FLUSH */
925
926 /* Free any memory used in png_ptr struct without freeing the struct itself. */
927 static void
png_write_destroy(png_structrp png_ptr)928 png_write_destroy(png_structrp png_ptr)
929 {
930 png_debug(1, "in png_write_destroy");
931
932 /* Free any memory zlib uses */
933 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
934 deflateEnd(&png_ptr->zstream);
935
936 /* Free our memory. png_free checks NULL for us. */
937 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
938 png_free(png_ptr, png_ptr->row_buf);
939 png_ptr->row_buf = NULL;
940 #ifdef PNG_WRITE_FILTER_SUPPORTED
941 png_free(png_ptr, png_ptr->prev_row);
942 png_free(png_ptr, png_ptr->try_row);
943 png_free(png_ptr, png_ptr->tst_row);
944 png_ptr->prev_row = NULL;
945 png_ptr->try_row = NULL;
946 png_ptr->tst_row = NULL;
947 #endif
948
949 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
950 png_free(png_ptr, png_ptr->chunk_list);
951 png_ptr->chunk_list = NULL;
952 #endif
953
954 /* The error handling and memory handling information is left intact at this
955 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
956 * for how this happens.
957 */
958 }
959
960 /* Free all memory used by the write.
961 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
962 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
963 * the passed in info_structs but it would quietly fail to free any of the data
964 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
965 * has no png_ptr.)
966 */
967 void PNGAPI
png_destroy_write_struct(png_structpp png_ptr_ptr,png_infopp info_ptr_ptr)968 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
969 {
970 png_debug(1, "in png_destroy_write_struct");
971
972 if (png_ptr_ptr != NULL)
973 {
974 png_structrp png_ptr = *png_ptr_ptr;
975
976 if (png_ptr != NULL) /* added in libpng 1.6.0 */
977 {
978 png_destroy_info_struct(png_ptr, info_ptr_ptr);
979
980 *png_ptr_ptr = NULL;
981 png_write_destroy(png_ptr);
982 png_destroy_png_struct(png_ptr);
983 }
984 }
985 }
986
987 /* Allow the application to select one or more row filters to use. */
988 void PNGAPI
png_set_filter(png_structrp png_ptr,int method,int filters)989 png_set_filter(png_structrp png_ptr, int method, int filters)
990 {
991 png_debug(1, "in png_set_filter");
992
993 if (png_ptr == NULL)
994 return;
995
996 #ifdef PNG_MNG_FEATURES_SUPPORTED
997 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
998 (method == PNG_INTRAPIXEL_DIFFERENCING))
999 method = PNG_FILTER_TYPE_BASE;
1000
1001 #endif
1002 if (method == PNG_FILTER_TYPE_BASE)
1003 {
1004 switch (filters & (PNG_ALL_FILTERS | 0x07))
1005 {
1006 #ifdef PNG_WRITE_FILTER_SUPPORTED
1007 case 5:
1008 case 6:
1009 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1010 /* FALL THROUGH */
1011 #endif /* WRITE_FILTER */
1012 case PNG_FILTER_VALUE_NONE:
1013 png_ptr->do_filter = PNG_FILTER_NONE; break;
1014
1015 #ifdef PNG_WRITE_FILTER_SUPPORTED
1016 case PNG_FILTER_VALUE_SUB:
1017 png_ptr->do_filter = PNG_FILTER_SUB; break;
1018
1019 case PNG_FILTER_VALUE_UP:
1020 png_ptr->do_filter = PNG_FILTER_UP; break;
1021
1022 case PNG_FILTER_VALUE_AVG:
1023 png_ptr->do_filter = PNG_FILTER_AVG; break;
1024
1025 case PNG_FILTER_VALUE_PAETH:
1026 png_ptr->do_filter = PNG_FILTER_PAETH; break;
1027
1028 default:
1029 png_ptr->do_filter = (png_byte)filters; break;
1030 #else
1031 default:
1032 png_app_error(png_ptr, "Unknown row filter for method 0");
1033 #endif /* WRITE_FILTER */
1034 }
1035
1036 #ifdef PNG_WRITE_FILTER_SUPPORTED
1037 /* If we have allocated the row_buf, this means we have already started
1038 * with the image and we should have allocated all of the filter buffers
1039 * that have been selected. If prev_row isn't already allocated, then
1040 * it is too late to start using the filters that need it, since we
1041 * will be missing the data in the previous row. If an application
1042 * wants to start and stop using particular filters during compression,
1043 * it should start out with all of the filters, and then remove them
1044 * or add them back after the start of compression.
1045 *
1046 * NOTE: this is a nasty constraint on the code, because it means that the
1047 * prev_row buffer must be maintained even if there are currently no
1048 * 'prev_row' requiring filters active.
1049 */
1050 if (png_ptr->row_buf != NULL)
1051 {
1052 int num_filters;
1053 png_alloc_size_t buf_size;
1054
1055 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1056 * images cannot benefit from certain filters. If this isn't done here
1057 * the check below will fire on 1 pixel high images.
1058 */
1059 if (png_ptr->height == 1)
1060 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1061
1062 if (png_ptr->width == 1)
1063 filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1064
1065 if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
1066 && png_ptr->prev_row == NULL)
1067 {
1068 /* This is the error case, however it is benign - the previous row
1069 * is not available so the filter can't be used. Just warn here.
1070 */
1071 png_app_warning(png_ptr,
1072 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1073 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1074 }
1075
1076 num_filters = 0;
1077
1078 if (filters & PNG_FILTER_SUB)
1079 num_filters++;
1080
1081 if (filters & PNG_FILTER_UP)
1082 num_filters++;
1083
1084 if (filters & PNG_FILTER_AVG)
1085 num_filters++;
1086
1087 if (filters & PNG_FILTER_PAETH)
1088 num_filters++;
1089
1090 /* Allocate needed row buffers if they have not already been
1091 * allocated.
1092 */
1093 buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1094 png_ptr->width) + 1;
1095
1096 if (png_ptr->try_row == NULL)
1097 png_ptr->try_row = png_voidcast(png_bytep,
1098 png_malloc(png_ptr, buf_size));
1099
1100 if (num_filters > 1)
1101 {
1102 if (png_ptr->tst_row == NULL)
1103 png_ptr->tst_row = png_voidcast(png_bytep,
1104 png_malloc(png_ptr, buf_size));
1105 }
1106 }
1107 png_ptr->do_filter = (png_byte)filters;
1108 #endif
1109 }
1110 else
1111 png_error(png_ptr, "Unknown custom filter method");
1112 }
1113
1114 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1115 /* Provide floating and fixed point APIs */
1116 #ifdef PNG_FLOATING_POINT_SUPPORTED
1117 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)1118 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1119 int num_weights, png_const_doublep filter_weights,
1120 png_const_doublep filter_costs)
1121 {
1122 PNG_UNUSED(png_ptr)
1123 PNG_UNUSED(heuristic_method)
1124 PNG_UNUSED(num_weights)
1125 PNG_UNUSED(filter_weights)
1126 PNG_UNUSED(filter_costs)
1127 }
1128 #endif /* FLOATING_POINT */
1129
1130 #ifdef PNG_FIXED_POINT_SUPPORTED
1131 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)1132 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1133 int num_weights, png_const_fixed_point_p filter_weights,
1134 png_const_fixed_point_p filter_costs)
1135 {
1136 PNG_UNUSED(png_ptr)
1137 PNG_UNUSED(heuristic_method)
1138 PNG_UNUSED(num_weights)
1139 PNG_UNUSED(filter_weights)
1140 PNG_UNUSED(filter_costs)
1141 }
1142 #endif /* FIXED_POINT */
1143 #endif /* WRITE_WEIGHTED_FILTER */
1144
1145 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1146 void PNGAPI
png_set_compression_level(png_structrp png_ptr,int level)1147 png_set_compression_level(png_structrp png_ptr, int level)
1148 {
1149 png_debug(1, "in png_set_compression_level");
1150
1151 if (png_ptr == NULL)
1152 return;
1153
1154 png_ptr->zlib_level = level;
1155 }
1156
1157 void PNGAPI
png_set_compression_mem_level(png_structrp png_ptr,int mem_level)1158 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1159 {
1160 png_debug(1, "in png_set_compression_mem_level");
1161
1162 if (png_ptr == NULL)
1163 return;
1164
1165 png_ptr->zlib_mem_level = mem_level;
1166 }
1167
1168 void PNGAPI
png_set_compression_strategy(png_structrp png_ptr,int strategy)1169 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1170 {
1171 png_debug(1, "in png_set_compression_strategy");
1172
1173 if (png_ptr == NULL)
1174 return;
1175
1176 /* The flag setting here prevents the libpng dynamic selection of strategy.
1177 */
1178 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1179 png_ptr->zlib_strategy = strategy;
1180 }
1181
1182 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1183 * smaller value of window_bits if it can do so safely.
1184 */
1185 void PNGAPI
png_set_compression_window_bits(png_structrp png_ptr,int window_bits)1186 png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1187 {
1188 if (png_ptr == NULL)
1189 return;
1190
1191 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1192 * meant that negative window bits values could be selected that would cause
1193 * libpng to write a non-standard PNG file with raw deflate or gzip
1194 * compressed IDAT or ancillary chunks. Such files can be read and there is
1195 * no warning on read, so this seems like a very bad idea.
1196 */
1197 if (window_bits > 15)
1198 {
1199 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1200 window_bits = 15;
1201 }
1202
1203 else if (window_bits < 8)
1204 {
1205 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1206 window_bits = 8;
1207 }
1208
1209 png_ptr->zlib_window_bits = window_bits;
1210 }
1211
1212 void PNGAPI
png_set_compression_method(png_structrp png_ptr,int method)1213 png_set_compression_method(png_structrp png_ptr, int method)
1214 {
1215 png_debug(1, "in png_set_compression_method");
1216
1217 if (png_ptr == NULL)
1218 return;
1219
1220 /* This would produce an invalid PNG file if it worked, but it doesn't and
1221 * deflate will fault it, so it is harmless to just warn here.
1222 */
1223 if (method != 8)
1224 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1225
1226 png_ptr->zlib_method = method;
1227 }
1228 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1229
1230 /* The following were added to libpng-1.5.4 */
1231 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1232 void PNGAPI
png_set_text_compression_level(png_structrp png_ptr,int level)1233 png_set_text_compression_level(png_structrp png_ptr, int level)
1234 {
1235 png_debug(1, "in png_set_text_compression_level");
1236
1237 if (png_ptr == NULL)
1238 return;
1239
1240 png_ptr->zlib_text_level = level;
1241 }
1242
1243 void PNGAPI
png_set_text_compression_mem_level(png_structrp png_ptr,int mem_level)1244 png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1245 {
1246 png_debug(1, "in png_set_text_compression_mem_level");
1247
1248 if (png_ptr == NULL)
1249 return;
1250
1251 png_ptr->zlib_text_mem_level = mem_level;
1252 }
1253
1254 void PNGAPI
png_set_text_compression_strategy(png_structrp png_ptr,int strategy)1255 png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1256 {
1257 png_debug(1, "in png_set_text_compression_strategy");
1258
1259 if (png_ptr == NULL)
1260 return;
1261
1262 png_ptr->zlib_text_strategy = strategy;
1263 }
1264
1265 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1266 * smaller value of window_bits if it can do so safely.
1267 */
1268 void PNGAPI
png_set_text_compression_window_bits(png_structrp png_ptr,int window_bits)1269 png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1270 {
1271 if (png_ptr == NULL)
1272 return;
1273
1274 if (window_bits > 15)
1275 {
1276 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1277 window_bits = 15;
1278 }
1279
1280 else if (window_bits < 8)
1281 {
1282 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1283 window_bits = 8;
1284 }
1285
1286 png_ptr->zlib_text_window_bits = window_bits;
1287 }
1288
1289 void PNGAPI
png_set_text_compression_method(png_structrp png_ptr,int method)1290 png_set_text_compression_method(png_structrp png_ptr, int method)
1291 {
1292 png_debug(1, "in png_set_text_compression_method");
1293
1294 if (png_ptr == NULL)
1295 return;
1296
1297 if (method != 8)
1298 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1299
1300 png_ptr->zlib_text_method = method;
1301 }
1302 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1303 /* end of API added to libpng-1.5.4 */
1304
1305 void PNGAPI
png_set_write_status_fn(png_structrp png_ptr,png_write_status_ptr write_row_fn)1306 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1307 {
1308 if (png_ptr == NULL)
1309 return;
1310
1311 png_ptr->write_row_fn = write_row_fn;
1312 }
1313
1314 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1315 void PNGAPI
png_set_write_user_transform_fn(png_structrp png_ptr,png_user_transform_ptr write_user_transform_fn)1316 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1317 write_user_transform_fn)
1318 {
1319 png_debug(1, "in png_set_write_user_transform_fn");
1320
1321 if (png_ptr == NULL)
1322 return;
1323
1324 png_ptr->transformations |= PNG_USER_TRANSFORM;
1325 png_ptr->write_user_transform_fn = write_user_transform_fn;
1326 }
1327 #endif
1328
1329
1330 #ifdef PNG_INFO_IMAGE_SUPPORTED
1331 void PNGAPI
png_write_png(png_structrp png_ptr,png_inforp info_ptr,int transforms,voidp params)1332 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1333 int transforms, voidp params)
1334 {
1335 if (png_ptr == NULL || info_ptr == NULL)
1336 return;
1337
1338 if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1339 {
1340 png_app_error(png_ptr, "no rows for png_write_image to write");
1341 return;
1342 }
1343
1344 /* Write the file header information. */
1345 png_write_info(png_ptr, info_ptr);
1346
1347 /* ------ these transformations don't touch the info structure ------- */
1348
1349 /* Invert monochrome pixels */
1350 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1351 #ifdef PNG_WRITE_INVERT_SUPPORTED
1352 png_set_invert_mono(png_ptr);
1353 #else
1354 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1355 #endif
1356
1357 /* Shift the pixels up to a legal bit depth and fill in
1358 * as appropriate to correctly scale the image.
1359 */
1360 if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1361 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1362 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1363 png_set_shift(png_ptr, &info_ptr->sig_bit);
1364 #else
1365 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1366 #endif
1367
1368 /* Pack pixels into bytes */
1369 if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1370 #ifdef PNG_WRITE_PACK_SUPPORTED
1371 png_set_packing(png_ptr);
1372 #else
1373 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1374 #endif
1375
1376 /* Swap location of alpha bytes from ARGB to RGBA */
1377 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1378 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1379 png_set_swap_alpha(png_ptr);
1380 #else
1381 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1382 #endif
1383
1384 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1385 * RGB, note that the code expects the input color type to be G or RGB; no
1386 * alpha channel.
1387 */
1388 if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
1389 PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1390 {
1391 #ifdef PNG_WRITE_FILLER_SUPPORTED
1392 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1393 {
1394 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1395 png_app_error(png_ptr,
1396 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1397
1398 /* Continue if ignored - this is the pre-1.6.10 behavior */
1399 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1400 }
1401
1402 else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1403 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1404 #else
1405 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1406 #endif
1407 }
1408
1409 /* Flip BGR pixels to RGB */
1410 if ((transforms & PNG_TRANSFORM_BGR) != 0)
1411 #ifdef PNG_WRITE_BGR_SUPPORTED
1412 png_set_bgr(png_ptr);
1413 #else
1414 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1415 #endif
1416
1417 /* Swap bytes of 16-bit files to most significant byte first */
1418 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1419 #ifdef PNG_WRITE_SWAP_SUPPORTED
1420 png_set_swap(png_ptr);
1421 #else
1422 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1423 #endif
1424
1425 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1426 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1427 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1428 png_set_packswap(png_ptr);
1429 #else
1430 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1431 #endif
1432
1433 /* Invert the alpha channel from opacity to transparency */
1434 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1435 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1436 png_set_invert_alpha(png_ptr);
1437 #else
1438 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1439 #endif
1440
1441 /* ----------------------- end of transformations ------------------- */
1442
1443 /* Write the bits */
1444 png_write_image(png_ptr, info_ptr->row_pointers);
1445
1446 /* It is REQUIRED to call this to finish writing the rest of the file */
1447 png_write_end(png_ptr, info_ptr);
1448
1449 PNG_UNUSED(params)
1450 }
1451 #endif
1452
1453
1454 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1455 /* Initialize the write structure - general purpose utility. */
1456 static int
png_image_write_init(png_imagep image)1457 png_image_write_init(png_imagep image)
1458 {
1459 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1460 png_safe_error, png_safe_warning);
1461
1462 if (png_ptr != NULL)
1463 {
1464 png_infop info_ptr = png_create_info_struct(png_ptr);
1465
1466 if (info_ptr != NULL)
1467 {
1468 png_controlp control = png_voidcast(png_controlp,
1469 png_malloc_warn(png_ptr, (sizeof *control)));
1470
1471 if (control != NULL)
1472 {
1473 memset(control, 0, (sizeof *control));
1474
1475 control->png_ptr = png_ptr;
1476 control->info_ptr = info_ptr;
1477 control->for_write = 1;
1478
1479 image->opaque = control;
1480 return 1;
1481 }
1482
1483 /* Error clean up */
1484 png_destroy_info_struct(png_ptr, &info_ptr);
1485 }
1486
1487 png_destroy_write_struct(&png_ptr, NULL);
1488 }
1489
1490 return png_image_error(image, "png_image_write_: out of memory");
1491 }
1492
1493 /* Arguments to png_image_write_main: */
1494 typedef struct
1495 {
1496 /* Arguments: */
1497 png_imagep image;
1498 png_const_voidp buffer;
1499 png_int_32 row_stride;
1500 png_const_voidp colormap;
1501 int convert_to_8bit;
1502 /* Local variables: */
1503 png_const_voidp first_row;
1504 ptrdiff_t row_bytes;
1505 png_voidp local_row;
1506 /* Byte count for memory writing */
1507 png_bytep memory;
1508 png_alloc_size_t memory_bytes; /* not used for STDIO */
1509 png_alloc_size_t output_bytes; /* running total */
1510 } png_image_write_control;
1511
1512 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1513 * do any necessary byte swapping. The component order is defined by the
1514 * png_image format value.
1515 */
1516 static int
png_write_image_16bit(png_voidp argument)1517 png_write_image_16bit(png_voidp argument)
1518 {
1519 png_image_write_control *display = png_voidcast(png_image_write_control*,
1520 argument);
1521 png_imagep image = display->image;
1522 png_structrp png_ptr = image->opaque->png_ptr;
1523
1524 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1525 display->first_row);
1526 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1527 png_uint_16p row_end;
1528 const unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1529 3 : 1;
1530 int aindex = 0;
1531 png_uint_32 y = image->height;
1532
1533 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1534 {
1535 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1536 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1537 {
1538 aindex = -1;
1539 ++input_row; /* To point to the first component */
1540 ++output_row;
1541 }
1542 else
1543 aindex = (int)channels;
1544 # else
1545 aindex = (int)channels;
1546 # endif
1547 }
1548
1549 else
1550 png_error(png_ptr, "png_write_image: internal call error");
1551
1552 /* Work out the output row end and count over this, note that the increment
1553 * above to 'row' means that row_end can actually be beyond the end of the
1554 * row; this is correct.
1555 */
1556 row_end = output_row + image->width * (channels+1);
1557
1558 for (; y > 0; --y)
1559 {
1560 png_const_uint_16p in_ptr = input_row;
1561 png_uint_16p out_ptr = output_row;
1562
1563 while (out_ptr < row_end)
1564 {
1565 const png_uint_16 alpha = in_ptr[aindex];
1566 png_uint_32 reciprocal = 0;
1567 int c;
1568
1569 out_ptr[aindex] = alpha;
1570
1571 /* Calculate a reciprocal. The correct calculation is simply
1572 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1573 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1574 * is only initialized when required.
1575 */
1576 if (alpha > 0 && alpha < 65535)
1577 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1578
1579 c = (int)channels;
1580 do /* always at least one channel */
1581 {
1582 png_uint_16 component = *in_ptr++;
1583
1584 /* The following gives 65535 for an alpha of 0, which is fine,
1585 * otherwise if 0/0 is represented as some other value there is more
1586 * likely to be a discontinuity which will probably damage
1587 * compression when moving from a fully transparent area to a
1588 * nearly transparent one. (The assumption here is that opaque
1589 * areas tend not to be 0 intensity.)
1590 */
1591 if (component >= alpha)
1592 component = 65535;
1593
1594 /* component<alpha, so component/alpha is less than one and
1595 * component*reciprocal is less than 2^31.
1596 */
1597 else if (component > 0 && alpha < 65535)
1598 {
1599 png_uint_32 calc = component * reciprocal;
1600 calc += 16384; /* round to nearest */
1601 component = (png_uint_16)(calc >> 15);
1602 }
1603
1604 *out_ptr++ = component;
1605 }
1606 while (--c > 0);
1607
1608 /* Skip to next component (skip the intervening alpha channel) */
1609 ++in_ptr;
1610 ++out_ptr;
1611 }
1612
1613 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1614 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1615 }
1616
1617 return 1;
1618 }
1619
1620 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1621 * is present it must be removed from the components, the components are then
1622 * written in sRGB encoding. No components are added or removed.
1623 *
1624 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1625 * calculation can be done to 15 bits of accuracy; however, the output needs to
1626 * be scaled in the range 0..255*65535, so include that scaling here.
1627 */
1628 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
1629
1630 static png_byte
png_unpremultiply(png_uint_32 component,png_uint_32 alpha,png_uint_32 reciprocal)1631 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1632 png_uint_32 reciprocal/*from the above macro*/)
1633 {
1634 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1635 * is represented as some other value there is more likely to be a
1636 * discontinuity which will probably damage compression when moving from a
1637 * fully transparent area to a nearly transparent one. (The assumption here
1638 * is that opaque areas tend not to be 0 intensity.)
1639 *
1640 * There is a rounding problem here; if alpha is less than 128 it will end up
1641 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1642 * output change for this too.
1643 */
1644 if (component >= alpha || alpha < 128)
1645 return 255;
1646
1647 /* component<alpha, so component/alpha is less than one and
1648 * component*reciprocal is less than 2^31.
1649 */
1650 else if (component > 0)
1651 {
1652 /* The test is that alpha/257 (rounded) is less than 255, the first value
1653 * that becomes 255 is 65407.
1654 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1655 * be exact!) [Could also test reciprocal != 0]
1656 */
1657 if (alpha < 65407)
1658 {
1659 component *= reciprocal;
1660 component += 64; /* round to nearest */
1661 component >>= 7;
1662 }
1663
1664 else
1665 component *= 255;
1666
1667 /* Convert the component to sRGB. */
1668 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1669 }
1670
1671 else
1672 return 0;
1673 }
1674
1675 static int
png_write_image_8bit(png_voidp argument)1676 png_write_image_8bit(png_voidp argument)
1677 {
1678 png_image_write_control *display = png_voidcast(png_image_write_control*,
1679 argument);
1680 png_imagep image = display->image;
1681 png_structrp png_ptr = image->opaque->png_ptr;
1682
1683 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1684 display->first_row);
1685 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1686 png_uint_32 y = image->height;
1687 const unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1688 3 : 1;
1689
1690 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1691 {
1692 png_bytep row_end;
1693 int aindex;
1694
1695 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1696 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1697 {
1698 aindex = -1;
1699 ++input_row; /* To point to the first component */
1700 ++output_row;
1701 }
1702
1703 else
1704 # endif
1705 aindex = (int)channels;
1706
1707 /* Use row_end in place of a loop counter: */
1708 row_end = output_row + image->width * (channels+1);
1709
1710 for (; y > 0; --y)
1711 {
1712 png_const_uint_16p in_ptr = input_row;
1713 png_bytep out_ptr = output_row;
1714
1715 while (out_ptr < row_end)
1716 {
1717 png_uint_16 alpha = in_ptr[aindex];
1718 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1719 png_uint_32 reciprocal = 0;
1720 int c;
1721
1722 /* Scale and write the alpha channel. */
1723 out_ptr[aindex] = alphabyte;
1724
1725 if (alphabyte > 0 && alphabyte < 255)
1726 reciprocal = UNP_RECIPROCAL(alpha);
1727
1728 c = (int)channels;
1729 do /* always at least one channel */
1730 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1731 while (--c > 0);
1732
1733 /* Skip to next component (skip the intervening alpha channel) */
1734 ++in_ptr;
1735 ++out_ptr;
1736 } /* while out_ptr < row_end */
1737
1738 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1739 display->local_row));
1740 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1741 } /* while y */
1742 }
1743
1744 else
1745 {
1746 /* No alpha channel, so the row_end really is the end of the row and it
1747 * is sufficient to loop over the components one by one.
1748 */
1749 png_bytep row_end = output_row + image->width * channels;
1750
1751 for (; y > 0; --y)
1752 {
1753 png_const_uint_16p in_ptr = input_row;
1754 png_bytep out_ptr = output_row;
1755
1756 while (out_ptr < row_end)
1757 {
1758 png_uint_32 component = *in_ptr++;
1759
1760 component *= 255;
1761 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1762 }
1763
1764 png_write_row(png_ptr, output_row);
1765 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1766 }
1767 }
1768
1769 return 1;
1770 }
1771
1772 static void
png_image_set_PLTE(png_image_write_control * display)1773 png_image_set_PLTE(png_image_write_control *display)
1774 {
1775 const png_imagep image = display->image;
1776 const void *cmap = display->colormap;
1777 const int entries = image->colormap_entries > 256 ? 256 :
1778 (int)image->colormap_entries;
1779
1780 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1781 const png_uint_32 format = image->format;
1782 const unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1783
1784 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1785 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1786 const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1787 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1788 # else
1789 # define afirst 0
1790 # endif
1791
1792 # ifdef PNG_FORMAT_BGR_SUPPORTED
1793 const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1794 # else
1795 # define bgr 0
1796 # endif
1797
1798 int i, num_trans;
1799 png_color palette[256];
1800 png_byte tRNS[256];
1801
1802 memset(tRNS, 255, (sizeof tRNS));
1803 memset(palette, 0, (sizeof palette));
1804
1805 for (i=num_trans=0; i<entries; ++i)
1806 {
1807 /* This gets automatically converted to sRGB with reversal of the
1808 * pre-multiplication if the color-map has an alpha channel.
1809 */
1810 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1811 {
1812 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1813
1814 entry += (unsigned int)i * channels;
1815
1816 if ((channels & 1) != 0) /* no alpha */
1817 {
1818 if (channels >= 3) /* RGB */
1819 {
1820 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1821 entry[(2 ^ bgr)]);
1822 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1823 entry[1]);
1824 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1825 entry[bgr]);
1826 }
1827
1828 else /* Gray */
1829 palette[i].blue = palette[i].red = palette[i].green =
1830 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1831 }
1832
1833 else /* alpha */
1834 {
1835 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1836 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1837 png_uint_32 reciprocal = 0;
1838
1839 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1840 * this is designed to produce a value scaled to 255*65535 when
1841 * divided by 128 (i.e. asr 7).
1842 */
1843 if (alphabyte > 0 && alphabyte < 255)
1844 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1845
1846 tRNS[i] = alphabyte;
1847 if (alphabyte < 255)
1848 num_trans = i+1;
1849
1850 if (channels >= 3) /* RGB */
1851 {
1852 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1853 alpha, reciprocal);
1854 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1855 reciprocal);
1856 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1857 reciprocal);
1858 }
1859
1860 else /* gray */
1861 palette[i].blue = palette[i].red = palette[i].green =
1862 png_unpremultiply(entry[afirst], alpha, reciprocal);
1863 }
1864 }
1865
1866 else /* Color-map has sRGB values */
1867 {
1868 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1869
1870 entry += (unsigned int)i * channels;
1871
1872 switch (channels)
1873 {
1874 case 4:
1875 tRNS[i] = entry[afirst ? 0 : 3];
1876 if (tRNS[i] < 255)
1877 num_trans = i+1;
1878 /* FALL THROUGH */
1879 case 3:
1880 palette[i].blue = entry[afirst + (2 ^ bgr)];
1881 palette[i].green = entry[afirst + 1];
1882 palette[i].red = entry[afirst + bgr];
1883 break;
1884
1885 case 2:
1886 tRNS[i] = entry[1 ^ afirst];
1887 if (tRNS[i] < 255)
1888 num_trans = i+1;
1889 /* FALL THROUGH */
1890 case 1:
1891 palette[i].blue = palette[i].red = palette[i].green =
1892 entry[afirst];
1893 break;
1894
1895 default:
1896 break;
1897 }
1898 }
1899 }
1900
1901 # ifdef afirst
1902 # undef afirst
1903 # endif
1904 # ifdef bgr
1905 # undef bgr
1906 # endif
1907
1908 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
1909 entries);
1910
1911 if (num_trans > 0)
1912 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
1913 num_trans, NULL);
1914
1915 image->colormap_entries = (png_uint_32)entries;
1916 }
1917
1918 static int
png_image_write_main(png_voidp argument)1919 png_image_write_main(png_voidp argument)
1920 {
1921 png_image_write_control *display = png_voidcast(png_image_write_control*,
1922 argument);
1923 png_imagep image = display->image;
1924 png_structrp png_ptr = image->opaque->png_ptr;
1925 png_inforp info_ptr = image->opaque->info_ptr;
1926 png_uint_32 format = image->format;
1927
1928 /* The following four ints are actually booleans */
1929 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
1930 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
1931 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
1932 int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);
1933
1934 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
1935 /* Make sure we error out on any bad situation */
1936 png_set_benign_errors(png_ptr, 0/*error*/);
1937 # endif
1938
1939 /* Default the 'row_stride' parameter if required, also check the row stride
1940 * and total image size to ensure that they are within the system limits.
1941 */
1942 {
1943 const unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
1944
1945 if (image->width <= 0x7fffffffU/channels) /* no overflow */
1946 {
1947 png_uint_32 check;
1948 const png_uint_32 png_row_stride = image->width * channels;
1949
1950 if (display->row_stride == 0)
1951 display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
1952
1953 if (display->row_stride < 0)
1954 check = (png_uint_32)(-display->row_stride);
1955
1956 else
1957 check = (png_uint_32)display->row_stride;
1958
1959 if (check >= png_row_stride)
1960 {
1961 /* Now check for overflow of the image buffer calculation; this
1962 * limits the whole image size to 32 bits for API compatibility with
1963 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
1964 */
1965 if (image->height > 0xffffffffU/png_row_stride)
1966 png_error(image->opaque->png_ptr, "memory image too large");
1967 }
1968
1969 else
1970 png_error(image->opaque->png_ptr, "supplied row stride too small");
1971 }
1972
1973 else
1974 png_error(image->opaque->png_ptr, "image row stride too large");
1975 }
1976
1977 /* Set the required transforms then write the rows in the correct order. */
1978 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
1979 {
1980 if (display->colormap != NULL && image->colormap_entries > 0)
1981 {
1982 png_uint_32 entries = image->colormap_entries;
1983
1984 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
1985 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
1986 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
1987 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
1988
1989 png_image_set_PLTE(display);
1990 }
1991
1992 else
1993 png_error(image->opaque->png_ptr,
1994 "no color-map for color-mapped image");
1995 }
1996
1997 else
1998 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
1999 write_16bit ? 16 : 8,
2000 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2001 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2002 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2003
2004 /* Counter-intuitively the data transformations must be called *after*
2005 * png_write_info, not before as in the read code, but the 'set' functions
2006 * must still be called before. Just set the color space information, never
2007 * write an interlaced image.
2008 */
2009
2010 if (write_16bit != 0)
2011 {
2012 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2013 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2014
2015 if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2016 png_set_cHRM_fixed(png_ptr, info_ptr,
2017 /* color x y */
2018 /* white */ 31270, 32900,
2019 /* red */ 64000, 33000,
2020 /* green */ 30000, 60000,
2021 /* blue */ 15000, 6000
2022 );
2023 }
2024
2025 else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2026 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2027
2028 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2029 * space must still be gamma encoded.
2030 */
2031 else
2032 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2033
2034 /* Write the file header. */
2035 png_write_info(png_ptr, info_ptr);
2036
2037 /* Now set up the data transformations (*after* the header is written),
2038 * remove the handled transformations from the 'format' flags for checking.
2039 *
2040 * First check for a little endian system if writing 16-bit files.
2041 */
2042 if (write_16bit != 0)
2043 {
2044 PNG_CONST png_uint_16 le = 0x0001;
2045
2046 if ((*(png_const_bytep) & le) != 0)
2047 png_set_swap(png_ptr);
2048 }
2049
2050 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2051 if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2052 {
2053 if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2054 png_set_bgr(png_ptr);
2055 format &= ~PNG_FORMAT_FLAG_BGR;
2056 }
2057 # endif
2058
2059 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2060 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2061 {
2062 if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2063 png_set_swap_alpha(png_ptr);
2064 format &= ~PNG_FORMAT_FLAG_AFIRST;
2065 }
2066 # endif
2067
2068 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2069 * above, but the application data is still byte packed.
2070 */
2071 if (colormap != 0 && image->colormap_entries <= 16)
2072 png_set_packing(png_ptr);
2073
2074 /* That should have handled all (both) the transforms. */
2075 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2076 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2077 png_error(png_ptr, "png_write_image: unsupported transformation");
2078
2079 {
2080 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2081 ptrdiff_t row_bytes = display->row_stride;
2082
2083 if (linear != 0)
2084 row_bytes *= (sizeof (png_uint_16));
2085
2086 if (row_bytes < 0)
2087 row += (image->height-1) * (-row_bytes);
2088
2089 display->first_row = row;
2090 display->row_bytes = row_bytes;
2091 }
2092
2093 /* Apply 'fast' options if the flag is set. */
2094 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2095 {
2096 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2097 /* NOTE: determined by experiment using pngstest, this reflects some
2098 * balance between the time to write the image once and the time to read
2099 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2100 * total (user) time on a heavily loaded system.
2101 */
2102 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2103 png_set_compression_level(png_ptr, 3);
2104 # endif
2105 }
2106
2107 /* Check for the cases that currently require a pre-transform on the row
2108 * before it is written. This only applies when the input is 16-bit and
2109 * either there is an alpha channel or it is converted to 8-bit.
2110 */
2111 if ((linear != 0 && alpha != 0 ) ||
2112 (colormap == 0 && display->convert_to_8bit != 0))
2113 {
2114 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2115 png_get_rowbytes(png_ptr, info_ptr)));
2116 int result;
2117
2118 display->local_row = row;
2119 if (write_16bit != 0)
2120 result = png_safe_execute(image, png_write_image_16bit, display);
2121 else
2122 result = png_safe_execute(image, png_write_image_8bit, display);
2123 display->local_row = NULL;
2124
2125 png_free(png_ptr, row);
2126
2127 /* Skip the 'write_end' on error: */
2128 if (result == 0)
2129 return 0;
2130 }
2131
2132 /* Otherwise this is the case where the input is in a format currently
2133 * supported by the rest of the libpng write code; call it directly.
2134 */
2135 else
2136 {
2137 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2138 ptrdiff_t row_bytes = display->row_bytes;
2139 png_uint_32 y = image->height;
2140
2141 for (; y > 0; --y)
2142 {
2143 png_write_row(png_ptr, row);
2144 row += row_bytes;
2145 }
2146 }
2147
2148 png_write_end(png_ptr, info_ptr);
2149 return 1;
2150 }
2151
2152
2153 static void (PNGCBAPI
2154 image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data,
2155 png_size_t size)
2156 {
2157 png_image_write_control *display = png_voidcast(png_image_write_control*,
2158 png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
2159 const png_alloc_size_t ob = display->output_bytes;
2160
2161 /* Check for overflow; this should never happen: */
2162 if (size <= ((png_alloc_size_t)-1) - ob)
2163 {
2164 /* I don't think libpng ever does this, but just in case: */
2165 if (size > 0)
2166 {
2167 if (display->memory_bytes >= ob+size) /* writing */
2168 memcpy(display->memory+ob, data, size);
2169
2170 /* Always update the size: */
2171 display->output_bytes = ob+size;
2172 }
2173 }
2174
2175 else
2176 png_error(png_ptr, "png_image_write_to_memory: PNG too big");
2177 }
2178
2179 static void (PNGCBAPI
2180 image_memory_flush)(png_structp png_ptr)
2181 {
2182 PNG_UNUSED(png_ptr)
2183 }
2184
2185 static int
png_image_write_memory(png_voidp argument)2186 png_image_write_memory(png_voidp argument)
2187 {
2188 png_image_write_control *display = png_voidcast(png_image_write_control*,
2189 argument);
2190
2191 /* The rest of the memory-specific init and write_main in an error protected
2192 * environment. This case needs to use callbacks for the write operations
2193 * since libpng has no built in support for writing to memory.
2194 */
2195 png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
2196 image_memory_write, image_memory_flush);
2197
2198 return png_image_write_main(display);
2199 }
2200
2201 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)2202 png_image_write_to_memory(png_imagep image, void *memory,
2203 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
2204 const void *buffer, png_int_32 row_stride, const void *colormap)
2205 {
2206 /* Write the image to the given buffer, or count the bytes if it is NULL */
2207 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2208 {
2209 if (memory_bytes != NULL && buffer != NULL)
2210 {
2211 /* This is to give the caller an easier error detection in the NULL
2212 * case and guard against uninitialized variable problems:
2213 */
2214 if (memory == NULL)
2215 *memory_bytes = 0;
2216
2217 if (png_image_write_init(image) != 0)
2218 {
2219 png_image_write_control display;
2220 int result;
2221
2222 memset(&display, 0, (sizeof display));
2223 display.image = image;
2224 display.buffer = buffer;
2225 display.row_stride = row_stride;
2226 display.colormap = colormap;
2227 display.convert_to_8bit = convert_to_8bit;
2228 display.memory = png_voidcast(png_bytep, memory);
2229 display.memory_bytes = *memory_bytes;
2230 display.output_bytes = 0;
2231
2232 result = png_safe_execute(image, png_image_write_memory, &display);
2233 png_image_free(image);
2234
2235 /* write_memory returns true even if we ran out of buffer. */
2236 if (result)
2237 {
2238 /* On out-of-buffer this function returns '0' but still updates
2239 * memory_bytes:
2240 */
2241 if (memory != NULL && display.output_bytes > *memory_bytes)
2242 result = 0;
2243
2244 *memory_bytes = display.output_bytes;
2245 }
2246
2247 return result;
2248 }
2249
2250 else
2251 return 0;
2252 }
2253
2254 else
2255 return png_image_error(image,
2256 "png_image_write_to_memory: invalid argument");
2257 }
2258
2259 else if (image != NULL)
2260 return png_image_error(image,
2261 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2262
2263 else
2264 return 0;
2265 }
2266
2267 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2268 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)2269 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2270 const void *buffer, png_int_32 row_stride, const void *colormap)
2271 {
2272 /* Write the image to the given (FILE*). */
2273 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2274 {
2275 if (file != NULL && buffer != NULL)
2276 {
2277 if (png_image_write_init(image) != 0)
2278 {
2279 png_image_write_control display;
2280 int result;
2281
2282 /* This is slightly evil, but png_init_io doesn't do anything other
2283 * than this and we haven't changed the standard IO functions so
2284 * this saves a 'safe' function.
2285 */
2286 image->opaque->png_ptr->io_ptr = file;
2287
2288 memset(&display, 0, (sizeof display));
2289 display.image = image;
2290 display.buffer = buffer;
2291 display.row_stride = row_stride;
2292 display.colormap = colormap;
2293 display.convert_to_8bit = convert_to_8bit;
2294
2295 result = png_safe_execute(image, png_image_write_main, &display);
2296 png_image_free(image);
2297 return result;
2298 }
2299
2300 else
2301 return 0;
2302 }
2303
2304 else
2305 return png_image_error(image,
2306 "png_image_write_to_stdio: invalid argument");
2307 }
2308
2309 else if (image != NULL)
2310 return png_image_error(image,
2311 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2312
2313 else
2314 return 0;
2315 }
2316
2317 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)2318 png_image_write_to_file(png_imagep image, const char *file_name,
2319 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2320 const void *colormap)
2321 {
2322 /* Write the image to the named file. */
2323 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2324 {
2325 if (file_name != NULL && buffer != NULL)
2326 {
2327 FILE *fp = fopen(file_name, "wb");
2328
2329 if (fp != NULL)
2330 {
2331 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2332 row_stride, colormap) != 0)
2333 {
2334 int error; /* from fflush/fclose */
2335
2336 /* Make sure the file is flushed correctly. */
2337 if (fflush(fp) == 0 && ferror(fp) == 0)
2338 {
2339 if (fclose(fp) == 0)
2340 return 1;
2341
2342 error = errno; /* from fclose */
2343 }
2344
2345 else
2346 {
2347 error = errno; /* from fflush or ferror */
2348 (void)fclose(fp);
2349 }
2350
2351 (void)remove(file_name);
2352 /* The image has already been cleaned up; this is just used to
2353 * set the error (because the original write succeeded).
2354 */
2355 return png_image_error(image, strerror(error));
2356 }
2357
2358 else
2359 {
2360 /* Clean up: just the opened file. */
2361 (void)fclose(fp);
2362 (void)remove(file_name);
2363 return 0;
2364 }
2365 }
2366
2367 else
2368 return png_image_error(image, strerror(errno));
2369 }
2370
2371 else
2372 return png_image_error(image,
2373 "png_image_write_to_file: invalid argument");
2374 }
2375
2376 else if (image != NULL)
2377 return png_image_error(image,
2378 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2379
2380 else
2381 return 0;
2382 }
2383 #endif /* SIMPLIFIED_WRITE_STDIO */
2384 #endif /* SIMPLIFIED_WRITE */
2385 #endif /* WRITE */
2386