1
2 /* pngwrite.c - general routines to write a PNG file
3 *
4 * Last changed in libpng 1.6.2 [April 25, 2013]
5 * Copyright (c) 1998-2013 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 #include "pngpriv.h"
14 #if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
15 # include <errno.h>
16 #endif
17
18 #ifdef PNG_WRITE_SUPPORTED
19
20 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
21 /* Write out all the unknown chunks for the current given location */
22 static void
write_unknown_chunks(png_structrp png_ptr,png_const_inforp info_ptr,unsigned int where)23 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
24 unsigned int where)
25 {
26 if (info_ptr->unknown_chunks_num)
27 {
28 png_const_unknown_chunkp up;
29
30 png_debug(5, "writing extra chunks");
31
32 for (up = info_ptr->unknown_chunks;
33 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
34 ++up)
35 if (up->location & where)
36 {
37 /* If per-chunk unknown chunk handling is enabled use it, otherwise
38 * just write the chunks the application has set.
39 */
40 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
41 int keep = png_handle_as_unknown(png_ptr, up->name);
42
43 /* NOTE: this code is radically different from the read side in the
44 * matter of handling an ancillary unknown chunk. In the read side
45 * the default behavior is to discard it, in the code below the default
46 * behavior is to write it. Critical chunks are, however, only
47 * written if explicitly listed or if the default is set to write all
48 * unknown chunks.
49 *
50 * The default handling is also slightly weird - it is not possible to
51 * stop the writing of all unsafe-to-copy chunks!
52 *
53 * TODO: REVIEW: this would seem to be a bug.
54 */
55 if (keep != PNG_HANDLE_CHUNK_NEVER &&
56 ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
57 keep == PNG_HANDLE_CHUNK_ALWAYS ||
58 (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
59 png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
60 #endif
61 {
62 /* TODO: review, what is wrong with a zero length unknown chunk? */
63 if (up->size == 0)
64 png_warning(png_ptr, "Writing zero-length unknown chunk");
65
66 png_write_chunk(png_ptr, up->name, up->data, up->size);
67 }
68 }
69 }
70 }
71 #endif /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */
72
73 /* Writes all the PNG information. This is the suggested way to use the
74 * library. If you have a new chunk to add, make a function to write it,
75 * and put it in the correct location here. If you want the chunk written
76 * after the image data, put it in png_write_end(). I strongly encourage
77 * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
78 * the chunk, as that will keep the code from breaking if you want to just
79 * write a plain PNG file. If you have long comments, I suggest writing
80 * them in png_write_end(), and compressing them.
81 */
82 void PNGAPI
png_write_info_before_PLTE(png_structrp png_ptr,png_const_inforp info_ptr)83 png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
84 {
85 png_debug(1, "in png_write_info_before_PLTE");
86
87 if (png_ptr == NULL || info_ptr == NULL)
88 return;
89
90 if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
91 {
92 /* Write PNG signature */
93 png_write_sig(png_ptr);
94
95 #ifdef PNG_MNG_FEATURES_SUPPORTED
96 if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \
97 (png_ptr->mng_features_permitted))
98 {
99 png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
100 png_ptr->mng_features_permitted = 0;
101 }
102 #endif
103
104 /* Write IHDR information. */
105 png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
106 info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
107 info_ptr->filter_type,
108 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
109 info_ptr->interlace_type
110 #else
111 0
112 #endif
113 );
114
115 /* The rest of these check to see if the valid field has the appropriate
116 * flag set, and if it does, writes the chunk.
117 *
118 * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
119 * the chunks will be written if the WRITE routine is there and information
120 * is available in the COLORSPACE. (See png_colorspace_sync_info in png.c
121 * for where the valid flags get set.)
122 *
123 * Under certain circumstances the colorspace can be invalidated without
124 * syncing the info_struct 'valid' flags; this happens if libpng detects and
125 * error and calls png_error while the color space is being set, yet the
126 * application continues writing the PNG. So check the 'invalid' flag here
127 * too.
128 */
129 #ifdef PNG_GAMMA_SUPPORTED
130 # ifdef PNG_WRITE_gAMA_SUPPORTED
131 if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
132 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) &&
133 (info_ptr->valid & PNG_INFO_gAMA))
134 png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
135 # endif
136 #endif
137
138 #ifdef PNG_COLORSPACE_SUPPORTED
139 /* Write only one of sRGB or an ICC profile. If a profile was supplied
140 * and it matches one of the known sRGB ones issue a warning.
141 */
142 # ifdef PNG_WRITE_iCCP_SUPPORTED
143 if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
144 (info_ptr->valid & PNG_INFO_iCCP))
145 {
146 # ifdef PNG_WRITE_sRGB_SUPPORTED
147 if (info_ptr->valid & PNG_INFO_sRGB)
148 png_app_warning(png_ptr,
149 "profile matches sRGB but writing iCCP instead");
150 # endif
151
152 png_write_iCCP(png_ptr, info_ptr->iccp_name,
153 info_ptr->iccp_profile);
154 }
155 # ifdef PNG_WRITE_sRGB_SUPPORTED
156 else
157 # endif
158 # endif
159
160 # ifdef PNG_WRITE_sRGB_SUPPORTED
161 if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
162 (info_ptr->valid & PNG_INFO_sRGB))
163 png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
164 # endif /* WRITE_sRGB */
165 #endif /* COLORSPACE */
166
167 #ifdef PNG_WRITE_sBIT_SUPPORTED
168 if (info_ptr->valid & PNG_INFO_sBIT)
169 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
170 #endif
171
172 #ifdef PNG_COLORSPACE_SUPPORTED
173 # ifdef PNG_WRITE_cHRM_SUPPORTED
174 if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) &&
175 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) &&
176 (info_ptr->valid & PNG_INFO_cHRM))
177 png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
178 # endif
179 #endif
180
181 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
182 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
183 #endif
184
185 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
186 }
187 }
188
189 void PNGAPI
png_write_info(png_structrp png_ptr,png_const_inforp info_ptr)190 png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
191 {
192 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
193 int i;
194 #endif
195
196 png_debug(1, "in png_write_info");
197
198 if (png_ptr == NULL || info_ptr == NULL)
199 return;
200
201 png_write_info_before_PLTE(png_ptr, info_ptr);
202
203 if (info_ptr->valid & PNG_INFO_PLTE)
204 png_write_PLTE(png_ptr, info_ptr->palette,
205 (png_uint_32)info_ptr->num_palette);
206
207 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
208 png_error(png_ptr, "Valid palette required for paletted images");
209
210 #ifdef PNG_WRITE_tRNS_SUPPORTED
211 if (info_ptr->valid & PNG_INFO_tRNS)
212 {
213 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
214 /* Invert the alpha channel (in tRNS) */
215 if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
216 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
217 {
218 int j;
219 for (j = 0; j<(int)info_ptr->num_trans; j++)
220 info_ptr->trans_alpha[j] =
221 (png_byte)(255 - info_ptr->trans_alpha[j]);
222 }
223 #endif
224 png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
225 info_ptr->num_trans, info_ptr->color_type);
226 }
227 #endif
228 #ifdef PNG_WRITE_bKGD_SUPPORTED
229 if (info_ptr->valid & PNG_INFO_bKGD)
230 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
231 #endif
232
233 #ifdef PNG_WRITE_hIST_SUPPORTED
234 if (info_ptr->valid & PNG_INFO_hIST)
235 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
236 #endif
237
238 #ifdef PNG_WRITE_oFFs_SUPPORTED
239 if (info_ptr->valid & PNG_INFO_oFFs)
240 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
241 info_ptr->offset_unit_type);
242 #endif
243
244 #ifdef PNG_WRITE_pCAL_SUPPORTED
245 if (info_ptr->valid & PNG_INFO_pCAL)
246 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
247 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
248 info_ptr->pcal_units, info_ptr->pcal_params);
249 #endif
250
251 #ifdef PNG_WRITE_sCAL_SUPPORTED
252 if (info_ptr->valid & PNG_INFO_sCAL)
253 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
254 info_ptr->scal_s_width, info_ptr->scal_s_height);
255 #endif /* sCAL */
256
257 #ifdef PNG_WRITE_pHYs_SUPPORTED
258 if (info_ptr->valid & PNG_INFO_pHYs)
259 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
260 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
261 #endif /* pHYs */
262
263 #ifdef PNG_WRITE_tIME_SUPPORTED
264 if (info_ptr->valid & PNG_INFO_tIME)
265 {
266 png_write_tIME(png_ptr, &(info_ptr->mod_time));
267 png_ptr->mode |= PNG_WROTE_tIME;
268 }
269 #endif /* tIME */
270
271 #ifdef PNG_WRITE_sPLT_SUPPORTED
272 if (info_ptr->valid & PNG_INFO_sPLT)
273 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
274 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
275 #endif /* sPLT */
276
277 #ifdef PNG_WRITE_TEXT_SUPPORTED
278 /* Check to see if we need to write text chunks */
279 for (i = 0; i < info_ptr->num_text; i++)
280 {
281 png_debug2(2, "Writing header text chunk %d, type %d", i,
282 info_ptr->text[i].compression);
283 /* An internationalized chunk? */
284 if (info_ptr->text[i].compression > 0)
285 {
286 #ifdef PNG_WRITE_iTXt_SUPPORTED
287 /* Write international chunk */
288 png_write_iTXt(png_ptr,
289 info_ptr->text[i].compression,
290 info_ptr->text[i].key,
291 info_ptr->text[i].lang,
292 info_ptr->text[i].lang_key,
293 info_ptr->text[i].text);
294 #else
295 png_warning(png_ptr, "Unable to write international text");
296 #endif
297 /* Mark this chunk as written */
298 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
299 }
300
301 /* If we want a compressed text chunk */
302 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
303 {
304 #ifdef PNG_WRITE_zTXt_SUPPORTED
305 /* Write compressed chunk */
306 png_write_zTXt(png_ptr, info_ptr->text[i].key,
307 info_ptr->text[i].text, 0,
308 info_ptr->text[i].compression);
309 #else
310 png_warning(png_ptr, "Unable to write compressed text");
311 #endif
312 /* Mark this chunk as written */
313 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
314 }
315
316 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
317 {
318 #ifdef PNG_WRITE_tEXt_SUPPORTED
319 /* Write uncompressed chunk */
320 png_write_tEXt(png_ptr, info_ptr->text[i].key,
321 info_ptr->text[i].text,
322 0);
323 /* Mark this chunk as written */
324 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
325 #else
326 /* Can't get here */
327 png_warning(png_ptr, "Unable to write uncompressed text");
328 #endif
329 }
330 }
331 #endif /* tEXt */
332
333 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
334 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
335 #endif
336 }
337
338 /* Writes the end of the PNG file. If you don't want to write comments or
339 * time information, you can pass NULL for info. If you already wrote these
340 * in png_write_info(), do not write them again here. If you have long
341 * comments, I suggest writing them here, and compressing them.
342 */
343 void PNGAPI
png_write_end(png_structrp png_ptr,png_inforp info_ptr)344 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
345 {
346 png_debug(1, "in png_write_end");
347
348 if (png_ptr == NULL)
349 return;
350
351 if (!(png_ptr->mode & PNG_HAVE_IDAT))
352 png_error(png_ptr, "No IDATs written into file");
353
354 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
355 if (png_ptr->num_palette_max > png_ptr->num_palette)
356 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
357 #endif
358
359 /* See if user wants us to write information chunks */
360 if (info_ptr != NULL)
361 {
362 #ifdef PNG_WRITE_TEXT_SUPPORTED
363 int i; /* local index variable */
364 #endif
365 #ifdef PNG_WRITE_tIME_SUPPORTED
366 /* Check to see if user has supplied a time chunk */
367 if ((info_ptr->valid & PNG_INFO_tIME) &&
368 !(png_ptr->mode & PNG_WROTE_tIME))
369 png_write_tIME(png_ptr, &(info_ptr->mod_time));
370
371 #endif
372 #ifdef PNG_WRITE_TEXT_SUPPORTED
373 /* Loop through comment chunks */
374 for (i = 0; i < info_ptr->num_text; i++)
375 {
376 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
377 info_ptr->text[i].compression);
378 /* An internationalized chunk? */
379 if (info_ptr->text[i].compression > 0)
380 {
381 #ifdef PNG_WRITE_iTXt_SUPPORTED
382 /* Write international chunk */
383 png_write_iTXt(png_ptr,
384 info_ptr->text[i].compression,
385 info_ptr->text[i].key,
386 info_ptr->text[i].lang,
387 info_ptr->text[i].lang_key,
388 info_ptr->text[i].text);
389 #else
390 png_warning(png_ptr, "Unable to write international text");
391 #endif
392 /* Mark this chunk as written */
393 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
394 }
395
396 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
397 {
398 #ifdef PNG_WRITE_zTXt_SUPPORTED
399 /* Write compressed chunk */
400 png_write_zTXt(png_ptr, info_ptr->text[i].key,
401 info_ptr->text[i].text, 0,
402 info_ptr->text[i].compression);
403 #else
404 png_warning(png_ptr, "Unable to write compressed text");
405 #endif
406 /* Mark this chunk as written */
407 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
408 }
409
410 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
411 {
412 #ifdef PNG_WRITE_tEXt_SUPPORTED
413 /* Write uncompressed chunk */
414 png_write_tEXt(png_ptr, info_ptr->text[i].key,
415 info_ptr->text[i].text, 0);
416 #else
417 png_warning(png_ptr, "Unable to write uncompressed text");
418 #endif
419
420 /* Mark this chunk as written */
421 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
422 }
423 }
424 #endif
425 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
426 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
427 #endif
428 }
429
430 png_ptr->mode |= PNG_AFTER_IDAT;
431
432 /* Write end of PNG file */
433 png_write_IEND(png_ptr);
434 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
435 * and restored again in libpng-1.2.30, may cause some applications that
436 * do not set png_ptr->output_flush_fn to crash. If your application
437 * experiences a problem, please try building libpng with
438 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
439 * png-mng-implement at lists.sf.net .
440 */
441 #ifdef PNG_WRITE_FLUSH_SUPPORTED
442 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
443 png_flush(png_ptr);
444 # endif
445 #endif
446 }
447
448 #ifdef PNG_CONVERT_tIME_SUPPORTED
449 void PNGAPI
png_convert_from_struct_tm(png_timep ptime,PNG_CONST struct tm * ttime)450 png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)
451 {
452 png_debug(1, "in png_convert_from_struct_tm");
453
454 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
455 ptime->month = (png_byte)(ttime->tm_mon + 1);
456 ptime->day = (png_byte)ttime->tm_mday;
457 ptime->hour = (png_byte)ttime->tm_hour;
458 ptime->minute = (png_byte)ttime->tm_min;
459 ptime->second = (png_byte)ttime->tm_sec;
460 }
461
462 void PNGAPI
png_convert_from_time_t(png_timep ptime,time_t ttime)463 png_convert_from_time_t(png_timep ptime, time_t ttime)
464 {
465 struct tm *tbuf;
466
467 png_debug(1, "in png_convert_from_time_t");
468
469 tbuf = gmtime(&ttime);
470 png_convert_from_struct_tm(ptime, tbuf);
471 }
472 #endif
473
474 /* Initialize png_ptr structure, and allocate any memory needed */
475 PNG_FUNCTION(png_structp,PNGAPI
476 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
477 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
478 {
479 #ifndef PNG_USER_MEM_SUPPORTED
480 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
481 error_fn, warn_fn, NULL, NULL, NULL);
482 #else
483 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
484 warn_fn, NULL, NULL, NULL);
485 }
486
487 /* Alternate initialize png_ptr structure, and allocate any memory needed */
488 PNG_FUNCTION(png_structp,PNGAPI
489 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
490 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
491 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
492 {
493 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
494 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
495 #endif /* PNG_USER_MEM_SUPPORTED */
496 if (png_ptr != NULL)
497 {
498 /* Set the zlib control values to defaults; they can be overridden by the
499 * application after the struct has been created.
500 */
501 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
502
503 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
504 * pngwutil.c defaults it according to whether or not filters will be
505 * used, and ignores this setting.
506 */
507 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
508 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
509 png_ptr->zlib_mem_level = 8;
510 png_ptr->zlib_window_bits = 15;
511 png_ptr->zlib_method = 8;
512
513 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
514 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
515 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
516 png_ptr->zlib_text_mem_level = 8;
517 png_ptr->zlib_text_window_bits = 15;
518 png_ptr->zlib_text_method = 8;
519 #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
520
521 /* This is a highly dubious configuration option; by default it is off,
522 * but it may be appropriate for private builds that are testing
523 * extensions not conformant to the current specification, or of
524 * applications that must not fail to write at all costs!
525 */
526 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
527 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
528 /* In stable builds only warn if an application error can be completely
529 * handled.
530 */
531 #endif
532
533 /* App warnings are warnings in release (or release candidate) builds but
534 * are errors during development.
535 */
536 #if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
537 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
538 #endif
539
540 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
541 * do it itself) avoiding setting the default function if it is not
542 * required.
543 */
544 png_set_write_fn(png_ptr, NULL, NULL, NULL);
545 }
546
547 return png_ptr;
548 }
549
550
551 /* Write a few rows of image data. If the image is interlaced,
552 * either you will have to write the 7 sub images, or, if you
553 * have called png_set_interlace_handling(), you will have to
554 * "write" the image seven times.
555 */
556 void PNGAPI
png_write_rows(png_structrp png_ptr,png_bytepp row,png_uint_32 num_rows)557 png_write_rows(png_structrp png_ptr, png_bytepp row,
558 png_uint_32 num_rows)
559 {
560 png_uint_32 i; /* row counter */
561 png_bytepp rp; /* row pointer */
562
563 png_debug(1, "in png_write_rows");
564
565 if (png_ptr == NULL)
566 return;
567
568 /* Loop through the rows */
569 for (i = 0, rp = row; i < num_rows; i++, rp++)
570 {
571 png_write_row(png_ptr, *rp);
572 }
573 }
574
575 /* Write the image. You only need to call this function once, even
576 * if you are writing an interlaced image.
577 */
578 void PNGAPI
png_write_image(png_structrp png_ptr,png_bytepp image)579 png_write_image(png_structrp png_ptr, png_bytepp image)
580 {
581 png_uint_32 i; /* row index */
582 int pass, num_pass; /* pass variables */
583 png_bytepp rp; /* points to current row */
584
585 if (png_ptr == NULL)
586 return;
587
588 png_debug(1, "in png_write_image");
589
590 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
591 /* Initialize interlace handling. If image is not interlaced,
592 * this will set pass to 1
593 */
594 num_pass = png_set_interlace_handling(png_ptr);
595 #else
596 num_pass = 1;
597 #endif
598 /* Loop through passes */
599 for (pass = 0; pass < num_pass; pass++)
600 {
601 /* Loop through image */
602 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
603 {
604 png_write_row(png_ptr, *rp);
605 }
606 }
607 }
608
609 /* Called by user to write a row of image data */
610 void PNGAPI
png_write_row(png_structrp png_ptr,png_const_bytep row)611 png_write_row(png_structrp png_ptr, png_const_bytep row)
612 {
613 /* 1.5.6: moved from png_struct to be a local structure: */
614 png_row_info row_info;
615
616 if (png_ptr == NULL)
617 return;
618
619 png_debug2(1, "in png_write_row (row %u, pass %d)",
620 png_ptr->row_number, png_ptr->pass);
621
622 /* Initialize transformations and other stuff if first time */
623 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
624 {
625 /* Make sure we wrote the header info */
626 if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
627 png_error(png_ptr,
628 "png_write_info was never called before png_write_row");
629
630 /* Check for transforms that have been set but were defined out */
631 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
632 if (png_ptr->transformations & PNG_INVERT_MONO)
633 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
634 #endif
635
636 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
637 if (png_ptr->transformations & PNG_FILLER)
638 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
639 #endif
640 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
641 defined(PNG_READ_PACKSWAP_SUPPORTED)
642 if (png_ptr->transformations & PNG_PACKSWAP)
643 png_warning(png_ptr,
644 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
645 #endif
646
647 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
648 if (png_ptr->transformations & PNG_PACK)
649 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
650 #endif
651
652 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
653 if (png_ptr->transformations & PNG_SHIFT)
654 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
655 #endif
656
657 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
658 if (png_ptr->transformations & PNG_BGR)
659 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
660 #endif
661
662 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
663 if (png_ptr->transformations & PNG_SWAP_BYTES)
664 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
665 #endif
666
667 png_write_start_row(png_ptr);
668 }
669
670 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
671 /* If interlaced and not interested in row, return */
672 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
673 {
674 switch (png_ptr->pass)
675 {
676 case 0:
677 if (png_ptr->row_number & 0x07)
678 {
679 png_write_finish_row(png_ptr);
680 return;
681 }
682 break;
683
684 case 1:
685 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
686 {
687 png_write_finish_row(png_ptr);
688 return;
689 }
690 break;
691
692 case 2:
693 if ((png_ptr->row_number & 0x07) != 4)
694 {
695 png_write_finish_row(png_ptr);
696 return;
697 }
698 break;
699
700 case 3:
701 if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
702 {
703 png_write_finish_row(png_ptr);
704 return;
705 }
706 break;
707
708 case 4:
709 if ((png_ptr->row_number & 0x03) != 2)
710 {
711 png_write_finish_row(png_ptr);
712 return;
713 }
714 break;
715
716 case 5:
717 if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
718 {
719 png_write_finish_row(png_ptr);
720 return;
721 }
722 break;
723
724 case 6:
725 if (!(png_ptr->row_number & 0x01))
726 {
727 png_write_finish_row(png_ptr);
728 return;
729 }
730 break;
731
732 default: /* error: ignore it */
733 break;
734 }
735 }
736 #endif
737
738 /* Set up row info for transformations */
739 row_info.color_type = png_ptr->color_type;
740 row_info.width = png_ptr->usr_width;
741 row_info.channels = png_ptr->usr_channels;
742 row_info.bit_depth = png_ptr->usr_bit_depth;
743 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
744 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
745
746 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
747 png_debug1(3, "row_info->width = %u", row_info.width);
748 png_debug1(3, "row_info->channels = %d", row_info.channels);
749 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
750 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
751 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
752
753 /* Copy user's row into buffer, leaving room for filter byte. */
754 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
755
756 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
757 /* Handle interlacing */
758 if (png_ptr->interlaced && png_ptr->pass < 6 &&
759 (png_ptr->transformations & PNG_INTERLACE))
760 {
761 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
762 /* This should always get caught above, but still ... */
763 if (!(row_info.width))
764 {
765 png_write_finish_row(png_ptr);
766 return;
767 }
768 }
769 #endif
770
771 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
772 /* Handle other transformations */
773 if (png_ptr->transformations)
774 png_do_write_transformations(png_ptr, &row_info);
775 #endif
776
777 /* At this point the row_info pixel depth must match the 'transformed' depth,
778 * which is also the output depth.
779 */
780 if (row_info.pixel_depth != png_ptr->pixel_depth ||
781 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
782 png_error(png_ptr, "internal write transform logic error");
783
784 #ifdef PNG_MNG_FEATURES_SUPPORTED
785 /* Write filter_method 64 (intrapixel differencing) only if
786 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
787 * 2. Libpng did not write a PNG signature (this filter_method is only
788 * used in PNG datastreams that are embedded in MNG datastreams) and
789 * 3. The application called png_permit_mng_features with a mask that
790 * included PNG_FLAG_MNG_FILTER_64 and
791 * 4. The filter_method is 64 and
792 * 5. The color_type is RGB or RGBA
793 */
794 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
795 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
796 {
797 /* Intrapixel differencing */
798 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
799 }
800 #endif
801
802 /* Added at libpng-1.5.10 */
803 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
804 /* Check for out-of-range palette index */
805 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
806 png_ptr->num_palette_max >= 0)
807 png_do_check_palette_indexes(png_ptr, &row_info);
808 #endif
809
810 /* Find a filter if necessary, filter the row and write it out. */
811 png_write_find_filter(png_ptr, &row_info);
812
813 if (png_ptr->write_row_fn != NULL)
814 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
815 }
816
817 #ifdef PNG_WRITE_FLUSH_SUPPORTED
818 /* Set the automatic flush interval or 0 to turn flushing off */
819 void PNGAPI
png_set_flush(png_structrp png_ptr,int nrows)820 png_set_flush(png_structrp png_ptr, int nrows)
821 {
822 png_debug(1, "in png_set_flush");
823
824 if (png_ptr == NULL)
825 return;
826
827 png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
828 }
829
830 /* Flush the current output buffers now */
831 void PNGAPI
png_write_flush(png_structrp png_ptr)832 png_write_flush(png_structrp png_ptr)
833 {
834 png_debug(1, "in png_write_flush");
835
836 if (png_ptr == NULL)
837 return;
838
839 /* We have already written out all of the data */
840 if (png_ptr->row_number >= png_ptr->num_rows)
841 return;
842
843 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
844 png_ptr->flush_rows = 0;
845 png_flush(png_ptr);
846 }
847 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
848
849 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
850 static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */
851 #endif
852
853 /* Free any memory used in png_ptr struct without freeing the struct itself. */
854 static void
png_write_destroy(png_structrp png_ptr)855 png_write_destroy(png_structrp png_ptr)
856 {
857 png_debug(1, "in png_write_destroy");
858
859 /* Free any memory zlib uses */
860 if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
861 deflateEnd(&png_ptr->zstream);
862
863 /* Free our memory. png_free checks NULL for us. */
864 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
865 png_free(png_ptr, png_ptr->row_buf);
866 #ifdef PNG_WRITE_FILTER_SUPPORTED
867 png_free(png_ptr, png_ptr->prev_row);
868 png_free(png_ptr, png_ptr->sub_row);
869 png_free(png_ptr, png_ptr->up_row);
870 png_free(png_ptr, png_ptr->avg_row);
871 png_free(png_ptr, png_ptr->paeth_row);
872 #endif
873
874 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
875 /* Use this to save a little code space, it doesn't free the filter_costs */
876 png_reset_filter_heuristics(png_ptr);
877 png_free(png_ptr, png_ptr->filter_costs);
878 png_free(png_ptr, png_ptr->inv_filter_costs);
879 #endif
880
881 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
882 png_free(png_ptr, png_ptr->chunk_list);
883 #endif
884
885 /* The error handling and memory handling information is left intact at this
886 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
887 * for how this happens.
888 */
889 }
890
891 /* Free all memory used by the write.
892 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
893 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
894 * the passed in info_structs but it would quietly fail to free any of the data
895 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
896 * has no png_ptr.)
897 */
898 void PNGAPI
png_destroy_write_struct(png_structpp png_ptr_ptr,png_infopp info_ptr_ptr)899 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
900 {
901 png_debug(1, "in png_destroy_write_struct");
902
903 if (png_ptr_ptr != NULL)
904 {
905 png_structrp png_ptr = *png_ptr_ptr;
906
907 if (png_ptr != NULL) /* added in libpng 1.6.0 */
908 {
909 png_destroy_info_struct(png_ptr, info_ptr_ptr);
910
911 *png_ptr_ptr = NULL;
912 png_write_destroy(png_ptr);
913 png_destroy_png_struct(png_ptr);
914 }
915 }
916 }
917
918 /* Allow the application to select one or more row filters to use. */
919 void PNGAPI
png_set_filter(png_structrp png_ptr,int method,int filters)920 png_set_filter(png_structrp png_ptr, int method, int filters)
921 {
922 png_debug(1, "in png_set_filter");
923
924 if (png_ptr == NULL)
925 return;
926
927 #ifdef PNG_MNG_FEATURES_SUPPORTED
928 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
929 (method == PNG_INTRAPIXEL_DIFFERENCING))
930 method = PNG_FILTER_TYPE_BASE;
931
932 #endif
933 if (method == PNG_FILTER_TYPE_BASE)
934 {
935 switch (filters & (PNG_ALL_FILTERS | 0x07))
936 {
937 #ifdef PNG_WRITE_FILTER_SUPPORTED
938 case 5:
939 case 6:
940 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
941 /* FALL THROUGH */
942 #endif /* PNG_WRITE_FILTER_SUPPORTED */
943 case PNG_FILTER_VALUE_NONE:
944 png_ptr->do_filter = PNG_FILTER_NONE; break;
945
946 #ifdef PNG_WRITE_FILTER_SUPPORTED
947 case PNG_FILTER_VALUE_SUB:
948 png_ptr->do_filter = PNG_FILTER_SUB; break;
949
950 case PNG_FILTER_VALUE_UP:
951 png_ptr->do_filter = PNG_FILTER_UP; break;
952
953 case PNG_FILTER_VALUE_AVG:
954 png_ptr->do_filter = PNG_FILTER_AVG; break;
955
956 case PNG_FILTER_VALUE_PAETH:
957 png_ptr->do_filter = PNG_FILTER_PAETH; break;
958
959 default:
960 png_ptr->do_filter = (png_byte)filters; break;
961 #else
962 default:
963 png_app_error(png_ptr, "Unknown row filter for method 0");
964 #endif /* PNG_WRITE_FILTER_SUPPORTED */
965 }
966
967 /* If we have allocated the row_buf, this means we have already started
968 * with the image and we should have allocated all of the filter buffers
969 * that have been selected. If prev_row isn't already allocated, then
970 * it is too late to start using the filters that need it, since we
971 * will be missing the data in the previous row. If an application
972 * wants to start and stop using particular filters during compression,
973 * it should start out with all of the filters, and then add and
974 * remove them after the start of compression.
975 */
976 if (png_ptr->row_buf != NULL)
977 {
978 #ifdef PNG_WRITE_FILTER_SUPPORTED
979 if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
980 {
981 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
982 (png_ptr->rowbytes + 1));
983 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
984 }
985
986 if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
987 {
988 if (png_ptr->prev_row == NULL)
989 {
990 png_warning(png_ptr, "Can't add Up filter after starting");
991 png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
992 ~PNG_FILTER_UP);
993 }
994
995 else
996 {
997 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
998 (png_ptr->rowbytes + 1));
999 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1000 }
1001 }
1002
1003 if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
1004 {
1005 if (png_ptr->prev_row == NULL)
1006 {
1007 png_warning(png_ptr, "Can't add Average filter after starting");
1008 png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
1009 ~PNG_FILTER_AVG);
1010 }
1011
1012 else
1013 {
1014 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1015 (png_ptr->rowbytes + 1));
1016 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1017 }
1018 }
1019
1020 if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
1021 png_ptr->paeth_row == NULL)
1022 {
1023 if (png_ptr->prev_row == NULL)
1024 {
1025 png_warning(png_ptr, "Can't add Paeth filter after starting");
1026 png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
1027 }
1028
1029 else
1030 {
1031 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1032 (png_ptr->rowbytes + 1));
1033 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1034 }
1035 }
1036
1037 if (png_ptr->do_filter == PNG_NO_FILTERS)
1038 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1039 png_ptr->do_filter = PNG_FILTER_NONE;
1040 }
1041 }
1042 else
1043 png_error(png_ptr, "Unknown custom filter method");
1044 }
1045
1046 /* This allows us to influence the way in which libpng chooses the "best"
1047 * filter for the current scanline. While the "minimum-sum-of-absolute-
1048 * differences metric is relatively fast and effective, there is some
1049 * question as to whether it can be improved upon by trying to keep the
1050 * filtered data going to zlib more consistent, hopefully resulting in
1051 * better compression.
1052 */
1053 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */
1054 /* Convenience reset API. */
1055 static void
png_reset_filter_heuristics(png_structrp png_ptr)1056 png_reset_filter_heuristics(png_structrp png_ptr)
1057 {
1058 /* Clear out any old values in the 'weights' - this must be done because if
1059 * the app calls set_filter_heuristics multiple times with different
1060 * 'num_weights' values we would otherwise potentially have wrong sized
1061 * arrays.
1062 */
1063 png_ptr->num_prev_filters = 0;
1064 png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
1065 if (png_ptr->prev_filters != NULL)
1066 {
1067 png_bytep old = png_ptr->prev_filters;
1068 png_ptr->prev_filters = NULL;
1069 png_free(png_ptr, old);
1070 }
1071 if (png_ptr->filter_weights != NULL)
1072 {
1073 png_uint_16p old = png_ptr->filter_weights;
1074 png_ptr->filter_weights = NULL;
1075 png_free(png_ptr, old);
1076 }
1077
1078 if (png_ptr->inv_filter_weights != NULL)
1079 {
1080 png_uint_16p old = png_ptr->inv_filter_weights;
1081 png_ptr->inv_filter_weights = NULL;
1082 png_free(png_ptr, old);
1083 }
1084
1085 /* Leave the filter_costs - this array is fixed size. */
1086 }
1087
1088 static int
png_init_filter_heuristics(png_structrp png_ptr,int heuristic_method,int num_weights)1089 png_init_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1090 int num_weights)
1091 {
1092 if (png_ptr == NULL)
1093 return 0;
1094
1095 /* Clear out the arrays */
1096 png_reset_filter_heuristics(png_ptr);
1097
1098 /* Check arguments; the 'reset' function makes the correct settings for the
1099 * unweighted case, but we must handle the weight case by initializing the
1100 * arrays for the caller.
1101 */
1102 if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
1103 {
1104 int i;
1105
1106 if (num_weights > 0)
1107 {
1108 png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
1109 (png_uint_32)((sizeof (png_byte)) * num_weights));
1110
1111 /* To make sure that the weighting starts out fairly */
1112 for (i = 0; i < num_weights; i++)
1113 {
1114 png_ptr->prev_filters[i] = 255;
1115 }
1116
1117 png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
1118 (png_uint_32)((sizeof (png_uint_16)) * num_weights));
1119
1120 png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
1121 (png_uint_32)((sizeof (png_uint_16)) * num_weights));
1122
1123 for (i = 0; i < num_weights; i++)
1124 {
1125 png_ptr->inv_filter_weights[i] =
1126 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1127 }
1128
1129 /* Safe to set this now */
1130 png_ptr->num_prev_filters = (png_byte)num_weights;
1131 }
1132
1133 /* If, in the future, there are other filter methods, this would
1134 * need to be based on png_ptr->filter.
1135 */
1136 if (png_ptr->filter_costs == NULL)
1137 {
1138 png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
1139 (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST));
1140
1141 png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
1142 (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST));
1143 }
1144
1145 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
1146 {
1147 png_ptr->inv_filter_costs[i] =
1148 png_ptr->filter_costs[i] = PNG_COST_FACTOR;
1149 }
1150
1151 /* All the arrays are inited, safe to set this: */
1152 png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_WEIGHTED;
1153
1154 /* Return the 'ok' code. */
1155 return 1;
1156 }
1157 else if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT ||
1158 heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
1159 {
1160 return 1;
1161 }
1162 else
1163 {
1164 png_warning(png_ptr, "Unknown filter heuristic method");
1165 return 0;
1166 }
1167 }
1168
1169 /* Provide floating and fixed point APIs */
1170 #ifdef PNG_FLOATING_POINT_SUPPORTED
1171 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)1172 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1173 int num_weights, png_const_doublep filter_weights,
1174 png_const_doublep filter_costs)
1175 {
1176 png_debug(1, "in png_set_filter_heuristics");
1177
1178 /* The internal API allocates all the arrays and ensures that the elements of
1179 * those arrays are set to the default value.
1180 */
1181 if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
1182 return;
1183
1184 /* If using the weighted method copy in the weights. */
1185 if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
1186 {
1187 int i;
1188 for (i = 0; i < num_weights; i++)
1189 {
1190 if (filter_weights[i] <= 0.0)
1191 {
1192 png_ptr->inv_filter_weights[i] =
1193 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1194 }
1195
1196 else
1197 {
1198 png_ptr->inv_filter_weights[i] =
1199 (png_uint_16)(PNG_WEIGHT_FACTOR*filter_weights[i]+.5);
1200
1201 png_ptr->filter_weights[i] =
1202 (png_uint_16)(PNG_WEIGHT_FACTOR/filter_weights[i]+.5);
1203 }
1204 }
1205
1206 /* Here is where we set the relative costs of the different filters. We
1207 * should take the desired compression level into account when setting
1208 * the costs, so that Paeth, for instance, has a high relative cost at low
1209 * compression levels, while it has a lower relative cost at higher
1210 * compression settings. The filter types are in order of increasing
1211 * relative cost, so it would be possible to do this with an algorithm.
1212 */
1213 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) if (filter_costs[i] >= 1.0)
1214 {
1215 png_ptr->inv_filter_costs[i] =
1216 (png_uint_16)(PNG_COST_FACTOR / filter_costs[i] + .5);
1217
1218 png_ptr->filter_costs[i] =
1219 (png_uint_16)(PNG_COST_FACTOR * filter_costs[i] + .5);
1220 }
1221 }
1222 }
1223 #endif /* FLOATING_POINT */
1224
1225 #ifdef PNG_FIXED_POINT_SUPPORTED
1226 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)1227 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1228 int num_weights, png_const_fixed_point_p filter_weights,
1229 png_const_fixed_point_p filter_costs)
1230 {
1231 png_debug(1, "in png_set_filter_heuristics_fixed");
1232
1233 /* The internal API allocates all the arrays and ensures that the elements of
1234 * those arrays are set to the default value.
1235 */
1236 if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights))
1237 return;
1238
1239 /* If using the weighted method copy in the weights. */
1240 if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
1241 {
1242 int i;
1243 for (i = 0; i < num_weights; i++)
1244 {
1245 if (filter_weights[i] <= 0)
1246 {
1247 png_ptr->inv_filter_weights[i] =
1248 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1249 }
1250
1251 else
1252 {
1253 png_ptr->inv_filter_weights[i] = (png_uint_16)
1254 ((PNG_WEIGHT_FACTOR*filter_weights[i]+PNG_FP_HALF)/PNG_FP_1);
1255
1256 png_ptr->filter_weights[i] = (png_uint_16)((PNG_WEIGHT_FACTOR*
1257 PNG_FP_1+(filter_weights[i]/2))/filter_weights[i]);
1258 }
1259 }
1260
1261 /* Here is where we set the relative costs of the different filters. We
1262 * should take the desired compression level into account when setting
1263 * the costs, so that Paeth, for instance, has a high relative cost at low
1264 * compression levels, while it has a lower relative cost at higher
1265 * compression settings. The filter types are in order of increasing
1266 * relative cost, so it would be possible to do this with an algorithm.
1267 */
1268 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
1269 if (filter_costs[i] >= PNG_FP_1)
1270 {
1271 png_uint_32 tmp;
1272
1273 /* Use a 32 bit unsigned temporary here because otherwise the
1274 * intermediate value will be a 32 bit *signed* integer (ANSI rules)
1275 * and this will get the wrong answer on division.
1276 */
1277 tmp = PNG_COST_FACTOR*PNG_FP_1 + (filter_costs[i]/2);
1278 tmp /= filter_costs[i];
1279
1280 png_ptr->inv_filter_costs[i] = (png_uint_16)tmp;
1281
1282 tmp = PNG_COST_FACTOR * filter_costs[i] + PNG_FP_HALF;
1283 tmp /= PNG_FP_1;
1284
1285 png_ptr->filter_costs[i] = (png_uint_16)tmp;
1286 }
1287 }
1288 }
1289 #endif /* FIXED_POINT */
1290 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1291
1292 void PNGAPI
png_set_compression_level(png_structrp png_ptr,int level)1293 png_set_compression_level(png_structrp png_ptr, int level)
1294 {
1295 png_debug(1, "in png_set_compression_level");
1296
1297 if (png_ptr == NULL)
1298 return;
1299
1300 png_ptr->zlib_level = level;
1301 }
1302
1303 void PNGAPI
png_set_compression_mem_level(png_structrp png_ptr,int mem_level)1304 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1305 {
1306 png_debug(1, "in png_set_compression_mem_level");
1307
1308 if (png_ptr == NULL)
1309 return;
1310
1311 png_ptr->zlib_mem_level = mem_level;
1312 }
1313
1314 void PNGAPI
png_set_compression_strategy(png_structrp png_ptr,int strategy)1315 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1316 {
1317 png_debug(1, "in png_set_compression_strategy");
1318
1319 if (png_ptr == NULL)
1320 return;
1321
1322 /* The flag setting here prevents the libpng dynamic selection of strategy.
1323 */
1324 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1325 png_ptr->zlib_strategy = strategy;
1326 }
1327
1328 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1329 * smaller value of window_bits if it can do so safely.
1330 */
1331 void PNGAPI
png_set_compression_window_bits(png_structrp png_ptr,int window_bits)1332 png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1333 {
1334 if (png_ptr == NULL)
1335 return;
1336
1337 /* Prior to 1.6.0 this would warn but then set the window_bits value, this
1338 * meant that negative window bits values could be selected which would cause
1339 * libpng to write a non-standard PNG file with raw deflate or gzip
1340 * compressed IDAT or ancillary chunks. Such files can be read and there is
1341 * no warning on read, so this seems like a very bad idea.
1342 */
1343 if (window_bits > 15)
1344 {
1345 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1346 window_bits = 15;
1347 }
1348
1349 else if (window_bits < 8)
1350 {
1351 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1352 window_bits = 8;
1353 }
1354
1355 png_ptr->zlib_window_bits = window_bits;
1356 }
1357
1358 void PNGAPI
png_set_compression_method(png_structrp png_ptr,int method)1359 png_set_compression_method(png_structrp png_ptr, int method)
1360 {
1361 png_debug(1, "in png_set_compression_method");
1362
1363 if (png_ptr == NULL)
1364 return;
1365
1366 /* This would produce an invalid PNG file if it worked, but it doesn't and
1367 * deflate will fault it, so it is harmless to just warn here.
1368 */
1369 if (method != 8)
1370 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1371
1372 png_ptr->zlib_method = method;
1373 }
1374
1375 /* The following were added to libpng-1.5.4 */
1376 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1377 void PNGAPI
png_set_text_compression_level(png_structrp png_ptr,int level)1378 png_set_text_compression_level(png_structrp png_ptr, int level)
1379 {
1380 png_debug(1, "in png_set_text_compression_level");
1381
1382 if (png_ptr == NULL)
1383 return;
1384
1385 png_ptr->zlib_text_level = level;
1386 }
1387
1388 void PNGAPI
png_set_text_compression_mem_level(png_structrp png_ptr,int mem_level)1389 png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1390 {
1391 png_debug(1, "in png_set_text_compression_mem_level");
1392
1393 if (png_ptr == NULL)
1394 return;
1395
1396 png_ptr->zlib_text_mem_level = mem_level;
1397 }
1398
1399 void PNGAPI
png_set_text_compression_strategy(png_structrp png_ptr,int strategy)1400 png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1401 {
1402 png_debug(1, "in png_set_text_compression_strategy");
1403
1404 if (png_ptr == NULL)
1405 return;
1406
1407 png_ptr->zlib_text_strategy = strategy;
1408 }
1409
1410 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1411 * smaller value of window_bits if it can do so safely.
1412 */
1413 void PNGAPI
png_set_text_compression_window_bits(png_structrp png_ptr,int window_bits)1414 png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1415 {
1416 if (png_ptr == NULL)
1417 return;
1418
1419 if (window_bits > 15)
1420 {
1421 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1422 window_bits = 15;
1423 }
1424
1425 else if (window_bits < 8)
1426 {
1427 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1428 window_bits = 8;
1429 }
1430
1431 png_ptr->zlib_text_window_bits = window_bits;
1432 }
1433
1434 void PNGAPI
png_set_text_compression_method(png_structrp png_ptr,int method)1435 png_set_text_compression_method(png_structrp png_ptr, int method)
1436 {
1437 png_debug(1, "in png_set_text_compression_method");
1438
1439 if (png_ptr == NULL)
1440 return;
1441
1442 if (method != 8)
1443 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1444
1445 png_ptr->zlib_text_method = method;
1446 }
1447 #endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
1448 /* end of API added to libpng-1.5.4 */
1449
1450 void PNGAPI
png_set_write_status_fn(png_structrp png_ptr,png_write_status_ptr write_row_fn)1451 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1452 {
1453 if (png_ptr == NULL)
1454 return;
1455
1456 png_ptr->write_row_fn = write_row_fn;
1457 }
1458
1459 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1460 void PNGAPI
png_set_write_user_transform_fn(png_structrp png_ptr,png_user_transform_ptr write_user_transform_fn)1461 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1462 write_user_transform_fn)
1463 {
1464 png_debug(1, "in png_set_write_user_transform_fn");
1465
1466 if (png_ptr == NULL)
1467 return;
1468
1469 png_ptr->transformations |= PNG_USER_TRANSFORM;
1470 png_ptr->write_user_transform_fn = write_user_transform_fn;
1471 }
1472 #endif
1473
1474
1475 #ifdef PNG_INFO_IMAGE_SUPPORTED
1476 void PNGAPI
png_write_png(png_structrp png_ptr,png_inforp info_ptr,int transforms,voidp params)1477 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1478 int transforms, voidp params)
1479 {
1480 if (png_ptr == NULL || info_ptr == NULL)
1481 return;
1482
1483 /* Write the file header information. */
1484 png_write_info(png_ptr, info_ptr);
1485
1486 /* ------ these transformations don't touch the info structure ------- */
1487
1488 #ifdef PNG_WRITE_INVERT_SUPPORTED
1489 /* Invert monochrome pixels */
1490 if (transforms & PNG_TRANSFORM_INVERT_MONO)
1491 png_set_invert_mono(png_ptr);
1492 #endif
1493
1494 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1495 /* Shift the pixels up to a legal bit depth and fill in
1496 * as appropriate to correctly scale the image.
1497 */
1498 if ((transforms & PNG_TRANSFORM_SHIFT)
1499 && (info_ptr->valid & PNG_INFO_sBIT))
1500 png_set_shift(png_ptr, &info_ptr->sig_bit);
1501 #endif
1502
1503 #ifdef PNG_WRITE_PACK_SUPPORTED
1504 /* Pack pixels into bytes */
1505 if (transforms & PNG_TRANSFORM_PACKING)
1506 png_set_packing(png_ptr);
1507 #endif
1508
1509 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1510 /* Swap location of alpha bytes from ARGB to RGBA */
1511 if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1512 png_set_swap_alpha(png_ptr);
1513 #endif
1514
1515 #ifdef PNG_WRITE_FILLER_SUPPORTED
1516 /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
1517 if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
1518 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1519
1520 else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
1521 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1522 #endif
1523
1524 #ifdef PNG_WRITE_BGR_SUPPORTED
1525 /* Flip BGR pixels to RGB */
1526 if (transforms & PNG_TRANSFORM_BGR)
1527 png_set_bgr(png_ptr);
1528 #endif
1529
1530 #ifdef PNG_WRITE_SWAP_SUPPORTED
1531 /* Swap bytes of 16-bit files to most significant byte first */
1532 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1533 png_set_swap(png_ptr);
1534 #endif
1535
1536 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1537 /* Swap bits of 1, 2, 4 bit packed pixel formats */
1538 if (transforms & PNG_TRANSFORM_PACKSWAP)
1539 png_set_packswap(png_ptr);
1540 #endif
1541
1542 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1543 /* Invert the alpha channel from opacity to transparency */
1544 if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1545 png_set_invert_alpha(png_ptr);
1546 #endif
1547
1548 /* ----------------------- end of transformations ------------------- */
1549
1550 /* Write the bits */
1551 if (info_ptr->valid & PNG_INFO_IDAT)
1552 png_write_image(png_ptr, info_ptr->row_pointers);
1553
1554 /* It is REQUIRED to call this to finish writing the rest of the file */
1555 png_write_end(png_ptr, info_ptr);
1556
1557 PNG_UNUSED(transforms) /* Quiet compiler warnings */
1558 PNG_UNUSED(params)
1559 }
1560 #endif
1561
1562
1563 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1564 #ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
1565 /* Initialize the write structure - general purpose utility. */
1566 static int
png_image_write_init(png_imagep image)1567 png_image_write_init(png_imagep image)
1568 {
1569 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1570 png_safe_error, png_safe_warning);
1571
1572 if (png_ptr != NULL)
1573 {
1574 png_infop info_ptr = png_create_info_struct(png_ptr);
1575
1576 if (info_ptr != NULL)
1577 {
1578 png_controlp control = png_voidcast(png_controlp,
1579 png_malloc_warn(png_ptr, (sizeof *control)));
1580
1581 if (control != NULL)
1582 {
1583 memset(control, 0, (sizeof *control));
1584
1585 control->png_ptr = png_ptr;
1586 control->info_ptr = info_ptr;
1587 control->for_write = 1;
1588
1589 image->opaque = control;
1590 return 1;
1591 }
1592
1593 /* Error clean up */
1594 png_destroy_info_struct(png_ptr, &info_ptr);
1595 }
1596
1597 png_destroy_write_struct(&png_ptr, NULL);
1598 }
1599
1600 return png_image_error(image, "png_image_write_: out of memory");
1601 }
1602
1603 /* Arguments to png_image_write_main: */
1604 typedef struct
1605 {
1606 /* Arguments: */
1607 png_imagep image;
1608 png_const_voidp buffer;
1609 png_int_32 row_stride;
1610 png_const_voidp colormap;
1611 int convert_to_8bit;
1612 /* Local variables: */
1613 png_const_voidp first_row;
1614 ptrdiff_t row_bytes;
1615 png_voidp local_row;
1616 } png_image_write_control;
1617
1618 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1619 * do any necessary byte swapping. The component order is defined by the
1620 * png_image format value.
1621 */
1622 static int
png_write_image_16bit(png_voidp argument)1623 png_write_image_16bit(png_voidp argument)
1624 {
1625 png_image_write_control *display = png_voidcast(png_image_write_control*,
1626 argument);
1627 png_imagep image = display->image;
1628 png_structrp png_ptr = image->opaque->png_ptr;
1629
1630 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1631 display->first_row);
1632 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1633 png_uint_16p row_end;
1634 const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
1635 int aindex = 0;
1636 png_uint_32 y = image->height;
1637
1638 if (image->format & PNG_FORMAT_FLAG_ALPHA)
1639 {
1640 if (image->format & PNG_FORMAT_FLAG_AFIRST)
1641 {
1642 aindex = -1;
1643 ++input_row; /* To point to the first component */
1644 ++output_row;
1645 }
1646
1647 else
1648 aindex = channels;
1649 }
1650
1651 else
1652 png_error(png_ptr, "png_write_image: internal call error");
1653
1654 /* Work out the output row end and count over this, note that the increment
1655 * above to 'row' means that row_end can actually be beyond the end of the
1656 * row; this is correct.
1657 */
1658 row_end = output_row + image->width * (channels+1);
1659
1660 while (y-- > 0)
1661 {
1662 png_const_uint_16p in_ptr = input_row;
1663 png_uint_16p out_ptr = output_row;
1664
1665 while (out_ptr < row_end)
1666 {
1667 const png_uint_16 alpha = in_ptr[aindex];
1668 png_uint_32 reciprocal = 0;
1669 int c;
1670
1671 out_ptr[aindex] = alpha;
1672
1673 /* Calculate a reciprocal. The correct calculation is simply
1674 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1675 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1676 * is only initialized when required.
1677 */
1678 if (alpha > 0 && alpha < 65535)
1679 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1680
1681 c = channels;
1682 do /* always at least one channel */
1683 {
1684 png_uint_16 component = *in_ptr++;
1685
1686 /* The following gives 65535 for an alpha of 0, which is fine,
1687 * otherwise if 0/0 is represented as some other value there is more
1688 * likely to be a discontinuity which will probably damage
1689 * compression when moving from a fully transparent area to a
1690 * nearly transparent one. (The assumption here is that opaque
1691 * areas tend not to be 0 intensity.)
1692 */
1693 if (component >= alpha)
1694 component = 65535;
1695
1696 /* component<alpha, so component/alpha is less than one and
1697 * component*reciprocal is less than 2^31.
1698 */
1699 else if (component > 0 && alpha < 65535)
1700 {
1701 png_uint_32 calc = component * reciprocal;
1702 calc += 16384; /* round to nearest */
1703 component = (png_uint_16)(calc >> 15);
1704 }
1705
1706 *out_ptr++ = component;
1707 }
1708 while (--c > 0);
1709
1710 /* Skip to next component (skip the intervening alpha channel) */
1711 ++in_ptr;
1712 ++out_ptr;
1713 }
1714
1715 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1716 input_row += display->row_bytes/(sizeof (png_uint_16));
1717 }
1718
1719 return 1;
1720 }
1721
1722 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1723 * is present it must be removed from the components, the components are then
1724 * written in sRGB encoding. No components are added or removed.
1725 *
1726 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1727 * calculation can be done to 15 bits of accuracy; however, the output needs to
1728 * be scaled in the range 0..255*65535, so include that scaling here.
1729 */
1730 #define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
1731
1732 static png_byte
png_unpremultiply(png_uint_32 component,png_uint_32 alpha,png_uint_32 reciprocal)1733 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1734 png_uint_32 reciprocal/*from the above macro*/)
1735 {
1736 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1737 * is represented as some other value there is more likely to be a
1738 * discontinuity which will probably damage compression when moving from a
1739 * fully transparent area to a nearly transparent one. (The assumption here
1740 * is that opaque areas tend not to be 0 intensity.)
1741 *
1742 * There is a rounding problem here; if alpha is less than 128 it will end up
1743 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1744 * output change for this too.
1745 */
1746 if (component >= alpha || alpha < 128)
1747 return 255;
1748
1749 /* component<alpha, so component/alpha is less than one and
1750 * component*reciprocal is less than 2^31.
1751 */
1752 else if (component > 0)
1753 {
1754 /* The test is that alpha/257 (rounded) is less than 255, the first value
1755 * that becomes 255 is 65407.
1756 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1757 * be exact!) [Could also test reciprocal != 0]
1758 */
1759 if (alpha < 65407)
1760 {
1761 component *= reciprocal;
1762 component += 64; /* round to nearest */
1763 component >>= 7;
1764 }
1765
1766 else
1767 component *= 255;
1768
1769 /* Convert the component to sRGB. */
1770 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1771 }
1772
1773 else
1774 return 0;
1775 }
1776
1777 static int
png_write_image_8bit(png_voidp argument)1778 png_write_image_8bit(png_voidp argument)
1779 {
1780 png_image_write_control *display = png_voidcast(png_image_write_control*,
1781 argument);
1782 png_imagep image = display->image;
1783 png_structrp png_ptr = image->opaque->png_ptr;
1784
1785 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1786 display->first_row);
1787 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1788 png_uint_32 y = image->height;
1789 const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
1790
1791 if (image->format & PNG_FORMAT_FLAG_ALPHA)
1792 {
1793 png_bytep row_end;
1794 int aindex;
1795
1796 if (image->format & PNG_FORMAT_FLAG_AFIRST)
1797 {
1798 aindex = -1;
1799 ++input_row; /* To point to the first component */
1800 ++output_row;
1801 }
1802
1803 else
1804 aindex = channels;
1805
1806 /* Use row_end in place of a loop counter: */
1807 row_end = output_row + image->width * (channels+1);
1808
1809 while (y-- > 0)
1810 {
1811 png_const_uint_16p in_ptr = input_row;
1812 png_bytep out_ptr = output_row;
1813
1814 while (out_ptr < row_end)
1815 {
1816 png_uint_16 alpha = in_ptr[aindex];
1817 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1818 png_uint_32 reciprocal = 0;
1819 int c;
1820
1821 /* Scale and write the alpha channel. */
1822 out_ptr[aindex] = alphabyte;
1823
1824 if (alphabyte > 0 && alphabyte < 255)
1825 reciprocal = UNP_RECIPROCAL(alpha);
1826
1827 c = channels;
1828 do /* always at least one channel */
1829 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1830 while (--c > 0);
1831
1832 /* Skip to next component (skip the intervening alpha channel) */
1833 ++in_ptr;
1834 ++out_ptr;
1835 } /* while out_ptr < row_end */
1836
1837 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1838 display->local_row));
1839 input_row += display->row_bytes/(sizeof (png_uint_16));
1840 } /* while y */
1841 }
1842
1843 else
1844 {
1845 /* No alpha channel, so the row_end really is the end of the row and it
1846 * is sufficient to loop over the components one by one.
1847 */
1848 png_bytep row_end = output_row + image->width * channels;
1849
1850 while (y-- > 0)
1851 {
1852 png_const_uint_16p in_ptr = input_row;
1853 png_bytep out_ptr = output_row;
1854
1855 while (out_ptr < row_end)
1856 {
1857 png_uint_32 component = *in_ptr++;
1858
1859 component *= 255;
1860 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1861 }
1862
1863 png_write_row(png_ptr, output_row);
1864 input_row += display->row_bytes/(sizeof (png_uint_16));
1865 }
1866 }
1867
1868 return 1;
1869 }
1870
1871 static void
png_image_set_PLTE(png_image_write_control * display)1872 png_image_set_PLTE(png_image_write_control *display)
1873 {
1874 const png_imagep image = display->image;
1875 const void *cmap = display->colormap;
1876 const int entries = image->colormap_entries > 256 ? 256 :
1877 (int)image->colormap_entries;
1878
1879 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1880 const png_uint_32 format = image->format;
1881 const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1882
1883 # ifdef PNG_FORMAT_BGR_SUPPORTED
1884 const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1885 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1886 # else
1887 # define afirst 0
1888 # endif
1889
1890 # ifdef PNG_FORMAT_BGR_SUPPORTED
1891 const int bgr = (format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
1892 # else
1893 # define bgr 0
1894 # endif
1895
1896 int i, num_trans;
1897 png_color palette[256];
1898 png_byte tRNS[256];
1899
1900 memset(tRNS, 255, (sizeof tRNS));
1901 memset(palette, 0, (sizeof palette));
1902
1903 for (i=num_trans=0; i<entries; ++i)
1904 {
1905 /* This gets automatically converted to sRGB with reversal of the
1906 * pre-multiplication if the color-map has an alpha channel.
1907 */
1908 if (format & PNG_FORMAT_FLAG_LINEAR)
1909 {
1910 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1911
1912 entry += i * channels;
1913
1914 if (channels & 1) /* no alpha */
1915 {
1916 if (channels >= 3) /* RGB */
1917 {
1918 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1919 entry[(2 ^ bgr)]);
1920 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1921 entry[1]);
1922 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1923 entry[bgr]);
1924 }
1925
1926 else /* Gray */
1927 palette[i].blue = palette[i].red = palette[i].green =
1928 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1929 }
1930
1931 else /* alpha */
1932 {
1933 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1934 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1935 png_uint_32 reciprocal = 0;
1936
1937 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1938 * this is designed to produce a value scaled to 255*65535 when
1939 * divided by 128 (i.e. asr 7).
1940 */
1941 if (alphabyte > 0 && alphabyte < 255)
1942 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1943
1944 tRNS[i] = alphabyte;
1945 if (alphabyte < 255)
1946 num_trans = i+1;
1947
1948 if (channels >= 3) /* RGB */
1949 {
1950 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1951 alpha, reciprocal);
1952 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1953 reciprocal);
1954 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1955 reciprocal);
1956 }
1957
1958 else /* gray */
1959 palette[i].blue = palette[i].red = palette[i].green =
1960 png_unpremultiply(entry[afirst], alpha, reciprocal);
1961 }
1962 }
1963
1964 else /* Color-map has sRGB values */
1965 {
1966 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1967
1968 entry += i * channels;
1969
1970 switch (channels)
1971 {
1972 case 4:
1973 tRNS[i] = entry[afirst ? 0 : 3];
1974 if (tRNS[i] < 255)
1975 num_trans = i+1;
1976 /* FALL THROUGH */
1977 case 3:
1978 palette[i].blue = entry[afirst + (2 ^ bgr)];
1979 palette[i].green = entry[afirst + 1];
1980 palette[i].red = entry[afirst + bgr];
1981 break;
1982
1983 case 2:
1984 tRNS[i] = entry[1 ^ afirst];
1985 if (tRNS[i] < 255)
1986 num_trans = i+1;
1987 /* FALL THROUGH */
1988 case 1:
1989 palette[i].blue = palette[i].red = palette[i].green =
1990 entry[afirst];
1991 break;
1992
1993 default:
1994 break;
1995 }
1996 }
1997 }
1998
1999 # ifdef afirst
2000 # undef afirst
2001 # endif
2002 # ifdef bgr
2003 # undef bgr
2004 # endif
2005
2006 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
2007 entries);
2008
2009 if (num_trans > 0)
2010 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
2011 num_trans, NULL);
2012
2013 image->colormap_entries = entries;
2014 }
2015
2016 static int
png_image_write_main(png_voidp argument)2017 png_image_write_main(png_voidp argument)
2018 {
2019 png_image_write_control *display = png_voidcast(png_image_write_control*,
2020 argument);
2021 png_imagep image = display->image;
2022 png_structrp png_ptr = image->opaque->png_ptr;
2023 png_inforp info_ptr = image->opaque->info_ptr;
2024 png_uint_32 format = image->format;
2025
2026 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP) != 0;
2027 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR) != 0; /* input */
2028 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0;
2029 int write_16bit = linear && !colormap && !display->convert_to_8bit;
2030
2031 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
2032 /* Make sure we error out on any bad situation */
2033 png_set_benign_errors(png_ptr, 0/*error*/);
2034 # endif
2035
2036 /* Default the 'row_stride' parameter if required. */
2037 if (display->row_stride == 0)
2038 display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);
2039
2040 /* Set the required transforms then write the rows in the correct order. */
2041 if (format & PNG_FORMAT_FLAG_COLORMAP)
2042 {
2043 if (display->colormap != NULL && image->colormap_entries > 0)
2044 {
2045 png_uint_32 entries = image->colormap_entries;
2046
2047 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2048 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
2049 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
2050 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2051
2052 png_image_set_PLTE(display);
2053 }
2054
2055 else
2056 png_error(image->opaque->png_ptr,
2057 "no color-map for color-mapped image");
2058 }
2059
2060 else
2061 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2062 write_16bit ? 16 : 8,
2063 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2064 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2065 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2066
2067 /* Counter-intuitively the data transformations must be called *after*
2068 * png_write_info, not before as in the read code, but the 'set' functions
2069 * must still be called before. Just set the color space information, never
2070 * write an interlaced image.
2071 */
2072
2073 if (write_16bit)
2074 {
2075 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2076 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2077
2078 if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
2079 png_set_cHRM_fixed(png_ptr, info_ptr,
2080 /* color x y */
2081 /* white */ 31270, 32900,
2082 /* red */ 64000, 33000,
2083 /* green */ 30000, 60000,
2084 /* blue */ 15000, 6000
2085 );
2086 }
2087
2088 else if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB))
2089 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2090
2091 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2092 * space must still be gamma encoded.
2093 */
2094 else
2095 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2096
2097 /* Write the file header. */
2098 png_write_info(png_ptr, info_ptr);
2099
2100 /* Now set up the data transformations (*after* the header is written),
2101 * remove the handled transformations from the 'format' flags for checking.
2102 *
2103 * First check for a little endian system if writing 16 bit files.
2104 */
2105 if (write_16bit)
2106 {
2107 PNG_CONST png_uint_16 le = 0x0001;
2108
2109 if (*(png_const_bytep)&le)
2110 png_set_swap(png_ptr);
2111 }
2112
2113 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2114 if (format & PNG_FORMAT_FLAG_BGR)
2115 {
2116 if (!colormap && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2117 png_set_bgr(png_ptr);
2118 format &= ~PNG_FORMAT_FLAG_BGR;
2119 }
2120 # endif
2121
2122 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2123 if (format & PNG_FORMAT_FLAG_AFIRST)
2124 {
2125 if (!colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2126 png_set_swap_alpha(png_ptr);
2127 format &= ~PNG_FORMAT_FLAG_AFIRST;
2128 }
2129 # endif
2130
2131 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2132 * above, but the application data is still byte packed.
2133 */
2134 if (colormap && image->colormap_entries <= 16)
2135 png_set_packing(png_ptr);
2136
2137 /* That should have handled all (both) the transforms. */
2138 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2139 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2140 png_error(png_ptr, "png_write_image: unsupported transformation");
2141
2142 {
2143 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2144 ptrdiff_t row_bytes = display->row_stride;
2145
2146 if (linear)
2147 row_bytes *= (sizeof (png_uint_16));
2148
2149 if (row_bytes < 0)
2150 row += (image->height-1) * (-row_bytes);
2151
2152 display->first_row = row;
2153 display->row_bytes = row_bytes;
2154 }
2155
2156 /* Apply 'fast' options if the flag is set. */
2157 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2158 {
2159 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2160 /* NOTE: determined by experiment using pngstest, this reflects some
2161 * balance between the time to write the image once and the time to read
2162 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2163 * total (user) time on a heavily loaded system.
2164 */
2165 png_set_compression_level(png_ptr, 3);
2166 }
2167
2168 /* Check for the cases that currently require a pre-transform on the row
2169 * before it is written. This only applies when the input is 16-bit and
2170 * either there is an alpha channel or it is converted to 8-bit.
2171 */
2172 if ((linear && alpha) || (!colormap && display->convert_to_8bit))
2173 {
2174 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2175 png_get_rowbytes(png_ptr, info_ptr)));
2176 int result;
2177
2178 display->local_row = row;
2179 if (write_16bit)
2180 result = png_safe_execute(image, png_write_image_16bit, display);
2181 else
2182 result = png_safe_execute(image, png_write_image_8bit, display);
2183 display->local_row = NULL;
2184
2185 png_free(png_ptr, row);
2186
2187 /* Skip the 'write_end' on error: */
2188 if (!result)
2189 return 0;
2190 }
2191
2192 /* Otherwise this is the case where the input is in a format currently
2193 * supported by the rest of the libpng write code; call it directly.
2194 */
2195 else
2196 {
2197 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2198 ptrdiff_t row_bytes = display->row_bytes;
2199 png_uint_32 y = image->height;
2200
2201 while (y-- > 0)
2202 {
2203 png_write_row(png_ptr, row);
2204 row += row_bytes;
2205 }
2206 }
2207
2208 png_write_end(png_ptr, info_ptr);
2209 return 1;
2210 }
2211
2212 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)2213 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2214 const void *buffer, png_int_32 row_stride, const void *colormap)
2215 {
2216 /* Write the image to the given (FILE*). */
2217 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2218 {
2219 if (file != NULL)
2220 {
2221 if (png_image_write_init(image))
2222 {
2223 png_image_write_control display;
2224 int result;
2225
2226 /* This is slightly evil, but png_init_io doesn't do anything other
2227 * than this and we haven't changed the standard IO functions so
2228 * this saves a 'safe' function.
2229 */
2230 image->opaque->png_ptr->io_ptr = file;
2231
2232 memset(&display, 0, (sizeof display));
2233 display.image = image;
2234 display.buffer = buffer;
2235 display.row_stride = row_stride;
2236 display.colormap = colormap;
2237 display.convert_to_8bit = convert_to_8bit;
2238
2239 result = png_safe_execute(image, png_image_write_main, &display);
2240 png_image_free(image);
2241 return result;
2242 }
2243
2244 else
2245 return 0;
2246 }
2247
2248 else
2249 return png_image_error(image,
2250 "png_image_write_to_stdio: invalid argument");
2251 }
2252
2253 else if (image != NULL)
2254 return png_image_error(image,
2255 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2256
2257 else
2258 return 0;
2259 }
2260
2261 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)2262 png_image_write_to_file(png_imagep image, const char *file_name,
2263 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2264 const void *colormap)
2265 {
2266 /* Write the image to the named file. */
2267 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2268 {
2269 if (file_name != NULL)
2270 {
2271 FILE *fp = fopen(file_name, "wb");
2272
2273 if (fp != NULL)
2274 {
2275 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2276 row_stride, colormap))
2277 {
2278 int error; /* from fflush/fclose */
2279
2280 /* Make sure the file is flushed correctly. */
2281 if (fflush(fp) == 0 && ferror(fp) == 0)
2282 {
2283 if (fclose(fp) == 0)
2284 return 1;
2285
2286 error = errno; /* from fclose */
2287 }
2288
2289 else
2290 {
2291 error = errno; /* from fflush or ferror */
2292 (void)fclose(fp);
2293 }
2294
2295 (void)remove(file_name);
2296 /* The image has already been cleaned up; this is just used to
2297 * set the error (because the original write succeeded).
2298 */
2299 return png_image_error(image, strerror(error));
2300 }
2301
2302 else
2303 {
2304 /* Clean up: just the opened file. */
2305 (void)fclose(fp);
2306 (void)remove(file_name);
2307 return 0;
2308 }
2309 }
2310
2311 else
2312 return png_image_error(image, strerror(errno));
2313 }
2314
2315 else
2316 return png_image_error(image,
2317 "png_image_write_to_file: invalid argument");
2318 }
2319
2320 else if (image != NULL)
2321 return png_image_error(image,
2322 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2323
2324 else
2325 return 0;
2326 }
2327 #endif /* PNG_STDIO_SUPPORTED */
2328 #endif /* SIMPLIFIED_WRITE */
2329 #endif /* PNG_WRITE_SUPPORTED */
2330