2 /* pngwrite.c - general routines to write a PNG file
4 * Copyright (c) 2018-2022 Cosmin Truta
5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6 * Copyright (c) 1996-1997 Andreas Dilger
7 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
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
15 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
17 #endif /* SIMPLIFIED_WRITE_STDIO */
19 #ifdef PNG_WRITE_SUPPORTED
21 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
22 /* Write out all the unknown chunks for the current given location */
24 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
27 if (info_ptr->unknown_chunks_num != 0)
29 png_const_unknown_chunkp up;
31 png_debug(5, "writing extra chunks");
33 for (up = info_ptr->unknown_chunks;
34 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
36 if ((up->location & where) != 0)
38 /* If per-chunk unknown chunk handling is enabled use it, otherwise
39 * just write the chunks the application has set.
41 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
42 int keep = png_handle_as_unknown(png_ptr, up->name);
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
51 * The default handling is also slightly weird - it is not possible to
52 * stop the writing of all unsafe-to-copy chunks!
54 * TODO: REVIEW: this would seem to be a bug.
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)))
63 /* TODO: review, what is wrong with a zero length unknown chunk? */
65 png_warning(png_ptr, "Writing zero-length unknown chunk");
67 png_write_chunk(png_ptr, up->name, up->data, up->size);
72 #endif /* WRITE_UNKNOWN_CHUNKS */
74 /* Writes all the PNG information. This is the suggested way to use the
75 * library. If you have a new chunk to add, make a function to write it,
76 * and put it in the correct location here. If you want the chunk written
77 * after the image data, put it in png_write_end(). I strongly encourage
78 * you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before
79 * writing the chunk, as that will keep the code from breaking if you want
80 * to just write a plain PNG file. If you have long comments, I suggest
81 * writing them in png_write_end(), and compressing them.
84 png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
86 png_debug(1, "in png_write_info_before_PLTE");
88 if (png_ptr == NULL || info_ptr == NULL)
91 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
93 /* Write PNG signature */
94 png_write_sig(png_ptr);
96 #ifdef PNG_MNG_FEATURES_SUPPORTED
97 if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
98 png_ptr->mng_features_permitted != 0)
101 "MNG features are not allowed in a PNG datastream");
102 png_ptr->mng_features_permitted = 0;
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
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.
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.)
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'
131 #ifdef PNG_WRITE_APNG_SUPPORTED
132 if (info_ptr->valid & PNG_INFO_acTL)
133 png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
135 #ifdef PNG_GAMMA_SUPPORTED
136 # ifdef PNG_WRITE_gAMA_SUPPORTED
137 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
138 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
139 (info_ptr->valid & PNG_INFO_gAMA) != 0)
140 png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
144 #ifdef PNG_COLORSPACE_SUPPORTED
145 /* Write only one of sRGB or an ICC profile. If a profile was supplied
146 * and it matches one of the known sRGB ones issue a warning.
148 # ifdef PNG_WRITE_iCCP_SUPPORTED
149 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
150 (info_ptr->valid & PNG_INFO_iCCP) != 0)
152 # ifdef PNG_WRITE_sRGB_SUPPORTED
153 if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
154 png_app_warning(png_ptr,
155 "profile matches sRGB but writing iCCP instead");
158 png_write_iCCP(png_ptr, info_ptr->iccp_name,
159 info_ptr->iccp_profile);
161 # ifdef PNG_WRITE_sRGB_SUPPORTED
166 # ifdef PNG_WRITE_sRGB_SUPPORTED
167 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
168 (info_ptr->valid & PNG_INFO_sRGB) != 0)
169 png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
170 # endif /* WRITE_sRGB */
171 #endif /* COLORSPACE */
173 #ifdef PNG_WRITE_sBIT_SUPPORTED
174 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
175 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
178 #ifdef PNG_COLORSPACE_SUPPORTED
179 # ifdef PNG_WRITE_cHRM_SUPPORTED
180 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
181 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
182 (info_ptr->valid & PNG_INFO_cHRM) != 0)
183 png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
187 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
188 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
191 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
196 png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
198 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
202 png_debug(1, "in png_write_info");
204 if (png_ptr == NULL || info_ptr == NULL)
207 png_write_info_before_PLTE(png_ptr, info_ptr);
209 if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
210 png_write_PLTE(png_ptr, info_ptr->palette,
211 (png_uint_32)info_ptr->num_palette);
213 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
214 png_error(png_ptr, "Valid palette required for paletted images");
216 #ifdef PNG_WRITE_tRNS_SUPPORTED
217 if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
219 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
220 /* Invert the alpha channel (in tRNS) */
221 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
222 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
226 jend = info_ptr->num_trans;
227 if (jend > PNG_MAX_PALETTE_LENGTH)
228 jend = PNG_MAX_PALETTE_LENGTH;
230 for (j = 0; j<jend; ++j)
231 info_ptr->trans_alpha[j] =
232 (png_byte)(255 - info_ptr->trans_alpha[j]);
235 png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
236 info_ptr->num_trans, info_ptr->color_type);
239 #ifdef PNG_WRITE_bKGD_SUPPORTED
240 if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
241 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
244 #ifdef PNG_WRITE_eXIf_SUPPORTED
245 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
246 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
249 #ifdef PNG_WRITE_hIST_SUPPORTED
250 if ((info_ptr->valid & PNG_INFO_hIST) != 0)
251 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
254 #ifdef PNG_WRITE_oFFs_SUPPORTED
255 if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
256 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
257 info_ptr->offset_unit_type);
260 #ifdef PNG_WRITE_pCAL_SUPPORTED
261 if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
262 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
263 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
264 info_ptr->pcal_units, info_ptr->pcal_params);
267 #ifdef PNG_WRITE_sCAL_SUPPORTED
268 if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
269 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
270 info_ptr->scal_s_width, info_ptr->scal_s_height);
273 #ifdef PNG_WRITE_pHYs_SUPPORTED
274 if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
275 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
276 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
279 #ifdef PNG_WRITE_tIME_SUPPORTED
280 if ((info_ptr->valid & PNG_INFO_tIME) != 0)
282 png_write_tIME(png_ptr, &(info_ptr->mod_time));
283 png_ptr->mode |= PNG_WROTE_tIME;
287 #ifdef PNG_WRITE_sPLT_SUPPORTED
288 if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
289 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
290 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
293 #ifdef PNG_WRITE_TEXT_SUPPORTED
294 /* Check to see if we need to write text chunks */
295 for (i = 0; i < info_ptr->num_text; i++)
297 png_debug2(2, "Writing header text chunk %d, type %d", i,
298 info_ptr->text[i].compression);
299 /* An internationalized chunk? */
300 if (info_ptr->text[i].compression > 0)
302 #ifdef PNG_WRITE_iTXt_SUPPORTED
303 /* Write international chunk */
304 png_write_iTXt(png_ptr,
305 info_ptr->text[i].compression,
306 info_ptr->text[i].key,
307 info_ptr->text[i].lang,
308 info_ptr->text[i].lang_key,
309 info_ptr->text[i].text);
310 /* Mark this chunk as written */
311 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
312 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
314 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
316 png_warning(png_ptr, "Unable to write international text");
320 /* If we want a compressed text chunk */
321 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
323 #ifdef PNG_WRITE_zTXt_SUPPORTED
324 /* Write compressed chunk */
325 png_write_zTXt(png_ptr, info_ptr->text[i].key,
326 info_ptr->text[i].text, info_ptr->text[i].compression);
327 /* Mark this chunk as written */
328 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
330 png_warning(png_ptr, "Unable to write compressed text");
334 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
336 #ifdef PNG_WRITE_tEXt_SUPPORTED
337 /* Write uncompressed chunk */
338 png_write_tEXt(png_ptr, info_ptr->text[i].key,
339 info_ptr->text[i].text,
341 /* Mark this chunk as written */
342 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
345 png_warning(png_ptr, "Unable to write uncompressed text");
351 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
352 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
356 /* Writes the end of the PNG file. If you don't want to write comments or
357 * time information, you can pass NULL for info. If you already wrote these
358 * in png_write_info(), do not write them again here. If you have long
359 * comments, I suggest writing them here, and compressing them.
362 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
364 png_debug(1, "in png_write_end");
369 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
370 png_error(png_ptr, "No IDATs written into file");
372 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
373 if (png_ptr->num_palette_max > png_ptr->num_palette)
374 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
377 #ifdef PNG_WRITE_APNG_SUPPORTED
378 if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
379 png_error(png_ptr, "Not enough frames written");
382 /* See if user wants us to write information chunks */
383 if (info_ptr != NULL)
385 #ifdef PNG_WRITE_TEXT_SUPPORTED
386 int i; /* local index variable */
388 #ifdef PNG_WRITE_tIME_SUPPORTED
389 /* Check to see if user has supplied a time chunk */
390 if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
391 (png_ptr->mode & PNG_WROTE_tIME) == 0)
392 png_write_tIME(png_ptr, &(info_ptr->mod_time));
395 #ifdef PNG_WRITE_TEXT_SUPPORTED
396 /* Loop through comment chunks */
397 for (i = 0; i < info_ptr->num_text; i++)
399 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
400 info_ptr->text[i].compression);
401 /* An internationalized chunk? */
402 if (info_ptr->text[i].compression > 0)
404 #ifdef PNG_WRITE_iTXt_SUPPORTED
405 /* Write international chunk */
406 png_write_iTXt(png_ptr,
407 info_ptr->text[i].compression,
408 info_ptr->text[i].key,
409 info_ptr->text[i].lang,
410 info_ptr->text[i].lang_key,
411 info_ptr->text[i].text);
412 /* Mark this chunk as written */
413 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
414 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
416 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
418 png_warning(png_ptr, "Unable to write international text");
422 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
424 #ifdef PNG_WRITE_zTXt_SUPPORTED
425 /* Write compressed chunk */
426 png_write_zTXt(png_ptr, info_ptr->text[i].key,
427 info_ptr->text[i].text, info_ptr->text[i].compression);
428 /* Mark this chunk as written */
429 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
431 png_warning(png_ptr, "Unable to write compressed text");
435 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
437 #ifdef PNG_WRITE_tEXt_SUPPORTED
438 /* Write uncompressed chunk */
439 png_write_tEXt(png_ptr, info_ptr->text[i].key,
440 info_ptr->text[i].text, 0);
441 /* Mark this chunk as written */
442 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
444 png_warning(png_ptr, "Unable to write uncompressed text");
450 #ifdef PNG_WRITE_eXIf_SUPPORTED
451 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
452 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
455 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
456 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
460 png_ptr->mode |= PNG_AFTER_IDAT;
462 /* Write end of PNG file */
463 png_write_IEND(png_ptr);
465 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
466 * and restored again in libpng-1.2.30, may cause some applications that
467 * do not set png_ptr->output_flush_fn to crash. If your application
468 * experiences a problem, please try building libpng with
469 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
470 * png-mng-implement at lists.sf.net .
472 #ifdef PNG_WRITE_FLUSH_SUPPORTED
473 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
479 #ifdef PNG_CONVERT_tIME_SUPPORTED
481 png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
483 png_debug(1, "in png_convert_from_struct_tm");
485 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
486 ptime->month = (png_byte)(ttime->tm_mon + 1);
487 ptime->day = (png_byte)ttime->tm_mday;
488 ptime->hour = (png_byte)ttime->tm_hour;
489 ptime->minute = (png_byte)ttime->tm_min;
490 ptime->second = (png_byte)ttime->tm_sec;
494 png_convert_from_time_t(png_timep ptime, time_t ttime)
498 png_debug(1, "in png_convert_from_time_t");
500 tbuf = gmtime(&ttime);
503 /* TODO: add a safe function which takes a png_ptr argument and raises
504 * a png_error if the ttime argument is invalid and the call to gmtime
505 * fails as a consequence.
507 memset(ptime, 0, sizeof(*ptime));
511 png_convert_from_struct_tm(ptime, tbuf);
515 /* Initialize png_ptr structure, and allocate any memory needed */
516 PNG_FUNCTION(png_structp,PNGAPI
517 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
518 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
520 #ifndef PNG_USER_MEM_SUPPORTED
521 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
522 error_fn, warn_fn, NULL, NULL, NULL);
524 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
525 warn_fn, NULL, NULL, NULL);
528 /* Alternate initialize png_ptr structure, and allocate any memory needed */
529 PNG_FUNCTION(png_structp,PNGAPI
530 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
531 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
532 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
534 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
535 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
536 #endif /* USER_MEM */
539 /* Set the zlib control values to defaults; they can be overridden by the
540 * application after the struct has been created.
542 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
544 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
545 * pngwutil.c defaults it according to whether or not filters will be
546 * used, and ignores this setting.
548 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
549 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
550 png_ptr->zlib_mem_level = 8;
551 png_ptr->zlib_window_bits = 15;
552 png_ptr->zlib_method = 8;
554 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
555 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
556 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
557 png_ptr->zlib_text_mem_level = 8;
558 png_ptr->zlib_text_window_bits = 15;
559 png_ptr->zlib_text_method = 8;
560 #endif /* WRITE_COMPRESSED_TEXT */
562 /* This is a highly dubious configuration option; by default it is off,
563 * but it may be appropriate for private builds that are testing
564 * extensions not conformant to the current specification, or of
565 * applications that must not fail to write at all costs!
567 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
568 /* In stable builds only warn if an application error can be completely
571 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
574 /* App warnings are warnings in release (or release candidate) builds but
575 * are errors during development.
577 #if PNG_RELEASE_BUILD
578 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
581 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
582 * do it itself) avoiding setting the default function if it is not
585 png_set_write_fn(png_ptr, NULL, NULL, NULL);
592 /* Write a few rows of image data. If the image is interlaced,
593 * either you will have to write the 7 sub images, or, if you
594 * have called png_set_interlace_handling(), you will have to
595 * "write" the image seven times.
598 png_write_rows(png_structrp png_ptr, png_bytepp row,
599 png_uint_32 num_rows)
601 png_uint_32 i; /* row counter */
602 png_bytepp rp; /* row pointer */
604 png_debug(1, "in png_write_rows");
609 /* Loop through the rows */
610 for (i = 0, rp = row; i < num_rows; i++, rp++)
612 png_write_row(png_ptr, *rp);
616 /* Write the image. You only need to call this function once, even
617 * if you are writing an interlaced image.
620 png_write_image(png_structrp png_ptr, png_bytepp image)
622 png_uint_32 i; /* row index */
623 int pass, num_pass; /* pass variables */
624 png_bytepp rp; /* points to current row */
629 png_debug(1, "in png_write_image");
631 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
632 /* Initialize interlace handling. If image is not interlaced,
633 * this will set pass to 1
635 num_pass = png_set_interlace_handling(png_ptr);
639 /* Loop through passes */
640 for (pass = 0; pass < num_pass; pass++)
642 /* Loop through image */
643 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
645 png_write_row(png_ptr, *rp);
650 #ifdef PNG_MNG_FEATURES_SUPPORTED
651 /* Performs intrapixel differencing */
653 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
655 png_debug(1, "in png_do_write_intrapixel");
657 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
660 png_uint_32 row_width = row_info->width;
661 if (row_info->bit_depth == 8)
666 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
669 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
675 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
677 *(rp) = (png_byte)(*rp - *(rp + 1));
678 *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
682 #ifdef PNG_WRITE_16BIT_SUPPORTED
683 else if (row_info->bit_depth == 16)
688 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
691 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
697 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
699 png_uint_32 s0 = (png_uint_32)(*(rp ) << 8) | *(rp + 1);
700 png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
701 png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
702 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
703 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
704 *(rp ) = (png_byte)(red >> 8);
705 *(rp + 1) = (png_byte)red;
706 *(rp + 4) = (png_byte)(blue >> 8);
707 *(rp + 5) = (png_byte)blue;
710 #endif /* WRITE_16BIT */
713 #endif /* MNG_FEATURES */
715 /* Called by user to write a row of image data */
717 png_write_row(png_structrp png_ptr, png_const_bytep row)
719 /* 1.5.6: moved from png_struct to be a local structure: */
720 png_row_info row_info;
725 png_debug2(1, "in png_write_row (row %u, pass %d)",
726 png_ptr->row_number, png_ptr->pass);
728 /* Initialize transformations and other stuff if first time */
729 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
731 /* Make sure we wrote the header info */
732 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
734 "png_write_info was never called before png_write_row");
736 /* Check for transforms that have been set but were defined out */
737 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
738 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
739 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
742 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
743 if ((png_ptr->transformations & PNG_FILLER) != 0)
744 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
746 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
747 defined(PNG_READ_PACKSWAP_SUPPORTED)
748 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
750 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
753 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
754 if ((png_ptr->transformations & PNG_PACK) != 0)
755 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
758 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
759 if ((png_ptr->transformations & PNG_SHIFT) != 0)
760 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
763 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
764 if ((png_ptr->transformations & PNG_BGR) != 0)
765 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
768 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
769 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
770 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
773 png_write_start_row(png_ptr);
776 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
777 /* If interlaced and not interested in row, return */
778 if (png_ptr->interlaced != 0 &&
779 (png_ptr->transformations & PNG_INTERLACE) != 0)
781 switch (png_ptr->pass)
784 if ((png_ptr->row_number & 0x07) != 0)
786 png_write_finish_row(png_ptr);
792 if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
794 png_write_finish_row(png_ptr);
800 if ((png_ptr->row_number & 0x07) != 4)
802 png_write_finish_row(png_ptr);
808 if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
810 png_write_finish_row(png_ptr);
816 if ((png_ptr->row_number & 0x03) != 2)
818 png_write_finish_row(png_ptr);
824 if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
826 png_write_finish_row(png_ptr);
832 if ((png_ptr->row_number & 0x01) == 0)
834 png_write_finish_row(png_ptr);
839 default: /* error: ignore it */
845 /* Set up row info for transformations */
846 row_info.color_type = png_ptr->color_type;
847 row_info.width = png_ptr->usr_width;
848 row_info.channels = png_ptr->usr_channels;
849 row_info.bit_depth = png_ptr->usr_bit_depth;
850 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
851 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
853 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
854 png_debug1(3, "row_info->width = %u", row_info.width);
855 png_debug1(3, "row_info->channels = %d", row_info.channels);
856 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
857 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
858 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
860 /* Copy user's row into buffer, leaving room for filter byte. */
861 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
863 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
864 /* Handle interlacing */
865 if (png_ptr->interlaced && png_ptr->pass < 6 &&
866 (png_ptr->transformations & PNG_INTERLACE) != 0)
868 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
869 /* This should always get caught above, but still ... */
870 if (row_info.width == 0)
872 png_write_finish_row(png_ptr);
878 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
879 /* Handle other transformations */
880 if (png_ptr->transformations != 0)
881 png_do_write_transformations(png_ptr, &row_info);
884 /* At this point the row_info pixel depth must match the 'transformed' depth,
885 * which is also the output depth.
887 if (row_info.pixel_depth != png_ptr->pixel_depth ||
888 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
889 png_error(png_ptr, "internal write transform logic error");
891 #ifdef PNG_MNG_FEATURES_SUPPORTED
892 /* Write filter_method 64 (intrapixel differencing) only if
893 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
894 * 2. Libpng did not write a PNG signature (this filter_method is only
895 * used in PNG datastreams that are embedded in MNG datastreams) and
896 * 3. The application called png_permit_mng_features with a mask that
897 * included PNG_FLAG_MNG_FILTER_64 and
898 * 4. The filter_method is 64 and
899 * 5. The color_type is RGB or RGBA
901 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
902 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
904 /* Intrapixel differencing */
905 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
909 /* Added at libpng-1.5.10 */
910 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
911 /* Check for out-of-range palette index */
912 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
913 png_ptr->num_palette_max >= 0)
914 png_do_check_palette_indexes(png_ptr, &row_info);
917 /* Find a filter if necessary, filter the row and write it out. */
918 png_write_find_filter(png_ptr, &row_info);
920 if (png_ptr->write_row_fn != NULL)
921 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
924 #ifdef PNG_WRITE_FLUSH_SUPPORTED
925 /* Set the automatic flush interval or 0 to turn flushing off */
927 png_set_flush(png_structrp png_ptr, int nrows)
929 png_debug(1, "in png_set_flush");
934 png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
937 /* Flush the current output buffers now */
939 png_write_flush(png_structrp png_ptr)
941 png_debug(1, "in png_write_flush");
946 /* We have already written out all of the data */
947 if (png_ptr->row_number >= png_ptr->num_rows)
950 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
951 png_ptr->flush_rows = 0;
954 #endif /* WRITE_FLUSH */
956 /* Free any memory used in png_ptr struct without freeing the struct itself. */
958 png_write_destroy(png_structrp png_ptr)
960 png_debug(1, "in png_write_destroy");
962 /* Free any memory zlib uses */
963 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
964 deflateEnd(&png_ptr->zstream);
966 /* Free our memory. png_free checks NULL for us. */
967 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
968 png_free(png_ptr, png_ptr->row_buf);
969 png_ptr->row_buf = NULL;
970 #ifdef PNG_WRITE_FILTER_SUPPORTED
971 png_free(png_ptr, png_ptr->prev_row);
972 png_free(png_ptr, png_ptr->try_row);
973 png_free(png_ptr, png_ptr->tst_row);
974 png_ptr->prev_row = NULL;
975 png_ptr->try_row = NULL;
976 png_ptr->tst_row = NULL;
979 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
980 png_free(png_ptr, png_ptr->chunk_list);
981 png_ptr->chunk_list = NULL;
984 /* The error handling and memory handling information is left intact at this
985 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
986 * for how this happens.
990 /* Free all memory used by the write.
991 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
992 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
993 * the passed in info_structs but it would quietly fail to free any of the data
994 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
998 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
1000 png_debug(1, "in png_destroy_write_struct");
1002 if (png_ptr_ptr != NULL)
1004 png_structrp png_ptr = *png_ptr_ptr;
1006 if (png_ptr != NULL) /* added in libpng 1.6.0 */
1008 png_destroy_info_struct(png_ptr, info_ptr_ptr);
1010 *png_ptr_ptr = NULL;
1011 png_write_destroy(png_ptr);
1012 png_destroy_png_struct(png_ptr);
1017 /* Allow the application to select one or more row filters to use. */
1019 png_set_filter(png_structrp png_ptr, int method, int filters)
1021 png_debug(1, "in png_set_filter");
1023 if (png_ptr == NULL)
1026 #ifdef PNG_MNG_FEATURES_SUPPORTED
1027 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
1028 (method == PNG_INTRAPIXEL_DIFFERENCING))
1029 method = PNG_FILTER_TYPE_BASE;
1032 if (method == PNG_FILTER_TYPE_BASE)
1034 switch (filters & (PNG_ALL_FILTERS | 0x07))
1036 #ifdef PNG_WRITE_FILTER_SUPPORTED
1039 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1040 #endif /* WRITE_FILTER */
1043 /* 'switch ~ case' is dead code.
1044 * If filters is #PNG_FILTER_VALUE_NONE, #PNG_FILTER_VALUE_SUB ...,
1045 * filter flag will be assigned to 'png_ptr->do_filter'. But
1046 * 'png_ptr->do_filter' is overwritten as 'filters' at below code.
1047 * Issue code(#1155) is 'png_ptr->do_filter = (png_byte)filters;'.
1048 * So the result of 'switch ~ case' has been lost at the line.
1049 * To keep the value of 'switch ~ case', we fixed it to apply
1050 * the result into 'filters'.
1051 * It will be updated into 'png_ptr->do_filter' at #1155 line.
1053 case PNG_FILTER_VALUE_NONE:
1054 filters = PNG_FILTER_NONE; break;
1056 case PNG_FILTER_VALUE_NONE:
1057 png_ptr->do_filter = PNG_FILTER_NONE; break;
1058 #endif /* __TIZEN__ */
1060 #ifdef PNG_WRITE_FILTER_SUPPORTED
1062 case PNG_FILTER_VALUE_SUB:
1063 filters = PNG_FILTER_SUB; break;
1065 case PNG_FILTER_VALUE_UP:
1066 filters = PNG_FILTER_UP; break;
1068 case PNG_FILTER_VALUE_AVG:
1069 filters = PNG_FILTER_AVG; break;
1071 case PNG_FILTER_VALUE_PAETH:
1072 filters = PNG_FILTER_PAETH; break;
1074 case PNG_FILTER_VALUE_SUB:
1075 png_ptr->do_filter = PNG_FILTER_SUB; break;
1077 case PNG_FILTER_VALUE_UP:
1078 png_ptr->do_filter = PNG_FILTER_UP; break;
1080 case PNG_FILTER_VALUE_AVG:
1081 png_ptr->do_filter = PNG_FILTER_AVG; break;
1083 case PNG_FILTER_VALUE_PAETH:
1084 png_ptr->do_filter = PNG_FILTER_PAETH; break;
1085 #endif /* __TIZEN__ */
1087 png_ptr->do_filter = (png_byte)filters; break;
1090 png_app_error(png_ptr, "Unknown row filter for method 0");
1091 #endif /* WRITE_FILTER */
1094 #ifdef PNG_WRITE_FILTER_SUPPORTED
1095 /* If we have allocated the row_buf, this means we have already started
1096 * with the image and we should have allocated all of the filter buffers
1097 * that have been selected. If prev_row isn't already allocated, then
1098 * it is too late to start using the filters that need it, since we
1099 * will be missing the data in the previous row. If an application
1100 * wants to start and stop using particular filters during compression,
1101 * it should start out with all of the filters, and then remove them
1102 * or add them back after the start of compression.
1104 * NOTE: this is a nasty constraint on the code, because it means that the
1105 * prev_row buffer must be maintained even if there are currently no
1106 * 'prev_row' requiring filters active.
1108 if (png_ptr->row_buf != NULL)
1111 png_alloc_size_t buf_size;
1113 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1114 * images cannot benefit from certain filters. If this isn't done here
1115 * the check below will fire on 1 pixel high images.
1117 if (png_ptr->height == 1)
1118 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1120 if (png_ptr->width == 1)
1121 filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1123 if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
1124 && png_ptr->prev_row == NULL)
1126 /* This is the error case, however it is benign - the previous row
1127 * is not available so the filter can't be used. Just warn here.
1129 png_app_warning(png_ptr,
1130 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1131 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1136 if (filters & PNG_FILTER_SUB)
1139 if (filters & PNG_FILTER_UP)
1142 if (filters & PNG_FILTER_AVG)
1145 if (filters & PNG_FILTER_PAETH)
1148 /* Allocate needed row buffers if they have not already been
1151 buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1152 png_ptr->width) + 1;
1154 if (png_ptr->try_row == NULL)
1155 png_ptr->try_row = png_voidcast(png_bytep,
1156 png_malloc(png_ptr, buf_size));
1158 if (num_filters > 1)
1160 if (png_ptr->tst_row == NULL)
1161 png_ptr->tst_row = png_voidcast(png_bytep,
1162 png_malloc(png_ptr, buf_size));
1165 png_ptr->do_filter = (png_byte)filters;
1169 png_error(png_ptr, "Unknown custom filter method");
1172 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1173 /* Provide floating and fixed point APIs */
1174 #ifdef PNG_FLOATING_POINT_SUPPORTED
1176 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1177 int num_weights, png_const_doublep filter_weights,
1178 png_const_doublep filter_costs)
1181 PNG_UNUSED(heuristic_method)
1182 PNG_UNUSED(num_weights)
1183 PNG_UNUSED(filter_weights)
1184 PNG_UNUSED(filter_costs)
1186 #endif /* FLOATING_POINT */
1188 #ifdef PNG_FIXED_POINT_SUPPORTED
1190 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1191 int num_weights, png_const_fixed_point_p filter_weights,
1192 png_const_fixed_point_p filter_costs)
1195 PNG_UNUSED(heuristic_method)
1196 PNG_UNUSED(num_weights)
1197 PNG_UNUSED(filter_weights)
1198 PNG_UNUSED(filter_costs)
1200 #endif /* FIXED_POINT */
1201 #endif /* WRITE_WEIGHTED_FILTER */
1203 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1205 png_set_compression_level(png_structrp png_ptr, int level)
1207 png_debug(1, "in png_set_compression_level");
1209 if (png_ptr == NULL)
1212 png_ptr->zlib_level = level;
1216 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1218 png_debug(1, "in png_set_compression_mem_level");
1220 if (png_ptr == NULL)
1223 png_ptr->zlib_mem_level = mem_level;
1227 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1229 png_debug(1, "in png_set_compression_strategy");
1231 if (png_ptr == NULL)
1234 /* The flag setting here prevents the libpng dynamic selection of strategy.
1236 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1237 png_ptr->zlib_strategy = strategy;
1240 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1241 * smaller value of window_bits if it can do so safely.
1244 png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1246 if (png_ptr == NULL)
1249 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1250 * meant that negative window bits values could be selected that would cause
1251 * libpng to write a non-standard PNG file with raw deflate or gzip
1252 * compressed IDAT or ancillary chunks. Such files can be read and there is
1253 * no warning on read, so this seems like a very bad idea.
1255 if (window_bits > 15)
1257 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1261 else if (window_bits < 8)
1263 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1267 png_ptr->zlib_window_bits = window_bits;
1271 png_set_compression_method(png_structrp png_ptr, int method)
1273 png_debug(1, "in png_set_compression_method");
1275 if (png_ptr == NULL)
1278 /* This would produce an invalid PNG file if it worked, but it doesn't and
1279 * deflate will fault it, so it is harmless to just warn here.
1282 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1284 png_ptr->zlib_method = method;
1286 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1288 /* The following were added to libpng-1.5.4 */
1289 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1291 png_set_text_compression_level(png_structrp png_ptr, int level)
1293 png_debug(1, "in png_set_text_compression_level");
1295 if (png_ptr == NULL)
1298 png_ptr->zlib_text_level = level;
1302 png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1304 png_debug(1, "in png_set_text_compression_mem_level");
1306 if (png_ptr == NULL)
1309 png_ptr->zlib_text_mem_level = mem_level;
1313 png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1315 png_debug(1, "in png_set_text_compression_strategy");
1317 if (png_ptr == NULL)
1320 png_ptr->zlib_text_strategy = strategy;
1323 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1324 * smaller value of window_bits if it can do so safely.
1327 png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1329 if (png_ptr == NULL)
1332 if (window_bits > 15)
1334 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1338 else if (window_bits < 8)
1340 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1344 png_ptr->zlib_text_window_bits = window_bits;
1348 png_set_text_compression_method(png_structrp png_ptr, int method)
1350 png_debug(1, "in png_set_text_compression_method");
1352 if (png_ptr == NULL)
1356 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1358 png_ptr->zlib_text_method = method;
1360 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1361 /* end of API added to libpng-1.5.4 */
1364 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1366 if (png_ptr == NULL)
1369 png_ptr->write_row_fn = write_row_fn;
1372 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1374 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1375 write_user_transform_fn)
1377 png_debug(1, "in png_set_write_user_transform_fn");
1379 if (png_ptr == NULL)
1382 png_ptr->transformations |= PNG_USER_TRANSFORM;
1383 png_ptr->write_user_transform_fn = write_user_transform_fn;
1388 #ifdef PNG_INFO_IMAGE_SUPPORTED
1390 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1391 int transforms, voidp params)
1393 if (png_ptr == NULL || info_ptr == NULL)
1396 if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1398 png_app_error(png_ptr, "no rows for png_write_image to write");
1402 /* Write the file header information. */
1403 png_write_info(png_ptr, info_ptr);
1405 /* ------ these transformations don't touch the info structure ------- */
1407 /* Invert monochrome pixels */
1408 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1409 #ifdef PNG_WRITE_INVERT_SUPPORTED
1410 png_set_invert_mono(png_ptr);
1412 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1415 /* Shift the pixels up to a legal bit depth and fill in
1416 * as appropriate to correctly scale the image.
1418 if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1419 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1420 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1421 png_set_shift(png_ptr, &info_ptr->sig_bit);
1423 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1426 /* Pack pixels into bytes */
1427 if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1428 #ifdef PNG_WRITE_PACK_SUPPORTED
1429 png_set_packing(png_ptr);
1431 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1434 /* Swap location of alpha bytes from ARGB to RGBA */
1435 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1436 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1437 png_set_swap_alpha(png_ptr);
1439 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1442 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1443 * RGB, note that the code expects the input color type to be G or RGB; no
1446 if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
1447 PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1449 #ifdef PNG_WRITE_FILLER_SUPPORTED
1450 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1452 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1453 png_app_error(png_ptr,
1454 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1456 /* Continue if ignored - this is the pre-1.6.10 behavior */
1457 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1460 else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1461 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1463 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1467 /* Flip BGR pixels to RGB */
1468 if ((transforms & PNG_TRANSFORM_BGR) != 0)
1469 #ifdef PNG_WRITE_BGR_SUPPORTED
1470 png_set_bgr(png_ptr);
1472 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1475 /* Swap bytes of 16-bit files to most significant byte first */
1476 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1477 #ifdef PNG_WRITE_SWAP_SUPPORTED
1478 png_set_swap(png_ptr);
1480 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1483 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1484 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1485 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1486 png_set_packswap(png_ptr);
1488 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1491 /* Invert the alpha channel from opacity to transparency */
1492 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1493 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1494 png_set_invert_alpha(png_ptr);
1496 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1499 /* ----------------------- end of transformations ------------------- */
1501 /* Write the bits */
1502 png_write_image(png_ptr, info_ptr->row_pointers);
1504 /* It is REQUIRED to call this to finish writing the rest of the file */
1505 png_write_end(png_ptr, info_ptr);
1511 #ifdef PNG_WRITE_APNG_SUPPORTED
1513 png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
1514 png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
1515 png_uint_32 x_offset, png_uint_32 y_offset,
1516 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
1519 png_debug(1, "in png_write_frame_head");
1521 /* there is a chance this has been set after png_write_info was called,
1522 * so it would be set but not written. is there a way to be sure? */
1523 if (!(info_ptr->valid & PNG_INFO_acTL))
1524 png_error(png_ptr, "png_write_frame_head(): acTL not set");
1526 png_write_reset(png_ptr);
1528 png_write_reinit(png_ptr, info_ptr, width, height);
1530 if ( !(png_ptr->num_frames_written == 0 &&
1531 (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) ) )
1532 png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
1533 delay_num, delay_den, dispose_op, blend_op);
1535 PNG_UNUSED(row_pointers)
1539 png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
1541 png_debug(1, "in png_write_frame_tail");
1543 png_ptr->num_frames_written++;
1545 PNG_UNUSED(info_ptr)
1547 #endif /* PNG_WRITE_APNG_SUPPORTED */
1549 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1550 /* Initialize the write structure - general purpose utility. */
1552 png_image_write_init(png_imagep image)
1554 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1555 png_safe_error, png_safe_warning);
1557 if (png_ptr != NULL)
1559 png_infop info_ptr = png_create_info_struct(png_ptr);
1561 if (info_ptr != NULL)
1563 png_controlp control = png_voidcast(png_controlp,
1564 png_malloc_warn(png_ptr, (sizeof *control)));
1566 if (control != NULL)
1568 memset(control, 0, (sizeof *control));
1570 control->png_ptr = png_ptr;
1571 control->info_ptr = info_ptr;
1572 control->for_write = 1;
1574 image->opaque = control;
1578 /* Error clean up */
1579 png_destroy_info_struct(png_ptr, &info_ptr);
1582 png_destroy_write_struct(&png_ptr, NULL);
1585 return png_image_error(image, "png_image_write_: out of memory");
1588 /* Arguments to png_image_write_main: */
1593 png_const_voidp buffer;
1594 png_int_32 row_stride;
1595 png_const_voidp colormap;
1596 int convert_to_8bit;
1597 /* Local variables: */
1598 png_const_voidp first_row;
1599 ptrdiff_t row_bytes;
1600 png_voidp local_row;
1601 /* Byte count for memory writing */
1603 png_alloc_size_t memory_bytes; /* not used for STDIO */
1604 png_alloc_size_t output_bytes; /* running total */
1605 } png_image_write_control;
1607 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1608 * do any necessary byte swapping. The component order is defined by the
1609 * png_image format value.
1612 png_write_image_16bit(png_voidp argument)
1614 png_image_write_control *display = png_voidcast(png_image_write_control*,
1616 png_imagep image = display->image;
1617 png_structrp png_ptr = image->opaque->png_ptr;
1619 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1620 display->first_row);
1621 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1622 png_uint_16p row_end;
1623 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1626 png_uint_32 y = image->height;
1628 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1630 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1631 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1634 ++input_row; /* To point to the first component */
1638 aindex = (int)channels;
1640 aindex = (int)channels;
1645 png_error(png_ptr, "png_write_image: internal call error");
1647 /* Work out the output row end and count over this, note that the increment
1648 * above to 'row' means that row_end can actually be beyond the end of the
1649 * row; this is correct.
1651 row_end = output_row + image->width * (channels+1);
1655 png_const_uint_16p in_ptr = input_row;
1656 png_uint_16p out_ptr = output_row;
1658 while (out_ptr < row_end)
1660 png_uint_16 alpha = in_ptr[aindex];
1661 png_uint_32 reciprocal = 0;
1664 out_ptr[aindex] = alpha;
1666 /* Calculate a reciprocal. The correct calculation is simply
1667 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1668 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1669 * is only initialized when required.
1671 if (alpha > 0 && alpha < 65535)
1672 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1675 do /* always at least one channel */
1677 png_uint_16 component = *in_ptr++;
1679 /* The following gives 65535 for an alpha of 0, which is fine,
1680 * otherwise if 0/0 is represented as some other value there is more
1681 * likely to be a discontinuity which will probably damage
1682 * compression when moving from a fully transparent area to a
1683 * nearly transparent one. (The assumption here is that opaque
1684 * areas tend not to be 0 intensity.)
1686 if (component >= alpha)
1689 /* component<alpha, so component/alpha is less than one and
1690 * component*reciprocal is less than 2^31.
1692 else if (component > 0 && alpha < 65535)
1694 png_uint_32 calc = component * reciprocal;
1695 calc += 16384; /* round to nearest */
1696 component = (png_uint_16)(calc >> 15);
1699 *out_ptr++ = component;
1703 /* Skip to next component (skip the intervening alpha channel) */
1708 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1709 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1715 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1716 * is present it must be removed from the components, the components are then
1717 * written in sRGB encoding. No components are added or removed.
1719 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1720 * calculation can be done to 15 bits of accuracy; however, the output needs to
1721 * be scaled in the range 0..255*65535, so include that scaling here.
1723 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1726 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1727 png_uint_32 reciprocal/*from the above macro*/)
1729 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1730 * is represented as some other value there is more likely to be a
1731 * discontinuity which will probably damage compression when moving from a
1732 * fully transparent area to a nearly transparent one. (The assumption here
1733 * is that opaque areas tend not to be 0 intensity.)
1735 * There is a rounding problem here; if alpha is less than 128 it will end up
1736 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1737 * output change for this too.
1739 if (component >= alpha || alpha < 128)
1742 /* component<alpha, so component/alpha is less than one and
1743 * component*reciprocal is less than 2^31.
1745 else if (component > 0)
1747 /* The test is that alpha/257 (rounded) is less than 255, the first value
1748 * that becomes 255 is 65407.
1749 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1750 * be exact!) [Could also test reciprocal != 0]
1754 component *= reciprocal;
1755 component += 64; /* round to nearest */
1762 /* Convert the component to sRGB. */
1763 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1771 png_write_image_8bit(png_voidp argument)
1773 png_image_write_control *display = png_voidcast(png_image_write_control*,
1775 png_imagep image = display->image;
1776 png_structrp png_ptr = image->opaque->png_ptr;
1778 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1779 display->first_row);
1780 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1781 png_uint_32 y = image->height;
1782 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1785 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1790 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1791 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1794 ++input_row; /* To point to the first component */
1800 aindex = (int)channels;
1802 /* Use row_end in place of a loop counter: */
1803 row_end = output_row + image->width * (channels+1);
1807 png_const_uint_16p in_ptr = input_row;
1808 png_bytep out_ptr = output_row;
1810 while (out_ptr < row_end)
1812 png_uint_16 alpha = in_ptr[aindex];
1813 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1814 png_uint_32 reciprocal = 0;
1817 /* Scale and write the alpha channel. */
1818 out_ptr[aindex] = alphabyte;
1820 if (alphabyte > 0 && alphabyte < 255)
1821 reciprocal = UNP_RECIPROCAL(alpha);
1824 do /* always at least one channel */
1825 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1828 /* Skip to next component (skip the intervening alpha channel) */
1831 } /* while out_ptr < row_end */
1833 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1834 display->local_row));
1835 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1841 /* No alpha channel, so the row_end really is the end of the row and it
1842 * is sufficient to loop over the components one by one.
1844 png_bytep row_end = output_row + image->width * channels;
1848 png_const_uint_16p in_ptr = input_row;
1849 png_bytep out_ptr = output_row;
1851 while (out_ptr < row_end)
1853 png_uint_32 component = *in_ptr++;
1856 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1859 png_write_row(png_ptr, output_row);
1860 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1868 png_image_set_PLTE(png_image_write_control *display)
1870 png_imagep image = display->image;
1871 const void *cmap = display->colormap;
1872 int entries = image->colormap_entries > 256 ? 256 :
1873 (int)image->colormap_entries;
1875 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1876 png_uint_32 format = image->format;
1877 unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1879 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1880 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1881 int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1882 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1887 # ifdef PNG_FORMAT_BGR_SUPPORTED
1888 int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1894 png_color palette[256];
1897 memset(tRNS, 255, (sizeof tRNS));
1898 memset(palette, 0, (sizeof palette));
1900 for (i=num_trans=0; i<entries; ++i)
1902 /* This gets automatically converted to sRGB with reversal of the
1903 * pre-multiplication if the color-map has an alpha channel.
1905 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1907 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1909 entry += (unsigned int)i * channels;
1911 if ((channels & 1) != 0) /* no alpha */
1913 if (channels >= 3) /* RGB */
1915 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1917 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1919 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1924 palette[i].blue = palette[i].red = palette[i].green =
1925 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1930 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1931 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1932 png_uint_32 reciprocal = 0;
1934 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1935 * this is designed to produce a value scaled to 255*65535 when
1936 * divided by 128 (i.e. asr 7).
1938 if (alphabyte > 0 && alphabyte < 255)
1939 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1941 tRNS[i] = alphabyte;
1942 if (alphabyte < 255)
1945 if (channels >= 3) /* RGB */
1947 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1949 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1951 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1956 palette[i].blue = palette[i].red = palette[i].green =
1957 png_unpremultiply(entry[afirst], alpha, reciprocal);
1961 else /* Color-map has sRGB values */
1963 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1965 entry += (unsigned int)i * channels;
1970 tRNS[i] = entry[afirst ? 0 : 3];
1975 palette[i].blue = entry[afirst + (2 ^ bgr)];
1976 palette[i].green = entry[afirst + 1];
1977 palette[i].red = entry[afirst + bgr];
1981 tRNS[i] = entry[1 ^ afirst];
1986 palette[i].blue = palette[i].red = palette[i].green =
2003 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
2007 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
2010 image->colormap_entries = (png_uint_32)entries;
2014 png_image_write_main(png_voidp argument)
2016 png_image_write_control *display = png_voidcast(png_image_write_control*,
2018 png_imagep image = display->image;
2019 png_structrp png_ptr = image->opaque->png_ptr;
2020 png_inforp info_ptr = image->opaque->info_ptr;
2021 png_uint_32 format = image->format;
2023 /* The following four ints are actually booleans */
2024 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
2025 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
2026 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
2027 int write_16bit = linear && (display->convert_to_8bit == 0);
2029 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
2030 /* Make sure we error out on any bad situation */
2031 png_set_benign_errors(png_ptr, 0/*error*/);
2034 /* Default the 'row_stride' parameter if required, also check the row stride
2035 * and total image size to ensure that they are within the system limits.
2038 unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
2040 if (image->width <= 0x7fffffffU/channels) /* no overflow */
2043 png_uint_32 png_row_stride = image->width * channels;
2045 if (display->row_stride == 0)
2046 display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
2048 if (display->row_stride < 0)
2049 check = (png_uint_32)(-display->row_stride);
2052 check = (png_uint_32)display->row_stride;
2054 if (check >= png_row_stride)
2056 /* Now check for overflow of the image buffer calculation; this
2057 * limits the whole image size to 32 bits for API compatibility with
2058 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
2060 if (image->height > 0xffffffffU/png_row_stride)
2061 png_error(image->opaque->png_ptr, "memory image too large");
2065 png_error(image->opaque->png_ptr, "supplied row stride too small");
2069 png_error(image->opaque->png_ptr, "image row stride too large");
2072 /* Set the required transforms then write the rows in the correct order. */
2073 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
2075 if (display->colormap != NULL && image->colormap_entries > 0)
2077 png_uint_32 entries = image->colormap_entries;
2079 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2080 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
2081 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
2082 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2084 png_image_set_PLTE(display);
2088 png_error(image->opaque->png_ptr,
2089 "no color-map for color-mapped image");
2093 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2094 write_16bit ? 16 : 8,
2095 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2096 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2097 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2099 /* Counter-intuitively the data transformations must be called *after*
2100 * png_write_info, not before as in the read code, but the 'set' functions
2101 * must still be called before. Just set the color space information, never
2102 * write an interlaced image.
2105 if (write_16bit != 0)
2107 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2108 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2110 if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2111 png_set_cHRM_fixed(png_ptr, info_ptr,
2113 /* white */ 31270, 32900,
2114 /* red */ 64000, 33000,
2115 /* green */ 30000, 60000,
2116 /* blue */ 15000, 6000
2120 else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2121 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2123 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2124 * space must still be gamma encoded.
2127 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2129 /* Write the file header. */
2130 png_write_info(png_ptr, info_ptr);
2132 /* Now set up the data transformations (*after* the header is written),
2133 * remove the handled transformations from the 'format' flags for checking.
2135 * First check for a little endian system if writing 16-bit files.
2137 if (write_16bit != 0)
2139 png_uint_16 le = 0x0001;
2141 if ((*(png_const_bytep) & le) != 0)
2142 png_set_swap(png_ptr);
2145 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2146 if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2148 if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2149 png_set_bgr(png_ptr);
2150 format &= ~PNG_FORMAT_FLAG_BGR;
2154 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2155 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2157 if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2158 png_set_swap_alpha(png_ptr);
2159 format &= ~PNG_FORMAT_FLAG_AFIRST;
2163 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2164 * above, but the application data is still byte packed.
2166 if (colormap != 0 && image->colormap_entries <= 16)
2167 png_set_packing(png_ptr);
2169 /* That should have handled all (both) the transforms. */
2170 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2171 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2172 png_error(png_ptr, "png_write_image: unsupported transformation");
2175 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2176 ptrdiff_t row_bytes = display->row_stride;
2179 row_bytes *= (sizeof (png_uint_16));
2182 row += (image->height-1) * (-row_bytes);
2184 display->first_row = row;
2185 display->row_bytes = row_bytes;
2188 /* Apply 'fast' options if the flag is set. */
2189 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2191 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2192 /* NOTE: determined by experiment using pngstest, this reflects some
2193 * balance between the time to write the image once and the time to read
2194 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2195 * total (user) time on a heavily loaded system.
2197 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2198 png_set_compression_level(png_ptr, 3);
2202 /* Check for the cases that currently require a pre-transform on the row
2203 * before it is written. This only applies when the input is 16-bit and
2204 * either there is an alpha channel or it is converted to 8-bit.
2206 if ((linear != 0 && alpha != 0 ) ||
2207 (colormap == 0 && display->convert_to_8bit != 0))
2209 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2210 png_get_rowbytes(png_ptr, info_ptr)));
2213 display->local_row = row;
2214 if (write_16bit != 0)
2215 result = png_safe_execute(image, png_write_image_16bit, display);
2217 result = png_safe_execute(image, png_write_image_8bit, display);
2218 display->local_row = NULL;
2220 png_free(png_ptr, row);
2222 /* Skip the 'write_end' on error: */
2227 /* Otherwise this is the case where the input is in a format currently
2228 * supported by the rest of the libpng write code; call it directly.
2232 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2233 ptrdiff_t row_bytes = display->row_bytes;
2234 png_uint_32 y = image->height;
2238 png_write_row(png_ptr, row);
2243 png_write_end(png_ptr, info_ptr);
2248 static void (PNGCBAPI
2249 image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
2251 png_image_write_control *display = png_voidcast(png_image_write_control*,
2252 png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
2253 png_alloc_size_t ob = display->output_bytes;
2255 /* Check for overflow; this should never happen: */
2256 if (size <= ((png_alloc_size_t)-1) - ob)
2258 /* I don't think libpng ever does this, but just in case: */
2261 if (display->memory_bytes >= ob+size) /* writing */
2262 memcpy(display->memory+ob, data, size);
2264 /* Always update the size: */
2265 display->output_bytes = ob+size;
2270 png_error(png_ptr, "png_image_write_to_memory: PNG too big");
2273 static void (PNGCBAPI
2274 image_memory_flush)(png_structp png_ptr)
2280 png_image_write_memory(png_voidp argument)
2282 png_image_write_control *display = png_voidcast(png_image_write_control*,
2285 /* The rest of the memory-specific init and write_main in an error protected
2286 * environment. This case needs to use callbacks for the write operations
2287 * since libpng has no built in support for writing to memory.
2289 png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
2290 image_memory_write, image_memory_flush);
2292 return png_image_write_main(display);
2296 png_image_write_to_memory(png_imagep image, void *memory,
2297 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
2298 const void *buffer, png_int_32 row_stride, const void *colormap)
2300 /* Write the image to the given buffer, or count the bytes if it is NULL */
2301 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2303 if (memory_bytes != NULL && buffer != NULL)
2305 /* This is to give the caller an easier error detection in the NULL
2306 * case and guard against uninitialized variable problems:
2311 if (png_image_write_init(image) != 0)
2313 png_image_write_control display;
2316 memset(&display, 0, (sizeof display));
2317 display.image = image;
2318 display.buffer = buffer;
2319 display.row_stride = row_stride;
2320 display.colormap = colormap;
2321 display.convert_to_8bit = convert_to_8bit;
2322 display.memory = png_voidcast(png_bytep, memory);
2323 display.memory_bytes = *memory_bytes;
2324 display.output_bytes = 0;
2326 result = png_safe_execute(image, png_image_write_memory, &display);
2327 png_image_free(image);
2329 /* write_memory returns true even if we ran out of buffer. */
2332 /* On out-of-buffer this function returns '0' but still updates
2335 if (memory != NULL && display.output_bytes > *memory_bytes)
2338 *memory_bytes = display.output_bytes;
2349 return png_image_error(image,
2350 "png_image_write_to_memory: invalid argument");
2353 else if (image != NULL)
2354 return png_image_error(image,
2355 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2361 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2363 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2364 const void *buffer, png_int_32 row_stride, const void *colormap)
2366 /* Write the image to the given (FILE*). */
2367 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2369 if (file != NULL && buffer != NULL)
2371 if (png_image_write_init(image) != 0)
2373 png_image_write_control display;
2376 /* This is slightly evil, but png_init_io doesn't do anything other
2377 * than this and we haven't changed the standard IO functions so
2378 * this saves a 'safe' function.
2380 image->opaque->png_ptr->io_ptr = file;
2382 memset(&display, 0, (sizeof display));
2383 display.image = image;
2384 display.buffer = buffer;
2385 display.row_stride = row_stride;
2386 display.colormap = colormap;
2387 display.convert_to_8bit = convert_to_8bit;
2389 result = png_safe_execute(image, png_image_write_main, &display);
2390 png_image_free(image);
2399 return png_image_error(image,
2400 "png_image_write_to_stdio: invalid argument");
2403 else if (image != NULL)
2404 return png_image_error(image,
2405 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2412 png_image_write_to_file(png_imagep image, const char *file_name,
2413 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2414 const void *colormap)
2416 /* Write the image to the named file. */
2417 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2419 if (file_name != NULL && buffer != NULL)
2421 FILE *fp = fopen(file_name, "wb");
2425 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2426 row_stride, colormap) != 0)
2428 int error; /* from fflush/fclose */
2430 /* Make sure the file is flushed correctly. */
2431 if (fflush(fp) == 0 && ferror(fp) == 0)
2433 if (fclose(fp) == 0)
2436 error = errno; /* from fclose */
2441 error = errno; /* from fflush or ferror */
2445 (void)remove(file_name);
2446 /* The image has already been cleaned up; this is just used to
2447 * set the error (because the original write succeeded).
2449 return png_image_error(image, strerror(error));
2454 /* Clean up: just the opened file. */
2456 (void)remove(file_name);
2462 return png_image_error(image, strerror(errno));
2466 return png_image_error(image,
2467 "png_image_write_to_file: invalid argument");
2470 else if (image != NULL)
2471 return png_image_error(image,
2472 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2477 #endif /* SIMPLIFIED_WRITE_STDIO */
2478 #endif /* SIMPLIFIED_WRITE */