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1
2/* pngread.c - read a PNG file
3 *
4 * Last changed in libpng 1.5.7 [December 15, 2011]
5 * Copyright (c) 1998-2011 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 * This file contains routines that an application calls directly to
14 * read a PNG file or stream.
15 */
16
17#include "pngpriv.h"
18
19#ifdef PNG_READ_SUPPORTED
20
21/* Create a PNG structure for reading, and allocate any memory needed. */
22PNG_FUNCTION(png_structp,PNGAPI
23png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
24 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
25{
26
27#ifdef PNG_USER_MEM_SUPPORTED
28 return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
29 warn_fn, NULL, NULL, NULL));
30}
31
32/* Alternate create PNG structure for reading, and allocate any memory
33 * needed.
34 */
35PNG_FUNCTION(png_structp,PNGAPI
36png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
37 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
38 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
39{
40#endif /* PNG_USER_MEM_SUPPORTED */
41
42#ifdef PNG_SETJMP_SUPPORTED
43 volatile
44#endif
45 png_structp png_ptr;
46 volatile int png_cleanup_needed = 0;
47
48#ifdef PNG_SETJMP_SUPPORTED
49#ifdef USE_FAR_KEYWORD
50 jmp_buf tmp_jmpbuf;
51#endif
52#endif
53
54 png_debug(1, "in png_create_read_struct");
55
56#ifdef PNG_USER_MEM_SUPPORTED
57 png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
58 malloc_fn, mem_ptr);
59#else
60 png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
61#endif
62 if (png_ptr == NULL)
63 return (NULL);
64
65 /* Added at libpng-1.2.6 */
66#ifdef PNG_USER_LIMITS_SUPPORTED
67 png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
68 png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
69
70# ifdef PNG_USER_CHUNK_CACHE_MAX
71 /* Added at libpng-1.2.43 and 1.4.0 */
72 png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
73# endif
74
75# ifdef PNG_SET_USER_CHUNK_MALLOC_MAX
76 /* Added at libpng-1.2.43 and 1.4.1 */
77 png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
78# endif
79#endif
80
81#ifdef PNG_SETJMP_SUPPORTED
82/* Applications that neglect to set up their own setjmp() and then
83 * encounter a png_error() will longjmp here. Since the jmpbuf is
84 * then meaningless we abort instead of returning.
85 */
86#ifdef USE_FAR_KEYWORD
87 if (setjmp(tmp_jmpbuf))
88#else
89 if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
90#endif
91 PNG_ABORT();
92#ifdef USE_FAR_KEYWORD
93 png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
94#endif
95#endif /* PNG_SETJMP_SUPPORTED */
96
97#ifdef PNG_USER_MEM_SUPPORTED
98 png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
99#endif
100
101 png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
102
103 /* Call the general version checker (shared with read and write code): */
104 if (!png_user_version_check(png_ptr, user_png_ver))
105 png_cleanup_needed = 1;
106
107 if (!png_cleanup_needed)
108 {
109 /* Initialize zbuf - compression buffer */
110 png_ptr->zbuf_size = PNG_ZBUF_SIZE;
111 png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr, png_ptr->zbuf_size);
112
113 if (png_ptr->zbuf == NULL)
114 png_cleanup_needed = 1;
115 }
116
117 png_ptr->zstream.zalloc = png_zalloc;
118 png_ptr->zstream.zfree = png_zfree;
119 png_ptr->zstream.opaque = (voidpf)png_ptr;
120
121 if (!png_cleanup_needed)
122 {
123 switch (inflateInit(&png_ptr->zstream))
124 {
125 case Z_OK:
126 break; /* Do nothing */
127
128 case Z_MEM_ERROR:
129 png_warning(png_ptr, "zlib memory error");
130 png_cleanup_needed = 1;
131 break;
132
133 case Z_STREAM_ERROR:
134 png_warning(png_ptr, "zlib stream error");
135 png_cleanup_needed = 1;
136 break;
137
138 case Z_VERSION_ERROR:
139 png_warning(png_ptr, "zlib version error");
140 png_cleanup_needed = 1;
141 break;
142
143 default: png_warning(png_ptr, "Unknown zlib error");
144 png_cleanup_needed = 1;
145 }
146 }
147
148 if (png_cleanup_needed)
149 {
150 /* Clean up PNG structure and deallocate any memory. */
151 png_free(png_ptr, png_ptr->zbuf);
152 png_ptr->zbuf = NULL;
153#ifdef PNG_USER_MEM_SUPPORTED
154 png_destroy_struct_2((png_voidp)png_ptr,
155 (png_free_ptr)free_fn, (png_voidp)mem_ptr);
156#else
157 png_destroy_struct((png_voidp)png_ptr);
158#endif
159 return (NULL);
160 }
161
162 png_ptr->zstream.next_out = png_ptr->zbuf;
163 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
164
165 png_set_read_fn(png_ptr, NULL, NULL);
166
167
168 return (png_ptr);
169}
170
171
172#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
173/* Read the information before the actual image data. This has been
174 * changed in v0.90 to allow reading a file that already has the magic
175 * bytes read from the stream. You can tell libpng how many bytes have
176 * been read from the beginning of the stream (up to the maximum of 8)
177 * via png_set_sig_bytes(), and we will only check the remaining bytes
178 * here. The application can then have access to the signature bytes we
179 * read if it is determined that this isn't a valid PNG file.
180 */
181void PNGAPI
182png_read_info(png_structp png_ptr, png_infop info_ptr)
183{
184 png_debug(1, "in png_read_info");
185
186 if (png_ptr == NULL || info_ptr == NULL)
187 return;
188
189 /* Read and check the PNG file signature. */
190 png_read_sig(png_ptr, info_ptr);
191
192 for (;;)
193 {
194 png_uint_32 length = png_read_chunk_header(png_ptr);
195 png_uint_32 chunk_name = png_ptr->chunk_name;
196
197 /* This should be a binary subdivision search or a hash for
198 * matching the chunk name rather than a linear search.
199 */
200 if (chunk_name == png_IDAT)
201 if (png_ptr->mode & PNG_AFTER_IDAT)
202 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
203
204 if (chunk_name == png_IHDR)
205 png_handle_IHDR(png_ptr, info_ptr, length);
206
207 else if (chunk_name == png_IEND)
208 png_handle_IEND(png_ptr, info_ptr, length);
209
210#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
211 else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
212 PNG_HANDLE_CHUNK_AS_DEFAULT)
213 {
214 if (chunk_name == png_IDAT)
215 png_ptr->mode |= PNG_HAVE_IDAT;
216
217 png_handle_unknown(png_ptr, info_ptr, length);
218
219 if (chunk_name == png_PLTE)
220 png_ptr->mode |= PNG_HAVE_PLTE;
221
222 else if (chunk_name == png_IDAT)
223 {
224 if (!(png_ptr->mode & PNG_HAVE_IHDR))
225 png_error(png_ptr, "Missing IHDR before IDAT");
226
227 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
228 !(png_ptr->mode & PNG_HAVE_PLTE))
229 png_error(png_ptr, "Missing PLTE before IDAT");
230
231 break;
232 }
233 }
234#endif
235 else if (chunk_name == png_PLTE)
236 png_handle_PLTE(png_ptr, info_ptr, length);
237
238 else if (chunk_name == png_IDAT)
239 {
240 if (!(png_ptr->mode & PNG_HAVE_IHDR))
241 png_error(png_ptr, "Missing IHDR before IDAT");
242
243 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
244 !(png_ptr->mode & PNG_HAVE_PLTE))
245 png_error(png_ptr, "Missing PLTE before IDAT");
246
247 png_ptr->idat_size = length;
248 png_ptr->mode |= PNG_HAVE_IDAT;
249 break;
250 }
251
252#ifdef PNG_READ_bKGD_SUPPORTED
253 else if (chunk_name == png_bKGD)
254 png_handle_bKGD(png_ptr, info_ptr, length);
255#endif
256
257#ifdef PNG_READ_cHRM_SUPPORTED
258 else if (chunk_name == png_cHRM)
259 png_handle_cHRM(png_ptr, info_ptr, length);
260#endif
261
262#ifdef PNG_READ_gAMA_SUPPORTED
263 else if (chunk_name == png_gAMA)
264 png_handle_gAMA(png_ptr, info_ptr, length);
265#endif
266
267#ifdef PNG_READ_hIST_SUPPORTED
268 else if (chunk_name == png_hIST)
269 png_handle_hIST(png_ptr, info_ptr, length);
270#endif
271
272#ifdef PNG_READ_oFFs_SUPPORTED
273 else if (chunk_name == png_oFFs)
274 png_handle_oFFs(png_ptr, info_ptr, length);
275#endif
276
277#ifdef PNG_READ_pCAL_SUPPORTED
278 else if (chunk_name == png_pCAL)
279 png_handle_pCAL(png_ptr, info_ptr, length);
280#endif
281
282#ifdef PNG_READ_sCAL_SUPPORTED
283 else if (chunk_name == png_sCAL)
284 png_handle_sCAL(png_ptr, info_ptr, length);
285#endif
286
287#ifdef PNG_READ_pHYs_SUPPORTED
288 else if (chunk_name == png_pHYs)
289 png_handle_pHYs(png_ptr, info_ptr, length);
290#endif
291
292#ifdef PNG_READ_sBIT_SUPPORTED
293 else if (chunk_name == png_sBIT)
294 png_handle_sBIT(png_ptr, info_ptr, length);
295#endif
296
297#ifdef PNG_READ_sRGB_SUPPORTED
298 else if (chunk_name == png_sRGB)
299 png_handle_sRGB(png_ptr, info_ptr, length);
300#endif
301
302#ifdef PNG_READ_iCCP_SUPPORTED
303 else if (chunk_name == png_iCCP)
304 png_handle_iCCP(png_ptr, info_ptr, length);
305#endif
306
307#ifdef PNG_READ_sPLT_SUPPORTED
308 else if (chunk_name == png_sPLT)
309 png_handle_sPLT(png_ptr, info_ptr, length);
310#endif
311
312#ifdef PNG_READ_tEXt_SUPPORTED
313 else if (chunk_name == png_tEXt)
314 png_handle_tEXt(png_ptr, info_ptr, length);
315#endif
316
317#ifdef PNG_READ_tIME_SUPPORTED
318 else if (chunk_name == png_tIME)
319 png_handle_tIME(png_ptr, info_ptr, length);
320#endif
321
322#ifdef PNG_READ_tRNS_SUPPORTED
323 else if (chunk_name == png_tRNS)
324 png_handle_tRNS(png_ptr, info_ptr, length);
325#endif
326
327#ifdef PNG_READ_zTXt_SUPPORTED
328 else if (chunk_name == png_zTXt)
329 png_handle_zTXt(png_ptr, info_ptr, length);
330#endif
331
332#ifdef PNG_READ_iTXt_SUPPORTED
333 else if (chunk_name == png_iTXt)
334 png_handle_iTXt(png_ptr, info_ptr, length);
335#endif
336
337 else
338 png_handle_unknown(png_ptr, info_ptr, length);
339 }
340}
341#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
342
343/* Optional call to update the users info_ptr structure */
344void PNGAPI
345png_read_update_info(png_structp png_ptr, png_infop info_ptr)
346{
347 png_debug(1, "in png_read_update_info");
348
349 if (png_ptr == NULL)
350 return;
351
352 png_read_start_row(png_ptr);
353
354#ifdef PNG_READ_TRANSFORMS_SUPPORTED
355 png_read_transform_info(png_ptr, info_ptr);
356#else
357 PNG_UNUSED(info_ptr)
358#endif
359}
360
361#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
362/* Initialize palette, background, etc, after transformations
363 * are set, but before any reading takes place. This allows
364 * the user to obtain a gamma-corrected palette, for example.
365 * If the user doesn't call this, we will do it ourselves.
366 */
367void PNGAPI
368png_start_read_image(png_structp png_ptr)
369{
370 png_debug(1, "in png_start_read_image");
371
372 if (png_ptr != NULL)
373 png_read_start_row(png_ptr);
374}
375#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
376
377#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
378void PNGAPI
379png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
380{
381 int ret;
382
383 png_row_info row_info;
384
385 if (png_ptr == NULL)
386 return;
387
388 png_debug2(1, "in png_read_row (row %lu, pass %d)",
389 (unsigned long)png_ptr->row_number, png_ptr->pass);
390
391 /* png_read_start_row sets the information (in particular iwidth) for this
392 * interlace pass.
393 */
394 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
395 png_read_start_row(png_ptr);
396
397 /* 1.5.6: row_info moved out of png_struct to a local here. */
398 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
399 row_info.color_type = png_ptr->color_type;
400 row_info.bit_depth = png_ptr->bit_depth;
401 row_info.channels = png_ptr->channels;
402 row_info.pixel_depth = png_ptr->pixel_depth;
403 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
404
405 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
406 {
407 /* Check for transforms that have been set but were defined out */
408#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
409 if (png_ptr->transformations & PNG_INVERT_MONO)
410 png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
411#endif
412
413#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
414 if (png_ptr->transformations & PNG_FILLER)
415 png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
416#endif
417
418#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
419 !defined(PNG_READ_PACKSWAP_SUPPORTED)
420 if (png_ptr->transformations & PNG_PACKSWAP)
421 png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
422#endif
423
424#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
425 if (png_ptr->transformations & PNG_PACK)
426 png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
427#endif
428
429#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
430 if (png_ptr->transformations & PNG_SHIFT)
431 png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
432#endif
433
434#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
435 if (png_ptr->transformations & PNG_BGR)
436 png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
437#endif
438
439#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
440 if (png_ptr->transformations & PNG_SWAP_BYTES)
441 png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
442#endif
443 }
444
445#ifdef PNG_READ_INTERLACING_SUPPORTED
446 /* If interlaced and we do not need a new row, combine row and return.
447 * Notice that the pixels we have from previous rows have been transformed
448 * already; we can only combine like with like (transformed or
449 * untransformed) and, because of the libpng API for interlaced images, this
450 * means we must transform before de-interlacing.
451 */
452 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
453 {
454 switch (png_ptr->pass)
455 {
456 case 0:
457 if (png_ptr->row_number & 0x07)
458 {
459 if (dsp_row != NULL)
460 png_combine_row(png_ptr, dsp_row, 1/*display*/);
461 png_read_finish_row(png_ptr);
462 return;
463 }
464 break;
465
466 case 1:
467 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
468 {
469 if (dsp_row != NULL)
470 png_combine_row(png_ptr, dsp_row, 1/*display*/);
471
472 png_read_finish_row(png_ptr);
473 return;
474 }
475 break;
476
477 case 2:
478 if ((png_ptr->row_number & 0x07) != 4)
479 {
480 if (dsp_row != NULL && (png_ptr->row_number & 4))
481 png_combine_row(png_ptr, dsp_row, 1/*display*/);
482
483 png_read_finish_row(png_ptr);
484 return;
485 }
486 break;
487
488 case 3:
489 if ((png_ptr->row_number & 3) || png_ptr->width < 3)
490 {
491 if (dsp_row != NULL)
492 png_combine_row(png_ptr, dsp_row, 1/*display*/);
493
494 png_read_finish_row(png_ptr);
495 return;
496 }
497 break;
498
499 case 4:
500 if ((png_ptr->row_number & 3) != 2)
501 {
502 if (dsp_row != NULL && (png_ptr->row_number & 2))
503 png_combine_row(png_ptr, dsp_row, 1/*display*/);
504
505 png_read_finish_row(png_ptr);
506 return;
507 }
508 break;
509 case 5:
510 if ((png_ptr->row_number & 1) || png_ptr->width < 2)
511 {
512 if (dsp_row != NULL)
513 png_combine_row(png_ptr, dsp_row, 1/*display*/);
514
515 png_read_finish_row(png_ptr);
516 return;
517 }
518 break;
519
520 default:
521 case 6:
522 if (!(png_ptr->row_number & 1))
523 {
524 png_read_finish_row(png_ptr);
525 return;
526 }
527 break;
528 }
529 }
530#endif
531
532 if (!(png_ptr->mode & PNG_HAVE_IDAT))
533 png_error(png_ptr, "Invalid attempt to read row data");
534
535 png_ptr->zstream.next_out = png_ptr->row_buf;
536 png_ptr->zstream.avail_out =
537 (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
538 png_ptr->iwidth) + 1);
539
540 do
541 {
542 if (!(png_ptr->zstream.avail_in))
543 {
544 while (!png_ptr->idat_size)
545 {
546 png_crc_finish(png_ptr, 0);
547
548 png_ptr->idat_size = png_read_chunk_header(png_ptr);
549 if (png_ptr->chunk_name != png_IDAT)
550 png_error(png_ptr, "Not enough image data");
551 }
552 png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
553 png_ptr->zstream.next_in = png_ptr->zbuf;
554 if (png_ptr->zbuf_size > png_ptr->idat_size)
555 png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
556 png_crc_read(png_ptr, png_ptr->zbuf,
557 (png_size_t)png_ptr->zstream.avail_in);
558 png_ptr->idat_size -= png_ptr->zstream.avail_in;
559 }
560
561 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
562
563 if (ret == Z_STREAM_END)
564 {
565 if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
566 png_ptr->idat_size)
567 png_benign_error(png_ptr, "Extra compressed data");
568 png_ptr->mode |= PNG_AFTER_IDAT;
569 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
570 break;
571 }
572
573 if (ret != Z_OK)
574 png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
575 "Decompression error");
576
577 } while (png_ptr->zstream.avail_out);
578
579 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
580 {
581 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
582 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
583 png_ptr->prev_row + 1, png_ptr->row_buf[0]);
584 else
585 png_error(png_ptr, "bad adaptive filter value");
586 }
587
588 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
589 * 1.5.6, while the buffer really is this big in current versions of libpng
590 * it may not be in the future, so this was changed just to copy the
591 * interlaced count:
592 */
593 png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
594
595#ifdef PNG_MNG_FEATURES_SUPPORTED
596 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
597 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
598 {
599 /* Intrapixel differencing */
600 png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
601 }
602#endif
603
604
605#ifdef PNG_READ_TRANSFORMS_SUPPORTED
606 if (png_ptr->transformations)
607 png_do_read_transformations(png_ptr, &row_info);
608#endif
609
610 /* The transformed pixel depth should match the depth now in row_info. */
611 if (png_ptr->transformed_pixel_depth == 0)
612 {
613 png_ptr->transformed_pixel_depth = row_info.pixel_depth;
614 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
615 png_error(png_ptr, "sequential row overflow");
616 }
617
618 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
619 png_error(png_ptr, "internal sequential row size calculation error");
620
621#ifdef PNG_READ_INTERLACING_SUPPORTED
622 /* Blow up interlaced rows to full size */
623 if (png_ptr->interlaced &&
624 (png_ptr->transformations & PNG_INTERLACE))
625 {
626 if (png_ptr->pass < 6)
627 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
628 png_ptr->transformations);
629
630 if (dsp_row != NULL)
631 png_combine_row(png_ptr, dsp_row, 1/*display*/);
632
633 if (row != NULL)
634 png_combine_row(png_ptr, row, 0/*row*/);
635 }
636
637 else
638#endif
639 {
640 if (row != NULL)
641 png_combine_row(png_ptr, row, -1/*ignored*/);
642
643 if (dsp_row != NULL)
644 png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
645 }
646 png_read_finish_row(png_ptr);
647
648 if (png_ptr->read_row_fn != NULL)
649 (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
650}
651#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
652
653#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
654/* Read one or more rows of image data. If the image is interlaced,
655 * and png_set_interlace_handling() has been called, the rows need to
656 * contain the contents of the rows from the previous pass. If the
657 * image has alpha or transparency, and png_handle_alpha()[*] has been
658 * called, the rows contents must be initialized to the contents of the
659 * screen.
660 *
661 * "row" holds the actual image, and pixels are placed in it
662 * as they arrive. If the image is displayed after each pass, it will
663 * appear to "sparkle" in. "display_row" can be used to display a
664 * "chunky" progressive image, with finer detail added as it becomes
665 * available. If you do not want this "chunky" display, you may pass
666 * NULL for display_row. If you do not want the sparkle display, and
667 * you have not called png_handle_alpha(), you may pass NULL for rows.
668 * If you have called png_handle_alpha(), and the image has either an
669 * alpha channel or a transparency chunk, you must provide a buffer for
670 * rows. In this case, you do not have to provide a display_row buffer
671 * also, but you may. If the image is not interlaced, or if you have
672 * not called png_set_interlace_handling(), the display_row buffer will
673 * be ignored, so pass NULL to it.
674 *
675 * [*] png_handle_alpha() does not exist yet, as of this version of libpng
676 */
677
678void PNGAPI
679png_read_rows(png_structp png_ptr, png_bytepp row,
680 png_bytepp display_row, png_uint_32 num_rows)
681{
682 png_uint_32 i;
683 png_bytepp rp;
684 png_bytepp dp;
685
686 png_debug(1, "in png_read_rows");
687
688 if (png_ptr == NULL)
689 return;
690
691 rp = row;
692 dp = display_row;
693 if (rp != NULL && dp != NULL)
694 for (i = 0; i < num_rows; i++)
695 {
696 png_bytep rptr = *rp++;
697 png_bytep dptr = *dp++;
698
699 png_read_row(png_ptr, rptr, dptr);
700 }
701
702 else if (rp != NULL)
703 for (i = 0; i < num_rows; i++)
704 {
705 png_bytep rptr = *rp;
706 png_read_row(png_ptr, rptr, NULL);
707 rp++;
708 }
709
710 else if (dp != NULL)
711 for (i = 0; i < num_rows; i++)
712 {
713 png_bytep dptr = *dp;
714 png_read_row(png_ptr, NULL, dptr);
715 dp++;
716 }
717}
718#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
719
720#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
721/* Read the entire image. If the image has an alpha channel or a tRNS
722 * chunk, and you have called png_handle_alpha()[*], you will need to
723 * initialize the image to the current image that PNG will be overlaying.
724 * We set the num_rows again here, in case it was incorrectly set in
725 * png_read_start_row() by a call to png_read_update_info() or
726 * png_start_read_image() if png_set_interlace_handling() wasn't called
727 * prior to either of these functions like it should have been. You can
728 * only call this function once. If you desire to have an image for
729 * each pass of a interlaced image, use png_read_rows() instead.
730 *
731 * [*] png_handle_alpha() does not exist yet, as of this version of libpng
732 */
733void PNGAPI
734png_read_image(png_structp png_ptr, png_bytepp image)
735{
736 png_uint_32 i, image_height;
737 int pass, j;
738 png_bytepp rp;
739
740 png_debug(1, "in png_read_image");
741
742 if (png_ptr == NULL)
743 return;
744
745#ifdef PNG_READ_INTERLACING_SUPPORTED
746 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
747 {
748 pass = png_set_interlace_handling(png_ptr);
749 /* And make sure transforms are initialized. */
750 png_start_read_image(png_ptr);
751 }
752 else
753 {
754 if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
755 {
756 /* Caller called png_start_read_image or png_read_update_info without
757 * first turning on the PNG_INTERLACE transform. We can fix this here,
758 * but the caller should do it!
759 */
760 png_warning(png_ptr, "Interlace handling should be turned on when "
761 "using png_read_image");
762 /* Make sure this is set correctly */
763 png_ptr->num_rows = png_ptr->height;
764 }
765
766 /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
767 * the above error case.
768 */
769 pass = png_set_interlace_handling(png_ptr);
770 }
771#else
772 if (png_ptr->interlaced)
773 png_error(png_ptr,
774 "Cannot read interlaced image -- interlace handler disabled");
775
776 pass = 1;
777#endif
778
779 image_height=png_ptr->height;
780
781 for (j = 0; j < pass; j++)
782 {
783 rp = image;
784 for (i = 0; i < image_height; i++)
785 {
786 png_read_row(png_ptr, *rp, NULL);
787 rp++;
788 }
789 }
790}
791#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
792
793#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
794/* Read the end of the PNG file. Will not read past the end of the
795 * file, will verify the end is accurate, and will read any comments
796 * or time information at the end of the file, if info is not NULL.
797 */
798void PNGAPI
799png_read_end(png_structp png_ptr, png_infop info_ptr)
800{
801 png_debug(1, "in png_read_end");
802
803 if (png_ptr == NULL)
804 return;
805
806 png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
807
808 do
809 {
810 png_uint_32 length = png_read_chunk_header(png_ptr);
811 png_uint_32 chunk_name = png_ptr->chunk_name;
812
813 if (chunk_name == png_IHDR)
814 png_handle_IHDR(png_ptr, info_ptr, length);
815
816 else if (chunk_name == png_IEND)
817 png_handle_IEND(png_ptr, info_ptr, length);
818
819#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
820 else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
821 PNG_HANDLE_CHUNK_AS_DEFAULT)
822 {
823 if (chunk_name == png_IDAT)
824 {
825 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
826 png_benign_error(png_ptr, "Too many IDATs found");
827 }
828 png_handle_unknown(png_ptr, info_ptr, length);
829 if (chunk_name == png_PLTE)
830 png_ptr->mode |= PNG_HAVE_PLTE;
831 }
832#endif
833
834 else if (chunk_name == png_IDAT)
835 {
836 /* Zero length IDATs are legal after the last IDAT has been
837 * read, but not after other chunks have been read.
838 */
839 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
840 png_benign_error(png_ptr, "Too many IDATs found");
841
842 png_crc_finish(png_ptr, length);
843 }
844 else if (chunk_name == png_PLTE)
845 png_handle_PLTE(png_ptr, info_ptr, length);
846
847#ifdef PNG_READ_bKGD_SUPPORTED
848 else if (chunk_name == png_bKGD)
849 png_handle_bKGD(png_ptr, info_ptr, length);
850#endif
851
852#ifdef PNG_READ_cHRM_SUPPORTED
853 else if (chunk_name == png_cHRM)
854 png_handle_cHRM(png_ptr, info_ptr, length);
855#endif
856
857#ifdef PNG_READ_gAMA_SUPPORTED
858 else if (chunk_name == png_gAMA)
859 png_handle_gAMA(png_ptr, info_ptr, length);
860#endif
861
862#ifdef PNG_READ_hIST_SUPPORTED
863 else if (chunk_name == png_hIST)
864 png_handle_hIST(png_ptr, info_ptr, length);
865#endif
866
867#ifdef PNG_READ_oFFs_SUPPORTED
868 else if (chunk_name == png_oFFs)
869 png_handle_oFFs(png_ptr, info_ptr, length);
870#endif
871
872#ifdef PNG_READ_pCAL_SUPPORTED
873 else if (chunk_name == png_pCAL)
874 png_handle_pCAL(png_ptr, info_ptr, length);
875#endif
876
877#ifdef PNG_READ_sCAL_SUPPORTED
878 else if (chunk_name == png_sCAL)
879 png_handle_sCAL(png_ptr, info_ptr, length);
880#endif
881
882#ifdef PNG_READ_pHYs_SUPPORTED
883 else if (chunk_name == png_pHYs)
884 png_handle_pHYs(png_ptr, info_ptr, length);
885#endif
886
887#ifdef PNG_READ_sBIT_SUPPORTED
888 else if (chunk_name == png_sBIT)
889 png_handle_sBIT(png_ptr, info_ptr, length);
890#endif
891
892#ifdef PNG_READ_sRGB_SUPPORTED
893 else if (chunk_name == png_sRGB)
894 png_handle_sRGB(png_ptr, info_ptr, length);
895#endif
896
897#ifdef PNG_READ_iCCP_SUPPORTED
898 else if (chunk_name == png_iCCP)
899 png_handle_iCCP(png_ptr, info_ptr, length);
900#endif
901
902#ifdef PNG_READ_sPLT_SUPPORTED
903 else if (chunk_name == png_sPLT)
904 png_handle_sPLT(png_ptr, info_ptr, length);
905#endif
906
907#ifdef PNG_READ_tEXt_SUPPORTED
908 else if (chunk_name == png_tEXt)
909 png_handle_tEXt(png_ptr, info_ptr, length);
910#endif
911
912#ifdef PNG_READ_tIME_SUPPORTED
913 else if (chunk_name == png_tIME)
914 png_handle_tIME(png_ptr, info_ptr, length);
915#endif
916
917#ifdef PNG_READ_tRNS_SUPPORTED
918 else if (chunk_name == png_tRNS)
919 png_handle_tRNS(png_ptr, info_ptr, length);
920#endif
921
922#ifdef PNG_READ_zTXt_SUPPORTED
923 else if (chunk_name == png_zTXt)
924 png_handle_zTXt(png_ptr, info_ptr, length);
925#endif
926
927#ifdef PNG_READ_iTXt_SUPPORTED
928 else if (chunk_name == png_iTXt)
929 png_handle_iTXt(png_ptr, info_ptr, length);
930#endif
931
932 else
933 png_handle_unknown(png_ptr, info_ptr, length);
934 } while (!(png_ptr->mode & PNG_HAVE_IEND));
935}
936#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
937
938/* Free all memory used by the read */
939void PNGAPI
940png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
941 png_infopp end_info_ptr_ptr)
942{
943 png_structp png_ptr = NULL;
944 png_infop info_ptr = NULL, end_info_ptr = NULL;
945#ifdef PNG_USER_MEM_SUPPORTED
946 png_free_ptr free_fn = NULL;
947 png_voidp mem_ptr = NULL;
948#endif
949
950 png_debug(1, "in png_destroy_read_struct");
951
952 if (png_ptr_ptr != NULL)
953 png_ptr = *png_ptr_ptr;
954 if (png_ptr == NULL)
955 return;
956
957#ifdef PNG_USER_MEM_SUPPORTED
958 free_fn = png_ptr->free_fn;
959 mem_ptr = png_ptr->mem_ptr;
960#endif
961
962 if (info_ptr_ptr != NULL)
963 info_ptr = *info_ptr_ptr;
964
965 if (end_info_ptr_ptr != NULL)
966 end_info_ptr = *end_info_ptr_ptr;
967
968 png_read_destroy(png_ptr, info_ptr, end_info_ptr);
969
970 if (info_ptr != NULL)
971 {
972#ifdef PNG_TEXT_SUPPORTED
973 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
974#endif
975
976#ifdef PNG_USER_MEM_SUPPORTED
977 png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
978 (png_voidp)mem_ptr);
979#else
980 png_destroy_struct((png_voidp)info_ptr);
981#endif
982 *info_ptr_ptr = NULL;
983 }
984
985 if (end_info_ptr != NULL)
986 {
987#ifdef PNG_READ_TEXT_SUPPORTED
988 png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
989#endif
990#ifdef PNG_USER_MEM_SUPPORTED
991 png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
992 (png_voidp)mem_ptr);
993#else
994 png_destroy_struct((png_voidp)end_info_ptr);
995#endif
996 *end_info_ptr_ptr = NULL;
997 }
998
999 if (png_ptr != NULL)
1000 {
1001#ifdef PNG_USER_MEM_SUPPORTED
1002 png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1003 (png_voidp)mem_ptr);
1004#else
1005 png_destroy_struct((png_voidp)png_ptr);
1006#endif
1007 *png_ptr_ptr = NULL;
1008 }
1009}
1010
1011/* Free all memory used by the read (old method) */
1012void /* PRIVATE */
1013png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1014 png_infop end_info_ptr)
1015{
1016#ifdef PNG_SETJMP_SUPPORTED
1017 jmp_buf tmp_jmp;
1018#endif
1019 png_error_ptr error_fn;
1020#ifdef PNG_WARNINGS_SUPPORTED
1021 png_error_ptr warning_fn;
1022#endif
1023 png_voidp error_ptr;
1024#ifdef PNG_USER_MEM_SUPPORTED
1025 png_free_ptr free_fn;
1026#endif
1027
1028 png_debug(1, "in png_read_destroy");
1029
1030 if (info_ptr != NULL)
1031 png_info_destroy(png_ptr, info_ptr);
1032
1033 if (end_info_ptr != NULL)
1034 png_info_destroy(png_ptr, end_info_ptr);
1035
1036#ifdef PNG_READ_GAMMA_SUPPORTED
1037 png_destroy_gamma_table(png_ptr);
1038#endif
1039
1040 png_free(png_ptr, png_ptr->zbuf);
1041 png_free(png_ptr, png_ptr->big_row_buf);
1042 png_free(png_ptr, png_ptr->big_prev_row);
1043 png_free(png_ptr, png_ptr->chunkdata);
1044
1045#ifdef PNG_READ_QUANTIZE_SUPPORTED
1046 png_free(png_ptr, png_ptr->palette_lookup);
1047 png_free(png_ptr, png_ptr->quantize_index);
1048#endif
1049
1050 if (png_ptr->free_me & PNG_FREE_PLTE)
1051 png_zfree(png_ptr, png_ptr->palette);
1052 png_ptr->free_me &= ~PNG_FREE_PLTE;
1053
1054#if defined(PNG_tRNS_SUPPORTED) || \
1055 defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1056 if (png_ptr->free_me & PNG_FREE_TRNS)
1057 png_free(png_ptr, png_ptr->trans_alpha);
1058 png_ptr->free_me &= ~PNG_FREE_TRNS;
1059#endif
1060
1061#ifdef PNG_READ_hIST_SUPPORTED
1062 if (png_ptr->free_me & PNG_FREE_HIST)
1063 png_free(png_ptr, png_ptr->hist);
1064 png_ptr->free_me &= ~PNG_FREE_HIST;
1065#endif
1066
1067 inflateEnd(&png_ptr->zstream);
1068
1069#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1070 png_free(png_ptr, png_ptr->save_buffer);
1071#endif
1072
1073#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1074#ifdef PNG_TEXT_SUPPORTED
1075 png_free(png_ptr, png_ptr->current_text);
1076#endif /* PNG_TEXT_SUPPORTED */
1077#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1078
1079 /* Save the important info out of the png_struct, in case it is
1080 * being used again.
1081 */
1082#ifdef PNG_SETJMP_SUPPORTED
1083 png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
1084#endif
1085
1086 error_fn = png_ptr->error_fn;
1087#ifdef PNG_WARNINGS_SUPPORTED
1088 warning_fn = png_ptr->warning_fn;
1089#endif
1090 error_ptr = png_ptr->error_ptr;
1091#ifdef PNG_USER_MEM_SUPPORTED
1092 free_fn = png_ptr->free_fn;
1093#endif
1094
1095 png_memset(png_ptr, 0, png_sizeof(png_struct));
1096
1097 png_ptr->error_fn = error_fn;
1098#ifdef PNG_WARNINGS_SUPPORTED
1099 png_ptr->warning_fn = warning_fn;
1100#endif
1101 png_ptr->error_ptr = error_ptr;
1102#ifdef PNG_USER_MEM_SUPPORTED
1103 png_ptr->free_fn = free_fn;
1104#endif
1105
1106#ifdef PNG_SETJMP_SUPPORTED
1107 png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
1108#endif
1109
1110}
1111
1112void PNGAPI
1113png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1114{
1115 if (png_ptr == NULL)
1116 return;
1117
1118 png_ptr->read_row_fn = read_row_fn;
1119}
1120
1121
1122#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1123#ifdef PNG_INFO_IMAGE_SUPPORTED
1124void PNGAPI
1125png_read_png(png_structp png_ptr, png_infop info_ptr,
1126 int transforms,
1127 voidp params)
1128{
1129 int row;
1130
1131 if (png_ptr == NULL || info_ptr == NULL)
1132 return;
1133
1134 /* png_read_info() gives us all of the information from the
1135 * PNG file before the first IDAT (image data chunk).
1136 */
1137 png_read_info(png_ptr, info_ptr);
1138 if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1139 png_error(png_ptr, "Image is too high to process with png_read_png()");
1140
1141 /* -------------- image transformations start here ------------------- */
1142
1143#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1144 /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
1145 */
1146 if (transforms & PNG_TRANSFORM_SCALE_16)
1147 {
1148 /* Added at libpng-1.5.4. "strip_16" produces the same result that it
1149 * did in earlier versions, while "scale_16" is now more accurate.
1150 */
1151 png_set_scale_16(png_ptr);
1152 }
1153#endif
1154
1155#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1156 /* If both SCALE and STRIP are required pngrtran will effectively cancel the
1157 * latter by doing SCALE first. This is ok and allows apps not to check for
1158 * which is supported to get the right answer.
1159 */
1160 if (transforms & PNG_TRANSFORM_STRIP_16)
1161 png_set_strip_16(png_ptr);
1162#endif
1163
1164#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1165 /* Strip alpha bytes from the input data without combining with
1166 * the background (not recommended).
1167 */
1168 if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1169 png_set_strip_alpha(png_ptr);
1170#endif
1171
1172#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1173 /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1174 * byte into separate bytes (useful for paletted and grayscale images).
1175 */
1176 if (transforms & PNG_TRANSFORM_PACKING)
1177 png_set_packing(png_ptr);
1178#endif
1179
1180#ifdef PNG_READ_PACKSWAP_SUPPORTED
1181 /* Change the order of packed pixels to least significant bit first
1182 * (not useful if you are using png_set_packing).
1183 */
1184 if (transforms & PNG_TRANSFORM_PACKSWAP)
1185 png_set_packswap(png_ptr);
1186#endif
1187
1188#ifdef PNG_READ_EXPAND_SUPPORTED
1189 /* Expand paletted colors into true RGB triplets
1190 * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1191 * Expand paletted or RGB images with transparency to full alpha
1192 * channels so the data will be available as RGBA quartets.
1193 */
1194 if (transforms & PNG_TRANSFORM_EXPAND)
1195 if ((png_ptr->bit_depth < 8) ||
1196 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1197 (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1198 png_set_expand(png_ptr);
1199#endif
1200
1201 /* We don't handle background color or gamma transformation or quantizing.
1202 */
1203
1204#ifdef PNG_READ_INVERT_SUPPORTED
1205 /* Invert monochrome files to have 0 as white and 1 as black
1206 */
1207 if (transforms & PNG_TRANSFORM_INVERT_MONO)
1208 png_set_invert_mono(png_ptr);
1209#endif
1210
1211#ifdef PNG_READ_SHIFT_SUPPORTED
1212 /* If you want to shift the pixel values from the range [0,255] or
1213 * [0,65535] to the original [0,7] or [0,31], or whatever range the
1214 * colors were originally in:
1215 */
1216 if ((transforms & PNG_TRANSFORM_SHIFT)
1217 && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1218 {
1219 png_color_8p sig_bit;
1220
1221 png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1222 png_set_shift(png_ptr, sig_bit);
1223 }
1224#endif
1225
1226#ifdef PNG_READ_BGR_SUPPORTED
1227 /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
1228 if (transforms & PNG_TRANSFORM_BGR)
1229 png_set_bgr(png_ptr);
1230#endif
1231
1232#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1233 /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
1234 if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1235 png_set_swap_alpha(png_ptr);
1236#endif
1237
1238#ifdef PNG_READ_SWAP_SUPPORTED
1239 /* Swap bytes of 16-bit files to least significant byte first */
1240 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1241 png_set_swap(png_ptr);
1242#endif
1243
1244/* Added at libpng-1.2.41 */
1245#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1246 /* Invert the alpha channel from opacity to transparency */
1247 if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1248 png_set_invert_alpha(png_ptr);
1249#endif
1250
1251/* Added at libpng-1.2.41 */
1252#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1253 /* Expand grayscale image to RGB */
1254 if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1255 png_set_gray_to_rgb(png_ptr);
1256#endif
1257
1258/* Added at libpng-1.5.4 */
1259#ifdef PNG_READ_EXPAND_16_SUPPORTED
1260 if (transforms & PNG_TRANSFORM_EXPAND_16)
1261 png_set_expand_16(png_ptr);
1262#endif
1263
1264 /* We don't handle adding filler bytes */
1265
1266 /* We use png_read_image and rely on that for interlace handling, but we also
1267 * call png_read_update_info therefore must turn on interlace handling now:
1268 */
1269 (void)png_set_interlace_handling(png_ptr);
1270
1271 /* Optional call to gamma correct and add the background to the palette
1272 * and update info structure. REQUIRED if you are expecting libpng to
1273 * update the palette for you (i.e., you selected such a transform above).
1274 */
1275 png_read_update_info(png_ptr, info_ptr);
1276
1277 /* -------------- image transformations end here ------------------- */
1278
1279 png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1280 if (info_ptr->row_pointers == NULL)
1281 {
1282 png_uint_32 iptr;
1283
1284 info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1285 info_ptr->height * png_sizeof(png_bytep));
1286 for (iptr=0; iptr<info_ptr->height; iptr++)
1287 info_ptr->row_pointers[iptr] = NULL;
1288
1289 info_ptr->free_me |= PNG_FREE_ROWS;
1290
1291 for (row = 0; row < (int)info_ptr->height; row++)
1292 info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1293 png_get_rowbytes(png_ptr, info_ptr));
1294 }
1295
1296 png_read_image(png_ptr, info_ptr->row_pointers);
1297 info_ptr->valid |= PNG_INFO_IDAT;
1298
1299 /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1300 png_read_end(png_ptr, info_ptr);
1301
1302 PNG_UNUSED(transforms) /* Quiet compiler warnings */
1303 PNG_UNUSED(params)
1304
1305}
1306#endif /* PNG_INFO_IMAGE_SUPPORTED */
1307#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1308#endif /* PNG_READ_SUPPORTED */
wxWidgets (Impactor)