2
/* pngread.c - read a PNG file
4
* Last changed in libpng 1.2.44 [June 26, 2010]
5
* Copyright (c) 1998-2010 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.)
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
13
* This file contains routines that an application calls directly to
14
* read a PNG file or stream.
18
#define PNG_NO_PEDANTIC_WARNINGS
20
#ifdef PNG_READ_SUPPORTED
23
/* Create a PNG structure for reading, and allocate any memory needed. */
25
png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
26
png_error_ptr error_fn, png_error_ptr warn_fn)
29
#ifdef PNG_USER_MEM_SUPPORTED
30
return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
31
warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
34
/* Alternate create PNG structure for reading, and allocate any memory
38
png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
39
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
40
png_malloc_ptr malloc_fn, png_free_ptr free_fn)
42
#endif /* PNG_USER_MEM_SUPPORTED */
44
#ifdef PNG_SETJMP_SUPPORTED
49
#ifdef PNG_SETJMP_SUPPORTED
50
#ifdef USE_FAR_KEYWORD
57
png_debug(1, "in png_create_read_struct");
59
#ifdef PNG_USER_MEM_SUPPORTED
60
png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
61
(png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
63
png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
68
/* Added at libpng-1.2.6 */
69
#ifdef PNG_USER_LIMITS_SUPPORTED
70
png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
71
png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
72
# ifdef PNG_USER_CHUNK_CACHE_MAX
73
/* Added at libpng-1.2.43 and 1.4.0 */
74
png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
76
# ifdef PNG_SET_USER_CHUNK_MALLOC_MAX
77
/* Added at libpng-1.2.43 and 1.4.1 */
78
png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
82
#ifdef PNG_SETJMP_SUPPORTED
83
#ifdef USE_FAR_KEYWORD
86
if (setjmp(png_ptr->jmpbuf))
89
png_free(png_ptr, png_ptr->zbuf);
91
#ifdef PNG_USER_MEM_SUPPORTED
92
png_destroy_struct_2((png_voidp)png_ptr,
93
(png_free_ptr)free_fn, (png_voidp)mem_ptr);
95
png_destroy_struct((png_voidp)png_ptr);
99
#ifdef USE_FAR_KEYWORD
100
png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf));
102
#endif /* PNG_SETJMP_SUPPORTED */
104
#ifdef PNG_USER_MEM_SUPPORTED
105
png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
108
png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
115
if (user_png_ver[i] != png_libpng_ver[i])
116
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
117
} while (png_libpng_ver[i++]);
120
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
123
if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
125
/* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
126
* we must recompile any applications that use any older library version.
127
* For versions after libpng 1.0, we will be compatible, so we need
128
* only check the first digit.
130
if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
131
(user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
132
(user_png_ver[0] == '0' && user_png_ver[2] < '9'))
134
#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
138
png_snprintf(msg, 80,
139
"Application was compiled with png.h from libpng-%.20s",
141
png_warning(png_ptr, msg);
143
png_snprintf(msg, 80,
144
"Application is running with png.c from libpng-%.20s",
146
png_warning(png_ptr, msg);
148
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
152
"Incompatible libpng version in application and library");
156
/* Initialize zbuf - compression buffer */
157
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
158
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
159
(png_uint_32)png_ptr->zbuf_size);
160
png_ptr->zstream.zalloc = png_zalloc;
161
png_ptr->zstream.zfree = png_zfree;
162
png_ptr->zstream.opaque = (voidpf)png_ptr;
164
switch (inflateInit(&png_ptr->zstream))
166
case Z_OK: /* Do nothing */ break;
168
case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error");
170
case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error");
172
default: png_error(png_ptr, "Unknown zlib error");
176
png_ptr->zstream.next_out = png_ptr->zbuf;
177
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
179
png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
181
#ifdef PNG_SETJMP_SUPPORTED
182
/* Applications that neglect to set up their own setjmp() and then
183
encounter a png_error() will longjmp here. Since the jmpbuf is
184
then meaningless we abort instead of returning. */
185
#ifdef USE_FAR_KEYWORD
188
png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf));
190
if (setjmp(png_ptr->jmpbuf))
193
#endif /* PNG_SETJMP_SUPPORTED */
198
#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
199
/* Initialize PNG structure for reading, and allocate any memory needed.
200
* This interface is deprecated in favour of the png_create_read_struct(),
201
* and it will disappear as of libpng-1.3.0.
205
png_read_init(png_structp png_ptr)
207
/* We only come here via pre-1.0.7-compiled applications */
208
png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
212
png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
213
png_size_t png_struct_size, png_size_t png_info_size)
215
/* We only come here via pre-1.0.12-compiled applications */
218
#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
219
if (png_sizeof(png_struct) > png_struct_size ||
220
png_sizeof(png_info) > png_info_size)
223
png_ptr->warning_fn = NULL;
226
png_snprintf(msg, 80,
227
"Application was compiled with png.h from libpng-%.20s",
229
png_warning(png_ptr, msg);
231
png_snprintf(msg, 80,
232
"Application is running with png.c from libpng-%.20s",
234
png_warning(png_ptr, msg);
237
if (png_sizeof(png_struct) > png_struct_size)
239
png_ptr->error_fn = NULL;
240
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
244
"The png struct allocated by the application for reading is"
247
if (png_sizeof(png_info) > png_info_size)
249
png_ptr->error_fn = NULL;
250
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
254
"The info struct allocated by application for reading is"
257
png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
259
#endif /* PNG_1_0_X || PNG_1_2_X */
262
png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
263
png_size_t png_struct_size)
265
#ifdef PNG_SETJMP_SUPPORTED
266
jmp_buf tmp_jmp; /* to save current jump buffer */
271
png_structp png_ptr=*ptr_ptr;
278
if (user_png_ver[i] != png_libpng_ver[i])
280
#ifdef PNG_LEGACY_SUPPORTED
281
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
283
png_ptr->warning_fn = NULL;
285
"Application uses deprecated png_read_init() and should be"
290
} while (png_libpng_ver[i++]);
292
png_debug(1, "in png_read_init_3");
294
#ifdef PNG_SETJMP_SUPPORTED
295
/* Save jump buffer and error functions */
296
png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
299
if (png_sizeof(png_struct) > png_struct_size)
301
png_destroy_struct(png_ptr);
302
*ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
306
/* Reset all variables to 0 */
307
png_memset(png_ptr, 0, png_sizeof(png_struct));
309
#ifdef PNG_SETJMP_SUPPORTED
310
/* Restore jump buffer */
311
png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
314
/* Added at libpng-1.2.6 */
315
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
316
png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
317
png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
320
/* Initialize zbuf - compression buffer */
321
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
322
png_ptr->zstream.zalloc = png_zalloc;
323
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
324
(png_uint_32)png_ptr->zbuf_size);
325
png_ptr->zstream.zalloc = png_zalloc;
326
png_ptr->zstream.zfree = png_zfree;
327
png_ptr->zstream.opaque = (voidpf)png_ptr;
329
switch (inflateInit(&png_ptr->zstream))
331
case Z_OK: /* Do nothing */ break;
332
case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
333
case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error");
335
default: png_error(png_ptr, "Unknown zlib error");
338
png_ptr->zstream.next_out = png_ptr->zbuf;
339
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
341
png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
344
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
345
/* Read the information before the actual image data. This has been
346
* changed in v0.90 to allow reading a file that already has the magic
347
* bytes read from the stream. You can tell libpng how many bytes have
348
* been read from the beginning of the stream (up to the maximum of 8)
349
* via png_set_sig_bytes(), and we will only check the remaining bytes
350
* here. The application can then have access to the signature bytes we
351
* read if it is determined that this isn't a valid PNG file.
354
png_read_info(png_structp png_ptr, png_infop info_ptr)
356
png_debug(1, "in png_read_info");
358
if (png_ptr == NULL || info_ptr == NULL)
361
/* If we haven't checked all of the PNG signature bytes, do so now. */
362
if (png_ptr->sig_bytes < 8)
364
png_size_t num_checked = png_ptr->sig_bytes,
365
num_to_check = 8 - num_checked;
367
png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
368
png_ptr->sig_bytes = 8;
370
if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
372
if (num_checked < 4 &&
373
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
374
png_error(png_ptr, "Not a PNG file");
376
png_error(png_ptr, "PNG file corrupted by ASCII conversion");
379
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
384
#ifdef PNG_USE_LOCAL_ARRAYS
389
#ifdef PNG_READ_bKGD_SUPPORTED
392
#ifdef PNG_READ_cHRM_SUPPORTED
395
#ifdef PNG_READ_gAMA_SUPPORTED
398
#ifdef PNG_READ_hIST_SUPPORTED
401
#ifdef PNG_READ_iCCP_SUPPORTED
404
#ifdef PNG_READ_iTXt_SUPPORTED
407
#ifdef PNG_READ_oFFs_SUPPORTED
410
#ifdef PNG_READ_pCAL_SUPPORTED
413
#ifdef PNG_READ_pHYs_SUPPORTED
416
#ifdef PNG_READ_sBIT_SUPPORTED
419
#ifdef PNG_READ_sCAL_SUPPORTED
422
#ifdef PNG_READ_sPLT_SUPPORTED
425
#ifdef PNG_READ_sRGB_SUPPORTED
428
#ifdef PNG_READ_tEXt_SUPPORTED
431
#ifdef PNG_READ_tIME_SUPPORTED
434
#ifdef PNG_READ_tRNS_SUPPORTED
437
#ifdef PNG_READ_zTXt_SUPPORTED
440
#endif /* PNG_USE_LOCAL_ARRAYS */
441
png_uint_32 length = png_read_chunk_header(png_ptr);
442
PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
444
/* This should be a binary subdivision search or a hash for
445
* matching the chunk name rather than a linear search.
447
if (!png_memcmp(chunk_name, png_IDAT, 4))
448
if (png_ptr->mode & PNG_AFTER_IDAT)
449
png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
451
if (!png_memcmp(chunk_name, png_IHDR, 4))
452
png_handle_IHDR(png_ptr, info_ptr, length);
453
else if (!png_memcmp(chunk_name, png_IEND, 4))
454
png_handle_IEND(png_ptr, info_ptr, length);
455
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
456
else if (png_handle_as_unknown(png_ptr, chunk_name))
458
if (!png_memcmp(chunk_name, png_IDAT, 4))
459
png_ptr->mode |= PNG_HAVE_IDAT;
460
png_handle_unknown(png_ptr, info_ptr, length);
461
if (!png_memcmp(chunk_name, png_PLTE, 4))
462
png_ptr->mode |= PNG_HAVE_PLTE;
463
else if (!png_memcmp(chunk_name, png_IDAT, 4))
465
if (!(png_ptr->mode & PNG_HAVE_IHDR))
466
png_error(png_ptr, "Missing IHDR before IDAT");
467
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
468
!(png_ptr->mode & PNG_HAVE_PLTE))
469
png_error(png_ptr, "Missing PLTE before IDAT");
474
else if (!png_memcmp(chunk_name, png_PLTE, 4))
475
png_handle_PLTE(png_ptr, info_ptr, length);
476
else if (!png_memcmp(chunk_name, png_IDAT, 4))
478
if (!(png_ptr->mode & PNG_HAVE_IHDR))
479
png_error(png_ptr, "Missing IHDR before IDAT");
480
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
481
!(png_ptr->mode & PNG_HAVE_PLTE))
482
png_error(png_ptr, "Missing PLTE before IDAT");
484
png_ptr->idat_size = length;
485
png_ptr->mode |= PNG_HAVE_IDAT;
488
#ifdef PNG_READ_bKGD_SUPPORTED
489
else if (!png_memcmp(chunk_name, png_bKGD, 4))
490
png_handle_bKGD(png_ptr, info_ptr, length);
492
#ifdef PNG_READ_cHRM_SUPPORTED
493
else if (!png_memcmp(chunk_name, png_cHRM, 4))
494
png_handle_cHRM(png_ptr, info_ptr, length);
496
#ifdef PNG_READ_gAMA_SUPPORTED
497
else if (!png_memcmp(chunk_name, png_gAMA, 4))
498
png_handle_gAMA(png_ptr, info_ptr, length);
500
#ifdef PNG_READ_hIST_SUPPORTED
501
else if (!png_memcmp(chunk_name, png_hIST, 4))
502
png_handle_hIST(png_ptr, info_ptr, length);
504
#ifdef PNG_READ_oFFs_SUPPORTED
505
else if (!png_memcmp(chunk_name, png_oFFs, 4))
506
png_handle_oFFs(png_ptr, info_ptr, length);
508
#ifdef PNG_READ_pCAL_SUPPORTED
509
else if (!png_memcmp(chunk_name, png_pCAL, 4))
510
png_handle_pCAL(png_ptr, info_ptr, length);
512
#ifdef PNG_READ_sCAL_SUPPORTED
513
else if (!png_memcmp(chunk_name, png_sCAL, 4))
514
png_handle_sCAL(png_ptr, info_ptr, length);
516
#ifdef PNG_READ_pHYs_SUPPORTED
517
else if (!png_memcmp(chunk_name, png_pHYs, 4))
518
png_handle_pHYs(png_ptr, info_ptr, length);
520
#ifdef PNG_READ_sBIT_SUPPORTED
521
else if (!png_memcmp(chunk_name, png_sBIT, 4))
522
png_handle_sBIT(png_ptr, info_ptr, length);
524
#ifdef PNG_READ_sRGB_SUPPORTED
525
else if (!png_memcmp(chunk_name, png_sRGB, 4))
526
png_handle_sRGB(png_ptr, info_ptr, length);
528
#ifdef PNG_READ_iCCP_SUPPORTED
529
else if (!png_memcmp(chunk_name, png_iCCP, 4))
530
png_handle_iCCP(png_ptr, info_ptr, length);
532
#ifdef PNG_READ_sPLT_SUPPORTED
533
else if (!png_memcmp(chunk_name, png_sPLT, 4))
534
png_handle_sPLT(png_ptr, info_ptr, length);
536
#ifdef PNG_READ_tEXt_SUPPORTED
537
else if (!png_memcmp(chunk_name, png_tEXt, 4))
538
png_handle_tEXt(png_ptr, info_ptr, length);
540
#ifdef PNG_READ_tIME_SUPPORTED
541
else if (!png_memcmp(chunk_name, png_tIME, 4))
542
png_handle_tIME(png_ptr, info_ptr, length);
544
#ifdef PNG_READ_tRNS_SUPPORTED
545
else if (!png_memcmp(chunk_name, png_tRNS, 4))
546
png_handle_tRNS(png_ptr, info_ptr, length);
548
#ifdef PNG_READ_zTXt_SUPPORTED
549
else if (!png_memcmp(chunk_name, png_zTXt, 4))
550
png_handle_zTXt(png_ptr, info_ptr, length);
552
#ifdef PNG_READ_iTXt_SUPPORTED
553
else if (!png_memcmp(chunk_name, png_iTXt, 4))
554
png_handle_iTXt(png_ptr, info_ptr, length);
557
png_handle_unknown(png_ptr, info_ptr, length);
560
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
562
/* Optional call to update the users info_ptr structure */
564
png_read_update_info(png_structp png_ptr, png_infop info_ptr)
566
png_debug(1, "in png_read_update_info");
570
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
571
png_read_start_row(png_ptr);
574
"Ignoring extra png_read_update_info() call; row buffer not reallocated");
576
png_read_transform_info(png_ptr, info_ptr);
579
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
580
/* Initialize palette, background, etc, after transformations
581
* are set, but before any reading takes place. This allows
582
* the user to obtain a gamma-corrected palette, for example.
583
* If the user doesn't call this, we will do it ourselves.
586
png_start_read_image(png_structp png_ptr)
588
png_debug(1, "in png_start_read_image");
592
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
593
png_read_start_row(png_ptr);
595
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
597
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
599
png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
602
PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
604
PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
610
png_debug2(1, "in png_read_row (row %lu, pass %d)",
611
png_ptr->row_number, png_ptr->pass);
613
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
614
png_read_start_row(png_ptr);
615
if (png_ptr->row_number == 0 && png_ptr->pass == 0)
617
/* Check for transforms that have been set but were defined out */
618
#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
619
if (png_ptr->transformations & PNG_INVERT_MONO)
620
png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
622
#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
623
if (png_ptr->transformations & PNG_FILLER)
624
png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
626
#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
627
!defined(PNG_READ_PACKSWAP_SUPPORTED)
628
if (png_ptr->transformations & PNG_PACKSWAP)
629
png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
631
#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
632
if (png_ptr->transformations & PNG_PACK)
633
png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
635
#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
636
if (png_ptr->transformations & PNG_SHIFT)
637
png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
639
#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
640
if (png_ptr->transformations & PNG_BGR)
641
png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
643
#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
644
if (png_ptr->transformations & PNG_SWAP_BYTES)
645
png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
649
#ifdef PNG_READ_INTERLACING_SUPPORTED
650
/* If interlaced and we do not need a new row, combine row and return */
651
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
653
switch (png_ptr->pass)
656
if (png_ptr->row_number & 0x07)
659
png_combine_row(png_ptr, dsp_row,
660
png_pass_dsp_mask[png_ptr->pass]);
661
png_read_finish_row(png_ptr);
666
if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
669
png_combine_row(png_ptr, dsp_row,
670
png_pass_dsp_mask[png_ptr->pass]);
671
png_read_finish_row(png_ptr);
676
if ((png_ptr->row_number & 0x07) != 4)
678
if (dsp_row != NULL && (png_ptr->row_number & 4))
679
png_combine_row(png_ptr, dsp_row,
680
png_pass_dsp_mask[png_ptr->pass]);
681
png_read_finish_row(png_ptr);
686
if ((png_ptr->row_number & 3) || png_ptr->width < 3)
689
png_combine_row(png_ptr, dsp_row,
690
png_pass_dsp_mask[png_ptr->pass]);
691
png_read_finish_row(png_ptr);
696
if ((png_ptr->row_number & 3) != 2)
698
if (dsp_row != NULL && (png_ptr->row_number & 2))
699
png_combine_row(png_ptr, dsp_row,
700
png_pass_dsp_mask[png_ptr->pass]);
701
png_read_finish_row(png_ptr);
706
if ((png_ptr->row_number & 1) || png_ptr->width < 2)
709
png_combine_row(png_ptr, dsp_row,
710
png_pass_dsp_mask[png_ptr->pass]);
711
png_read_finish_row(png_ptr);
716
if (!(png_ptr->row_number & 1))
718
png_read_finish_row(png_ptr);
726
if (!(png_ptr->mode & PNG_HAVE_IDAT))
727
png_error(png_ptr, "Invalid attempt to read row data");
729
png_ptr->zstream.next_out = png_ptr->row_buf;
730
png_ptr->zstream.avail_out =
731
(uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
732
png_ptr->iwidth) + 1);
735
if (!(png_ptr->zstream.avail_in))
737
while (!png_ptr->idat_size)
739
png_crc_finish(png_ptr, 0);
741
png_ptr->idat_size = png_read_chunk_header(png_ptr);
742
if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
743
png_error(png_ptr, "Not enough image data");
745
png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
746
png_ptr->zstream.next_in = png_ptr->zbuf;
747
if (png_ptr->zbuf_size > png_ptr->idat_size)
748
png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
749
png_crc_read(png_ptr, png_ptr->zbuf,
750
(png_size_t)png_ptr->zstream.avail_in);
751
png_ptr->idat_size -= png_ptr->zstream.avail_in;
753
ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
754
if (ret == Z_STREAM_END)
756
if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
758
png_error(png_ptr, "Extra compressed data");
759
png_ptr->mode |= PNG_AFTER_IDAT;
760
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
764
png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
765
"Decompression error");
767
} while (png_ptr->zstream.avail_out);
769
png_ptr->row_info.color_type = png_ptr->color_type;
770
png_ptr->row_info.width = png_ptr->iwidth;
771
png_ptr->row_info.channels = png_ptr->channels;
772
png_ptr->row_info.bit_depth = png_ptr->bit_depth;
773
png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
774
png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
775
png_ptr->row_info.width);
777
if (png_ptr->row_buf[0])
778
png_read_filter_row(png_ptr, &(png_ptr->row_info),
779
png_ptr->row_buf + 1, png_ptr->prev_row + 1,
780
(int)(png_ptr->row_buf[0]));
782
png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
783
png_ptr->rowbytes + 1);
785
#ifdef PNG_MNG_FEATURES_SUPPORTED
786
if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
787
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
789
/* Intrapixel differencing */
790
png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
795
if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
796
png_do_read_transformations(png_ptr);
798
#ifdef PNG_READ_INTERLACING_SUPPORTED
799
/* Blow up interlaced rows to full size */
800
if (png_ptr->interlaced &&
801
(png_ptr->transformations & PNG_INTERLACE))
803
if (png_ptr->pass < 6)
804
/* Old interface (pre-1.0.9):
805
* png_do_read_interlace(&(png_ptr->row_info),
806
* png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
808
png_do_read_interlace(png_ptr);
811
png_combine_row(png_ptr, dsp_row,
812
png_pass_dsp_mask[png_ptr->pass]);
814
png_combine_row(png_ptr, row,
815
png_pass_mask[png_ptr->pass]);
821
png_combine_row(png_ptr, row, 0xff);
823
png_combine_row(png_ptr, dsp_row, 0xff);
825
png_read_finish_row(png_ptr);
827
if (png_ptr->read_row_fn != NULL)
828
(*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
830
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
832
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
833
/* Read one or more rows of image data. If the image is interlaced,
834
* and png_set_interlace_handling() has been called, the rows need to
835
* contain the contents of the rows from the previous pass. If the
836
* image has alpha or transparency, and png_handle_alpha()[*] has been
837
* called, the rows contents must be initialized to the contents of the
840
* "row" holds the actual image, and pixels are placed in it
841
* as they arrive. If the image is displayed after each pass, it will
842
* appear to "sparkle" in. "display_row" can be used to display a
843
* "chunky" progressive image, with finer detail added as it becomes
844
* available. If you do not want this "chunky" display, you may pass
845
* NULL for display_row. If you do not want the sparkle display, and
846
* you have not called png_handle_alpha(), you may pass NULL for rows.
847
* If you have called png_handle_alpha(), and the image has either an
848
* alpha channel or a transparency chunk, you must provide a buffer for
849
* rows. In this case, you do not have to provide a display_row buffer
850
* also, but you may. If the image is not interlaced, or if you have
851
* not called png_set_interlace_handling(), the display_row buffer will
852
* be ignored, so pass NULL to it.
854
* [*] png_handle_alpha() does not exist yet, as of this version of libpng
858
png_read_rows(png_structp png_ptr, png_bytepp row,
859
png_bytepp display_row, png_uint_32 num_rows)
865
png_debug(1, "in png_read_rows");
871
if (rp != NULL && dp != NULL)
872
for (i = 0; i < num_rows; i++)
874
png_bytep rptr = *rp++;
875
png_bytep dptr = *dp++;
877
png_read_row(png_ptr, rptr, dptr);
880
for (i = 0; i < num_rows; i++)
882
png_bytep rptr = *rp;
883
png_read_row(png_ptr, rptr, png_bytep_NULL);
887
for (i = 0; i < num_rows; i++)
889
png_bytep dptr = *dp;
890
png_read_row(png_ptr, png_bytep_NULL, dptr);
894
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
896
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
897
/* Read the entire image. If the image has an alpha channel or a tRNS
898
* chunk, and you have called png_handle_alpha()[*], you will need to
899
* initialize the image to the current image that PNG will be overlaying.
900
* We set the num_rows again here, in case it was incorrectly set in
901
* png_read_start_row() by a call to png_read_update_info() or
902
* png_start_read_image() if png_set_interlace_handling() wasn't called
903
* prior to either of these functions like it should have been. You can
904
* only call this function once. If you desire to have an image for
905
* each pass of a interlaced image, use png_read_rows() instead.
907
* [*] png_handle_alpha() does not exist yet, as of this version of libpng
910
png_read_image(png_structp png_ptr, png_bytepp image)
912
png_uint_32 i, image_height;
916
png_debug(1, "in png_read_image");
921
#ifdef PNG_READ_INTERLACING_SUPPORTED
922
pass = png_set_interlace_handling(png_ptr);
924
if (png_ptr->interlaced)
926
"Cannot read interlaced image -- interlace handler disabled.");
931
image_height=png_ptr->height;
932
png_ptr->num_rows = image_height; /* Make sure this is set correctly */
934
for (j = 0; j < pass; j++)
937
for (i = 0; i < image_height; i++)
939
png_read_row(png_ptr, *rp, png_bytep_NULL);
944
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
946
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
947
/* Read the end of the PNG file. Will not read past the end of the
948
* file, will verify the end is accurate, and will read any comments
949
* or time information at the end of the file, if info is not NULL.
952
png_read_end(png_structp png_ptr, png_infop info_ptr)
954
png_debug(1, "in png_read_end");
958
png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
962
#ifdef PNG_USE_LOCAL_ARRAYS
967
#ifdef PNG_READ_bKGD_SUPPORTED
970
#ifdef PNG_READ_cHRM_SUPPORTED
973
#ifdef PNG_READ_gAMA_SUPPORTED
976
#ifdef PNG_READ_hIST_SUPPORTED
979
#ifdef PNG_READ_iCCP_SUPPORTED
982
#ifdef PNG_READ_iTXt_SUPPORTED
985
#ifdef PNG_READ_oFFs_SUPPORTED
988
#ifdef PNG_READ_pCAL_SUPPORTED
991
#ifdef PNG_READ_pHYs_SUPPORTED
994
#ifdef PNG_READ_sBIT_SUPPORTED
997
#ifdef PNG_READ_sCAL_SUPPORTED
1000
#ifdef PNG_READ_sPLT_SUPPORTED
1003
#ifdef PNG_READ_sRGB_SUPPORTED
1006
#ifdef PNG_READ_tEXt_SUPPORTED
1009
#ifdef PNG_READ_tIME_SUPPORTED
1012
#ifdef PNG_READ_tRNS_SUPPORTED
1015
#ifdef PNG_READ_zTXt_SUPPORTED
1018
#endif /* PNG_USE_LOCAL_ARRAYS */
1019
png_uint_32 length = png_read_chunk_header(png_ptr);
1020
PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
1022
if (!png_memcmp(chunk_name, png_IHDR, 4))
1023
png_handle_IHDR(png_ptr, info_ptr, length);
1024
else if (!png_memcmp(chunk_name, png_IEND, 4))
1025
png_handle_IEND(png_ptr, info_ptr, length);
1026
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
1027
else if (png_handle_as_unknown(png_ptr, chunk_name))
1029
if (!png_memcmp(chunk_name, png_IDAT, 4))
1031
if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
1032
png_error(png_ptr, "Too many IDAT's found");
1034
png_handle_unknown(png_ptr, info_ptr, length);
1035
if (!png_memcmp(chunk_name, png_PLTE, 4))
1036
png_ptr->mode |= PNG_HAVE_PLTE;
1039
else if (!png_memcmp(chunk_name, png_IDAT, 4))
1041
/* Zero length IDATs are legal after the last IDAT has been
1042
* read, but not after other chunks have been read.
1044
if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
1045
png_error(png_ptr, "Too many IDAT's found");
1046
png_crc_finish(png_ptr, length);
1048
else if (!png_memcmp(chunk_name, png_PLTE, 4))
1049
png_handle_PLTE(png_ptr, info_ptr, length);
1050
#ifdef PNG_READ_bKGD_SUPPORTED
1051
else if (!png_memcmp(chunk_name, png_bKGD, 4))
1052
png_handle_bKGD(png_ptr, info_ptr, length);
1054
#ifdef PNG_READ_cHRM_SUPPORTED
1055
else if (!png_memcmp(chunk_name, png_cHRM, 4))
1056
png_handle_cHRM(png_ptr, info_ptr, length);
1058
#ifdef PNG_READ_gAMA_SUPPORTED
1059
else if (!png_memcmp(chunk_name, png_gAMA, 4))
1060
png_handle_gAMA(png_ptr, info_ptr, length);
1062
#ifdef PNG_READ_hIST_SUPPORTED
1063
else if (!png_memcmp(chunk_name, png_hIST, 4))
1064
png_handle_hIST(png_ptr, info_ptr, length);
1066
#ifdef PNG_READ_oFFs_SUPPORTED
1067
else if (!png_memcmp(chunk_name, png_oFFs, 4))
1068
png_handle_oFFs(png_ptr, info_ptr, length);
1070
#ifdef PNG_READ_pCAL_SUPPORTED
1071
else if (!png_memcmp(chunk_name, png_pCAL, 4))
1072
png_handle_pCAL(png_ptr, info_ptr, length);
1074
#ifdef PNG_READ_sCAL_SUPPORTED
1075
else if (!png_memcmp(chunk_name, png_sCAL, 4))
1076
png_handle_sCAL(png_ptr, info_ptr, length);
1078
#ifdef PNG_READ_pHYs_SUPPORTED
1079
else if (!png_memcmp(chunk_name, png_pHYs, 4))
1080
png_handle_pHYs(png_ptr, info_ptr, length);
1082
#ifdef PNG_READ_sBIT_SUPPORTED
1083
else if (!png_memcmp(chunk_name, png_sBIT, 4))
1084
png_handle_sBIT(png_ptr, info_ptr, length);
1086
#ifdef PNG_READ_sRGB_SUPPORTED
1087
else if (!png_memcmp(chunk_name, png_sRGB, 4))
1088
png_handle_sRGB(png_ptr, info_ptr, length);
1090
#ifdef PNG_READ_iCCP_SUPPORTED
1091
else if (!png_memcmp(chunk_name, png_iCCP, 4))
1092
png_handle_iCCP(png_ptr, info_ptr, length);
1094
#ifdef PNG_READ_sPLT_SUPPORTED
1095
else if (!png_memcmp(chunk_name, png_sPLT, 4))
1096
png_handle_sPLT(png_ptr, info_ptr, length);
1098
#ifdef PNG_READ_tEXt_SUPPORTED
1099
else if (!png_memcmp(chunk_name, png_tEXt, 4))
1100
png_handle_tEXt(png_ptr, info_ptr, length);
1102
#ifdef PNG_READ_tIME_SUPPORTED
1103
else if (!png_memcmp(chunk_name, png_tIME, 4))
1104
png_handle_tIME(png_ptr, info_ptr, length);
1106
#ifdef PNG_READ_tRNS_SUPPORTED
1107
else if (!png_memcmp(chunk_name, png_tRNS, 4))
1108
png_handle_tRNS(png_ptr, info_ptr, length);
1110
#ifdef PNG_READ_zTXt_SUPPORTED
1111
else if (!png_memcmp(chunk_name, png_zTXt, 4))
1112
png_handle_zTXt(png_ptr, info_ptr, length);
1114
#ifdef PNG_READ_iTXt_SUPPORTED
1115
else if (!png_memcmp(chunk_name, png_iTXt, 4))
1116
png_handle_iTXt(png_ptr, info_ptr, length);
1119
png_handle_unknown(png_ptr, info_ptr, length);
1120
} while (!(png_ptr->mode & PNG_HAVE_IEND));
1122
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1124
/* Free all memory used by the read */
1126
png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1127
png_infopp end_info_ptr_ptr)
1129
png_structp png_ptr = NULL;
1130
png_infop info_ptr = NULL, end_info_ptr = NULL;
1131
#ifdef PNG_USER_MEM_SUPPORTED
1132
png_free_ptr free_fn = NULL;
1133
png_voidp mem_ptr = NULL;
1136
png_debug(1, "in png_destroy_read_struct");
1138
if (png_ptr_ptr != NULL)
1139
png_ptr = *png_ptr_ptr;
1140
if (png_ptr == NULL)
1143
#ifdef PNG_USER_MEM_SUPPORTED
1144
free_fn = png_ptr->free_fn;
1145
mem_ptr = png_ptr->mem_ptr;
1148
if (info_ptr_ptr != NULL)
1149
info_ptr = *info_ptr_ptr;
1151
if (end_info_ptr_ptr != NULL)
1152
end_info_ptr = *end_info_ptr_ptr;
1154
png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1156
if (info_ptr != NULL)
1158
#ifdef PNG_TEXT_SUPPORTED
1159
png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1162
#ifdef PNG_USER_MEM_SUPPORTED
1163
png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1164
(png_voidp)mem_ptr);
1166
png_destroy_struct((png_voidp)info_ptr);
1168
*info_ptr_ptr = NULL;
1171
if (end_info_ptr != NULL)
1173
#ifdef PNG_READ_TEXT_SUPPORTED
1174
png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1176
#ifdef PNG_USER_MEM_SUPPORTED
1177
png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1178
(png_voidp)mem_ptr);
1180
png_destroy_struct((png_voidp)end_info_ptr);
1182
*end_info_ptr_ptr = NULL;
1185
if (png_ptr != NULL)
1187
#ifdef PNG_USER_MEM_SUPPORTED
1188
png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1189
(png_voidp)mem_ptr);
1191
png_destroy_struct((png_voidp)png_ptr);
1193
*png_ptr_ptr = NULL;
1197
/* Free all memory used by the read (old method) */
1199
png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1200
png_infop end_info_ptr)
1202
#ifdef PNG_SETJMP_SUPPORTED
1205
png_error_ptr error_fn;
1206
png_error_ptr warning_fn;
1207
png_voidp error_ptr;
1208
#ifdef PNG_USER_MEM_SUPPORTED
1209
png_free_ptr free_fn;
1212
png_debug(1, "in png_read_destroy");
1214
if (info_ptr != NULL)
1215
png_info_destroy(png_ptr, info_ptr);
1217
if (end_info_ptr != NULL)
1218
png_info_destroy(png_ptr, end_info_ptr);
1220
png_free(png_ptr, png_ptr->zbuf);
1221
png_free(png_ptr, png_ptr->big_row_buf);
1222
png_free(png_ptr, png_ptr->prev_row);
1223
png_free(png_ptr, png_ptr->chunkdata);
1224
#ifdef PNG_READ_DITHER_SUPPORTED
1225
png_free(png_ptr, png_ptr->palette_lookup);
1226
png_free(png_ptr, png_ptr->dither_index);
1228
#ifdef PNG_READ_GAMMA_SUPPORTED
1229
png_free(png_ptr, png_ptr->gamma_table);
1231
#ifdef PNG_READ_BACKGROUND_SUPPORTED
1232
png_free(png_ptr, png_ptr->gamma_from_1);
1233
png_free(png_ptr, png_ptr->gamma_to_1);
1235
#ifdef PNG_FREE_ME_SUPPORTED
1236
if (png_ptr->free_me & PNG_FREE_PLTE)
1237
png_zfree(png_ptr, png_ptr->palette);
1238
png_ptr->free_me &= ~PNG_FREE_PLTE;
1240
if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
1241
png_zfree(png_ptr, png_ptr->palette);
1242
png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
1244
#if defined(PNG_tRNS_SUPPORTED) || \
1245
defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1246
#ifdef PNG_FREE_ME_SUPPORTED
1247
if (png_ptr->free_me & PNG_FREE_TRNS)
1248
png_free(png_ptr, png_ptr->trans);
1249
png_ptr->free_me &= ~PNG_FREE_TRNS;
1251
if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
1252
png_free(png_ptr, png_ptr->trans);
1253
png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
1256
#ifdef PNG_READ_hIST_SUPPORTED
1257
#ifdef PNG_FREE_ME_SUPPORTED
1258
if (png_ptr->free_me & PNG_FREE_HIST)
1259
png_free(png_ptr, png_ptr->hist);
1260
png_ptr->free_me &= ~PNG_FREE_HIST;
1262
if (png_ptr->flags & PNG_FLAG_FREE_HIST)
1263
png_free(png_ptr, png_ptr->hist);
1264
png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
1267
#ifdef PNG_READ_GAMMA_SUPPORTED
1268
if (png_ptr->gamma_16_table != NULL)
1271
int istop = (1 << (8 - png_ptr->gamma_shift));
1272
for (i = 0; i < istop; i++)
1274
png_free(png_ptr, png_ptr->gamma_16_table[i]);
1276
png_free(png_ptr, png_ptr->gamma_16_table);
1278
#ifdef PNG_READ_BACKGROUND_SUPPORTED
1279
if (png_ptr->gamma_16_from_1 != NULL)
1282
int istop = (1 << (8 - png_ptr->gamma_shift));
1283
for (i = 0; i < istop; i++)
1285
png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1287
png_free(png_ptr, png_ptr->gamma_16_from_1);
1289
if (png_ptr->gamma_16_to_1 != NULL)
1292
int istop = (1 << (8 - png_ptr->gamma_shift));
1293
for (i = 0; i < istop; i++)
1295
png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1297
png_free(png_ptr, png_ptr->gamma_16_to_1);
1301
#ifdef PNG_TIME_RFC1123_SUPPORTED
1302
png_free(png_ptr, png_ptr->time_buffer);
1305
inflateEnd(&png_ptr->zstream);
1306
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1307
png_free(png_ptr, png_ptr->save_buffer);
1310
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1311
#ifdef PNG_TEXT_SUPPORTED
1312
png_free(png_ptr, png_ptr->current_text);
1313
#endif /* PNG_TEXT_SUPPORTED */
1314
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1316
/* Save the important info out of the png_struct, in case it is
1319
#ifdef PNG_SETJMP_SUPPORTED
1320
png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
1323
error_fn = png_ptr->error_fn;
1324
warning_fn = png_ptr->warning_fn;
1325
error_ptr = png_ptr->error_ptr;
1326
#ifdef PNG_USER_MEM_SUPPORTED
1327
free_fn = png_ptr->free_fn;
1330
png_memset(png_ptr, 0, png_sizeof(png_struct));
1332
png_ptr->error_fn = error_fn;
1333
png_ptr->warning_fn = warning_fn;
1334
png_ptr->error_ptr = error_ptr;
1335
#ifdef PNG_USER_MEM_SUPPORTED
1336
png_ptr->free_fn = free_fn;
1339
#ifdef PNG_SETJMP_SUPPORTED
1340
png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
1346
png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1348
if (png_ptr == NULL)
1350
png_ptr->read_row_fn = read_row_fn;
1354
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1355
#ifdef PNG_INFO_IMAGE_SUPPORTED
1357
png_read_png(png_structp png_ptr, png_infop info_ptr,
1363
if (png_ptr == NULL)
1365
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1366
/* Invert the alpha channel from opacity to transparency
1368
if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1369
png_set_invert_alpha(png_ptr);
1372
/* png_read_info() gives us all of the information from the
1373
* PNG file before the first IDAT (image data chunk).
1375
png_read_info(png_ptr, info_ptr);
1376
if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1377
png_error(png_ptr, "Image is too high to process with png_read_png()");
1379
/* -------------- image transformations start here ------------------- */
1381
#ifdef PNG_READ_16_TO_8_SUPPORTED
1382
/* Tell libpng to strip 16 bit/color files down to 8 bits per color.
1384
if (transforms & PNG_TRANSFORM_STRIP_16)
1385
png_set_strip_16(png_ptr);
1388
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1389
/* Strip alpha bytes from the input data without combining with
1390
* the background (not recommended).
1392
if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1393
png_set_strip_alpha(png_ptr);
1396
#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1397
/* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1398
* byte into separate bytes (useful for paletted and grayscale images).
1400
if (transforms & PNG_TRANSFORM_PACKING)
1401
png_set_packing(png_ptr);
1404
#ifdef PNG_READ_PACKSWAP_SUPPORTED
1405
/* Change the order of packed pixels to least significant bit first
1406
* (not useful if you are using png_set_packing).
1408
if (transforms & PNG_TRANSFORM_PACKSWAP)
1409
png_set_packswap(png_ptr);
1412
#ifdef PNG_READ_EXPAND_SUPPORTED
1413
/* Expand paletted colors into true RGB triplets
1414
* Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1415
* Expand paletted or RGB images with transparency to full alpha
1416
* channels so the data will be available as RGBA quartets.
1418
if (transforms & PNG_TRANSFORM_EXPAND)
1419
if ((png_ptr->bit_depth < 8) ||
1420
(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1421
(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1422
png_set_expand(png_ptr);
1425
/* We don't handle background color or gamma transformation or dithering.
1428
#ifdef PNG_READ_INVERT_SUPPORTED
1429
/* Invert monochrome files to have 0 as white and 1 as black
1431
if (transforms & PNG_TRANSFORM_INVERT_MONO)
1432
png_set_invert_mono(png_ptr);
1435
#ifdef PNG_READ_SHIFT_SUPPORTED
1436
/* If you want to shift the pixel values from the range [0,255] or
1437
* [0,65535] to the original [0,7] or [0,31], or whatever range the
1438
* colors were originally in:
1440
if ((transforms & PNG_TRANSFORM_SHIFT)
1441
&& png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1443
png_color_8p sig_bit;
1445
png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1446
png_set_shift(png_ptr, sig_bit);
1450
#ifdef PNG_READ_BGR_SUPPORTED
1451
/* Flip the RGB pixels to BGR (or RGBA to BGRA)
1453
if (transforms & PNG_TRANSFORM_BGR)
1454
png_set_bgr(png_ptr);
1457
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1458
/* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1460
if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1461
png_set_swap_alpha(png_ptr);
1464
#ifdef PNG_READ_SWAP_SUPPORTED
1465
/* Swap bytes of 16 bit files to least significant byte first
1467
if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1468
png_set_swap(png_ptr);
1471
/* Added at libpng-1.2.41 */
1472
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1473
/* Invert the alpha channel from opacity to transparency
1475
if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1476
png_set_invert_alpha(png_ptr);
1479
/* Added at libpng-1.2.41 */
1480
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1481
/* Expand grayscale image to RGB
1483
if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1484
png_set_gray_to_rgb(png_ptr);
1487
/* We don't handle adding filler bytes */
1489
/* Optional call to gamma correct and add the background to the palette
1490
* and update info structure. REQUIRED if you are expecting libpng to
1491
* update the palette for you (i.e., you selected such a transform above).
1493
png_read_update_info(png_ptr, info_ptr);
1495
/* -------------- image transformations end here ------------------- */
1497
#ifdef PNG_FREE_ME_SUPPORTED
1498
png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1500
if (info_ptr->row_pointers == NULL)
1502
info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1503
info_ptr->height * png_sizeof(png_bytep));
1504
png_memset(info_ptr->row_pointers, 0, info_ptr->height
1505
* png_sizeof(png_bytep));
1507
#ifdef PNG_FREE_ME_SUPPORTED
1508
info_ptr->free_me |= PNG_FREE_ROWS;
1511
for (row = 0; row < (int)info_ptr->height; row++)
1512
info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1513
png_get_rowbytes(png_ptr, info_ptr));
1516
png_read_image(png_ptr, info_ptr->row_pointers);
1517
info_ptr->valid |= PNG_INFO_IDAT;
1519
/* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1520
png_read_end(png_ptr, info_ptr);
1522
transforms = transforms; /* Quiet compiler warnings */
1526
#endif /* PNG_INFO_IMAGE_SUPPORTED */
1527
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1528
#endif /* PNG_READ_SUPPORTED */