2
/* pngread.c - read a PNG file
4
* libpng 1.2.7 - September 12, 2004
5
* For conditions of distribution and use, see copyright notice in png.h
6
* Copyright (c) 1998-2004 Glenn Randers-Pehrson
7
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
10
* This file contains routines that an application calls directly to
11
* read a PNG file or stream.
17
/* Create a PNG structure for reading, and allocate any memory needed. */
19
png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
20
png_error_ptr error_fn, png_error_ptr warn_fn)
23
#ifdef PNG_USER_MEM_SUPPORTED
24
return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
25
warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
28
/* Alternate create PNG structure for reading, and allocate any memory needed. */
30
png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
31
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
32
png_malloc_ptr malloc_fn, png_free_ptr free_fn)
34
#endif /* PNG_USER_MEM_SUPPORTED */
38
#ifdef PNG_SETJMP_SUPPORTED
39
#ifdef USE_FAR_KEYWORD
46
png_debug(1, "in png_create_read_struct\n");
47
#ifdef PNG_USER_MEM_SUPPORTED
48
png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
49
(png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
51
png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
56
#if !defined(PNG_1_0_X)
57
#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
58
png_init_mmx_flags(png_ptr); /* 1.2.0 addition */
60
#endif /* PNG_1_0_X */
62
/* added at libpng-1.2.6 */
63
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
64
png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
65
png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
68
#ifdef PNG_SETJMP_SUPPORTED
69
#ifdef USE_FAR_KEYWORD
72
if (setjmp(png_ptr->jmpbuf))
75
png_free(png_ptr, png_ptr->zbuf);
77
#ifdef PNG_USER_MEM_SUPPORTED
78
png_destroy_struct_2((png_voidp)png_ptr,
79
(png_free_ptr)free_fn, (png_voidp)mem_ptr);
81
png_destroy_struct((png_voidp)png_ptr);
85
#ifdef USE_FAR_KEYWORD
86
png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
90
#ifdef PNG_USER_MEM_SUPPORTED
91
png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
94
png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
99
if(user_png_ver[i] != png_libpng_ver[i])
100
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
101
} while (png_libpng_ver[i++]);
103
if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
105
/* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
106
* we must recompile any applications that use any older library version.
107
* For versions after libpng 1.0, we will be compatible, so we need
108
* only check the first digit.
110
if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
111
(user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
112
(user_png_ver[0] == '0' && user_png_ver[2] < '9'))
114
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
118
sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
120
png_warning(png_ptr, msg);
122
sprintf(msg, "Application is running with png.c from libpng-%.20s",
124
png_warning(png_ptr, msg);
126
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
130
"Incompatible libpng version in application and library");
134
/* initialize zbuf - compression buffer */
135
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
136
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
137
(png_uint_32)png_ptr->zbuf_size);
138
png_ptr->zstream.zalloc = png_zalloc;
139
png_ptr->zstream.zfree = png_zfree;
140
png_ptr->zstream.opaque = (voidpf)png_ptr;
142
switch (inflateInit(&png_ptr->zstream))
144
case Z_OK: /* Do nothing */ break;
146
case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
147
case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
148
default: png_error(png_ptr, "Unknown zlib error");
151
png_ptr->zstream.next_out = png_ptr->zbuf;
152
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
154
png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
156
#ifdef PNG_SETJMP_SUPPORTED
157
/* Applications that neglect to set up their own setjmp() and then encounter
158
a png_error() will longjmp here. Since the jmpbuf is then meaningless we
159
abort instead of returning. */
160
#ifdef USE_FAR_KEYWORD
163
png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
165
if (setjmp(png_ptr->jmpbuf))
172
/* Initialize PNG structure for reading, and allocate any memory needed.
173
This interface is deprecated in favour of the png_create_read_struct(),
174
and it will eventually disappear. */
177
png_read_init(png_structp png_ptr)
179
/* We only come here via pre-1.0.7-compiled applications */
180
png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
184
png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
185
png_size_t png_struct_size, png_size_t png_info_size)
187
/* We only come here via pre-1.0.12-compiled applications */
188
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
189
if(png_sizeof(png_struct) > png_struct_size ||
190
png_sizeof(png_info) > png_info_size)
193
png_ptr->warning_fn=NULL;
196
sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
198
png_warning(png_ptr, msg);
200
sprintf(msg, "Application is running with png.c from libpng-%.20s",
202
png_warning(png_ptr, msg);
205
if(png_sizeof(png_struct) > png_struct_size)
207
png_ptr->error_fn=NULL;
208
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
212
"The png struct allocated by the application for reading is too small.");
214
if(png_sizeof(png_info) > png_info_size)
216
png_ptr->error_fn=NULL;
217
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
221
"The info struct allocated by application for reading is too small.");
223
png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
227
png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
228
png_size_t png_struct_size)
230
#ifdef PNG_SETJMP_SUPPORTED
231
jmp_buf tmp_jmp; /* to save current jump buffer */
236
png_structp png_ptr=*ptr_ptr;
240
if(user_png_ver[i] != png_libpng_ver[i])
242
#ifdef PNG_LEGACY_SUPPORTED
243
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
245
png_ptr->warning_fn=NULL;
247
"Application uses deprecated png_read_init() and should be recompiled.");
251
} while (png_libpng_ver[i++]);
253
png_debug(1, "in png_read_init_3\n");
255
#ifdef PNG_SETJMP_SUPPORTED
256
/* save jump buffer and error functions */
257
png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
260
if(png_sizeof(png_struct) > png_struct_size)
262
png_destroy_struct(png_ptr);
263
*ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
267
/* reset all variables to 0 */
268
png_memset(png_ptr, 0, png_sizeof (png_struct));
270
#ifdef PNG_SETJMP_SUPPORTED
271
/* restore jump buffer */
272
png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
275
/* added at libpng-1.2.6 */
276
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
277
png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
278
png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
281
/* initialize zbuf - compression buffer */
282
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
283
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
284
(png_uint_32)png_ptr->zbuf_size);
285
png_ptr->zstream.zalloc = png_zalloc;
286
png_ptr->zstream.zfree = png_zfree;
287
png_ptr->zstream.opaque = (voidpf)png_ptr;
289
switch (inflateInit(&png_ptr->zstream))
291
case Z_OK: /* Do nothing */ break;
293
case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
294
case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
295
default: png_error(png_ptr, "Unknown zlib error");
298
png_ptr->zstream.next_out = png_ptr->zbuf;
299
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
301
png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
304
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
305
/* Read the information before the actual image data. This has been
306
* changed in v0.90 to allow reading a file that already has the magic
307
* bytes read from the stream. You can tell libpng how many bytes have
308
* been read from the beginning of the stream (up to the maximum of 8)
309
* via png_set_sig_bytes(), and we will only check the remaining bytes
310
* here. The application can then have access to the signature bytes we
311
* read if it is determined that this isn't a valid PNG file.
314
png_read_info(png_structp png_ptr, png_infop info_ptr)
316
png_debug(1, "in png_read_info\n");
317
/* If we haven't checked all of the PNG signature bytes, do so now. */
318
if (png_ptr->sig_bytes < 8)
320
png_size_t num_checked = png_ptr->sig_bytes,
321
num_to_check = 8 - num_checked;
323
png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
324
png_ptr->sig_bytes = 8;
326
if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
328
if (num_checked < 4 &&
329
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
330
png_error(png_ptr, "Not a PNG file");
332
png_error(png_ptr, "PNG file corrupted by ASCII conversion");
335
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
340
#ifdef PNG_USE_LOCAL_ARRAYS
345
#if defined(PNG_READ_bKGD_SUPPORTED)
348
#if defined(PNG_READ_cHRM_SUPPORTED)
351
#if defined(PNG_READ_gAMA_SUPPORTED)
354
#if defined(PNG_READ_hIST_SUPPORTED)
357
#if defined(PNG_READ_iCCP_SUPPORTED)
360
#if defined(PNG_READ_iTXt_SUPPORTED)
363
#if defined(PNG_READ_oFFs_SUPPORTED)
366
#if defined(PNG_READ_pCAL_SUPPORTED)
369
#if defined(PNG_READ_pHYs_SUPPORTED)
372
#if defined(PNG_READ_sBIT_SUPPORTED)
375
#if defined(PNG_READ_sCAL_SUPPORTED)
378
#if defined(PNG_READ_sPLT_SUPPORTED)
381
#if defined(PNG_READ_sRGB_SUPPORTED)
384
#if defined(PNG_READ_tEXt_SUPPORTED)
387
#if defined(PNG_READ_tIME_SUPPORTED)
390
#if defined(PNG_READ_tRNS_SUPPORTED)
393
#if defined(PNG_READ_zTXt_SUPPORTED)
396
#endif /* PNG_GLOBAL_ARRAYS */
397
png_byte chunk_length[4];
400
png_read_data(png_ptr, chunk_length, 4);
401
length = png_get_uint_31(png_ptr,chunk_length);
403
png_reset_crc(png_ptr);
404
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
406
png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
409
/* This should be a binary subdivision search or a hash for
410
* matching the chunk name rather than a linear search.
412
if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
413
png_handle_IHDR(png_ptr, info_ptr, length);
414
else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
415
png_handle_IEND(png_ptr, info_ptr, length);
416
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
417
else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
419
if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
420
png_ptr->mode |= PNG_HAVE_IDAT;
421
png_handle_unknown(png_ptr, info_ptr, length);
422
if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
423
png_ptr->mode |= PNG_HAVE_PLTE;
424
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
426
if (!(png_ptr->mode & PNG_HAVE_IHDR))
427
png_error(png_ptr, "Missing IHDR before IDAT");
428
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
429
!(png_ptr->mode & PNG_HAVE_PLTE))
430
png_error(png_ptr, "Missing PLTE before IDAT");
435
else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
436
png_handle_PLTE(png_ptr, info_ptr, length);
437
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
439
if (!(png_ptr->mode & PNG_HAVE_IHDR))
440
png_error(png_ptr, "Missing IHDR before IDAT");
441
else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
442
!(png_ptr->mode & PNG_HAVE_PLTE))
443
png_error(png_ptr, "Missing PLTE before IDAT");
445
png_ptr->idat_size = length;
446
png_ptr->mode |= PNG_HAVE_IDAT;
449
#if defined(PNG_READ_bKGD_SUPPORTED)
450
else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
451
png_handle_bKGD(png_ptr, info_ptr, length);
453
#if defined(PNG_READ_cHRM_SUPPORTED)
454
else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
455
png_handle_cHRM(png_ptr, info_ptr, length);
457
#if defined(PNG_READ_gAMA_SUPPORTED)
458
else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
459
png_handle_gAMA(png_ptr, info_ptr, length);
461
#if defined(PNG_READ_hIST_SUPPORTED)
462
else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
463
png_handle_hIST(png_ptr, info_ptr, length);
465
#if defined(PNG_READ_oFFs_SUPPORTED)
466
else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
467
png_handle_oFFs(png_ptr, info_ptr, length);
469
#if defined(PNG_READ_pCAL_SUPPORTED)
470
else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
471
png_handle_pCAL(png_ptr, info_ptr, length);
473
#if defined(PNG_READ_sCAL_SUPPORTED)
474
else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
475
png_handle_sCAL(png_ptr, info_ptr, length);
477
#if defined(PNG_READ_pHYs_SUPPORTED)
478
else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
479
png_handle_pHYs(png_ptr, info_ptr, length);
481
#if defined(PNG_READ_sBIT_SUPPORTED)
482
else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
483
png_handle_sBIT(png_ptr, info_ptr, length);
485
#if defined(PNG_READ_sRGB_SUPPORTED)
486
else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
487
png_handle_sRGB(png_ptr, info_ptr, length);
489
#if defined(PNG_READ_iCCP_SUPPORTED)
490
else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
491
png_handle_iCCP(png_ptr, info_ptr, length);
493
#if defined(PNG_READ_sPLT_SUPPORTED)
494
else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
495
png_handle_sPLT(png_ptr, info_ptr, length);
497
#if defined(PNG_READ_tEXt_SUPPORTED)
498
else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
499
png_handle_tEXt(png_ptr, info_ptr, length);
501
#if defined(PNG_READ_tIME_SUPPORTED)
502
else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
503
png_handle_tIME(png_ptr, info_ptr, length);
505
#if defined(PNG_READ_tRNS_SUPPORTED)
506
else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
507
png_handle_tRNS(png_ptr, info_ptr, length);
509
#if defined(PNG_READ_zTXt_SUPPORTED)
510
else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
511
png_handle_zTXt(png_ptr, info_ptr, length);
513
#if defined(PNG_READ_iTXt_SUPPORTED)
514
else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
515
png_handle_iTXt(png_ptr, info_ptr, length);
518
png_handle_unknown(png_ptr, info_ptr, length);
521
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
523
/* optional call to update the users info_ptr structure */
525
png_read_update_info(png_structp png_ptr, png_infop info_ptr)
527
png_debug(1, "in png_read_update_info\n");
528
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
529
png_read_start_row(png_ptr);
532
"Ignoring extra png_read_update_info() call; row buffer not reallocated");
533
png_read_transform_info(png_ptr, info_ptr);
536
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
537
/* Initialize palette, background, etc, after transformations
538
* are set, but before any reading takes place. This allows
539
* the user to obtain a gamma-corrected palette, for example.
540
* If the user doesn't call this, we will do it ourselves.
543
png_start_read_image(png_structp png_ptr)
545
png_debug(1, "in png_start_read_image\n");
546
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
547
png_read_start_row(png_ptr);
549
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
551
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
553
png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
555
#ifdef PNG_USE_LOCAL_ARRAYS
557
const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
558
const int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
561
png_debug2(1, "in png_read_row (row %lu, pass %d)\n",
562
png_ptr->row_number, png_ptr->pass);
563
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
564
png_read_start_row(png_ptr);
565
if (png_ptr->row_number == 0 && png_ptr->pass == 0)
567
/* check for transforms that have been set but were defined out */
568
#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
569
if (png_ptr->transformations & PNG_INVERT_MONO)
570
png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
572
#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
573
if (png_ptr->transformations & PNG_FILLER)
574
png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
576
#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
577
if (png_ptr->transformations & PNG_PACKSWAP)
578
png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
580
#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
581
if (png_ptr->transformations & PNG_PACK)
582
png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
584
#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
585
if (png_ptr->transformations & PNG_SHIFT)
586
png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
588
#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
589
if (png_ptr->transformations & PNG_BGR)
590
png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
592
#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
593
if (png_ptr->transformations & PNG_SWAP_BYTES)
594
png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
598
#if defined(PNG_READ_INTERLACING_SUPPORTED)
599
/* if interlaced and we do not need a new row, combine row and return */
600
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
602
switch (png_ptr->pass)
605
if (png_ptr->row_number & 0x07)
608
png_combine_row(png_ptr, dsp_row,
609
png_pass_dsp_mask[png_ptr->pass]);
610
png_read_finish_row(png_ptr);
615
if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
618
png_combine_row(png_ptr, dsp_row,
619
png_pass_dsp_mask[png_ptr->pass]);
620
png_read_finish_row(png_ptr);
625
if ((png_ptr->row_number & 0x07) != 4)
627
if (dsp_row != NULL && (png_ptr->row_number & 4))
628
png_combine_row(png_ptr, dsp_row,
629
png_pass_dsp_mask[png_ptr->pass]);
630
png_read_finish_row(png_ptr);
635
if ((png_ptr->row_number & 3) || png_ptr->width < 3)
638
png_combine_row(png_ptr, dsp_row,
639
png_pass_dsp_mask[png_ptr->pass]);
640
png_read_finish_row(png_ptr);
645
if ((png_ptr->row_number & 3) != 2)
647
if (dsp_row != NULL && (png_ptr->row_number & 2))
648
png_combine_row(png_ptr, dsp_row,
649
png_pass_dsp_mask[png_ptr->pass]);
650
png_read_finish_row(png_ptr);
655
if ((png_ptr->row_number & 1) || png_ptr->width < 2)
658
png_combine_row(png_ptr, dsp_row,
659
png_pass_dsp_mask[png_ptr->pass]);
660
png_read_finish_row(png_ptr);
665
if (!(png_ptr->row_number & 1))
667
png_read_finish_row(png_ptr);
675
if (!(png_ptr->mode & PNG_HAVE_IDAT))
676
png_error(png_ptr, "Invalid attempt to read row data");
678
png_ptr->zstream.next_out = png_ptr->row_buf;
679
png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
682
if (!(png_ptr->zstream.avail_in))
684
while (!png_ptr->idat_size)
686
png_byte chunk_length[4];
688
png_crc_finish(png_ptr, 0);
690
png_read_data(png_ptr, chunk_length, 4);
691
png_ptr->idat_size = png_get_uint_31(png_ptr,chunk_length);
693
png_reset_crc(png_ptr);
694
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
695
if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
696
png_error(png_ptr, "Not enough image data");
698
png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
699
png_ptr->zstream.next_in = png_ptr->zbuf;
700
if (png_ptr->zbuf_size > png_ptr->idat_size)
701
png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
702
png_crc_read(png_ptr, png_ptr->zbuf,
703
(png_size_t)png_ptr->zstream.avail_in);
704
png_ptr->idat_size -= png_ptr->zstream.avail_in;
706
ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
707
if (ret == Z_STREAM_END)
709
if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
711
png_error(png_ptr, "Extra compressed data");
712
png_ptr->mode |= PNG_AFTER_IDAT;
713
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
717
png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
718
"Decompression error");
720
} while (png_ptr->zstream.avail_out);
722
png_ptr->row_info.color_type = png_ptr->color_type;
723
png_ptr->row_info.width = png_ptr->iwidth;
724
png_ptr->row_info.channels = png_ptr->channels;
725
png_ptr->row_info.bit_depth = png_ptr->bit_depth;
726
png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
727
png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
728
png_ptr->row_info.width);
730
if(png_ptr->row_buf[0])
731
png_read_filter_row(png_ptr, &(png_ptr->row_info),
732
png_ptr->row_buf + 1, png_ptr->prev_row + 1,
733
(int)(png_ptr->row_buf[0]));
735
png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
736
png_ptr->rowbytes + 1);
738
#if defined(PNG_MNG_FEATURES_SUPPORTED)
739
if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
740
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
742
/* Intrapixel differencing */
743
png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
747
if (png_ptr->transformations)
748
png_do_read_transformations(png_ptr);
750
#if defined(PNG_READ_INTERLACING_SUPPORTED)
751
/* blow up interlaced rows to full size */
752
if (png_ptr->interlaced &&
753
(png_ptr->transformations & PNG_INTERLACE))
755
if (png_ptr->pass < 6)
756
/* old interface (pre-1.0.9):
757
png_do_read_interlace(&(png_ptr->row_info),
758
png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
760
png_do_read_interlace(png_ptr);
763
png_combine_row(png_ptr, dsp_row,
764
png_pass_dsp_mask[png_ptr->pass]);
766
png_combine_row(png_ptr, row,
767
png_pass_mask[png_ptr->pass]);
773
png_combine_row(png_ptr, row, 0xff);
775
png_combine_row(png_ptr, dsp_row, 0xff);
777
png_read_finish_row(png_ptr);
779
if (png_ptr->read_row_fn != NULL)
780
(*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
782
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
784
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
785
/* Read one or more rows of image data. If the image is interlaced,
786
* and png_set_interlace_handling() has been called, the rows need to
787
* contain the contents of the rows from the previous pass. If the
788
* image has alpha or transparency, and png_handle_alpha()[*] has been
789
* called, the rows contents must be initialized to the contents of the
792
* "row" holds the actual image, and pixels are placed in it
793
* as they arrive. If the image is displayed after each pass, it will
794
* appear to "sparkle" in. "display_row" can be used to display a
795
* "chunky" progressive image, with finer detail added as it becomes
796
* available. If you do not want this "chunky" display, you may pass
797
* NULL for display_row. If you do not want the sparkle display, and
798
* you have not called png_handle_alpha(), you may pass NULL for rows.
799
* If you have called png_handle_alpha(), and the image has either an
800
* alpha channel or a transparency chunk, you must provide a buffer for
801
* rows. In this case, you do not have to provide a display_row buffer
802
* also, but you may. If the image is not interlaced, or if you have
803
* not called png_set_interlace_handling(), the display_row buffer will
804
* be ignored, so pass NULL to it.
806
* [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.7
810
png_read_rows(png_structp png_ptr, png_bytepp row,
811
png_bytepp display_row, png_uint_32 num_rows)
817
png_debug(1, "in png_read_rows\n");
820
if (rp != NULL && dp != NULL)
821
for (i = 0; i < num_rows; i++)
823
png_bytep rptr = *rp++;
824
png_bytep dptr = *dp++;
826
png_read_row(png_ptr, rptr, dptr);
829
for (i = 0; i < num_rows; i++)
831
png_bytep rptr = *rp;
832
png_read_row(png_ptr, rptr, png_bytep_NULL);
836
for (i = 0; i < num_rows; i++)
838
png_bytep dptr = *dp;
839
png_read_row(png_ptr, png_bytep_NULL, dptr);
843
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
845
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
846
/* Read the entire image. If the image has an alpha channel or a tRNS
847
* chunk, and you have called png_handle_alpha()[*], you will need to
848
* initialize the image to the current image that PNG will be overlaying.
849
* We set the num_rows again here, in case it was incorrectly set in
850
* png_read_start_row() by a call to png_read_update_info() or
851
* png_start_read_image() if png_set_interlace_handling() wasn't called
852
* prior to either of these functions like it should have been. You can
853
* only call this function once. If you desire to have an image for
854
* each pass of a interlaced image, use png_read_rows() instead.
856
* [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.7
859
png_read_image(png_structp png_ptr, png_bytepp image)
861
png_uint_32 i,image_height;
865
png_debug(1, "in png_read_image\n");
867
#ifdef PNG_READ_INTERLACING_SUPPORTED
868
pass = png_set_interlace_handling(png_ptr);
870
if (png_ptr->interlaced)
872
"Cannot read interlaced image -- interlace handler disabled.");
877
image_height=png_ptr->height;
878
png_ptr->num_rows = image_height; /* Make sure this is set correctly */
880
for (j = 0; j < pass; j++)
883
for (i = 0; i < image_height; i++)
885
png_read_row(png_ptr, *rp, png_bytep_NULL);
890
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
892
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
893
/* Read the end of the PNG file. Will not read past the end of the
894
* file, will verify the end is accurate, and will read any comments
895
* or time information at the end of the file, if info is not NULL.
898
png_read_end(png_structp png_ptr, png_infop info_ptr)
900
png_byte chunk_length[4];
903
png_debug(1, "in png_read_end\n");
904
png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
908
#ifdef PNG_USE_LOCAL_ARRAYS
913
#if defined(PNG_READ_bKGD_SUPPORTED)
916
#if defined(PNG_READ_cHRM_SUPPORTED)
919
#if defined(PNG_READ_gAMA_SUPPORTED)
922
#if defined(PNG_READ_hIST_SUPPORTED)
925
#if defined(PNG_READ_iCCP_SUPPORTED)
928
#if defined(PNG_READ_iTXt_SUPPORTED)
931
#if defined(PNG_READ_oFFs_SUPPORTED)
934
#if defined(PNG_READ_pCAL_SUPPORTED)
937
#if defined(PNG_READ_pHYs_SUPPORTED)
940
#if defined(PNG_READ_sBIT_SUPPORTED)
943
#if defined(PNG_READ_sCAL_SUPPORTED)
946
#if defined(PNG_READ_sPLT_SUPPORTED)
949
#if defined(PNG_READ_sRGB_SUPPORTED)
952
#if defined(PNG_READ_tEXt_SUPPORTED)
955
#if defined(PNG_READ_tIME_SUPPORTED)
958
#if defined(PNG_READ_tRNS_SUPPORTED)
961
#if defined(PNG_READ_zTXt_SUPPORTED)
964
#endif /* PNG_GLOBAL_ARRAYS */
966
png_read_data(png_ptr, chunk_length, 4);
967
length = png_get_uint_31(png_ptr,chunk_length);
969
png_reset_crc(png_ptr);
970
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
972
png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);
974
if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
975
png_handle_IHDR(png_ptr, info_ptr, length);
976
else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
977
png_handle_IEND(png_ptr, info_ptr, length);
978
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
979
else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
981
if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
983
if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
984
png_error(png_ptr, "Too many IDAT's found");
987
png_ptr->mode |= PNG_AFTER_IDAT;
988
png_handle_unknown(png_ptr, info_ptr, length);
989
if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
990
png_ptr->mode |= PNG_HAVE_PLTE;
993
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
995
/* Zero length IDATs are legal after the last IDAT has been
996
* read, but not after other chunks have been read.
998
if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
999
png_error(png_ptr, "Too many IDAT's found");
1000
png_crc_finish(png_ptr, length);
1002
else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
1003
png_handle_PLTE(png_ptr, info_ptr, length);
1004
#if defined(PNG_READ_bKGD_SUPPORTED)
1005
else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
1006
png_handle_bKGD(png_ptr, info_ptr, length);
1008
#if defined(PNG_READ_cHRM_SUPPORTED)
1009
else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
1010
png_handle_cHRM(png_ptr, info_ptr, length);
1012
#if defined(PNG_READ_gAMA_SUPPORTED)
1013
else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
1014
png_handle_gAMA(png_ptr, info_ptr, length);
1016
#if defined(PNG_READ_hIST_SUPPORTED)
1017
else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
1018
png_handle_hIST(png_ptr, info_ptr, length);
1020
#if defined(PNG_READ_oFFs_SUPPORTED)
1021
else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
1022
png_handle_oFFs(png_ptr, info_ptr, length);
1024
#if defined(PNG_READ_pCAL_SUPPORTED)
1025
else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
1026
png_handle_pCAL(png_ptr, info_ptr, length);
1028
#if defined(PNG_READ_sCAL_SUPPORTED)
1029
else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
1030
png_handle_sCAL(png_ptr, info_ptr, length);
1032
#if defined(PNG_READ_pHYs_SUPPORTED)
1033
else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
1034
png_handle_pHYs(png_ptr, info_ptr, length);
1036
#if defined(PNG_READ_sBIT_SUPPORTED)
1037
else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
1038
png_handle_sBIT(png_ptr, info_ptr, length);
1040
#if defined(PNG_READ_sRGB_SUPPORTED)
1041
else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
1042
png_handle_sRGB(png_ptr, info_ptr, length);
1044
#if defined(PNG_READ_iCCP_SUPPORTED)
1045
else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
1046
png_handle_iCCP(png_ptr, info_ptr, length);
1048
#if defined(PNG_READ_sPLT_SUPPORTED)
1049
else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
1050
png_handle_sPLT(png_ptr, info_ptr, length);
1052
#if defined(PNG_READ_tEXt_SUPPORTED)
1053
else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
1054
png_handle_tEXt(png_ptr, info_ptr, length);
1056
#if defined(PNG_READ_tIME_SUPPORTED)
1057
else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
1058
png_handle_tIME(png_ptr, info_ptr, length);
1060
#if defined(PNG_READ_tRNS_SUPPORTED)
1061
else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
1062
png_handle_tRNS(png_ptr, info_ptr, length);
1064
#if defined(PNG_READ_zTXt_SUPPORTED)
1065
else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
1066
png_handle_zTXt(png_ptr, info_ptr, length);
1068
#if defined(PNG_READ_iTXt_SUPPORTED)
1069
else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
1070
png_handle_iTXt(png_ptr, info_ptr, length);
1073
png_handle_unknown(png_ptr, info_ptr, length);
1074
} while (!(png_ptr->mode & PNG_HAVE_IEND));
1076
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
1078
/* free all memory used by the read */
1080
png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1081
png_infopp end_info_ptr_ptr)
1083
png_structp png_ptr = NULL;
1084
png_infop info_ptr = NULL, end_info_ptr = NULL;
1085
#ifdef PNG_USER_MEM_SUPPORTED
1086
png_free_ptr free_fn;
1090
png_debug(1, "in png_destroy_read_struct\n");
1091
if (png_ptr_ptr != NULL)
1092
png_ptr = *png_ptr_ptr;
1094
if (info_ptr_ptr != NULL)
1095
info_ptr = *info_ptr_ptr;
1097
if (end_info_ptr_ptr != NULL)
1098
end_info_ptr = *end_info_ptr_ptr;
1100
#ifdef PNG_USER_MEM_SUPPORTED
1101
free_fn = png_ptr->free_fn;
1102
mem_ptr = png_ptr->mem_ptr;
1105
png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1107
if (info_ptr != NULL)
1109
#if defined(PNG_TEXT_SUPPORTED)
1110
png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1113
#ifdef PNG_USER_MEM_SUPPORTED
1114
png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1115
(png_voidp)mem_ptr);
1117
png_destroy_struct((png_voidp)info_ptr);
1119
*info_ptr_ptr = NULL;
1122
if (end_info_ptr != NULL)
1124
#if defined(PNG_READ_TEXT_SUPPORTED)
1125
png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1127
#ifdef PNG_USER_MEM_SUPPORTED
1128
png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1129
(png_voidp)mem_ptr);
1131
png_destroy_struct((png_voidp)end_info_ptr);
1133
*end_info_ptr_ptr = NULL;
1136
if (png_ptr != NULL)
1138
#ifdef PNG_USER_MEM_SUPPORTED
1139
png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1140
(png_voidp)mem_ptr);
1142
png_destroy_struct((png_voidp)png_ptr);
1144
*png_ptr_ptr = NULL;
1148
/* free all memory used by the read (old method) */
1150
png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
1152
#ifdef PNG_SETJMP_SUPPORTED
1155
png_error_ptr error_fn;
1156
png_error_ptr warning_fn;
1157
png_voidp error_ptr;
1158
#ifdef PNG_USER_MEM_SUPPORTED
1159
png_free_ptr free_fn;
1162
png_debug(1, "in png_read_destroy\n");
1163
if (info_ptr != NULL)
1164
png_info_destroy(png_ptr, info_ptr);
1166
if (end_info_ptr != NULL)
1167
png_info_destroy(png_ptr, end_info_ptr);
1169
png_free(png_ptr, png_ptr->zbuf);
1170
png_free(png_ptr, png_ptr->big_row_buf);
1171
png_free(png_ptr, png_ptr->prev_row);
1172
#if defined(PNG_READ_DITHER_SUPPORTED)
1173
png_free(png_ptr, png_ptr->palette_lookup);
1174
png_free(png_ptr, png_ptr->dither_index);
1176
#if defined(PNG_READ_GAMMA_SUPPORTED)
1177
png_free(png_ptr, png_ptr->gamma_table);
1179
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
1180
png_free(png_ptr, png_ptr->gamma_from_1);
1181
png_free(png_ptr, png_ptr->gamma_to_1);
1183
#ifdef PNG_FREE_ME_SUPPORTED
1184
if (png_ptr->free_me & PNG_FREE_PLTE)
1185
png_zfree(png_ptr, png_ptr->palette);
1186
png_ptr->free_me &= ~PNG_FREE_PLTE;
1188
if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
1189
png_zfree(png_ptr, png_ptr->palette);
1190
png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
1192
#if defined(PNG_tRNS_SUPPORTED) || \
1193
defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1194
#ifdef PNG_FREE_ME_SUPPORTED
1195
if (png_ptr->free_me & PNG_FREE_TRNS)
1196
png_free(png_ptr, png_ptr->trans);
1197
png_ptr->free_me &= ~PNG_FREE_TRNS;
1199
if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
1200
png_free(png_ptr, png_ptr->trans);
1201
png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
1204
#if defined(PNG_READ_hIST_SUPPORTED)
1205
#ifdef PNG_FREE_ME_SUPPORTED
1206
if (png_ptr->free_me & PNG_FREE_HIST)
1207
png_free(png_ptr, png_ptr->hist);
1208
png_ptr->free_me &= ~PNG_FREE_HIST;
1210
if (png_ptr->flags & PNG_FLAG_FREE_HIST)
1211
png_free(png_ptr, png_ptr->hist);
1212
png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
1215
#if defined(PNG_READ_GAMMA_SUPPORTED)
1216
if (png_ptr->gamma_16_table != NULL)
1219
int istop = (1 << (8 - png_ptr->gamma_shift));
1220
for (i = 0; i < istop; i++)
1222
png_free(png_ptr, png_ptr->gamma_16_table[i]);
1224
png_free(png_ptr, png_ptr->gamma_16_table);
1226
#if defined(PNG_READ_BACKGROUND_SUPPORTED)
1227
if (png_ptr->gamma_16_from_1 != NULL)
1230
int istop = (1 << (8 - png_ptr->gamma_shift));
1231
for (i = 0; i < istop; i++)
1233
png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1235
png_free(png_ptr, png_ptr->gamma_16_from_1);
1237
if (png_ptr->gamma_16_to_1 != NULL)
1240
int istop = (1 << (8 - png_ptr->gamma_shift));
1241
for (i = 0; i < istop; i++)
1243
png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1245
png_free(png_ptr, png_ptr->gamma_16_to_1);
1249
#if defined(PNG_TIME_RFC1123_SUPPORTED)
1250
png_free(png_ptr, png_ptr->time_buffer);
1253
inflateEnd(&png_ptr->zstream);
1254
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1255
png_free(png_ptr, png_ptr->save_buffer);
1258
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1259
#ifdef PNG_TEXT_SUPPORTED
1260
png_free(png_ptr, png_ptr->current_text);
1261
#endif /* PNG_TEXT_SUPPORTED */
1262
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1264
/* Save the important info out of the png_struct, in case it is
1267
#ifdef PNG_SETJMP_SUPPORTED
1268
png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
1271
error_fn = png_ptr->error_fn;
1272
warning_fn = png_ptr->warning_fn;
1273
error_ptr = png_ptr->error_ptr;
1274
#ifdef PNG_USER_MEM_SUPPORTED
1275
free_fn = png_ptr->free_fn;
1278
png_memset(png_ptr, 0, png_sizeof (png_struct));
1280
png_ptr->error_fn = error_fn;
1281
png_ptr->warning_fn = warning_fn;
1282
png_ptr->error_ptr = error_ptr;
1283
#ifdef PNG_USER_MEM_SUPPORTED
1284
png_ptr->free_fn = free_fn;
1287
#ifdef PNG_SETJMP_SUPPORTED
1288
png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
1294
png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1296
png_ptr->read_row_fn = read_row_fn;
1300
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
1301
#if defined(PNG_INFO_IMAGE_SUPPORTED)
1303
png_read_png(png_structp png_ptr, png_infop info_ptr,
1309
#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
1310
/* invert the alpha channel from opacity to transparency
1312
if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1313
png_set_invert_alpha(png_ptr);
1316
/* png_read_info() gives us all of the information from the
1317
* PNG file before the first IDAT (image data chunk).
1319
png_read_info(png_ptr, info_ptr);
1320
if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1321
png_error(png_ptr,"Image is too high to process with png_read_png()");
1323
/* -------------- image transformations start here ------------------- */
1325
#if defined(PNG_READ_16_TO_8_SUPPORTED)
1326
/* tell libpng to strip 16 bit/color files down to 8 bits per color
1328
if (transforms & PNG_TRANSFORM_STRIP_16)
1329
png_set_strip_16(png_ptr);
1332
#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1333
/* Strip alpha bytes from the input data without combining with
1334
* the background (not recommended).
1336
if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1337
png_set_strip_alpha(png_ptr);
1340
#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1341
/* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1342
* byte into separate bytes (useful for paletted and grayscale images).
1344
if (transforms & PNG_TRANSFORM_PACKING)
1345
png_set_packing(png_ptr);
1348
#if defined(PNG_READ_PACKSWAP_SUPPORTED)
1349
/* Change the order of packed pixels to least significant bit first
1350
* (not useful if you are using png_set_packing).
1352
if (transforms & PNG_TRANSFORM_PACKSWAP)
1353
png_set_packswap(png_ptr);
1356
#if defined(PNG_READ_EXPAND_SUPPORTED)
1357
/* Expand paletted colors into true RGB triplets
1358
* Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1359
* Expand paletted or RGB images with transparency to full alpha
1360
* channels so the data will be available as RGBA quartets.
1362
if (transforms & PNG_TRANSFORM_EXPAND)
1363
if ((png_ptr->bit_depth < 8) ||
1364
(png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1365
(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1366
png_set_expand(png_ptr);
1369
/* We don't handle background color or gamma transformation or dithering.
1372
#if defined(PNG_READ_INVERT_SUPPORTED)
1373
/* invert monochrome files to have 0 as white and 1 as black
1375
if (transforms & PNG_TRANSFORM_INVERT_MONO)
1376
png_set_invert_mono(png_ptr);
1379
#if defined(PNG_READ_SHIFT_SUPPORTED)
1380
/* If you want to shift the pixel values from the range [0,255] or
1381
* [0,65535] to the original [0,7] or [0,31], or whatever range the
1382
* colors were originally in:
1384
if ((transforms & PNG_TRANSFORM_SHIFT)
1385
&& png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1387
png_color_8p sig_bit;
1389
png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1390
png_set_shift(png_ptr, sig_bit);
1394
#if defined(PNG_READ_BGR_SUPPORTED)
1395
/* flip the RGB pixels to BGR (or RGBA to BGRA)
1397
if (transforms & PNG_TRANSFORM_BGR)
1398
png_set_bgr(png_ptr);
1401
#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
1402
/* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1404
if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1405
png_set_swap_alpha(png_ptr);
1408
#if defined(PNG_READ_SWAP_SUPPORTED)
1409
/* swap bytes of 16 bit files to least significant byte first
1411
if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1412
png_set_swap(png_ptr);
1415
/* We don't handle adding filler bytes */
1417
/* Optional call to gamma correct and add the background to the palette
1418
* and update info structure. REQUIRED if you are expecting libpng to
1419
* update the palette for you (i.e., you selected such a transform above).
1421
png_read_update_info(png_ptr, info_ptr);
1423
/* -------------- image transformations end here ------------------- */
1425
#ifdef PNG_FREE_ME_SUPPORTED
1426
png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1428
if(info_ptr->row_pointers == NULL)
1430
info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1431
info_ptr->height * png_sizeof(png_bytep));
1432
#ifdef PNG_FREE_ME_SUPPORTED
1433
info_ptr->free_me |= PNG_FREE_ROWS;
1435
for (row = 0; row < (int)info_ptr->height; row++)
1437
info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1438
png_get_rowbytes(png_ptr, info_ptr));
1442
png_read_image(png_ptr, info_ptr->row_pointers);
1443
info_ptr->valid |= PNG_INFO_IDAT;
1445
/* read rest of file, and get additional chunks in info_ptr - REQUIRED */
1446
png_read_end(png_ptr, info_ptr);
1448
if(transforms == 0 || params == NULL)
1449
/* quiet compiler warnings */ return;
1453
#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */