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png.h
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1 /*
2  * PNG image format
3  * Copyright (c) 2003 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVCODEC_PNG_H
23 #define AVCODEC_PNG_H
24 
25 #include <stdint.h>
26 
27 #define PNG_COLOR_MASK_PALETTE 1
28 #define PNG_COLOR_MASK_COLOR 2
29 #define PNG_COLOR_MASK_ALPHA 4
30 
31 #define PNG_COLOR_TYPE_GRAY 0
32 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
33 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
34 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
35 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
36 
37 #define PNG_FILTER_TYPE_LOCO 64
38 #define PNG_FILTER_VALUE_NONE 0
39 #define PNG_FILTER_VALUE_SUB 1
40 #define PNG_FILTER_VALUE_UP 2
41 #define PNG_FILTER_VALUE_AVG 3
42 #define PNG_FILTER_VALUE_PAETH 4
43 #define PNG_FILTER_VALUE_MIXED 5
44 
45 #define PNG_IHDR 0x0001
46 #define PNG_IDAT 0x0002
47 #define PNG_ALLIMAGE 0x0004
48 #define PNG_PLTE 0x0008
49 
50 #define NB_PASSES 7
51 
52 #define PNGSIG 0x89504e470d0a1a0a
53 #define MNGSIG 0x8a4d4e470d0a1a0a
54 
55 /* Mask to determine which y pixels are valid in a pass */
56 extern const uint8_t ff_png_pass_ymask[NB_PASSES];
57 
58 void *ff_png_zalloc(void *opaque, unsigned int items, unsigned int size);
59 
60 void ff_png_zfree(void *opaque, void *ptr);
61 
62 int ff_png_get_nb_channels(int color_type);
63 
64 /* compute the row size of an interleaved pass */
65 int ff_png_pass_row_size(int pass, int bits_per_pixel, int width);
66 
67 void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp);
68 
69 #endif /* AVCODEC_PNG_H */