repositories / deb_ffmpeg.git / blame
| Commit | Line | Data |
|---|---|---|
| 2ba45a60 DM |
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 | #include "avcodec.h" | |
| 22 | #include "png.h" | |
| 23 | ||
| 24 | /* Mask to determine which y pixels are valid in a pass */ | |
| 25 | const uint8_t ff_png_pass_ymask[NB_PASSES] = { | |
| 26 | 0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, | |
| 27 | }; | |
| 28 | ||
| 29 | /* minimum x value */ | |
| 30 | static const uint8_t ff_png_pass_xmin[NB_PASSES] = { | |
| 31 | 0, 4, 0, 2, 0, 1, 0 | |
| 32 | }; | |
| 33 | ||
| 34 | /* x shift to get row width */ | |
| 35 | static const uint8_t ff_png_pass_xshift[NB_PASSES] = { | |
| 36 | 3, 3, 2, 2, 1, 1, 0 | |
| 37 | }; | |
| 38 | ||
| 39 | void *ff_png_zalloc(void *opaque, unsigned int items, unsigned int size) | |
| 40 | { | |
| 41 | return av_mallocz_array(items, size); | |
| 42 | } | |
| 43 | ||
| 44 | void ff_png_zfree(void *opaque, void *ptr) | |
| 45 | { | |
| 46 | av_free(ptr); | |
| 47 | } | |
| 48 | ||
| 49 | int ff_png_get_nb_channels(int color_type) | |
| 50 | { | |
| 51 | int channels; | |
| 52 | channels = 1; | |
| 53 | if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) == | |
| 54 | PNG_COLOR_MASK_COLOR) | |
| 55 | channels = 3; | |
| 56 | if (color_type & PNG_COLOR_MASK_ALPHA) | |
| 57 | channels++; | |
| 58 | return channels; | |
| 59 | } | |
| 60 | ||
| 61 | /* compute the row size of an interleaved pass */ | |
| 62 | int ff_png_pass_row_size(int pass, int bits_per_pixel, int width) | |
| 63 | { | |
| 64 | int shift, xmin, pass_width; | |
| 65 | ||
| 66 | xmin = ff_png_pass_xmin[pass]; | |
| 67 | if (width <= xmin) | |
| 68 | return 0; | |
| 69 | shift = ff_png_pass_xshift[pass]; | |
| 70 | pass_width = (width - xmin + (1 << shift) - 1) >> shift; | |
| 71 | return (pass_width * bits_per_pixel + 7) >> 3; | |
| 72 | } |