png.h 2.31 KB
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/*
 * PNG image format
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 * Copyright (c) 2003 Fabrice Bellard
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

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#ifndef AVCODEC_PNG_H
#define AVCODEC_PNG_H
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#include <stdint.h>

#define PNG_COLOR_MASK_PALETTE    1
#define PNG_COLOR_MASK_COLOR      2
#define PNG_COLOR_MASK_ALPHA      4

#define PNG_COLOR_TYPE_GRAY 0
#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)

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#define PNG_FILTER_TYPE_LOCO   64
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#define PNG_FILTER_VALUE_NONE  0
#define PNG_FILTER_VALUE_SUB   1
#define PNG_FILTER_VALUE_UP    2
#define PNG_FILTER_VALUE_AVG   3
#define PNG_FILTER_VALUE_PAETH 4
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#define PNG_FILTER_VALUE_MIXED 5
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#define PNG_IHDR      0x0001
#define PNG_IDAT      0x0002
#define PNG_ALLIMAGE  0x0004
#define PNG_PLTE      0x0008

#define NB_PASSES 7

extern const uint8_t ff_pngsig[8];
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extern const uint8_t ff_mngsig[8];
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/* Mask to determine which y pixels are valid in a pass */
extern const uint8_t ff_png_pass_ymask[NB_PASSES];

/* Mask to determine which pixels are valid in a pass */
extern const uint8_t ff_png_pass_mask[NB_PASSES];

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void *ff_png_zalloc(void *opaque, unsigned int items, unsigned int size);
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void ff_png_zfree(void *opaque, void *ptr);
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int ff_png_get_nb_channels(int color_type);
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/* compute the row size of an interleaved pass */
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int ff_png_pass_row_size(int pass, int bits_per_pixel, int width);
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void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp);

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#endif /* AVCODEC_PNG_H */