/*
  * PNG image format

  * Copyright (c) 2003 Fabrice Bellard

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * 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.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * 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
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #ifndef AVCODEC_PNG_H
 #define AVCODEC_PNG_H

 
 #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)
 

 #define PNG_FILTER_TYPE_LOCO   64

 #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

 #define PNG_FILTER_VALUE_MIXED 5

 
 #define NB_PASSES 7
 

 #define PNGSIG 0x89504e470d0a1a0a
 #define MNGSIG 0x8a4d4e470d0a1a0a

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

 void *ff_png_zalloc(void *opaque, unsigned int items, unsigned int size);

 void ff_png_zfree(void *opaque, void *ptr);

 int ff_png_get_nb_channels(int color_type);

 
 /* compute the row size of an interleaved pass */

 int ff_png_pass_row_size(int pass, int bits_per_pixel, int width);

 void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp);
 

 #endif /* AVCODEC_PNG_H */