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ffmpeg-4.2.2/libavcodec/png.h 2.09 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * 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 */