third_party/libwebp/dec/alphai.h

   1 // Copyright 2013 Google Inc. All Rights Reserved.
   2 //
   3 // Use of this source code is governed by a BSD-style license
   4 // that can be found in the COPYING file in the root of the source
   5 // tree. An additional intellectual property rights grant can be found
   6 // in the file PATENTS. All contributing project authors may
   7 // be found in the AUTHORS file in the root of the source tree.
   8 // -----------------------------------------------------------------------------
   9 //
  10 // Alpha decoder: internal header.
  11 //
  12 // Author: Urvang (urvang@google.com)
  13
  14 #ifndef WEBP_DEC_ALPHAI_H_
  15 #define WEBP_DEC_ALPHAI_H_
  16
  17 #include "./webpi.h"
  18 #include "../utils/filters.h"
  19
  20 #ifdef __cplusplus
  21 extern "C" {
  22 #endif
  23
  24 struct VP8LDecoder;  // Defined in dec/vp8li.h.
  25
  26 typedef struct ALPHDecoder ALPHDecoder;
  27 struct ALPHDecoder {
  28   int width_;
  29   int height_;
  30   int method_;
  31   WEBP_FILTER_TYPE filter_;
  32   int pre_processing_;
  33   struct VP8LDecoder* vp8l_dec_;
  34   VP8Io io_;
  35   int use_8b_decode;  // Although alpha channel requires only 1 byte per
  36                       // pixel, sometimes VP8LDecoder may need to allocate
  37                       // 4 bytes per pixel internally during decode.
  38 };
  39
  40 //------------------------------------------------------------------------------
  41 // internal functions. Not public.
  42
  43 // Allocates a new alpha decoder instance.
  44 ALPHDecoder* ALPHNew(void);
  45
  46 // Clears and deallocates an alpha decoder instance.
  47 void ALPHDelete(ALPHDecoder* const dec);
  48
  49 //------------------------------------------------------------------------------
  50
  51 #ifdef __cplusplus
  52 }    // extern "C"
  53 #endif
  54
  55 #endif  /* WEBP_DEC_ALPHAI_H_ */