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
21extern "C" {
22#endif
23
24struct VP8LDecoder;  // Defined in dec/vp8li.h.
25
26typedef struct ALPHDecoder ALPHDecoder;
27struct 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.
44ALPHDecoder* ALPHNew(void);
45
46// Clears and deallocates an alpha decoder instance.
47void ALPHDelete(ALPHDecoder* const dec);
48
49//------------------------------------------------------------------------------
50
51#ifdef __cplusplus
52}    // extern "C"
53#endif
54
55#endif  /* WEBP_DEC_ALPHAI_H_ */
56