1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef SKIA_EXT_LAZY_PIXEL_REF_H_
6#define SKIA_EXT_LAZY_PIXEL_REF_H_
7
8#include "third_party/skia/include/core/SkPixelRef.h"
9#include "third_party/skia/include/core/SkRect.h"
10
11namespace skia {
12
13// This class extends SkPixelRef to facilitate lazy image decoding on the impl
14// thread.
15class SK_API LazyPixelRef : public SkPixelRef {
16 public:
17  explicit LazyPixelRef(const SkImageInfo& info);
18  virtual ~LazyPixelRef();
19
20  struct PrepareParams {
21    // Clipping rect for this pixel ref.
22    SkIRect clip_rect;
23  };
24
25  // Request the ImageDecodingStore to prepare image decoding for the
26  // given clipping rect. Returns true is succeeded, or false otherwise.
27  virtual bool PrepareToDecode(const PrepareParams& params) = 0;
28
29  // Returns true if this pixel ref is already in the ImageDecodingStore's
30  // cache, false otherwise. Much cheaper than PrepareToDecode().
31  virtual bool MaybeDecoded() = 0;
32
33  // Start decoding the image.
34  virtual void Decode() = 0;
35};
36
37}  // namespace skia
38
39#endif  // SKIA_EXT_LAZY_PIXEL_REF_H_
40