1/*
2 * Copyright 2015 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7#ifndef SkSampledCodec_DEFINED
8#define SkSampledCodec_DEFINED
9
10#include "SkAndroidCodec.h"
11#include "SkCodec.h"
12
13/**
14 *  This class implements the functionality of SkAndroidCodec.  Scaling will
15 *  be provided by sampling if it cannot be provided by fCodec.
16 */
17class SkSampledCodec : public SkAndroidCodec {
18public:
19    explicit SkSampledCodec(SkCodec*, ExifOrientationBehavior);
20
21    ~SkSampledCodec() override {}
22
23protected:
24
25    SkISize onGetSampledDimensions(int sampleSize) const override;
26
27    bool onGetSupportedSubset(SkIRect* desiredSubset) const override { return true; }
28
29    SkCodec::Result onGetAndroidPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
30            const AndroidOptions& options) override;
31
32private:
33    /**
34     *  Find the best way to account for native scaling.
35     *
36     *  Return a size that fCodec can scale to, and adjust sampleSize to finish scaling.
37     *
38     *  @param sampleSize As an input, the requested sample size.
39     *                    As an output, sampling needed after letting fCodec
40     *                    scale to the returned dimensions.
41     *  @param nativeSampleSize Optional output parameter. Will be set to the
42     *                          effective sample size done by fCodec.
43     *  @return SkISize The size that fCodec should scale to.
44     */
45    SkISize accountForNativeScaling(int* sampleSize, int* nativeSampleSize = nullptr) const;
46
47    /**
48     *  This fulfills the same contract as onGetAndroidPixels().
49     *
50     *  We call this function from onGetAndroidPixels() if we have determined
51     *  that fCodec does not support the requested scale, and we need to
52     *  provide the scale by sampling.
53     */
54    SkCodec::Result sampledDecode(const SkImageInfo& info, void* pixels, size_t rowBytes,
55            const AndroidOptions& options);
56
57    typedef SkAndroidCodec INHERITED;
58};
59#endif // SkSampledCodec_DEFINED
60