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/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkScaledCodec_DEFINED
#define SkScaledCodec_DEFINED
#include "SkCodec.h"
class SkStream;
/**
* This class implements scaling, by sampling scanlines in the y direction.
* x-wise sampling is implemented in the swizzler, when getScanlines() is called.
*/
class SkScaledCodec : public SkCodec {
public:
static SkCodec* NewFromStream(SkStream*);
static SkCodec* NewFromData(SkData*);
virtual ~SkScaledCodec();
/**
* returns whether a destination's dimensions are supported for down sampling
*/
static bool DimensionsSupportedForSampling(const SkImageInfo& srcInfo,
const SkImageInfo& dstInfo) {
// heights must be equal as no native y sampling is supported
if (dstInfo.height() != srcInfo.height()) {
return false;
}
// only support down sampling, dstWidth cannot be larger that srcWidth
if(dstInfo.width() > srcInfo.width()) {
return false;
}
return true;
}
static void ComputeSampleSize(const SkImageInfo& dstInfo, const SkImageInfo& srcInfo,
int* sampleSizeX, int* sampleSizeY);
protected:
/**
* Recommend a set of destination dimensions given a requested scale
*/
SkISize onGetScaledDimensions(float desiredScale) const override;
Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, SkPMColor*, int*)
override;
SkEncodedFormat onGetEncodedFormat() const override {
return fCodec->getEncodedFormat();
}
bool onReallyHasAlpha() const override {
return fCodec->reallyHasAlpha();
}
private:
SkAutoTDelete<SkCodec> fCodec;
explicit SkScaledCodec(SkCodec*);
typedef SkCodec INHERITED;
};
#endif // SkScaledCodec_DEFINED
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