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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkLumaColorFilter_DEFINED
#define SkLumaColorFilter_DEFINED
#include "SkColorFilter.h"
#include "SkRefCnt.h"
class SkRasterPipeline;
/**
* Luminance-to-alpha color filter, as defined in
* http://www.w3.org/TR/SVG/masking.html#Masking
* http://www.w3.org/TR/css-masking/#MaskValues
*
* The resulting color is black with transparency equal to the
* luminance value modulated by alpha:
*
* C' = [ Lum * a, 0, 0, 0 ]
*
*/
class SK_API SkLumaColorFilter : public SkColorFilter {
public:
static sk_sp<SkColorFilter> Make();
#if SK_SUPPORT_GPU
sk_sp<GrFragmentProcessor> asFragmentProcessor(GrContext*, SkColorSpace*) const override;
#endif
SK_TO_STRING_OVERRIDE()
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLumaColorFilter)
protected:
void flatten(SkWriteBuffer&) const override;
private:
SkLumaColorFilter();
void onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*,
bool shaderIsOpaque) const override;
typedef SkColorFilter INHERITED;
};
#endif