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      1 /*
      2  * Copyright 2007 The Android Open Source Project
      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 
      8 #ifndef SkColorShader_DEFINED
      9 #define SkColorShader_DEFINED
     10 
     11 #include "SkShader.h"
     12 #include "SkPM4f.h"
     13 
     14 /** \class SkColorShader
     15     A Shader that represents a single color. In general, this effect can be
     16     accomplished by just using the color field on the paint, but if an
     17     actual shader object is needed, this provides that feature.
     18 */
     19 class SK_API SkColorShader : public SkShader {
     20 public:
     21     /** Create a ColorShader that ignores the color in the paint, and uses the
     22         specified color. Note: like all shaders, at draw time the paint's alpha
     23         will be respected, and is applied to the specified color.
     24     */
     25     explicit SkColorShader(SkColor c);
     26 
     27     bool isOpaque() const override;
     28     bool isConstant() const override { return true; }
     29 
     30     class ColorShaderContext : public SkShader::Context {
     31     public:
     32         ColorShaderContext(const SkColorShader& shader, const ContextRec&);
     33 
     34         uint32_t getFlags() const override;
     35         void shadeSpan(int x, int y, SkPMColor span[], int count) override;
     36         void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) override;
     37         void shadeSpan4f(int x, int y, SkPM4f[], int count) override;
     38 
     39     protected:
     40         bool onChooseBlitProcs(const SkImageInfo&, BlitState*) override;
     41 
     42     private:
     43         SkPM4f      fPM4f;
     44         SkPMColor   fPMColor;
     45         uint32_t    fFlags;
     46 
     47         typedef SkShader::Context INHERITED;
     48     };
     49 
     50     GradientType asAGradient(GradientInfo* info) const override;
     51 
     52 #if SK_SUPPORT_GPU
     53     sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override;
     54 #endif
     55 
     56     SK_TO_STRING_OVERRIDE()
     57     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkColorShader)
     58 
     59 protected:
     60     SkColorShader(SkReadBuffer&);
     61     void flatten(SkWriteBuffer&) const override;
     62     Context* onMakeContext(const ContextRec&, SkArenaAlloc* storage) const override;
     63 
     64     bool onAsLuminanceColor(SkColor* lum) const override {
     65         *lum = fColor;
     66         return true;
     67     }
     68 
     69     bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*,
     70                         const SkMatrix& ctm, const SkPaint&, const SkMatrix*) const override;
     71 
     72 private:
     73     SkColor fColor;
     74 
     75     typedef SkShader INHERITED;
     76 };
     77 
     78 class SkColor4Shader : public SkShader {
     79 public:
     80     SkColor4Shader(const SkColor4f&, sk_sp<SkColorSpace>);
     81 
     82     bool isOpaque() const override {
     83         return SkColorGetA(fCachedByteColor) == 255;
     84     }
     85     bool isConstant() const override { return true; }
     86 
     87     class Color4Context : public SkShader::Context {
     88     public:
     89         Color4Context(const SkColor4Shader& shader, const ContextRec&);
     90 
     91         uint32_t getFlags() const override;
     92         void shadeSpan(int x, int y, SkPMColor span[], int count) override;
     93         void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) override;
     94         void shadeSpan4f(int x, int y, SkPM4f[], int count) override;
     95 
     96     protected:
     97         bool onChooseBlitProcs(const SkImageInfo&, BlitState*) override;
     98 
     99     private:
    100         SkPM4f      fPM4f;
    101         SkPMColor   fPMColor;
    102         uint32_t    fFlags;
    103 
    104         typedef SkShader::Context INHERITED;
    105     };
    106 
    107     GradientType asAGradient(GradientInfo* info) const override;
    108 
    109 #if SK_SUPPORT_GPU
    110     sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override;
    111 #endif
    112 
    113     SK_TO_STRING_OVERRIDE()
    114     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkColorShader)
    115 
    116 protected:
    117     SkColor4Shader(SkReadBuffer&);
    118     void flatten(SkWriteBuffer&) const override;
    119     Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override;
    120     bool onAsLuminanceColor(SkColor* lum) const override {
    121         *lum = fCachedByteColor;
    122         return true;
    123     }
    124     bool onAppendStages(SkRasterPipeline*, SkColorSpace*, SkArenaAlloc*,
    125                         const SkMatrix& ctm, const SkPaint&, const SkMatrix*) const override;
    126 
    127 private:
    128     sk_sp<SkColorSpace> fColorSpace;
    129     const SkColor4f     fColor4;
    130     const SkColor       fCachedByteColor;
    131 
    132     typedef SkShader INHERITED;
    133 };
    134 
    135 #endif
    136