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