Line data    Source code

       1             : /*
       2             :  * Copyright 2006 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 SkComposeShader_DEFINED
       9             : #define SkComposeShader_DEFINED
      10             : 
      11             : #include "SkShader.h"
      12             : #include "SkBlendMode.h"
      13             : 
      14             : ///////////////////////////////////////////////////////////////////////////////////////////
      15             : 
      16             : /** \class SkComposeShader
      17             :     This subclass of shader returns the composition of two other shaders, combined by
      18             :     a xfermode.
      19             : */
      20           0 : class SK_API SkComposeShader : public SkShader {
      21             : public:
      22             :     /** Create a new compose shader, given shaders A, B, and a combining xfermode mode.
      23             :         When the xfermode is called, it will be given the result from shader A as its
      24             :         "dst", and the result from shader B as its "src".
      25             :         mode->xfer32(sA_result, sB_result, ...)
      26             :         @param shaderA  The colors from this shader are seen as the "dst" by the xfermode
      27             :         @param shaderB  The colors from this shader are seen as the "src" by the xfermode
      28             :         @param mode     The xfermode that combines the colors from the two shaders. If mode
      29             :                         is null, then SRC_OVER is assumed.
      30             :     */
      31           0 :     SkComposeShader(sk_sp<SkShader> sA, sk_sp<SkShader> sB, SkBlendMode mode)
      32           0 :         : fShaderA(std::move(sA))
      33           0 :         , fShaderB(std::move(sB))
      34           0 :         , fMode(mode)
      35           0 :     {}
      36             : 
      37             : #if SK_SUPPORT_GPU
      38             :     sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override;
      39             : #endif
      40             : 
      41           0 :     class ComposeShaderContext : public SkShader::Context {
      42             :     public:
      43             :         // When this object gets destroyed, it will call contextA and contextB's destructor
      44             :         // but it will NOT free the memory.
      45             :         ComposeShaderContext(const SkComposeShader&, const ContextRec&,
      46             :                              SkShader::Context* contextA, SkShader::Context* contextB);
      47             : 
      48             :         void shadeSpan(int x, int y, SkPMColor[], int count) override;
      49             : 
      50             :     private:
      51             :         SkShader::Context* fShaderContextA;
      52             :         SkShader::Context* fShaderContextB;
      53             : 
      54             :         typedef SkShader::Context INHERITED;
      55             :     };
      56             : 
      57             : #ifdef SK_DEBUG
      58             :     SkShader* getShaderA() { return fShaderA.get(); }
      59             :     SkShader* getShaderB() { return fShaderB.get(); }
      60             : #endif
      61             : 
      62             :     bool asACompose(ComposeRec* rec) const override;
      63             : 
      64             :     SK_TO_STRING_OVERRIDE()
      65           0 :     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkComposeShader)
      66             : 
      67             : protected:
      68             :     SkComposeShader(SkReadBuffer&);
      69             :     void flatten(SkWriteBuffer&) const override;
      70             :     Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override;
      71             : 
      72             : private:
      73             :     sk_sp<SkShader>     fShaderA;
      74             :     sk_sp<SkShader>     fShaderB;
      75             :     SkBlendMode         fMode;
      76             : 
      77             :     typedef SkShader INHERITED;
      78             : };
      79             : 
      80             : #endif