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 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 SkComposeShader(sk_sp<SkShader> sA, sk_sp<SkShader> sB, SkBlendMode mode) 32 : fShaderA(std::move(sA)) 33 , fShaderB(std::move(sB)) 34 , fMode(mode) 35 {} 36 37 #if SK_SUPPORT_GPU 38 sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override; 39 #endif 40 41 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 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 81
