1 /* 2 * Copyright 2011 Google Inc. 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 SkEmptyShader_DEFINED 9 #define SkEmptyShader_DEFINED 10 11 #include "SkShader.h" 12 13 // TODO: move this to private, as there is a public factory on SkShader 14 15 /** 16 * \class SkEmptyShader 17 * A Shader that always draws nothing. Its createContext always returns NULL. 18 */ 19 class SK_API SkEmptyShader : public SkShader { 20 public: SkEmptyShader()21 SkEmptyShader() {} 22 contextSize()23 virtual size_t contextSize() const SK_OVERRIDE { 24 // Even though createContext returns NULL we have to return a value of at least 25 // sizeof(SkShader::Context) to satisfy SkSmallAllocator. 26 return sizeof(SkShader::Context); 27 } 28 29 SK_TO_STRING_OVERRIDE() SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkEmptyShader)30 SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkEmptyShader) 31 32 protected: 33 SkEmptyShader(SkReadBuffer& buffer) : INHERITED(buffer) {} 34 onCreateContext(const ContextRec &,void *)35 virtual SkShader::Context* onCreateContext(const ContextRec&, void*) const SK_OVERRIDE { 36 return NULL; 37 } 38 39 private: 40 typedef SkShader INHERITED; 41 }; 42 43 #endif 44