1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SkXfermode_DEFINED 18 #define SkXfermode_DEFINED 19 20 #include "SkFlattenable.h" 21 #include "SkColor.h" 22 23 /** \class SkXfermode 24 25 SkXfermode is the base class for objects that are called to implement custom 26 "transfer-modes" in the drawing pipeline. The static function Create(Modes) 27 can be called to return an instance of any of the predefined subclasses as 28 specified in the Modes enum. When an SkXfermode is assigned to an SkPaint, 29 then objects drawn with that paint have the xfermode applied. 30 */ 31 class SkXfermode : public SkFlattenable { 32 public: SkXfermode()33 SkXfermode() {} 34 35 virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count, 36 const SkAlpha aa[]); 37 virtual void xfer16(uint16_t dst[], const SkPMColor src[], int count, 38 const SkAlpha aa[]); 39 virtual void xfer4444(uint16_t dst[], const SkPMColor src[], int count, 40 const SkAlpha aa[]); 41 virtual void xferA8(SkAlpha dst[], const SkPMColor src[], int count, 42 const SkAlpha aa[]); 43 44 enum Coeff { 45 kZero_Coeff, 46 kOne_Coeff, 47 kSC_Coeff, 48 kISC_Coeff, 49 kDC_Coeff, 50 kIDC_Coeff, 51 kSA_Coeff, 52 kISA_Coeff, 53 kDA_Coeff, 54 kIDA_Coeff, 55 56 kCoeffCount 57 }; 58 virtual bool asCoeff(Coeff* src, Coeff* dst); 59 60 protected: SkXfermode(SkFlattenableReadBuffer & rb)61 SkXfermode(SkFlattenableReadBuffer& rb) : SkFlattenable(rb) {} 62 63 /** The default implementation of xfer32/xfer16/xferA8 in turn call this 64 method, 1 color at a time (upscaled to a SkPMColor). The default 65 implmentation of this method just returns dst. If performance is 66 important, your subclass should override xfer32/xfer16/xferA8 directly. 67 68 This method will not be called directly by the client, so it need not 69 be implemented if your subclass has overridden xfer32/xfer16/xferA8 70 */ 71 virtual SkPMColor xferColor(SkPMColor src, SkPMColor dst); 72 73 private: 74 typedef SkFlattenable INHERITED; 75 }; 76 77 /////////////////////////////////////////////////////////////////////////////// 78 79 /** \class SkProcXfermode 80 81 SkProcXfermode is a xfermode that applies the specified proc to its colors. 82 This class is not exported to java. 83 */ 84 class SkProcXfermode : public SkXfermode { 85 public: SkProcXfermode(SkXfermodeProc proc)86 SkProcXfermode(SkXfermodeProc proc) : fProc(proc) {} 87 88 // overrides from SkXfermode 89 virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count, 90 const SkAlpha aa[]); 91 virtual void xfer16(uint16_t dst[], const SkPMColor src[], int count, 92 const SkAlpha aa[]); 93 virtual void xfer4444(uint16_t dst[], const SkPMColor src[], int count, 94 const SkAlpha aa[]); 95 virtual void xferA8(SkAlpha dst[], const SkPMColor src[], int count, 96 const SkAlpha aa[]); 97 98 // overrides from SkFlattenable getFactory()99 virtual Factory getFactory() { return CreateProc; } 100 virtual void flatten(SkFlattenableWriteBuffer&); 101 102 protected: 103 SkProcXfermode(SkFlattenableReadBuffer&); 104 105 private: 106 SkXfermodeProc fProc; 107 CreateProc(SkFlattenableReadBuffer & buffer)108 static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) { 109 return SkNEW_ARGS(SkProcXfermode, (buffer)); } 110 111 typedef SkXfermode INHERITED; 112 }; 113 114 #endif 115 116