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 SkColorFilter_DEFINED 18 #define SkColorFilter_DEFINED 19 20 #include "SkColor.h" 21 #include "SkFlattenable.h" 22 #include "SkXfermode.h" 23 24 class SK_API SkColorFilter : public SkFlattenable { 25 public: 26 /** 27 * If the filter can be represented by a source color plus Mode, this 28 * returns true, and sets (if not NULL) the color and mode appropriately. 29 * If not, this returns false and ignores the parameters. 30 */ 31 virtual bool asColorMode(SkColor* color, SkXfermode::Mode* mode); 32 33 /** Called with a scanline of colors, as if there was a shader installed. 34 The implementation writes out its filtered version into result[]. 35 Note: shader and result may be the same buffer. 36 @param src array of colors, possibly generated by a shader 37 @param count the number of entries in the src[] and result[] arrays 38 @param result written by the filter 39 */ 40 virtual void filterSpan(const SkPMColor src[], int count, 41 SkPMColor result[]) = 0; 42 /** Called with a scanline of colors, as if there was a shader installed. 43 The implementation writes out its filtered version into result[]. 44 Note: shader and result may be the same buffer. 45 @param src array of colors, possibly generated by a shader 46 @param count the number of entries in the src[] and result[] arrays 47 @param result written by the filter 48 */ 49 virtual void filterSpan16(const uint16_t shader[], int count, 50 uint16_t result[]); 51 52 enum Flags { 53 /** If set the filter methods will not change the alpha channel of the 54 colors. 55 */ 56 kAlphaUnchanged_Flag = 0x01, 57 /** If set, this subclass implements filterSpan16(). If this flag is 58 set, then kAlphaUnchanged_Flag must also be set. 59 */ 60 kHasFilter16_Flag = 0x02 61 }; 62 63 /** Returns the flags for this filter. Override in subclasses to return 64 custom flags. 65 */ 66 virtual uint32_t getFlags() { return 0; } 67 68 /** 69 * Apply this colorfilter to the specified SkColor. This routine handles 70 * converting to SkPMColor, calling the filter, and then converting back 71 * to SkColor. This method is not virtual, but will call filterSpan() 72 * which is virtual. 73 */ 74 SkColor filterColor(SkColor); 75 76 77 /** Create a colorfilter that uses the specified color and mode. 78 If the Mode is DST, this function will return NULL (since that 79 mode will have no effect on the result). 80 @param c The source color used with the specified mode 81 @param mode The xfermode mode that is applied to each color in 82 the colorfilter's filterSpan[16,32] methods 83 @return colorfilter object that applies the src color and mode, 84 or NULL if the mode will have no effect. 85 */ 86 static SkColorFilter* CreateModeFilter(SkColor c, SkXfermode::Mode mode); 87 88 /** Create a colorfilter that calls through to the specified procs to 89 filter the colors. The SkXfermodeProc parameter must be non-null, but 90 the SkXfermodeProc16 is optional, and may be null. 91 */ 92 static SkColorFilter* CreateProcFilter(SkColor srcColor, 93 SkXfermodeProc proc, 94 SkXfermodeProc16 proc16 = NULL); 95 96 /** Create a colorfilter that multiplies the RGB channels by one color, and 97 then adds a second color, pinning the result for each component to 98 [0..255]. The alpha components of the mul and add arguments 99 are ignored. 100 */ 101 static SkColorFilter* CreateLightingFilter(SkColor mul, SkColor add); 102 103 protected: 104 SkColorFilter() {} 105 SkColorFilter(SkFlattenableReadBuffer& rb) : INHERITED(rb) {} 106 107 private: 108 typedef SkFlattenable INHERITED; 109 }; 110 111 #include "SkShader.h" 112 113 class SkFilterShader : public SkShader { 114 public: 115 SkFilterShader(SkShader* shader, SkColorFilter* filter); 116 virtual ~SkFilterShader(); 117 118 // override 119 virtual uint32_t getFlags(); 120 virtual bool setContext(const SkBitmap& device, const SkPaint& paint, 121 const SkMatrix& matrix); 122 virtual void shadeSpan(int x, int y, SkPMColor result[], int count); 123 virtual void shadeSpan16(int x, int y, uint16_t result[], int count); 124 virtual void beginSession(); 125 virtual void endSession(); 126 127 protected: 128 SkFilterShader(SkFlattenableReadBuffer& ); 129 virtual void flatten(SkFlattenableWriteBuffer& ); 130 virtual Factory getFactory() { return CreateProc; } 131 private: 132 static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) { 133 return SkNEW_ARGS(SkFilterShader, (buffer)); } 134 SkShader* fShader; 135 SkColorFilter* fFilter; 136 137 typedef SkShader INHERITED; 138 }; 139 140 #endif 141
