1 2 /* 3 * Copyright 2006 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #ifndef SkColorFilter_DEFINED 11 #define SkColorFilter_DEFINED 12 13 #include "SkColor.h" 14 #include "SkFlattenable.h" 15 #include "SkXfermode.h" 16 17 class SkBitmap; 18 class GrEffectRef; 19 class GrContext; 20 21 class SK_API SkColorFilter : public SkFlattenable { 22 public: 23 SK_DECLARE_INST_COUNT(SkColorFilter) 24 25 /** 26 * If the filter can be represented by a source color plus Mode, this 27 * returns true, and sets (if not NULL) the color and mode appropriately. 28 * If not, this returns false and ignores the parameters. 29 */ 30 virtual bool asColorMode(SkColor* color, SkXfermode::Mode* mode) const; 31 32 /** 33 * If the filter can be represented by a 5x4 matrix, this 34 * returns true, and sets the matrix appropriately. 35 * If not, this returns false and ignores the parameter. 36 */ 37 virtual bool asColorMatrix(SkScalar matrix[20]) const; 38 39 /** 40 * If the filter can be represented by per-component table, return true, 41 * and if table is not null, copy the bitmap containing the table into it. 42 * 43 * The table bitmap will be in SkBitmap::kA8_Config. Each row corresponding 44 * to each component in ARGB order. e.g. row[0] == alpha, row[1] == red, 45 * etc. To transform a color, you (logically) perform the following: 46 * 47 * a' = *table.getAddr8(a, 0); 48 * r' = *table.getAddr8(r, 1); 49 * g' = *table.getAddr8(g, 2); 50 * b' = *table.getAddr8(b, 3); 51 * 52 * The original component value is the horizontal index for a given row, 53 * and the stored value at that index is the new value for that component. 54 */ 55 virtual bool asComponentTable(SkBitmap* table) const; 56 57 /** Called with a scanline of colors, as if there was a shader installed. 58 The implementation writes out its filtered version into result[]. 59 Note: shader and result may be the same buffer. 60 @param src array of colors, possibly generated by a shader 61 @param count the number of entries in the src[] and result[] arrays 62 @param result written by the filter 63 */ 64 virtual void filterSpan(const SkPMColor src[], int count, 65 SkPMColor result[]) const = 0; 66 /** Called with a scanline of colors, as if there was a shader installed. 67 The implementation writes out its filtered version into result[]. 68 Note: shader and result may be the same buffer. 69 @param src array of colors, possibly generated by a shader 70 @param count the number of entries in the src[] and result[] arrays 71 @param result written by the filter 72 */ 73 virtual void filterSpan16(const uint16_t shader[], int count, 74 uint16_t result[]) const; 75 76 enum Flags { 77 /** If set the filter methods will not change the alpha channel of the 78 colors. 79 */ 80 kAlphaUnchanged_Flag = 0x01, 81 /** If set, this subclass implements filterSpan16(). If this flag is 82 set, then kAlphaUnchanged_Flag must also be set. 83 */ 84 kHasFilter16_Flag = 0x02 85 }; 86 87 /** Returns the flags for this filter. Override in subclasses to return 88 custom flags. 89 */ 90 virtual uint32_t getFlags() const { return 0; } 91 92 /** 93 * Apply this colorfilter to the specified SkColor. This routine handles 94 * converting to SkPMColor, calling the filter, and then converting back 95 * to SkColor. This method is not virtual, but will call filterSpan() 96 * which is virtual. 97 */ 98 SkColor filterColor(SkColor) const; 99 100 /** Create a colorfilter that uses the specified color and mode. 101 If the Mode is DST, this function will return NULL (since that 102 mode will have no effect on the result). 103 @param c The source color used with the specified mode 104 @param mode The xfermode mode that is applied to each color in 105 the colorfilter's filterSpan[16,32] methods 106 @return colorfilter object that applies the src color and mode, 107 or NULL if the mode will have no effect. 108 */ 109 static SkColorFilter* CreateModeFilter(SkColor c, SkXfermode::Mode mode); 110 111 /** Create a colorfilter that multiplies the RGB channels by one color, and 112 then adds a second color, pinning the result for each component to 113 [0..255]. The alpha components of the mul and add arguments 114 are ignored. 115 */ 116 static SkColorFilter* CreateLightingFilter(SkColor mul, SkColor add); 117 118 /** A subclass may implement this factory function to work with the GPU backend. If the return 119 is non-NULL then the caller owns a ref on the returned object. 120 */ 121 virtual GrEffectRef* asNewEffect(GrContext*) const; 122 123 SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() 124 protected: 125 SkColorFilter() {} 126 SkColorFilter(SkFlattenableReadBuffer& rb) : INHERITED(rb) {} 127 128 private: 129 typedef SkFlattenable INHERITED; 130 }; 131 132 #endif 133
