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 SkLayerDrawLooper_DEFINED 9#define SkLayerDrawLooper_DEFINED 10 11#include "SkDrawLooper.h" 12#include "SkPaint.h" 13#include "SkPoint.h" 14#include "SkXfermode.h" 15 16class SK_API SkLayerDrawLooper : public SkDrawLooper { 17public: 18 SK_DECLARE_INST_COUNT(SkLayerDrawLooper) 19 20 virtual ~SkLayerDrawLooper(); 21 22 /** 23 * Bits specifies which aspects of the layer's paint should replace the 24 * corresponding aspects on the draw's paint. 25 * kEntirePaint_Bits means use the layer's paint completely. 26 * 0 means ignore the layer's paint... except for fColorMode, which is 27 * always applied. 28 */ 29 enum Bits { 30 kStyle_Bit = 1 << 0, //!< use this layer's Style/stroke settings 31 kTextSkewX_Bit = 1 << 1, //!< use this layer's textskewx 32 kPathEffect_Bit = 1 << 2, //!< use this layer's patheffect 33 kMaskFilter_Bit = 1 << 3, //!< use this layer's maskfilter 34 kShader_Bit = 1 << 4, //!< use this layer's shader 35 kColorFilter_Bit = 1 << 5, //!< use this layer's colorfilter 36 kXfermode_Bit = 1 << 6, //!< use this layer's xfermode 37 38 /** 39 * Use the layer's paint entirely, with these exceptions: 40 * - We never override the draw's paint's text_encoding, since that is 41 * used to interpret the text/len parameters in draw[Pos]Text. 42 * - Color is always computed using the LayerInfo's fColorMode. 43 */ 44 kEntirePaint_Bits = -1 45 46 }; 47 typedef int32_t BitFlags; 48 49 /** 50 * Info for how to apply the layer's paint and offset. 51 * 52 * fColorMode controls how we compute the final color for the layer: 53 * The layer's paint's color is treated as the SRC 54 * The draw's paint's color is treated as the DST 55 * final-color = Mode(layers-color, draws-color); 56 * Any SkXfermode::Mode will work. Two common choices are: 57 * kSrc_Mode: to use the layer's color, ignoring the draw's 58 * kDst_Mode: to just keep the draw's color, ignoring the layer's 59 */ 60 struct SK_API LayerInfo { 61 BitFlags fPaintBits; 62 SkXfermode::Mode fColorMode; 63 SkVector fOffset; 64 bool fPostTranslate; //!< applies to fOffset 65 66 /** 67 * Initial the LayerInfo. Defaults to settings that will draw the 68 * layer with no changes: e.g. 69 * fPaintBits == 0 70 * fColorMode == kDst_Mode 71 * fOffset == (0, 0) 72 */ 73 LayerInfo(); 74 }; 75 76 virtual SkDrawLooper::Context* createContext(SkCanvas*, void* storage) const SK_OVERRIDE; 77 78 virtual size_t contextSize() const SK_OVERRIDE { return sizeof(LayerDrawLooperContext); } 79 80 virtual bool asABlurShadow(BlurShadowRec* rec) const SK_OVERRIDE; 81 82 SK_TO_STRING_OVERRIDE() 83 84 /// Implements Flattenable. 85 virtual Factory getFactory() const SK_OVERRIDE { return CreateProc; } 86 static SkFlattenable* CreateProc(SkReadBuffer& buffer); 87 88protected: 89 SkLayerDrawLooper(); 90 91 virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE; 92 93private: 94 struct Rec { 95 Rec* fNext; 96 SkPaint fPaint; 97 LayerInfo fInfo; 98 }; 99 Rec* fRecs; 100 Rec* fTopRec; 101 int fCount; 102 103 // state-machine during the init/next cycle 104 class LayerDrawLooperContext : public SkDrawLooper::Context { 105 public: 106 explicit LayerDrawLooperContext(const SkLayerDrawLooper* looper); 107 108 protected: 109 virtual bool next(SkCanvas*, SkPaint* paint) SK_OVERRIDE; 110 111 private: 112 Rec* fCurrRec; 113 114 static void ApplyInfo(SkPaint* dst, const SkPaint& src, const LayerInfo&); 115 }; 116 117 class MyRegistrar : public SkFlattenable::Registrar { 118 public: 119 MyRegistrar(); 120 }; 121 122 typedef SkDrawLooper INHERITED; 123 124public: 125 class SK_API Builder { 126 public: 127 Builder(); 128 ~Builder(); 129 130 /** 131 * Call for each layer you want to add (from top to bottom). 132 * This returns a paint you can modify, but that ptr is only valid until 133 * the next call made to addLayer(). 134 */ 135 SkPaint* addLayer(const LayerInfo&); 136 137 /** 138 * This layer will draw with the original paint, at the specified offset 139 */ 140 void addLayer(SkScalar dx, SkScalar dy); 141 142 /** 143 * This layer will with the original paint and no offset. 144 */ 145 void addLayer() { this->addLayer(0, 0); } 146 147 /// Similar to addLayer, but adds a layer to the top. 148 SkPaint* addLayerOnTop(const LayerInfo&); 149 150 /** 151 * Pass list of layers on to newly built looper and return it. This will 152 * also reset the builder, so it can be used to build another looper. 153 */ 154 SkLayerDrawLooper* detachLooper(); 155 156 private: 157 Rec* fRecs; 158 Rec* fTopRec; 159 int fCount; 160 }; 161}; 162 163#endif 164