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 16 class SK_API SkLayerDrawLooper : public SkDrawLooper { 17 public: 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 SkDrawLooper::Context* createContext(SkCanvas*, void* storage) const override; 77 contextSize()78 size_t contextSize() const override { return sizeof(LayerDrawLooperContext); } 79 80 bool asABlurShadow(BlurShadowRec* rec) const override; 81 SK_TO_STRING_OVERRIDE()82 SK_TO_STRING_OVERRIDE() 83 84 Factory getFactory() const override { return CreateProc; } 85 static SkFlattenable* CreateProc(SkReadBuffer& buffer); 86 87 protected: 88 SkLayerDrawLooper(); 89 90 void flatten(SkWriteBuffer&) const override; 91 92 private: 93 struct Rec { 94 Rec* fNext; 95 SkPaint fPaint; 96 LayerInfo fInfo; 97 }; 98 Rec* fRecs; 99 Rec* fTopRec; 100 int fCount; 101 102 // state-machine during the init/next cycle 103 class LayerDrawLooperContext : public SkDrawLooper::Context { 104 public: 105 explicit LayerDrawLooperContext(const SkLayerDrawLooper* looper); 106 107 protected: 108 bool next(SkCanvas*, SkPaint* paint) override; 109 110 private: 111 Rec* fCurrRec; 112 113 static void ApplyInfo(SkPaint* dst, const SkPaint& src, const LayerInfo&); 114 }; 115 116 class MyRegistrar : public SkFlattenable::Registrar { 117 public: 118 MyRegistrar(); 119 }; 120 121 typedef SkDrawLooper INHERITED; 122 123 public: 124 class SK_API Builder { 125 public: 126 Builder(); 127 ~Builder(); 128 129 /** 130 * Call for each layer you want to add (from top to bottom). 131 * This returns a paint you can modify, but that ptr is only valid until 132 * the next call made to addLayer(). 133 */ 134 SkPaint* addLayer(const LayerInfo&); 135 136 /** 137 * This layer will draw with the original paint, at the specified offset 138 */ 139 void addLayer(SkScalar dx, SkScalar dy); 140 141 /** 142 * This layer will with the original paint and no offset. 143 */ addLayer()144 void addLayer() { this->addLayer(0, 0); } 145 146 /// Similar to addLayer, but adds a layer to the top. 147 SkPaint* addLayerOnTop(const LayerInfo&); 148 149 /** 150 * Pass list of layers on to newly built looper and return it. This will 151 * also reset the builder, so it can be used to build another looper. 152 */ 153 SkLayerDrawLooper* detachLooper(); 154 155 private: 156 Rec* fRecs; 157 Rec* fTopRec; 158 int fCount; 159 }; 160 }; 161 162 #endif 163