1 /* 2 * Copyright 2012 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 SkDeferredCanvas_DEFINED 9 #define SkDeferredCanvas_DEFINED 10 11 #include "SkCanvas.h" 12 #include "SkPixelRef.h" 13 14 class DeferredDevice; 15 class SkImage; 16 class SkSurface; 17 18 /** \class SkDeferredCanvas 19 Subclass of SkCanvas that encapsulates an SkPicture or SkGPipe for deferred 20 drawing. The main difference between this class and SkPictureRecord (the 21 canvas provided by SkPicture) is that this is a full drop-in replacement 22 for SkCanvas, while SkPictureRecord only supports draw operations. 23 SkDeferredCanvas will transparently trigger the flushing of deferred 24 draw operations when an attempt is made to access the pixel data. 25 */ 26 class SK_API SkDeferredCanvas : public SkCanvas { 27 public: 28 class SK_API NotificationClient; 29 30 /** Construct a canvas with the specified surface to draw into. 31 This factory must be used for newImageSnapshot to work. 32 @param surface Specifies a surface for the canvas to draw into. 33 */ 34 static SkDeferredCanvas* Create(SkSurface* surface); 35 36 static SkDeferredCanvas* Create(SkBaseDevice* device); 37 38 virtual ~SkDeferredCanvas(); 39 40 /** 41 * Specify the surface to be used by this canvas. Calling setSurface will 42 * release the previously set surface or device. Takes a reference on the 43 * surface. 44 * 45 * @param surface The surface that the canvas will raw into 46 * @return The surface argument, for convenience. 47 */ 48 SkSurface* setSurface(SkSurface* surface); 49 50 /** 51 * Specify a NotificationClient to be used by this canvas. Calling 52 * setNotificationClient will release the previously set 53 * NotificationClient, if any. SkDeferredCanvas does not take ownership 54 * of the notification client. Therefore user code is resposible 55 * for its destruction. The notification client must be unregistered 56 * by calling setNotificationClient(NULL) if it is destroyed before 57 * this canvas. 58 * Note: Must be called after the device is set with setDevice. 59 * 60 * @param notificationClient interface for dispatching notifications 61 * @return The notificationClient argument, for convenience. 62 */ 63 NotificationClient* setNotificationClient(NotificationClient* notificationClient); 64 65 /** 66 * Enable or disable deferred drawing. When deferral is disabled, 67 * pending draw operations are immediately flushed and from then on, 68 * the SkDeferredCanvas behaves just like a regular SkCanvas. 69 * This method must not be called while the save/restore stack is in use. 70 * @param deferred true/false 71 */ 72 void setDeferredDrawing(bool deferred); 73 74 /** 75 * Returns true if deferred drawing is currenlty enabled. 76 */ 77 bool isDeferredDrawing() const; 78 79 /** 80 * Returns true if the canvas contains a fresh frame. A frame is 81 * considered fresh when its content do not depend on the contents 82 * of the previous frame. For example, if a canvas is cleared before 83 * drawing each frame, the frames will all be considered fresh. 84 * A frame is defined as the graphics image produced by as a result 85 * of all the canvas draws operation executed between two successive 86 * calls to isFreshFrame. The result of isFreshFrame is computed 87 * conservatively, so it may report false negatives. 88 */ 89 bool isFreshFrame() const; 90 91 /** 92 * Returns true if the canvas has recorded draw commands that have 93 * not yet been played back. 94 */ 95 bool hasPendingCommands() const; 96 97 /** 98 * Flushes pending draw commands, if any, and returns an image of the 99 * current state of the surface pixels up to this point. Subsequent 100 * changes to the surface (by drawing into its canvas) will not be 101 * reflected in this image. Will return NULL if the deferred canvas 102 * was not constructed from an SkSurface. 103 */ 104 SkImage* newImageSnapshot(); 105 106 /** 107 * Specify the maximum number of bytes to be allocated for the purpose 108 * of recording draw commands to this canvas. The default limit, is 109 * 64MB. 110 * @param maxStorage The maximum number of bytes to be allocated. 111 */ 112 void setMaxRecordingStorage(size_t maxStorage); 113 114 /** 115 * Returns the number of bytes currently allocated for the purpose of 116 * recording draw commands. 117 */ 118 size_t storageAllocatedForRecording() const; 119 120 /** 121 * Attempt to reduce the storage allocated for recording by evicting 122 * cache resources. 123 * @param bytesToFree minimum number of bytes that should be attempted to 124 * be freed. 125 * @return number of bytes actually freed. 126 */ 127 size_t freeMemoryIfPossible(size_t bytesToFree); 128 129 /** 130 * Specifies the maximum size (in bytes) allowed for a given image to be 131 * rendered using the deferred canvas. 132 */ 133 void setBitmapSizeThreshold(size_t sizeThreshold); 134 135 /** 136 * Executes all pending commands without drawing 137 */ 138 void silentFlush(); 139 140 // Overrides of the SkCanvas interface 141 virtual int save(SaveFlags flags) SK_OVERRIDE; 142 virtual int saveLayer(const SkRect* bounds, const SkPaint* paint, 143 SaveFlags flags) SK_OVERRIDE; 144 virtual void restore() SK_OVERRIDE; 145 virtual bool isDrawingToLayer() const SK_OVERRIDE; 146 virtual bool translate(SkScalar dx, SkScalar dy) SK_OVERRIDE; 147 virtual bool scale(SkScalar sx, SkScalar sy) SK_OVERRIDE; 148 virtual bool rotate(SkScalar degrees) SK_OVERRIDE; 149 virtual bool skew(SkScalar sx, SkScalar sy) SK_OVERRIDE; 150 virtual bool concat(const SkMatrix& matrix) SK_OVERRIDE; 151 virtual void setMatrix(const SkMatrix& matrix) SK_OVERRIDE; 152 virtual bool clipRect(const SkRect& rect, SkRegion::Op op, 153 bool doAntiAlias) SK_OVERRIDE; 154 virtual bool clipRRect(const SkRRect& rect, SkRegion::Op op, 155 bool doAntiAlias) SK_OVERRIDE; 156 virtual bool clipPath(const SkPath& path, SkRegion::Op op, 157 bool doAntiAlias) SK_OVERRIDE; 158 virtual bool clipRegion(const SkRegion& deviceRgn, 159 SkRegion::Op op) SK_OVERRIDE; 160 virtual void clear(SkColor) SK_OVERRIDE; 161 virtual void drawPaint(const SkPaint& paint) SK_OVERRIDE; 162 virtual void drawPoints(PointMode mode, size_t count, const SkPoint pts[], 163 const SkPaint& paint) SK_OVERRIDE; 164 virtual void drawOval(const SkRect&, const SkPaint& paint) SK_OVERRIDE; 165 virtual void drawRect(const SkRect& rect, const SkPaint& paint) SK_OVERRIDE; 166 virtual void drawRRect(const SkRRect&, const SkPaint& paint) SK_OVERRIDE; 167 virtual void drawPath(const SkPath& path, const SkPaint& paint) 168 SK_OVERRIDE; 169 virtual void drawBitmap(const SkBitmap& bitmap, SkScalar left, 170 SkScalar top, const SkPaint* paint) 171 SK_OVERRIDE; 172 virtual void drawBitmapRectToRect(const SkBitmap& bitmap, const SkRect* src, 173 const SkRect& dst, const SkPaint* paint, 174 DrawBitmapRectFlags flags) SK_OVERRIDE; 175 176 virtual void drawBitmapMatrix(const SkBitmap& bitmap, const SkMatrix& m, 177 const SkPaint* paint) SK_OVERRIDE; 178 virtual void drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center, 179 const SkRect& dst, const SkPaint* paint) 180 SK_OVERRIDE; 181 virtual void drawSprite(const SkBitmap& bitmap, int left, int top, 182 const SkPaint* paint) SK_OVERRIDE; 183 virtual void drawText(const void* text, size_t byteLength, SkScalar x, 184 SkScalar y, const SkPaint& paint) SK_OVERRIDE; 185 virtual void drawPosText(const void* text, size_t byteLength, 186 const SkPoint pos[], const SkPaint& paint) 187 SK_OVERRIDE; 188 virtual void drawPosTextH(const void* text, size_t byteLength, 189 const SkScalar xpos[], SkScalar constY, 190 const SkPaint& paint) SK_OVERRIDE; 191 virtual void drawTextOnPath(const void* text, size_t byteLength, 192 const SkPath& path, const SkMatrix* matrix, 193 const SkPaint& paint) SK_OVERRIDE; 194 virtual void drawPicture(SkPicture& picture) SK_OVERRIDE; 195 virtual void drawVertices(VertexMode vmode, int vertexCount, 196 const SkPoint vertices[], const SkPoint texs[], 197 const SkColor colors[], SkXfermode* xmode, 198 const uint16_t indices[], int indexCount, 199 const SkPaint& paint) SK_OVERRIDE; 200 virtual SkBounder* setBounder(SkBounder* bounder) SK_OVERRIDE; 201 virtual SkDrawFilter* setDrawFilter(SkDrawFilter* filter) SK_OVERRIDE; 202 203 public: 204 class NotificationClient { 205 public: 206 virtual ~NotificationClient() {} 207 208 /** 209 * Called before executing one or several draw commands, which means 210 * once per flush when deferred rendering is enabled. 211 */ 212 virtual void prepareForDraw() {} 213 214 /** 215 * Called after a recording a draw command if additional memory 216 * had to be allocated for recording. 217 * @param newAllocatedStorage same value as would be returned by 218 * storageAllocatedForRecording(), for convenience. 219 */ 220 virtual void storageAllocatedForRecordingChanged( 221 size_t newAllocatedStorage) {} 222 223 /** 224 * Called after pending draw commands have been flushed 225 */ 226 virtual void flushedDrawCommands() {} 227 228 /** 229 * Called after pending draw commands have been skipped, meaning 230 * that they were optimized-out because the canvas is cleared 231 * or completely overwritten by the command currently being recorded. 232 */ 233 virtual void skippedPendingDrawCommands() {} 234 }; 235 236 protected: 237 virtual SkCanvas* canvasForDrawIter(); 238 DeferredDevice* getDeferredDevice() const; 239 240 private: 241 SkDeferredCanvas(DeferredDevice*); 242 243 void recordedDrawCommand(); 244 SkCanvas* drawingCanvas() const; 245 SkCanvas* immediateCanvas() const; 246 bool isFullFrame(const SkRect*, const SkPaint*) const; 247 void validate() const; 248 void init(); 249 bool fDeferredDrawing; 250 251 friend class SkDeferredCanvasTester; // for unit testing 252 typedef SkCanvas INHERITED; 253 }; 254 255 256 #endif 257
