SkPicture.h revision d281c9240c7bd51ce0c29c6d4de27819e359e1d1
1 2/* 3 * Copyright 2007 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 SkPicture_DEFINED 11#define SkPicture_DEFINED 12 13#include "SkBitmap.h" 14#include "SkImageDecoder.h" 15#include "SkRefCnt.h" 16 17class SkBBoxHierarchy; 18class SkCanvas; 19class SkDrawPictureCallback; 20class SkData; 21class SkPicturePlayback; 22class SkPictureRecord; 23class SkStream; 24class SkWStream; 25 26struct SkPictInfo; 27 28/** \class SkPicture 29 30 The SkPicture class records the drawing commands made to a canvas, to 31 be played back at a later time. 32*/ 33class SK_API SkPicture : public SkRefCnt { 34public: 35 SK_DECLARE_INST_COUNT(SkPicture) 36 37 /** The constructor prepares the picture to record. 38 @param width the width of the virtual device the picture records. 39 @param height the height of the virtual device the picture records. 40 */ 41 SkPicture(); 42 /** Make a copy of the contents of src. If src records more drawing after 43 this call, those elements will not appear in this picture. 44 */ 45 SkPicture(const SkPicture& src); 46 47 /** 48 * Function signature defining a function that sets up an SkBitmap from encoded data. On 49 * success, the SkBitmap should have its Config, width, height, rowBytes and pixelref set. 50 * If the installed pixelref has decoded the data into pixels, then the src buffer need not be 51 * copied. If the pixelref defers the actual decode until its lockPixels() is called, then it 52 * must make a copy of the src buffer. 53 * @param src Encoded data. 54 * @param length Size of the encoded data, in bytes. 55 * @param dst SkBitmap to install the pixel ref on. 56 * @param bool Whether or not a pixel ref was successfully installed. 57 */ 58 typedef bool (*InstallPixelRefProc)(const void* src, size_t length, SkBitmap* dst); 59 60 /** 61 * Recreate a picture that was serialized into a stream. 62 * @param SkStream Serialized picture data. 63 * @param proc Function pointer for installing pixelrefs on SkBitmaps representing the 64 * encoded bitmap data from the stream. 65 * @return A new SkPicture representing the serialized data, or NULL if the stream is 66 * invalid. 67 */ 68 static SkPicture* CreateFromStream(SkStream*, 69 InstallPixelRefProc proc = &SkImageDecoder::DecodeMemory); 70 71 /** 72 * Recreate a picture that was serialized into a buffer. If the creation requires bitmap 73 * decoding, the decoder must be set on the SkReadBuffer parameter by calling 74 * SkReadBuffer::setBitmapDecoder() before calling SkPicture::CreateFromBuffer(). 75 * @param SkReadBuffer Serialized picture data. 76 * @return A new SkPicture representing the serialized data, or NULL if the buffer is 77 * invalid. 78 */ 79 static SkPicture* CreateFromBuffer(SkReadBuffer&); 80 81 virtual ~SkPicture(); 82 83 /** 84 * Swap the contents of the two pictures. Guaranteed to succeed. 85 */ 86 void swap(SkPicture& other); 87 88 /** 89 * Creates a thread-safe clone of the picture that is ready for playback. 90 */ 91 SkPicture* clone() const; 92 93 /** 94 * Creates multiple thread-safe clones of this picture that are ready for 95 * playback. The resulting clones are stored in the provided array of 96 * SkPictures. 97 */ 98 void clone(SkPicture* pictures, int count) const; 99 100 enum RecordingFlags { 101 /* This flag specifies that when clipPath() is called, the path will 102 be faithfully recorded, but the recording canvas' current clip will 103 only see the path's bounds. This speeds up the recording process 104 without compromising the fidelity of the playback. The only side- 105 effect for recording is that calling getTotalClip() or related 106 clip-query calls will reflect the path's bounds, not the actual 107 path. 108 */ 109 kUsePathBoundsForClip_RecordingFlag = 0x01, 110 /* This flag causes the picture to compute bounding boxes and build 111 up a spatial hierarchy (currently an R-Tree), plus a tree of Canvas' 112 usually stack-based clip/etc state. This requires an increase in 113 recording time (often ~2x; likely more for very complex pictures), 114 but allows us to perform much faster culling at playback time, and 115 completely avoid some unnecessary clips and other operations. This 116 is ideal for tiled rendering, or any other situation where you're 117 drawing a fraction of a large scene into a smaller viewport. 118 119 In most cases the record cost is offset by the playback improvement 120 after a frame or two of tiled rendering (and complex pictures that 121 induce the worst record times will generally get the largest 122 speedups at playback time). 123 124 Note: Currently this is not serializable, the bounding data will be 125 discarded if you serialize into a stream and then deserialize. 126 */ 127 kOptimizeForClippedPlayback_RecordingFlag = 0x02, 128 /* 129 This flag disables all the picture recording optimizations (i.e., 130 those in SkPictureRecord). It is mainly intended for testing the 131 existing optimizations (i.e., to actually have the pattern 132 appear in an .skp we have to disable the optimization). This 133 option doesn't affect the optimizations controlled by 134 'kOptimizeForClippedPlayback_RecordingFlag'. 135 */ 136 kDisableRecordOptimizations_RecordingFlag = 0x04 137 }; 138 139 /** Returns the canvas that records the drawing commands. 140 @param width the base width for the picture, as if the recording 141 canvas' bitmap had this width. 142 @param height the base width for the picture, as if the recording 143 canvas' bitmap had this height. 144 @param recordFlags optional flags that control recording. 145 @return the picture canvas. 146 */ 147 SkCanvas* beginRecording(int width, int height, uint32_t recordFlags = 0); 148 149 /** Returns the recording canvas if one is active, or NULL if recording is 150 not active. This does not alter the refcnt on the canvas (if present). 151 */ 152 SkCanvas* getRecordingCanvas() const; 153 /** Signal that the caller is done recording. This invalidates the canvas 154 returned by beginRecording/getRecordingCanvas, and prepares the picture 155 for drawing. Note: this happens implicitly the first time the picture 156 is drawn. 157 */ 158 void endRecording(); 159 160 /** Replays the drawing commands on the specified canvas. This internally 161 calls endRecording() if that has not already been called. 162 @param canvas the canvas receiving the drawing commands. 163 */ 164 void draw(SkCanvas* canvas, SkDrawPictureCallback* = NULL); 165 166 /** Return the width of the picture's recording canvas. This 167 value reflects what was passed to setSize(), and does not necessarily 168 reflect the bounds of what has been recorded into the picture. 169 @return the width of the picture's recording canvas 170 */ 171 int width() const { return fWidth; } 172 173 /** Return the height of the picture's recording canvas. This 174 value reflects what was passed to setSize(), and does not necessarily 175 reflect the bounds of what has been recorded into the picture. 176 @return the height of the picture's recording canvas 177 */ 178 int height() const { return fHeight; } 179 180 /** 181 * Function to encode an SkBitmap to an SkData. A function with this 182 * signature can be passed to serialize() and SkWriteBuffer. 183 * Returning NULL will tell the SkWriteBuffer to use 184 * SkBitmap::flatten() to store the bitmap. 185 * 186 * @param pixelRefOffset DEPRECATED -- caller assumes it will return 0. 187 * @return SkData If non-NULL, holds encoded data representing the passed 188 * in bitmap. The caller is responsible for calling unref(). 189 */ 190 typedef SkData* (*EncodeBitmap)(size_t* pixelRefOffset, const SkBitmap& bm); 191 192 /** 193 * Serialize to a stream. If non NULL, encoder will be used to encode 194 * any bitmaps in the picture. 195 * encoder will never be called with a NULL pixelRefOffset. 196 */ 197 void serialize(SkWStream*, EncodeBitmap encoder = NULL) const; 198 199 /** 200 * Serialize to a buffer. 201 */ 202 void flatten(SkWriteBuffer&) const; 203 204 /** 205 * Returns true if any bitmaps may be produced when this SkPicture 206 * is replayed. 207 * Returns false if called while still recording. 208 */ 209 bool willPlayBackBitmaps() const; 210 211#ifdef SK_BUILD_FOR_ANDROID 212 /** Signals that the caller is prematurely done replaying the drawing 213 commands. This can be called from a canvas virtual while the picture 214 is drawing. Has no effect if the picture is not drawing. 215 @deprecated preserving for legacy purposes 216 */ 217 void abortPlayback(); 218#endif 219 220protected: 221 // V2 : adds SkPixelRef's generation ID. 222 // V3 : PictInfo tag at beginning, and EOF tag at the end 223 // V4 : move SkPictInfo to be the header 224 // V5 : don't read/write FunctionPtr on cross-process (we can detect that) 225 // V6 : added serialization of SkPath's bounds (and packed its flags tighter) 226 // V7 : changed drawBitmapRect(IRect) to drawBitmapRectToRect(Rect) 227 // V8 : Add an option for encoding bitmaps 228 // V9 : Allow the reader and writer of an SKP disagree on whether to support 229 // SK_SUPPORT_HINTING_SCALE_FACTOR 230 // V10: add drawRRect, drawOval, clipRRect 231 // V11: modify how readBitmap and writeBitmap store their info. 232 // V12: add conics to SkPath, use new SkPathRef flattening 233 // V13: add flag to drawBitmapRectToRect 234 // parameterize blurs by sigma rather than radius 235 // V14: Add flags word to PathRef serialization 236 // V15: Remove A1 bitmpa config (and renumber remaining configs) 237 // V16: Move SkPath's isOval flag to SkPathRef 238 // V17: SkPixelRef now writes SkImageInfo 239 // V18: SkBitmap now records x,y for its pixelref origin, instead of offset. 240 // V19: encode matrices and regions into the ops stream 241 // V20: added bool to SkPictureImageFilter's serialization (to allow SkPicture serialization) 242 243 // Note: If the picture version needs to be increased then please follow the 244 // steps to generate new SKPs in (only accessible to Googlers): http://goo.gl/qATVcw 245 static const uint32_t PICTURE_VERSION = 20; 246 247 // fPlayback, fRecord, fWidth & fHeight are protected to allow derived classes to 248 // install their own SkPicturePlayback-derived players,SkPictureRecord-derived 249 // recorders and set the picture size 250 SkPicturePlayback* fPlayback; 251 SkPictureRecord* fRecord; 252 int fWidth, fHeight; 253 254 // Create a new SkPicture from an existing SkPicturePlayback. Ref count of 255 // playback is unchanged. 256 SkPicture(SkPicturePlayback*, int width, int height); 257 258 // For testing. Derived classes may instantiate an alternate 259 // SkBBoxHierarchy implementation 260 virtual SkBBoxHierarchy* createBBoxHierarchy() const; 261 262 // Return true if the SkStream represents a serialized picture, and fills out 263 // SkPictInfo. After this function returns, the SkStream is not rewound; it 264 // will be ready to be parsed to create an SkPicturePlayback. 265 // If false is returned, SkPictInfo is unmodified. 266 static bool StreamIsSKP(SkStream*, SkPictInfo*); 267 static bool BufferIsSKP(SkReadBuffer&, SkPictInfo*); 268private: 269 void createHeader(void* header) const; 270 271 friend class SkFlatPicture; 272 friend class SkPicturePlayback; 273 274 typedef SkRefCnt INHERITED; 275}; 276 277/** 278 * Subclasses of this can be passed to canvas.drawPicture. During the drawing 279 * of the picture, this callback will periodically be invoked. If its 280 * abortDrawing() returns true, then picture playback will be interrupted. 281 * 282 * The resulting drawing is undefined, as there is no guarantee how often the 283 * callback will be invoked. If the abort happens inside some level of nested 284 * calls to save(), restore will automatically be called to return the state 285 * to the same level it was before the drawPicture call was made. 286 */ 287class SK_API SkDrawPictureCallback { 288public: 289 SkDrawPictureCallback() {} 290 virtual ~SkDrawPictureCallback() {} 291 292 virtual bool abortDrawing() = 0; 293}; 294 295#endif 296