1 #Topic Picture 2 #Alias Pictures ## 3 #Alias Picture_Reference ## 4 5 #Class SkPicture 6 7 #Code 8 #Populate 9 ## 10 11 Picture records drawing commands made to Canvas. The command stream may be 12 played in whole or in part at a later time. 13 14 Picture is an abstract class. Picture may be generated by Picture_Recorder 15 or Drawable, or from Picture previously saved to Data or Stream. 16 17 Picture may contain any Canvas drawing command, as well as one or more 18 Canvas_Matrix or Canvas_Clip. Picture has a cull Rect, which is used as 19 a bounding box hint. To limit Picture bounds, use Canvas_Clip when 20 recording or drawing Picture. 21 22 # ------------------------------------------------------------------------------ 23 24 #Class AbortCallback 25 #Line # utility to stop picture playback ## 26 27 #Code 28 class AbortCallback { 29 public: 30 AbortCallback() {} 31 virtual ~AbortCallback() {} 32 virtual bool abort() = 0; 33 }; 34 ## 35 36 AbortCallback is an abstract class. An implementation of AbortCallback may 37 passed as a parameter to SkPicture::playback, to stop it before all drawing 38 commands have been processed. 39 40 If AbortCallback::abort returns true, SkPicture::playback is interrupted. 41 42 # ------------------------------------------------------------------------------ 43 44 #Method AbortCallback() 45 #In Constructors 46 #Line # defines default constructor ## 47 #Populate 48 49 #NoExample 50 ## 51 52 #SeeAlso playback 53 54 #Method ## 55 56 # ------------------------------------------------------------------------------ 57 58 #Method virtual ~AbortCallback() 59 #In Constructors 60 #Line # defines default destructor ## 61 #Populate 62 63 #NoExample 64 ## 65 66 #SeeAlso playback 67 68 #Method ## 69 70 # ------------------------------------------------------------------------------ 71 72 #Method virtual bool abort() = 0 73 #In Utility 74 #Line # aborts playback by callback ## 75 #Populate 76 77 #NoExample 78 ## 79 80 #SeeAlso playback 81 82 #Method ## 83 84 #Example 85 #Description 86 JustOneDraw allows the black rectangle to draw but stops playback before the 87 white rectangle appears. 88 ## 89 #Function 90 class JustOneDraw : public SkPicture::AbortCallback { 91 public: 92 bool abort() override { return fCalls++ > 0; } 93 private: 94 int fCalls = 0; 95 }; 96 ## 97 98 void draw(SkCanvas* canvas) { 99 SkPictureRecorder recorder; 100 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 101 SkPaint paint; 102 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 103 paint.setColor(SK_ColorWHITE); 104 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 105 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 106 JustOneDraw callback; 107 picture->playback(canvas, &callback); 108 } 109 110 ## 111 112 #Class AbortCallback ## 113 114 # ------------------------------------------------------------------------------ 115 116 #Method static sk_sp<SkPicture> MakeFromStream(SkStream* stream, 117 const SkDeserialProcs* procs = nullptr) 118 #In Constructors 119 #Line # constructs Picture from stream ## 120 #Populate 121 122 #Example 123 SkPictureRecorder recorder; 124 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 125 SkPaint paint; 126 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 127 paint.setColor(SK_ColorWHITE); 128 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 129 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 130 SkDynamicMemoryWStream writableStream; 131 picture->serialize(&writableStream); 132 std::unique_ptr<SkStreamAsset> readableStream = writableStream.detachAsStream(); 133 sk_sp<SkPicture> copy = SkPicture::MakeFromStream(readableStream.get()); 134 copy->playback(canvas); 135 ## 136 137 #SeeAlso MakeFromData SkPictureRecorder 138 139 #Method ## 140 141 # ------------------------------------------------------------------------------ 142 143 #Method static sk_sp<SkPicture> MakeFromData(const SkData* data, 144 const SkDeserialProcs* procs = nullptr) 145 #In Constructors 146 #Line # constructs Picture from data ## 147 #Populate 148 149 #Example 150 SkPictureRecorder recorder; 151 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 152 SkPaint paint; 153 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 154 paint.setColor(SK_ColorWHITE); 155 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 156 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 157 SkDynamicMemoryWStream writableStream; 158 picture->serialize(&writableStream); 159 sk_sp<SkData> readableData = writableStream.detachAsData(); 160 sk_sp<SkPicture> copy = SkPicture::MakeFromData(readableData.get()); 161 copy->playback(canvas); 162 ## 163 164 #SeeAlso MakeFromStream SkPictureRecorder 165 166 #Method ## 167 168 # ------------------------------------------------------------------------------ 169 170 #Method static sk_sp<SkPicture> MakeFromData(const void* data, size_t size, 171 const SkDeserialProcs* procs = nullptr) 172 #Populate 173 174 #Example 175 SkPictureRecorder recorder; 176 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 177 SkPaint paint; 178 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 179 paint.setColor(SK_ColorWHITE); 180 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 181 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 182 SkDynamicMemoryWStream writableStream; 183 picture->serialize(&writableStream); 184 sk_sp<SkData> readableData = writableStream.detachAsData(); 185 sk_sp<SkPicture> copy = SkPicture::MakeFromData(readableData->data(), readableData->size()); 186 copy->playback(canvas); 187 ## 188 189 #SeeAlso MakeFromStream SkPictureRecorder 190 191 #Method ## 192 193 # ------------------------------------------------------------------------------ 194 195 #Method virtual void playback(SkCanvas* canvas, AbortCallback* callback = nullptr) const = 0 196 #In Action 197 #Line # replays drawing commands on canvas ## 198 #Populate 199 200 #Example 201 SkPictureRecorder recorder; 202 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 203 SkPaint paint; 204 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 205 paint.setColor(SK_ColorWHITE); 206 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 207 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 208 picture->playback(canvas); 209 ## 210 211 #SeeAlso SkCanvas::drawPicture 212 213 #Method ## 214 215 # ------------------------------------------------------------------------------ 216 217 #Method virtual SkRect cullRect() const = 0 218 #In Property 219 #Line # returns bounds used to record Picture ## 220 #Populate 221 222 #Example 223 #Description 224 Picture recorded bounds are smaller than contents; contents outside recorded 225 bounds may be drawn, and are drawn in this example. 226 ## 227 SkPictureRecorder recorder; 228 SkCanvas* pictureCanvas = recorder.beginRecording({64, 64, 192, 192}); 229 SkPaint paint; 230 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 231 paint.setColor(SK_ColorWHITE); 232 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 233 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 234 picture->playback(canvas); 235 paint.setBlendMode(SkBlendMode::kModulate); 236 paint.setColor(0x40404040); 237 canvas->drawRect(picture->cullRect(), paint); 238 ## 239 240 #SeeAlso SkCanvas::clipRect 241 242 #Method ## 243 244 # ------------------------------------------------------------------------------ 245 246 #Method uint32_t uniqueID() const 247 #In Property 248 #Line # returns identifier for Picture ## 249 #Populate 250 251 #Example 252 SkPictureRecorder recorder; 253 recorder.beginRecording({0, 0, 0, 0}); 254 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 255 SkDebugf("empty picture id = %d\n", picture->uniqueID()); 256 sk_sp<SkPicture> placeholder = SkPicture::MakePlaceholder({0, 0, 0, 0}); 257 SkDebugf("placeholder id = %d\n", placeholder->uniqueID()); 258 #StdOut 259 empty picture id = 1 260 placeholder id = 2 261 ## 262 ## 263 264 #SeeAlso SkRefCnt 265 266 #Method ## 267 268 # ------------------------------------------------------------------------------ 269 270 #Method sk_sp<SkData> serialize(const SkSerialProcs* procs = nullptr) const 271 #In Utility 272 #Line # writes Picture to Data ## 273 #Populate 274 275 #Example 276 SkPictureRecorder recorder; 277 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 278 SkPaint paint; 279 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 280 paint.setColor(SK_ColorWHITE); 281 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 282 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 283 sk_sp<SkData> readableData = picture->serialize(); 284 sk_sp<SkPicture> copy = SkPicture::MakeFromData(readableData->data(), readableData->size()); 285 copy->playback(canvas); 286 ## 287 288 #SeeAlso MakeFromData SkData SkSerialProcs 289 290 #Method ## 291 292 # ------------------------------------------------------------------------------ 293 294 #Method void serialize(SkWStream* stream, const SkSerialProcs* procs = nullptr) const 295 #Populate 296 297 #Example 298 SkPictureRecorder recorder; 299 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 300 SkPaint paint; 301 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 302 paint.setColor(SK_ColorWHITE); 303 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 304 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 305 SkDynamicMemoryWStream writableStream; 306 picture->serialize(&writableStream); 307 sk_sp<SkData> readableData = writableStream.detachAsData(); 308 sk_sp<SkPicture> copy = SkPicture::MakeFromData(readableData->data(), readableData->size()); 309 copy->playback(canvas); 310 ## 311 312 #SeeAlso MakeFromStream SkWStream SkSerialProcs 313 314 #Method ## 315 316 # ------------------------------------------------------------------------------ 317 318 #Method static sk_sp<SkPicture> MakePlaceholder(SkRect cull) 319 #In Constructors 320 #Line # constructs placeholder with unique identifier ## 321 #Populate 322 323 #Example 324 #Function 325 class MyCanvas : public SkCanvas { 326 public: 327 MyCanvas(SkCanvas* c) : canvas(c) {} 328 void onDrawPicture(const SkPicture* picture, const SkMatrix* , 329 const SkPaint* ) override { 330 const SkRect rect = picture->cullRect(); 331 SkPaint redPaint; 332 redPaint.setColor(SK_ColorRED); 333 canvas->drawRect(rect, redPaint); 334 } 335 336 SkCanvas* canvas; 337 }; 338 ## 339 SkPictureRecorder recorder; 340 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 341 sk_sp<SkPicture> placeholder = SkPicture::MakePlaceholder({10, 40, 80, 110}); 342 pictureCanvas->drawPicture(placeholder); 343 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 344 MyCanvas myCanvas(canvas); 345 myCanvas.drawPicture(picture); 346 ## 347 348 #SeeAlso MakeFromStream MakeFromData uniqueID 349 350 #Method ## 351 352 # ------------------------------------------------------------------------------ 353 354 #Method virtual int approximateOpCount() const = 0 355 #In Property 356 #Line # returns approximate operation count ## 357 #Populate 358 359 #Example 360 SkPictureRecorder recorder; 361 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 362 SkPaint paint; 363 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 364 paint.setColor(SK_ColorWHITE); 365 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 366 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 367 picture->playback(canvas); 368 std::string opCount = "approximate op count: " + std::to_string(picture->approximateOpCount()); 369 canvas->drawString(opCount.c_str(), 50, 220, SkPaint()); 370 ## 371 372 #SeeAlso approximateBytesUsed 373 374 #Method ## 375 376 # ------------------------------------------------------------------------------ 377 378 #Method virtual size_t approximateBytesUsed() const = 0 379 #In Property 380 #Line # returns approximate size ## 381 #Populate 382 383 #Example 384 SkPictureRecorder recorder; 385 SkCanvas* pictureCanvas = recorder.beginRecording({0, 0, 256, 256}); 386 SkPaint paint; 387 pictureCanvas->drawRect(SkRect::MakeWH(200, 200), paint); 388 paint.setColor(SK_ColorWHITE); 389 pictureCanvas->drawRect(SkRect::MakeLTRB(20, 20, 180, 180), paint); 390 sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture(); 391 picture->playback(canvas); 392 std::string opCount = "approximate bytes used: " + std::to_string(picture->approximateBytesUsed()); 393 canvas->drawString(opCount.c_str(), 20, 220, SkPaint()); 394 ## 395 396 #SeeAlso approximateOpCount 397 398 #Method ## 399 400 #Class SkPicture ## 401 402 #Topic Picture ## 403
