1 /* 2 * Copyright 2013 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 #include "SkCanvasStateUtils.h" 9 10 #include "SkBitmapDevice.h" 11 #include "SkCanvas.h" 12 #include "SkCanvasStack.h" 13 #include "SkErrorInternals.h" 14 #include "SkWriter32.h" 15 16 /* 17 * WARNING: The structs below are part of a stable ABI and as such we explicitly 18 * use unambigious primitives (e.g. int32_t instead of an enum). 19 * 20 * ANY CHANGES TO THE STRUCTS BELOW THAT IMPACT THE ABI SHOULD RESULT IN A NEW 21 * NEW SUBCLASS OF SkCanvasState. SUCH CHANGES SHOULD ONLY BE MADE IF ABSOLUTELY 22 * NECESSARY! 23 */ 24 enum RasterConfigs { 25 kUnknown_RasterConfig = 0, 26 kRGB_565_RasterConfig = 1, 27 kARGB_8888_RasterConfig = 2 28 }; 29 typedef int32_t RasterConfig; 30 31 enum CanvasBackends { 32 kUnknown_CanvasBackend = 0, 33 kRaster_CanvasBackend = 1, 34 kGPU_CanvasBackend = 2, 35 kPDF_CanvasBackend = 3 36 }; 37 typedef int32_t CanvasBackend; 38 39 struct ClipRect { 40 int32_t left, top, right, bottom; 41 }; 42 43 struct SkMCState { 44 float matrix[9]; 45 // NOTE: this only works for non-antialiased clips 46 int32_t clipRectCount; 47 ClipRect* clipRects; 48 }; 49 50 // NOTE: If you add more members, create a new subclass of SkCanvasState with a 51 // new CanvasState::version. 52 struct SkCanvasLayerState { 53 CanvasBackend type; 54 int32_t x, y; 55 int32_t width; 56 int32_t height; 57 58 SkMCState mcState; 59 60 union { 61 struct { 62 RasterConfig config; // pixel format: a value from RasterConfigs. 63 uint64_t rowBytes; // Number of bytes from start of one line to next. 64 void* pixels; // The pixels, all (height * rowBytes) of them. 65 } raster; 66 struct { 67 int32_t textureID; 68 } gpu; 69 }; 70 }; 71 72 class SkCanvasState { 73 public: 74 SkCanvasState(int32_t version, SkCanvas* canvas) { 75 SkASSERT(canvas); 76 this->version = version; 77 width = canvas->getBaseLayerSize().width(); 78 height = canvas->getBaseLayerSize().height(); 79 80 } 81 82 /** 83 * The version this struct was built with. This field must always appear 84 * first in the struct so that when the versions don't match (and the 85 * remaining contents and size are potentially different) we can still 86 * compare the version numbers. 87 */ 88 int32_t version; 89 int32_t width; 90 int32_t height; 91 int32_t alignmentPadding; 92 }; 93 94 class SkCanvasState_v1 : public SkCanvasState { 95 public: 96 static const int32_t kVersion = 1; 97 98 SkCanvasState_v1(SkCanvas* canvas) 99 : INHERITED(kVersion, canvas) 100 { 101 layerCount = 0; 102 layers = NULL; 103 mcState.clipRectCount = 0; 104 mcState.clipRects = NULL; 105 originalCanvas = SkRef(canvas); 106 } 107 108 ~SkCanvasState_v1() { 109 // loop through the layers and free the data allocated to the clipRects 110 for (int i = 0; i < layerCount; ++i) { 111 sk_free(layers[i].mcState.clipRects); 112 } 113 114 sk_free(mcState.clipRects); 115 sk_free(layers); 116 117 // it is now safe to free the canvas since there should be no remaining 118 // references to the content that is referenced by this canvas (e.g. pixels) 119 originalCanvas->unref(); 120 } 121 122 SkMCState mcState; 123 124 int32_t layerCount; 125 SkCanvasLayerState* layers; 126 private: 127 SkCanvas* originalCanvas; 128 typedef SkCanvasState INHERITED; 129 }; 130 131 //////////////////////////////////////////////////////////////////////////////// 132 133 class ClipValidator : public SkCanvas::ClipVisitor { 134 public: 135 ClipValidator() : fFailed(false) {} 136 bool failed() { return fFailed; } 137 138 // ClipVisitor 139 virtual void clipRect(const SkRect& rect, SkRegion::Op op, bool antialias) SK_OVERRIDE { 140 fFailed |= antialias; 141 } 142 143 virtual void clipRRect(const SkRRect& rrect, SkRegion::Op op, bool antialias) SK_OVERRIDE { 144 fFailed |= antialias; 145 } 146 147 virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) SK_OVERRIDE { 148 fFailed |= antialias; 149 } 150 151 private: 152 bool fFailed; 153 }; 154 155 static void setup_MC_state(SkMCState* state, const SkMatrix& matrix, const SkRegion& clip) { 156 // initialize the struct 157 state->clipRectCount = 0; 158 159 // capture the matrix 160 for (int i = 0; i < 9; i++) { 161 state->matrix[i] = matrix.get(i); 162 } 163 164 /* 165 * capture the clip 166 * 167 * storage is allocated on the stack for the first 4 rects. This value was 168 * chosen somewhat arbitrarily, but does allow us to represent simple clips 169 * and some more common complex clips (e.g. a clipRect with a sub-rect 170 * clipped out of its interior) without needing to malloc any additional memory. 171 */ 172 SkSWriter32<4*sizeof(ClipRect)> clipWriter; 173 174 if (!clip.isEmpty()) { 175 // only returns the b/w clip so aa clips fail 176 SkRegion::Iterator clip_iterator(clip); 177 for (; !clip_iterator.done(); clip_iterator.next()) { 178 // this assumes the SkIRect is stored in l,t,r,b ordering which 179 // matches the ordering of our ClipRect struct 180 clipWriter.writeIRect(clip_iterator.rect()); 181 state->clipRectCount++; 182 } 183 } 184 185 // allocate memory for the clip then and copy them to the struct 186 state->clipRects = (ClipRect*) sk_malloc_throw(clipWriter.bytesWritten()); 187 clipWriter.flatten(state->clipRects); 188 } 189 190 191 192 SkCanvasState* SkCanvasStateUtils::CaptureCanvasState(SkCanvas* canvas) { 193 SkASSERT(canvas); 194 195 // Check the clip can be decomposed into rectangles (i.e. no soft clips). 196 ClipValidator validator; 197 canvas->replayClips(&validator); 198 if (validator.failed()) { 199 SkErrorInternals::SetError(kInvalidOperation_SkError, 200 "CaptureCanvasState does not support canvases with antialiased clips.\n"); 201 return NULL; 202 } 203 204 SkAutoTDelete<SkCanvasState_v1> canvasState(SkNEW_ARGS(SkCanvasState_v1, (canvas))); 205 206 // decompose the total matrix and clip 207 setup_MC_state(&canvasState->mcState, canvas->getTotalMatrix(), 208 canvas->internal_private_getTotalClip()); 209 210 /* 211 * decompose the layers 212 * 213 * storage is allocated on the stack for the first 3 layers. It is common in 214 * some view systems (e.g. Android) that a few non-clipped layers are present 215 * and we will not need to malloc any additional memory in those cases. 216 */ 217 SkSWriter32<3*sizeof(SkCanvasLayerState)> layerWriter; 218 int layerCount = 0; 219 for (SkCanvas::LayerIter layer(canvas, true/*skipEmptyClips*/); !layer.done(); layer.next()) { 220 221 // we currently only work for bitmap backed devices 222 const SkBitmap& bitmap = layer.device()->accessBitmap(true/*changePixels*/); 223 if (bitmap.empty() || bitmap.isNull() || !bitmap.lockPixelsAreWritable()) { 224 return NULL; 225 } 226 227 SkCanvasLayerState* layerState = 228 (SkCanvasLayerState*) layerWriter.reserve(sizeof(SkCanvasLayerState)); 229 layerState->type = kRaster_CanvasBackend; 230 layerState->x = layer.x(); 231 layerState->y = layer.y(); 232 layerState->width = bitmap.width(); 233 layerState->height = bitmap.height(); 234 235 switch (bitmap.colorType()) { 236 case kN32_SkColorType: 237 layerState->raster.config = kARGB_8888_RasterConfig; 238 break; 239 case kRGB_565_SkColorType: 240 layerState->raster.config = kRGB_565_RasterConfig; 241 break; 242 default: 243 return NULL; 244 } 245 layerState->raster.rowBytes = bitmap.rowBytes(); 246 layerState->raster.pixels = bitmap.getPixels(); 247 248 setup_MC_state(&layerState->mcState, layer.matrix(), layer.clip()); 249 layerCount++; 250 } 251 252 // allocate memory for the layers and then and copy them to the struct 253 SkASSERT(layerWriter.bytesWritten() == layerCount * sizeof(SkCanvasLayerState)); 254 canvasState->layerCount = layerCount; 255 canvasState->layers = (SkCanvasLayerState*) sk_malloc_throw(layerWriter.bytesWritten()); 256 layerWriter.flatten(canvasState->layers); 257 258 // for now, just ignore any client supplied DrawFilter. 259 if (canvas->getDrawFilter()) { 260 // SkDEBUGF(("CaptureCanvasState will ignore the canvas's draw filter.\n")); 261 } 262 263 return canvasState.detach(); 264 } 265 266 //////////////////////////////////////////////////////////////////////////////// 267 268 static void setup_canvas_from_MC_state(const SkMCState& state, SkCanvas* canvas) { 269 // reconstruct the matrix 270 SkMatrix matrix; 271 for (int i = 0; i < 9; i++) { 272 matrix.set(i, state.matrix[i]); 273 } 274 275 // reconstruct the clip 276 SkRegion clip; 277 for (int i = 0; i < state.clipRectCount; ++i) { 278 clip.op(SkIRect::MakeLTRB(state.clipRects[i].left, 279 state.clipRects[i].top, 280 state.clipRects[i].right, 281 state.clipRects[i].bottom), 282 SkRegion::kUnion_Op); 283 } 284 285 canvas->setMatrix(matrix); 286 canvas->setClipRegion(clip); 287 } 288 289 static SkCanvas* create_canvas_from_canvas_layer(const SkCanvasLayerState& layerState) { 290 SkASSERT(kRaster_CanvasBackend == layerState.type); 291 292 SkBitmap bitmap; 293 SkColorType colorType = 294 layerState.raster.config == kARGB_8888_RasterConfig ? kN32_SkColorType : 295 layerState.raster.config == kRGB_565_RasterConfig ? kRGB_565_SkColorType : 296 kUnknown_SkColorType; 297 298 if (colorType == kUnknown_SkColorType) { 299 return NULL; 300 } 301 302 bitmap.installPixels(SkImageInfo::Make(layerState.width, layerState.height, 303 colorType, kPremul_SkAlphaType), 304 layerState.raster.pixels, (size_t) layerState.raster.rowBytes); 305 306 SkASSERT(!bitmap.empty()); 307 SkASSERT(!bitmap.isNull()); 308 309 SkAutoTUnref<SkCanvas> canvas(SkNEW_ARGS(SkCanvas, (bitmap))); 310 311 // setup the matrix and clip 312 setup_canvas_from_MC_state(layerState.mcState, canvas.get()); 313 314 return canvas.detach(); 315 } 316 317 SkCanvas* SkCanvasStateUtils::CreateFromCanvasState(const SkCanvasState* state) { 318 SkASSERT(state); 319 // Currently there is only one possible version. 320 SkASSERT(SkCanvasState_v1::kVersion == state->version); 321 322 const SkCanvasState_v1* state_v1 = static_cast<const SkCanvasState_v1*>(state); 323 324 if (state_v1->layerCount < 1) { 325 return NULL; 326 } 327 328 SkAutoTUnref<SkCanvasStack> canvas(SkNEW_ARGS(SkCanvasStack, (state->width, state->height))); 329 330 // setup the matrix and clip on the n-way canvas 331 setup_canvas_from_MC_state(state_v1->mcState, canvas); 332 333 // Iterate over the layers and add them to the n-way canvas 334 for (int i = state_v1->layerCount - 1; i >= 0; --i) { 335 SkAutoTUnref<SkCanvas> canvasLayer(create_canvas_from_canvas_layer(state_v1->layers[i])); 336 if (!canvasLayer.get()) { 337 return NULL; 338 } 339 canvas->pushCanvas(canvasLayer.get(), SkIPoint::Make(state_v1->layers[i].x, 340 state_v1->layers[i].y)); 341 } 342 343 return canvas.detach(); 344 } 345 346 //////////////////////////////////////////////////////////////////////////////// 347 348 void SkCanvasStateUtils::ReleaseCanvasState(SkCanvasState* state) { 349 SkASSERT(!state || SkCanvasState_v1::kVersion == state->version); 350 // Upcast to the correct version of SkCanvasState. This avoids having a virtual destructor on 351 // SkCanvasState. That would be strange since SkCanvasState has no other virtual functions, and 352 // instead uses the field "version" to determine how to behave. 353 SkDELETE(static_cast<SkCanvasState_v1*>(state)); 354 } 355