reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame^] | 1 | /* libs/graphics/sgl/SkRegion_path.cpp |
| 2 | ** |
| 3 | ** Copyright 2006, The Android Open Source Project |
| 4 | ** |
| 5 | ** Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | ** you may not use this file except in compliance with the License. |
| 7 | ** You may obtain a copy of the License at |
| 8 | ** |
| 9 | ** http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | ** |
| 11 | ** Unless required by applicable law or agreed to in writing, software |
| 12 | ** distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | ** See the License for the specific language governing permissions and |
| 15 | ** limitations under the License. |
| 16 | */ |
| 17 | |
| 18 | #include "SkRegionPriv.h" |
| 19 | #include "SkBlitter.h" |
| 20 | #include "SkScan.h" |
| 21 | #include "SkTDArray.h" |
| 22 | #include "SkPath.h" |
| 23 | |
| 24 | class SkRgnBuilder : public SkBlitter { |
| 25 | public: |
| 26 | virtual ~SkRgnBuilder(); |
| 27 | |
| 28 | // returns true if it could allocate the working storage needed |
| 29 | bool init(int maxHeight, int maxTransitions); |
| 30 | |
| 31 | void done() { |
| 32 | if (fCurrScanline != NULL) { |
| 33 | fCurrScanline->fXCount = (SkRegion::RunType)((int)(fCurrXPtr - fCurrScanline->firstX())); |
| 34 | if (!this->collapsWithPrev()) { // flush the last line |
| 35 | fCurrScanline = fCurrScanline->nextScanline(); |
| 36 | } |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | int computeRunCount() const; |
| 41 | void copyToRect(SkIRect*) const; |
| 42 | void copyToRgn(SkRegion::RunType runs[]) const; |
| 43 | |
| 44 | virtual void blitH(int x, int y, int width); |
| 45 | |
| 46 | #ifdef SK_DEBUG |
| 47 | void dump() const { |
| 48 | SkDebugf("SkRgnBuilder: Top = %d\n", fTop); |
| 49 | const Scanline* line = (Scanline*)fStorage; |
| 50 | while (line < fCurrScanline) { |
| 51 | SkDebugf("SkRgnBuilder::Scanline: LastY=%d, fXCount=%d", line->fLastY, line->fXCount); |
| 52 | for (int i = 0; i < line->fXCount; i++) { |
| 53 | SkDebugf(" %d", line->firstX()[i]); |
| 54 | } |
| 55 | SkDebugf("\n"); |
| 56 | |
| 57 | line = line->nextScanline(); |
| 58 | } |
| 59 | } |
| 60 | #endif |
| 61 | private: |
| 62 | struct Scanline { |
| 63 | SkRegion::RunType fLastY; |
| 64 | SkRegion::RunType fXCount; |
| 65 | |
| 66 | SkRegion::RunType* firstX() const { return (SkRegion::RunType*)(this + 1); } |
| 67 | Scanline* nextScanline() const { |
| 68 | return (Scanline*)((SkRegion::RunType*)(this + 1) + fXCount); |
| 69 | } |
| 70 | }; |
| 71 | SkRegion::RunType* fStorage; |
| 72 | Scanline* fCurrScanline; |
| 73 | Scanline* fPrevScanline; |
| 74 | // points at next avialable x[] in fCurrScanline |
| 75 | SkRegion::RunType* fCurrXPtr; |
| 76 | SkRegion::RunType fTop; // first Y value |
| 77 | |
| 78 | int fStorageCount; |
| 79 | |
| 80 | bool collapsWithPrev() { |
| 81 | if (fPrevScanline != NULL && |
| 82 | fPrevScanline->fLastY + 1 == fCurrScanline->fLastY && |
| 83 | fPrevScanline->fXCount == fCurrScanline->fXCount && |
| 84 | !memcmp(fPrevScanline->firstX(), |
| 85 | fCurrScanline->firstX(), |
| 86 | fCurrScanline->fXCount * sizeof(SkRegion::RunType))) |
| 87 | { |
| 88 | // update the height of fPrevScanline |
| 89 | fPrevScanline->fLastY = fCurrScanline->fLastY; |
| 90 | return true; |
| 91 | } |
| 92 | return false; |
| 93 | } |
| 94 | }; |
| 95 | |
| 96 | SkRgnBuilder::~SkRgnBuilder() { |
| 97 | sk_free(fStorage); |
| 98 | } |
| 99 | |
| 100 | bool SkRgnBuilder::init(int maxHeight, int maxTransitions) { |
| 101 | if ((maxHeight | maxTransitions) < 0) { |
| 102 | return false; |
| 103 | } |
| 104 | |
| 105 | Sk64 count, size; |
| 106 | |
| 107 | // compute the count with +1 and +3 slop for the working buffer |
| 108 | count.setMul(maxHeight + 1, 3 + maxTransitions); |
| 109 | if (!count.is32() || count.isNeg()) { |
| 110 | return false; |
| 111 | } |
| 112 | fStorageCount = count.get32(); |
| 113 | |
| 114 | size.setMul(fStorageCount, sizeof(SkRegion::RunType)); |
| 115 | if (!size.is32() || size.isNeg()) { |
| 116 | return false; |
| 117 | } |
| 118 | |
| 119 | fStorage = (SkRegion::RunType*)sk_malloc_flags(size.get32(), 0); |
| 120 | if (NULL == fStorage) { |
| 121 | return false; |
| 122 | } |
| 123 | |
| 124 | fCurrScanline = NULL; // signal empty collection |
| 125 | fPrevScanline = NULL; // signal first scanline |
| 126 | return true; |
| 127 | } |
| 128 | |
| 129 | void SkRgnBuilder::blitH(int x, int y, int width) { |
| 130 | if (fCurrScanline == NULL) { // first time |
| 131 | fTop = (SkRegion::RunType)(y); |
| 132 | fCurrScanline = (Scanline*)fStorage; |
| 133 | fCurrScanline->fLastY = (SkRegion::RunType)(y); |
| 134 | fCurrXPtr = fCurrScanline->firstX(); |
| 135 | } else { |
| 136 | SkASSERT(y >= fCurrScanline->fLastY); |
| 137 | |
| 138 | if (y > fCurrScanline->fLastY) { |
| 139 | // if we get here, we're done with fCurrScanline |
| 140 | fCurrScanline->fXCount = (SkRegion::RunType)((int)(fCurrXPtr - fCurrScanline->firstX())); |
| 141 | |
| 142 | int prevLastY = fCurrScanline->fLastY; |
| 143 | if (!this->collapsWithPrev()) { |
| 144 | fPrevScanline = fCurrScanline; |
| 145 | fCurrScanline = fCurrScanline->nextScanline(); |
| 146 | |
| 147 | } |
| 148 | if (y - 1 > prevLastY) { // insert empty run |
| 149 | fCurrScanline->fLastY = (SkRegion::RunType)(y - 1); |
| 150 | fCurrScanline->fXCount = 0; |
| 151 | fCurrScanline = fCurrScanline->nextScanline(); |
| 152 | } |
| 153 | // setup for the new curr line |
| 154 | fCurrScanline->fLastY = (SkRegion::RunType)(y); |
| 155 | fCurrXPtr = fCurrScanline->firstX(); |
| 156 | } |
| 157 | } |
| 158 | // check if we should extend the current run, or add a new one |
| 159 | if (fCurrXPtr > fCurrScanline->firstX() && fCurrXPtr[-1] == x) { |
| 160 | fCurrXPtr[-1] = (SkRegion::RunType)(x + width); |
| 161 | } else { |
| 162 | fCurrXPtr[0] = (SkRegion::RunType)(x); |
| 163 | fCurrXPtr[1] = (SkRegion::RunType)(x + width); |
| 164 | fCurrXPtr += 2; |
| 165 | } |
| 166 | SkASSERT(fCurrXPtr - fStorage < fStorageCount); |
| 167 | } |
| 168 | |
| 169 | int SkRgnBuilder::computeRunCount() const { |
| 170 | if (fCurrScanline == NULL) { |
| 171 | return 0; |
| 172 | } |
| 173 | |
| 174 | const SkRegion::RunType* line = fStorage; |
| 175 | const SkRegion::RunType* stop = (const SkRegion::RunType*)fCurrScanline; |
| 176 | |
| 177 | return 2 + (int)(stop - line); |
| 178 | } |
| 179 | |
| 180 | void SkRgnBuilder::copyToRect(SkIRect* r) const { |
| 181 | SkASSERT(fCurrScanline != NULL); |
| 182 | SkASSERT((const SkRegion::RunType*)fCurrScanline - fStorage == 4); |
| 183 | |
| 184 | const Scanline* line = (const Scanline*)fStorage; |
| 185 | SkASSERT(line->fXCount == 2); |
| 186 | |
| 187 | r->set(line->firstX()[0], fTop, line->firstX()[1], line->fLastY + 1); |
| 188 | } |
| 189 | |
| 190 | void SkRgnBuilder::copyToRgn(SkRegion::RunType runs[]) const { |
| 191 | SkASSERT(fCurrScanline != NULL); |
| 192 | SkASSERT((const SkRegion::RunType*)fCurrScanline - fStorage > 4); |
| 193 | |
| 194 | const Scanline* line = (const Scanline*)fStorage; |
| 195 | const Scanline* stop = fCurrScanline; |
| 196 | |
| 197 | *runs++ = fTop; |
| 198 | do { |
| 199 | *runs++ = (SkRegion::RunType)(line->fLastY + 1); |
| 200 | int count = line->fXCount; |
| 201 | if (count) { |
| 202 | memcpy(runs, line->firstX(), count * sizeof(SkRegion::RunType)); |
| 203 | runs += count; |
| 204 | } |
| 205 | *runs++ = SkRegion::kRunTypeSentinel; |
| 206 | line = line->nextScanline(); |
| 207 | } while (line < stop); |
| 208 | SkASSERT(line == stop); |
| 209 | *runs = SkRegion::kRunTypeSentinel; |
| 210 | } |
| 211 | |
| 212 | static int count_path_runtype_values(const SkPath& path, int* itop, int* ibot) { |
| 213 | static const uint8_t gPathVerbToInitialLastIndex[] = { |
| 214 | 0, // kMove_Verb |
| 215 | 1, // kLine_Verb |
| 216 | 2, // kQuad_Verb |
| 217 | 3, // kCubic_Verb |
| 218 | 0, // kClose_Verb |
| 219 | 0 // kDone_Verb |
| 220 | }; |
| 221 | |
| 222 | static const uint8_t gPathVerbToMaxEdges[] = { |
| 223 | 0, // kMove_Verb |
| 224 | 1, // kLine_Verb |
| 225 | 2, // kQuad_VerbB |
| 226 | 3, // kCubic_Verb |
| 227 | 0, // kClose_Verb |
| 228 | 0 // kDone_Verb |
| 229 | }; |
| 230 | |
| 231 | SkPath::Iter iter(path, true); |
| 232 | SkPoint pts[4]; |
| 233 | SkPath::Verb verb; |
| 234 | |
| 235 | int maxEdges = 0; |
| 236 | SkScalar top = SkIntToScalar(SK_MaxS16); |
| 237 | SkScalar bot = SkIntToScalar(SK_MinS16); |
| 238 | |
| 239 | while ((verb = iter.next(pts)) != SkPath::kDone_Verb) { |
| 240 | maxEdges += gPathVerbToMaxEdges[verb]; |
| 241 | |
| 242 | int lastIndex = gPathVerbToInitialLastIndex[verb]; |
| 243 | if (lastIndex > 0) { |
| 244 | for (int i = 1; i <= lastIndex; i++) { |
| 245 | if (top > pts[i].fY) { |
| 246 | top = pts[i].fY; |
| 247 | } else if (bot < pts[i].fY) { |
| 248 | bot = pts[i].fY; |
| 249 | } |
| 250 | } |
| 251 | } else if (SkPath::kMove_Verb == verb) { |
| 252 | if (top > pts[0].fY) { |
| 253 | top = pts[0].fY; |
| 254 | } else if (bot < pts[0].fY) { |
| 255 | bot = pts[0].fY; |
| 256 | } |
| 257 | } |
| 258 | } |
| 259 | SkASSERT(top <= bot); |
| 260 | |
| 261 | *itop = SkScalarRound(top); |
| 262 | *ibot = SkScalarRound(bot); |
| 263 | return maxEdges; |
| 264 | } |
| 265 | |
| 266 | bool SkRegion::setPath(const SkPath& path, const SkRegion& clip) { |
| 267 | SkDEBUGCODE(this->validate();) |
| 268 | |
| 269 | if (clip.isEmpty()) { |
| 270 | return this->setEmpty(); |
| 271 | } |
| 272 | |
| 273 | if (path.isEmpty()) { |
| 274 | if (path.isInverseFillType()) { |
| 275 | return this->set(clip); |
| 276 | } else { |
| 277 | return this->setEmpty(); |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | // compute worst-case rgn-size for the path |
| 282 | int pathTop, pathBot; |
| 283 | int pathTransitions = count_path_runtype_values(path, &pathTop, &pathBot); |
| 284 | int clipTop, clipBot; |
| 285 | int clipTransitions; |
| 286 | |
| 287 | clipTransitions = clip.count_runtype_values(&clipTop, &clipBot); |
| 288 | |
| 289 | int top = SkMax32(pathTop, clipTop); |
| 290 | int bot = SkMin32(pathBot, clipBot); |
| 291 | |
| 292 | if (top >= bot) |
| 293 | return this->setEmpty(); |
| 294 | |
| 295 | SkRgnBuilder builder; |
| 296 | |
| 297 | if (!builder.init(bot - top, SkMax32(pathTransitions, clipTransitions))) { |
| 298 | // can't allocate working space, so return false |
| 299 | return this->setEmpty(); |
| 300 | } |
| 301 | |
| 302 | SkScan::FillPath(path, clip, &builder); |
| 303 | builder.done(); |
| 304 | |
| 305 | int count = builder.computeRunCount(); |
| 306 | if (count == 0) { |
| 307 | return this->setEmpty(); |
| 308 | } else if (count == kRectRegionRuns) { |
| 309 | builder.copyToRect(&fBounds); |
| 310 | this->setRect(fBounds); |
| 311 | } else { |
| 312 | SkRegion tmp; |
| 313 | |
| 314 | tmp.fRunHead = RunHead::Alloc(count); |
| 315 | builder.copyToRgn(tmp.fRunHead->writable_runs()); |
| 316 | ComputeRunBounds(tmp.fRunHead->readonly_runs(), count, &tmp.fBounds); |
| 317 | this->swap(tmp); |
| 318 | } |
| 319 | SkDEBUGCODE(this->validate();) |
| 320 | return true; |
| 321 | } |
| 322 | |
| 323 | ///////////////////////////////////////////////////////////////////////////////////////////////// |
| 324 | ///////////////////////////////////////////////////////////////////////////////////////////////// |
| 325 | |
| 326 | struct Edge { |
| 327 | enum { |
| 328 | kY0Link = 0x01, |
| 329 | kY1Link = 0x02, |
| 330 | |
| 331 | kCompleteLink = (kY0Link | kY1Link) |
| 332 | }; |
| 333 | |
| 334 | SkRegion::RunType fX; |
| 335 | SkRegion::RunType fY0, fY1; |
| 336 | uint8_t fFlags; |
| 337 | Edge* fNext; |
| 338 | |
| 339 | void set(int x, int y0, int y1) { |
| 340 | SkASSERT(y0 != y1); |
| 341 | |
| 342 | fX = (SkRegion::RunType)(x); |
| 343 | fY0 = (SkRegion::RunType)(y0); |
| 344 | fY1 = (SkRegion::RunType)(y1); |
| 345 | fFlags = 0; |
| 346 | SkDEBUGCODE(fNext = NULL;) |
| 347 | } |
| 348 | |
| 349 | int top() const { |
| 350 | return SkFastMin32(fY0, fY1); |
| 351 | } |
| 352 | }; |
| 353 | |
| 354 | static void find_link(Edge* base, Edge* stop) { |
| 355 | SkASSERT(base < stop); |
| 356 | |
| 357 | if (base->fFlags == Edge::kCompleteLink) { |
| 358 | SkASSERT(base->fNext); |
| 359 | return; |
| 360 | } |
| 361 | |
| 362 | SkASSERT(base + 1 < stop); |
| 363 | |
| 364 | int y0 = base->fY0; |
| 365 | int y1 = base->fY1; |
| 366 | |
| 367 | Edge* e = base; |
| 368 | if ((base->fFlags & Edge::kY0Link) == 0) { |
| 369 | for (;;) { |
| 370 | e += 1; |
| 371 | if ((e->fFlags & Edge::kY1Link) == 0 && y0 == e->fY1) { |
| 372 | SkASSERT(NULL == e->fNext); |
| 373 | e->fNext = base; |
| 374 | e->fFlags = SkToU8(e->fFlags | Edge::kY1Link); |
| 375 | break; |
| 376 | } |
| 377 | } |
| 378 | } |
| 379 | |
| 380 | e = base; |
| 381 | if ((base->fFlags & Edge::kY1Link) == 0) { |
| 382 | for (;;) { |
| 383 | e += 1; |
| 384 | if ((e->fFlags & Edge::kY0Link) == 0 && y1 == e->fY0) { |
| 385 | SkASSERT(NULL == base->fNext); |
| 386 | base->fNext = e; |
| 387 | e->fFlags = SkToU8(e->fFlags | Edge::kY0Link); |
| 388 | break; |
| 389 | } |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | base->fFlags = Edge::kCompleteLink; |
| 394 | } |
| 395 | |
| 396 | static int extract_path(Edge* edge, Edge* stop, SkPath* path) { |
| 397 | while (0 == edge->fFlags) { |
| 398 | edge++; // skip over "used" edges |
| 399 | } |
| 400 | |
| 401 | SkASSERT(edge < stop); |
| 402 | |
| 403 | Edge* base = edge; |
| 404 | Edge* prev = edge; |
| 405 | edge = edge->fNext; |
| 406 | SkASSERT(edge != base); |
| 407 | |
| 408 | int count = 1; |
| 409 | path->moveTo(SkIntToScalar(prev->fX), SkIntToScalar(prev->fY0)); |
| 410 | prev->fFlags = 0; |
| 411 | do { |
| 412 | if (prev->fX != edge->fX || prev->fY1 != edge->fY0) { // skip collinear |
| 413 | path->lineTo(SkIntToScalar(prev->fX), SkIntToScalar(prev->fY1)); // V |
| 414 | path->lineTo(SkIntToScalar(edge->fX), SkIntToScalar(edge->fY0)); // H |
| 415 | } |
| 416 | prev = edge; |
| 417 | edge = edge->fNext; |
| 418 | count += 1; |
| 419 | prev->fFlags = 0; |
| 420 | } while (edge != base); |
| 421 | path->lineTo(SkIntToScalar(prev->fX), SkIntToScalar(prev->fY1)); // V |
| 422 | path->close(); |
| 423 | return count; |
| 424 | } |
| 425 | |
| 426 | #include "SkTSearch.h" |
| 427 | |
| 428 | static int EdgeProc(const Edge* a, const Edge* b) { |
| 429 | return (a->fX == b->fX) ? a->top() - b->top() : a->fX - b->fX; |
| 430 | } |
| 431 | |
| 432 | bool SkRegion::getBoundaryPath(SkPath* path) const { |
| 433 | if (this->isEmpty()) { |
| 434 | return false; |
| 435 | } |
| 436 | |
| 437 | const SkIRect& bounds = this->getBounds(); |
| 438 | |
| 439 | if (this->isRect()) { |
| 440 | SkRect r; |
| 441 | r.set(bounds); // this converts the ints to scalars |
| 442 | path->addRect(r); |
| 443 | return true; |
| 444 | } |
| 445 | |
| 446 | SkRegion::Iterator iter(*this); |
| 447 | SkTDArray<Edge> edges; |
| 448 | |
| 449 | for (const SkIRect& r = iter.rect(); !iter.done(); iter.next()) { |
| 450 | Edge* edge = edges.append(2); |
| 451 | edge[0].set(r.fLeft, r.fBottom, r.fTop); |
| 452 | edge[1].set(r.fRight, r.fTop, r.fBottom); |
| 453 | } |
| 454 | SkQSort(edges.begin(), edges.count(), sizeof(Edge), (SkQSortCompareProc)EdgeProc); |
| 455 | |
| 456 | int count = edges.count(); |
| 457 | Edge* start = edges.begin(); |
| 458 | Edge* stop = start + count; |
| 459 | Edge* e; |
| 460 | |
| 461 | for (e = start; e != stop; e++) { |
| 462 | find_link(e, stop); |
| 463 | } |
| 464 | |
| 465 | #ifdef SK_DEBUG |
| 466 | for (e = start; e != stop; e++) { |
| 467 | SkASSERT(e->fNext != NULL); |
| 468 | SkASSERT(e->fFlags == Edge::kCompleteLink); |
| 469 | } |
| 470 | #endif |
| 471 | |
| 472 | path->incReserve(count << 1); |
| 473 | do { |
| 474 | SkASSERT(count > 1); |
| 475 | count -= extract_path(start, stop, path); |
| 476 | } while (count > 0); |
| 477 | |
| 478 | return true; |
| 479 | } |
| 480 | |