SkPathOpsCommon.cpp revision cffbcc3b9665f2c928544b6fc6b8a0e22a4210fb
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#include "SkOpEdgeBuilder.h" 8#include "SkPathOpsCommon.h" 9#include "SkPathWriter.h" 10#include "SkTSort.h" 11 12static int contourRangeCheckY(const SkTDArray<SkOpContour*>& contourList, SkOpSegment** currentPtr, 13 int* indexPtr, int* endIndexPtr, double* bestHit, SkScalar* bestDx, 14 bool* tryAgain, double* midPtr, bool opp) { 15 const int index = *indexPtr; 16 const int endIndex = *endIndexPtr; 17 const double mid = *midPtr; 18 const SkOpSegment* current = *currentPtr; 19 double tAtMid = current->tAtMid(index, endIndex, mid); 20 SkPoint basePt = current->xyAtT(tAtMid); 21 int contourCount = contourList.count(); 22 SkScalar bestY = SK_ScalarMin; 23 SkOpSegment* bestSeg = NULL; 24 int bestTIndex = 0; 25 bool bestOpp; 26 bool hitSomething = false; 27 for (int cTest = 0; cTest < contourCount; ++cTest) { 28 SkOpContour* contour = contourList[cTest]; 29 bool testOpp = contour->operand() ^ current->operand() ^ opp; 30 if (basePt.fY < contour->bounds().fTop) { 31 continue; 32 } 33 if (bestY > contour->bounds().fBottom) { 34 continue; 35 } 36 int segmentCount = contour->segments().count(); 37 for (int test = 0; test < segmentCount; ++test) { 38 SkOpSegment* testSeg = &contour->segments()[test]; 39 SkScalar testY = bestY; 40 double testHit; 41 int testTIndex = testSeg->crossedSpanY(basePt, &testY, &testHit, &hitSomething, tAtMid, 42 testOpp, testSeg == current); 43 if (testTIndex < 0) { 44 if (testTIndex == SK_MinS32) { 45 hitSomething = true; 46 bestSeg = NULL; 47 goto abortContours; // vertical encountered, return and try different point 48 } 49 continue; 50 } 51 if (testSeg == current && current->betweenTs(index, testHit, endIndex)) { 52 double baseT = current->t(index); 53 double endT = current->t(endIndex); 54 double newMid = (testHit - baseT) / (endT - baseT); 55#if DEBUG_WINDING 56 double midT = current->tAtMid(index, endIndex, mid); 57 SkPoint midXY = current->xyAtT(midT); 58 double newMidT = current->tAtMid(index, endIndex, newMid); 59 SkPoint newXY = current->xyAtT(newMidT); 60 SkDebugf("%s [%d] mid=%1.9g->%1.9g s=%1.9g (%1.9g,%1.9g) m=%1.9g (%1.9g,%1.9g)" 61 " n=%1.9g (%1.9g,%1.9g) e=%1.9g (%1.9g,%1.9g)\n", __FUNCTION__, 62 current->debugID(), mid, newMid, 63 baseT, current->xAtT(index), current->yAtT(index), 64 baseT + mid * (endT - baseT), midXY.fX, midXY.fY, 65 baseT + newMid * (endT - baseT), newXY.fX, newXY.fY, 66 endT, current->xAtT(endIndex), current->yAtT(endIndex)); 67#endif 68 *midPtr = newMid * 2; // calling loop with divide by 2 before continuing 69 return SK_MinS32; 70 } 71 bestSeg = testSeg; 72 *bestHit = testHit; 73 bestOpp = testOpp; 74 bestTIndex = testTIndex; 75 bestY = testY; 76 } 77 } 78abortContours: 79 int result; 80 if (!bestSeg) { 81 result = hitSomething ? SK_MinS32 : 0; 82 } else { 83 if (bestSeg->windSum(bestTIndex) == SK_MinS32) { 84 *currentPtr = bestSeg; 85 *indexPtr = bestTIndex; 86 *endIndexPtr = bestSeg->nextSpan(bestTIndex, 1); 87 SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0); 88 *tryAgain = true; 89 return 0; 90 } 91 result = bestSeg->windingAtT(*bestHit, bestTIndex, bestOpp, bestDx); 92 SkASSERT(result == SK_MinS32 || *bestDx); 93 } 94 double baseT = current->t(index); 95 double endT = current->t(endIndex); 96 *bestHit = baseT + mid * (endT - baseT); 97 return result; 98} 99 100SkOpSegment* FindUndone(SkTDArray<SkOpContour*>& contourList, int* start, int* end) { 101 int contourCount = contourList.count(); 102 SkOpSegment* result; 103 for (int cIndex = 0; cIndex < contourCount; ++cIndex) { 104 SkOpContour* contour = contourList[cIndex]; 105 result = contour->undoneSegment(start, end); 106 if (result) { 107 return result; 108 } 109 } 110 return NULL; 111} 112 113SkOpSegment* FindChase(SkTDArray<SkOpSpan*>& chase, int& tIndex, int& endIndex) { 114 while (chase.count()) { 115 SkOpSpan* span; 116 chase.pop(&span); 117 const SkOpSpan& backPtr = span->fOther->span(span->fOtherIndex); 118 SkOpSegment* segment = backPtr.fOther; 119 tIndex = backPtr.fOtherIndex; 120 SkTDArray<SkOpAngle> angles; 121 int done = 0; 122 if (segment->activeAngle(tIndex, &done, &angles)) { 123 SkOpAngle* last = angles.end() - 1; 124 tIndex = last->start(); 125 endIndex = last->end(); 126 #if TRY_ROTATE 127 *chase.insert(0) = span; 128 #else 129 *chase.append() = span; 130 #endif 131 return last->segment(); 132 } 133 if (done == angles.count()) { 134 continue; 135 } 136 SkTDArray<SkOpAngle*> sorted; 137 bool sortable = SkOpSegment::SortAngles(angles, &sorted, 138 SkOpSegment::kMayBeUnordered_SortAngleKind); 139 int angleCount = sorted.count(); 140#if DEBUG_SORT 141 sorted[0]->segment()->debugShowSort(__FUNCTION__, sorted, 0, 0, 0); 142#endif 143 if (!sortable) { 144 continue; 145 } 146 // find first angle, initialize winding to computed fWindSum 147 int firstIndex = -1; 148 const SkOpAngle* angle; 149 int winding; 150 do { 151 angle = sorted[++firstIndex]; 152 segment = angle->segment(); 153 winding = segment->windSum(angle); 154 } while (winding == SK_MinS32); 155 int spanWinding = segment->spanSign(angle->start(), angle->end()); 156 #if DEBUG_WINDING 157 SkDebugf("%s winding=%d spanWinding=%d\n", 158 __FUNCTION__, winding, spanWinding); 159 #endif 160 // turn span winding into contour winding 161 if (spanWinding * winding < 0) { 162 winding += spanWinding; 163 } 164 #if DEBUG_SORT 165 segment->debugShowSort(__FUNCTION__, sorted, firstIndex, winding, 0); 166 #endif 167 // we care about first sign and whether wind sum indicates this 168 // edge is inside or outside. Maybe need to pass span winding 169 // or first winding or something into this function? 170 // advance to first undone angle, then return it and winding 171 // (to set whether edges are active or not) 172 int nextIndex = firstIndex + 1; 173 int lastIndex = firstIndex != 0 ? firstIndex : angleCount; 174 angle = sorted[firstIndex]; 175 winding -= angle->segment()->spanSign(angle); 176 do { 177 SkASSERT(nextIndex != firstIndex); 178 if (nextIndex == angleCount) { 179 nextIndex = 0; 180 } 181 angle = sorted[nextIndex]; 182 segment = angle->segment(); 183 int maxWinding = winding; 184 winding -= segment->spanSign(angle); 185 #if DEBUG_SORT 186 SkDebugf("%s id=%d maxWinding=%d winding=%d sign=%d\n", __FUNCTION__, 187 segment->debugID(), maxWinding, winding, angle->sign()); 188 #endif 189 tIndex = angle->start(); 190 endIndex = angle->end(); 191 int lesser = SkMin32(tIndex, endIndex); 192 const SkOpSpan& nextSpan = segment->span(lesser); 193 if (!nextSpan.fDone) { 194 // FIXME: this be wrong? assign startWinding if edge is in 195 // same direction. If the direction is opposite, winding to 196 // assign is flipped sign or +/- 1? 197 if (SkOpSegment::UseInnerWinding(maxWinding, winding)) { 198 maxWinding = winding; 199 } 200 segment->markAndChaseWinding(angle, maxWinding, 0); 201 break; 202 } 203 } while (++nextIndex != lastIndex); 204 *chase.insert(0) = span; 205 return segment; 206 } 207 return NULL; 208} 209 210#if DEBUG_ACTIVE_SPANS || DEBUG_ACTIVE_SPANS_FIRST_ONLY 211void DebugShowActiveSpans(SkTDArray<SkOpContour*>& contourList) { 212 int index; 213 for (index = 0; index < contourList.count(); ++ index) { 214 contourList[index]->debugShowActiveSpans(); 215 } 216} 217#endif 218 219static SkOpSegment* findSortableTop(const SkTDArray<SkOpContour*>& contourList, 220 int* index, int* endIndex, SkPoint* topLeft, bool* unsortable, 221 bool* done, bool onlySortable) { 222 SkOpSegment* result; 223 do { 224 SkPoint bestXY = {SK_ScalarMax, SK_ScalarMax}; 225 int contourCount = contourList.count(); 226 SkOpSegment* topStart = NULL; 227 *done = true; 228 for (int cIndex = 0; cIndex < contourCount; ++cIndex) { 229 SkOpContour* contour = contourList[cIndex]; 230 if (contour->done()) { 231 continue; 232 } 233 const SkPathOpsBounds& bounds = contour->bounds(); 234 if (bounds.fBottom < topLeft->fY) { 235 *done = false; 236 continue; 237 } 238 if (bounds.fBottom == topLeft->fY && bounds.fRight < topLeft->fX) { 239 *done = false; 240 continue; 241 } 242 contour->topSortableSegment(*topLeft, &bestXY, &topStart); 243 if (!contour->done()) { 244 *done = false; 245 } 246 } 247 if (!topStart) { 248 return NULL; 249 } 250 *topLeft = bestXY; 251 result = topStart->findTop(index, endIndex, unsortable, onlySortable); 252 } while (!result); 253 return result; 254} 255 256static int rightAngleWinding(const SkTDArray<SkOpContour*>& contourList, 257 SkOpSegment** current, int* index, int* endIndex, double* tHit, 258 SkScalar* hitDx, bool* tryAgain, bool opp) { 259 double test = 0.9; 260 int contourWinding; 261 do { 262 contourWinding = contourRangeCheckY(contourList, current, index, endIndex, tHit, hitDx, 263 tryAgain, &test, opp); 264 if (contourWinding != SK_MinS32 || *tryAgain) { 265 return contourWinding; 266 } 267 test /= 2; 268 } while (!approximately_negative(test)); 269 SkASSERT(0); // should be OK to comment out, but interested when this hits 270 return contourWinding; 271} 272 273static void skipVertical(const SkTDArray<SkOpContour*>& contourList, 274 SkOpSegment** current, int* index, int* endIndex) { 275 if (!(*current)->isVertical(*index, *endIndex)) { 276 return; 277 } 278 int contourCount = contourList.count(); 279 for (int cIndex = 0; cIndex < contourCount; ++cIndex) { 280 SkOpContour* contour = contourList[cIndex]; 281 if (contour->done()) { 282 continue; 283 } 284 *current = contour->nonVerticalSegment(index, endIndex); 285 if (*current) { 286 return; 287 } 288 } 289} 290 291SkOpSegment* FindSortableTop(const SkTDArray<SkOpContour*>& contourList, bool* firstContour, 292 int* indexPtr, int* endIndexPtr, SkPoint* topLeft, bool* unsortable, 293 bool* done, bool binary) { 294 SkOpSegment* current = findSortableTop(contourList, indexPtr, endIndexPtr, topLeft, unsortable, 295 done, true); 296 if (!current) { 297 return NULL; 298 } 299 const int index = *indexPtr; 300 const int endIndex = *endIndexPtr; 301 if (*firstContour) { 302 current->initWinding(index, endIndex); 303 *firstContour = false; 304 return current; 305 } 306 int minIndex = SkMin32(index, endIndex); 307 int sumWinding = current->windSum(minIndex); 308 if (sumWinding != SK_MinS32) { 309 return current; 310 } 311 sumWinding = current->computeSum(index, endIndex, binary); 312 if (sumWinding != SK_MinS32) { 313 return current; 314 } 315 int contourWinding; 316 int oppContourWinding = 0; 317 // the simple upward projection of the unresolved points hit unsortable angles 318 // shoot rays at right angles to the segment to find its winding, ignoring angle cases 319 bool tryAgain; 320 double tHit; 321 SkScalar hitDx = 0; 322 SkScalar hitOppDx = 0; 323 do { 324 // if current is vertical, find another candidate which is not 325 // if only remaining candidates are vertical, then they can be marked done 326 SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0); 327 skipVertical(contourList, ¤t, indexPtr, endIndexPtr); 328 329 SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0); 330 tryAgain = false; 331 contourWinding = rightAngleWinding(contourList, ¤t, indexPtr, endIndexPtr, &tHit, 332 &hitDx, &tryAgain, false); 333 if (tryAgain) { 334 continue; 335 } 336 if (!binary) { 337 break; 338 } 339 oppContourWinding = rightAngleWinding(contourList, ¤t, indexPtr, endIndexPtr, &tHit, 340 &hitOppDx, &tryAgain, true); 341 } while (tryAgain); 342 current->initWinding(*indexPtr, *endIndexPtr, tHit, contourWinding, hitDx, oppContourWinding, 343 hitOppDx); 344 return current; 345} 346 347void FixOtherTIndex(SkTDArray<SkOpContour*>* contourList) { 348 int contourCount = (*contourList).count(); 349 for (int cTest = 0; cTest < contourCount; ++cTest) { 350 SkOpContour* contour = (*contourList)[cTest]; 351 contour->fixOtherTIndex(); 352 } 353} 354 355void SortSegments(SkTDArray<SkOpContour*>* contourList) { 356 int contourCount = (*contourList).count(); 357 for (int cTest = 0; cTest < contourCount; ++cTest) { 358 SkOpContour* contour = (*contourList)[cTest]; 359 contour->sortSegments(); 360 } 361} 362 363void MakeContourList(SkTArray<SkOpContour>& contours, SkTDArray<SkOpContour*>& list, 364 bool evenOdd, bool oppEvenOdd) { 365 int count = contours.count(); 366 if (count == 0) { 367 return; 368 } 369 for (int index = 0; index < count; ++index) { 370 SkOpContour& contour = contours[index]; 371 contour.setOppXor(contour.operand() ? evenOdd : oppEvenOdd); 372 *list.append() = &contour; 373 } 374 SkTQSort<SkOpContour>(list.begin(), list.end() - 1); 375} 376 377static bool approximatelyEqual(const SkPoint& a, const SkPoint& b) { 378 return AlmostEqualUlps(a.fX, b.fX) && AlmostEqualUlps(a.fY, b.fY); 379} 380 381class DistanceLessThan { 382public: 383 DistanceLessThan(double* distances) : fDistances(distances) { } 384 double* fDistances; 385 bool operator()(const int one, const int two) { 386 return fDistances[one] < fDistances[two]; 387 } 388}; 389 390 /* 391 check start and end of each contour 392 if not the same, record them 393 match them up 394 connect closest 395 reassemble contour pieces into new path 396 */ 397void Assemble(const SkPathWriter& path, SkPathWriter* simple) { 398#if DEBUG_PATH_CONSTRUCTION 399 SkDebugf("%s\n", __FUNCTION__); 400#endif 401 SkTArray<SkOpContour> contours; 402 SkOpEdgeBuilder builder(path, contours); 403 builder.finish(); 404 int count = contours.count(); 405 int outer; 406 SkTDArray<int> runs; // indices of partial contours 407 for (outer = 0; outer < count; ++outer) { 408 const SkOpContour& eContour = contours[outer]; 409 const SkPoint& eStart = eContour.start(); 410 const SkPoint& eEnd = eContour.end(); 411#if DEBUG_ASSEMBLE 412 SkDebugf("%s contour", __FUNCTION__); 413 if (!approximatelyEqual(eStart, eEnd)) { 414 SkDebugf("[%d]", runs.count()); 415 } else { 416 SkDebugf(" "); 417 } 418 SkDebugf(" start=(%1.9g,%1.9g) end=(%1.9g,%1.9g)\n", 419 eStart.fX, eStart.fY, eEnd.fX, eEnd.fY); 420#endif 421 if (approximatelyEqual(eStart, eEnd)) { 422 eContour.toPath(simple); 423 continue; 424 } 425 *runs.append() = outer; 426 } 427 count = runs.count(); 428 if (count == 0) { 429 return; 430 } 431 SkTDArray<int> sLink, eLink; 432 sLink.setCount(count); 433 eLink.setCount(count); 434 int rIndex, iIndex; 435 for (rIndex = 0; rIndex < count; ++rIndex) { 436 sLink[rIndex] = eLink[rIndex] = SK_MaxS32; 437 } 438 SkTDArray<double> distances; 439 const int ends = count * 2; // all starts and ends 440 const int entries = (ends - 1) * count; // folded triangle : n * (n - 1) / 2 441 distances.setCount(entries); 442 for (rIndex = 0; rIndex < ends - 1; ++rIndex) { 443 outer = runs[rIndex >> 1]; 444 const SkOpContour& oContour = contours[outer]; 445 const SkPoint& oPt = rIndex & 1 ? oContour.end() : oContour.start(); 446 const int row = rIndex < count - 1 ? rIndex * ends : (ends - rIndex - 2) 447 * ends - rIndex - 1; 448 for (iIndex = rIndex + 1; iIndex < ends; ++iIndex) { 449 int inner = runs[iIndex >> 1]; 450 const SkOpContour& iContour = contours[inner]; 451 const SkPoint& iPt = iIndex & 1 ? iContour.end() : iContour.start(); 452 double dx = iPt.fX - oPt.fX; 453 double dy = iPt.fY - oPt.fY; 454 double dist = dx * dx + dy * dy; 455 distances[row + iIndex] = dist; // oStart distance from iStart 456 } 457 } 458 SkTDArray<int> sortedDist; 459 sortedDist.setCount(entries); 460 for (rIndex = 0; rIndex < entries; ++rIndex) { 461 sortedDist[rIndex] = rIndex; 462 } 463 SkTQSort<int>(sortedDist.begin(), sortedDist.end() - 1, DistanceLessThan(distances.begin())); 464 int remaining = count; // number of start/end pairs 465 for (rIndex = 0; rIndex < entries; ++rIndex) { 466 int pair = sortedDist[rIndex]; 467 int row = pair / ends; 468 int col = pair - row * ends; 469 int thingOne = row < col ? row : ends - row - 2; 470 int ndxOne = thingOne >> 1; 471 bool endOne = thingOne & 1; 472 int* linkOne = endOne ? eLink.begin() : sLink.begin(); 473 if (linkOne[ndxOne] != SK_MaxS32) { 474 continue; 475 } 476 int thingTwo = row < col ? col : ends - row + col - 1; 477 int ndxTwo = thingTwo >> 1; 478 bool endTwo = thingTwo & 1; 479 int* linkTwo = endTwo ? eLink.begin() : sLink.begin(); 480 if (linkTwo[ndxTwo] != SK_MaxS32) { 481 continue; 482 } 483 SkASSERT(&linkOne[ndxOne] != &linkTwo[ndxTwo]); 484 bool flip = endOne == endTwo; 485 linkOne[ndxOne] = flip ? ~ndxTwo : ndxTwo; 486 linkTwo[ndxTwo] = flip ? ~ndxOne : ndxOne; 487 if (!--remaining) { 488 break; 489 } 490 } 491 SkASSERT(!remaining); 492#if DEBUG_ASSEMBLE 493 for (rIndex = 0; rIndex < count; ++rIndex) { 494 int s = sLink[rIndex]; 495 int e = eLink[rIndex]; 496 SkDebugf("%s %c%d <- s%d - e%d -> %c%d\n", __FUNCTION__, s < 0 ? 's' : 'e', 497 s < 0 ? ~s : s, rIndex, rIndex, e < 0 ? 'e' : 's', e < 0 ? ~e : e); 498 } 499#endif 500 rIndex = 0; 501 do { 502 bool forward = true; 503 bool first = true; 504 int sIndex = sLink[rIndex]; 505 SkASSERT(sIndex != SK_MaxS32); 506 sLink[rIndex] = SK_MaxS32; 507 int eIndex; 508 if (sIndex < 0) { 509 eIndex = sLink[~sIndex]; 510 sLink[~sIndex] = SK_MaxS32; 511 } else { 512 eIndex = eLink[sIndex]; 513 eLink[sIndex] = SK_MaxS32; 514 } 515 SkASSERT(eIndex != SK_MaxS32); 516#if DEBUG_ASSEMBLE 517 SkDebugf("%s sIndex=%c%d eIndex=%c%d\n", __FUNCTION__, sIndex < 0 ? 's' : 'e', 518 sIndex < 0 ? ~sIndex : sIndex, eIndex < 0 ? 's' : 'e', 519 eIndex < 0 ? ~eIndex : eIndex); 520#endif 521 do { 522 outer = runs[rIndex]; 523 const SkOpContour& contour = contours[outer]; 524 if (first) { 525 first = false; 526 const SkPoint* startPtr = &contour.start(); 527 simple->deferredMove(startPtr[0]); 528 } 529 if (forward) { 530 contour.toPartialForward(simple); 531 } else { 532 contour.toPartialBackward(simple); 533 } 534#if DEBUG_ASSEMBLE 535 SkDebugf("%s rIndex=%d eIndex=%s%d close=%d\n", __FUNCTION__, rIndex, 536 eIndex < 0 ? "~" : "", eIndex < 0 ? ~eIndex : eIndex, 537 sIndex == ((rIndex != eIndex) ^ forward ? eIndex : ~eIndex)); 538#endif 539 if (sIndex == ((rIndex != eIndex) ^ forward ? eIndex : ~eIndex)) { 540 simple->close(); 541 break; 542 } 543 if (forward) { 544 eIndex = eLink[rIndex]; 545 SkASSERT(eIndex != SK_MaxS32); 546 eLink[rIndex] = SK_MaxS32; 547 if (eIndex >= 0) { 548 SkASSERT(sLink[eIndex] == rIndex); 549 sLink[eIndex] = SK_MaxS32; 550 } else { 551 SkASSERT(eLink[~eIndex] == ~rIndex); 552 eLink[~eIndex] = SK_MaxS32; 553 } 554 } else { 555 eIndex = sLink[rIndex]; 556 SkASSERT(eIndex != SK_MaxS32); 557 sLink[rIndex] = SK_MaxS32; 558 if (eIndex >= 0) { 559 SkASSERT(eLink[eIndex] == rIndex); 560 eLink[eIndex] = SK_MaxS32; 561 } else { 562 SkASSERT(sLink[~eIndex] == ~rIndex); 563 sLink[~eIndex] = SK_MaxS32; 564 } 565 } 566 rIndex = eIndex; 567 if (rIndex < 0) { 568 forward ^= 1; 569 rIndex = ~rIndex; 570 } 571 } while (true); 572 for (rIndex = 0; rIndex < count; ++rIndex) { 573 if (sLink[rIndex] != SK_MaxS32) { 574 break; 575 } 576 } 577 } while (rIndex < count); 578#if DEBUG_ASSEMBLE 579 for (rIndex = 0; rIndex < count; ++rIndex) { 580 SkASSERT(sLink[rIndex] == SK_MaxS32); 581 SkASSERT(eLink[rIndex] == SK_MaxS32); 582 } 583#endif 584} 585