| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| #include "src/pathops/SkOpEdgeBuilder.h" |
| |
| #include "include/core/SkPath.h" |
| #include "include/core/SkPoint.h" |
| #include "include/core/SkTypes.h" |
| #include "src/core/SkGeometry.h" |
| #include "src/core/SkPathPriv.h" |
| #include "src/core/SkTSort.h" |
| #include "src/pathops/SkPathOpsCubic.h" |
| #include "src/pathops/SkPathOpsPoint.h" |
| #include "src/pathops/SkReduceOrder.h" |
| |
| #include <algorithm> |
| #include <array> |
| |
| void SkOpEdgeBuilder::init() { |
| fOperand = false; |
| fXorMask[0] = fXorMask[1] = ((int)fPath->getFillType() & 1) ? kEvenOdd_PathOpsMask |
| : kWinding_PathOpsMask; |
| fUnparseable = false; |
| fSecondHalf = preFetch(); |
| } |
| |
| // very tiny points cause numerical instability : don't allow them |
| static SkPoint force_small_to_zero(const SkPoint& pt) { |
| SkPoint ret = pt; |
| if (SkScalarAbs(ret.fX) < FLT_EPSILON_ORDERABLE_ERR) { |
| ret.fX = 0; |
| } |
| if (SkScalarAbs(ret.fY) < FLT_EPSILON_ORDERABLE_ERR) { |
| ret.fY = 0; |
| } |
| return ret; |
| } |
| |
| static bool can_add_curve(SkPath::Verb verb, SkPoint* curve) { |
| if (SkPath::kMove_Verb == verb) { |
| return false; |
| } |
| for (int index = 0; index <= SkPathOpsVerbToPoints(verb); ++index) { |
| curve[index] = force_small_to_zero(curve[index]); |
| } |
| return SkPath::kLine_Verb != verb || !SkDPoint::ApproximatelyEqual(curve[0], curve[1]); |
| } |
| |
| void SkOpEdgeBuilder::addOperand(const SkPath& path) { |
| SkASSERT(!fPathVerbs.empty() && fPathVerbs.back() == SkPath::kDone_Verb); |
| fPathVerbs.pop_back(); |
| fPath = &path; |
| fXorMask[1] = ((int)fPath->getFillType() & 1) ? kEvenOdd_PathOpsMask |
| : kWinding_PathOpsMask; |
| preFetch(); |
| } |
| |
| bool SkOpEdgeBuilder::finish() { |
| fOperand = false; |
| if (fUnparseable || !walk()) { |
| return false; |
| } |
| complete(); |
| SkOpContour* contour = fContourBuilder.contour(); |
| if (contour && !contour->count()) { |
| fContoursHead->remove(contour); |
| } |
| return true; |
| } |
| |
| void SkOpEdgeBuilder::closeContour(const SkPoint& curveEnd, const SkPoint& curveStart) { |
| if (!SkDPoint::ApproximatelyEqual(curveEnd, curveStart)) { |
| *fPathVerbs.append() = SkPath::kLine_Verb; |
| *fPathPts.append() = curveStart; |
| } else { |
| int verbCount = fPathVerbs.size(); |
| int ptsCount = fPathPts.size(); |
| if (SkPath::kLine_Verb == fPathVerbs[verbCount - 1] |
| && fPathPts[ptsCount - 2] == curveStart) { |
| fPathVerbs.pop_back(); |
| fPathPts.pop_back(); |
| } else { |
| fPathPts[ptsCount - 1] = curveStart; |
| } |
| } |
| *fPathVerbs.append() = SkPath::kClose_Verb; |
| } |
| |
| int SkOpEdgeBuilder::preFetch() { |
| if (!fPath->isFinite()) { |
| fUnparseable = true; |
| return 0; |
| } |
| SkPoint curveStart; |
| SkPoint curve[4]; |
| bool lastCurve = false; |
| for (auto [pathVerb, pts, w] : SkPathPriv::Iterate(*fPath)) { |
| auto verb = static_cast<SkPath::Verb>(pathVerb); |
| switch (verb) { |
| case SkPath::kMove_Verb: |
| if (!fAllowOpenContours && lastCurve) { |
| closeContour(curve[0], curveStart); |
| } |
| *fPathVerbs.append() = verb; |
| curve[0] = force_small_to_zero(pts[0]); |
| *fPathPts.append() = curve[0]; |
| curveStart = curve[0]; |
| lastCurve = false; |
| continue; |
| case SkPath::kLine_Verb: |
| curve[1] = force_small_to_zero(pts[1]); |
| if (SkDPoint::ApproximatelyEqual(curve[0], curve[1])) { |
| uint8_t lastVerb = fPathVerbs.back(); |
| if (lastVerb != SkPath::kLine_Verb && lastVerb != SkPath::kMove_Verb) { |
| fPathPts.back() = curve[0] = curve[1]; |
| } |
| continue; // skip degenerate points |
| } |
| break; |
| case SkPath::kQuad_Verb: |
| curve[1] = force_small_to_zero(pts[1]); |
| curve[2] = force_small_to_zero(pts[2]); |
| verb = SkReduceOrder::Quad(curve, curve); |
| if (verb == SkPath::kMove_Verb) { |
| continue; // skip degenerate points |
| } |
| break; |
| case SkPath::kConic_Verb: |
| curve[1] = force_small_to_zero(pts[1]); |
| curve[2] = force_small_to_zero(pts[2]); |
| verb = SkReduceOrder::Quad(curve, curve); |
| if (SkPath::kQuad_Verb == verb && 1 != *w) { |
| verb = SkPath::kConic_Verb; |
| } else if (verb == SkPath::kMove_Verb) { |
| continue; // skip degenerate points |
| } |
| break; |
| case SkPath::kCubic_Verb: |
| curve[1] = force_small_to_zero(pts[1]); |
| curve[2] = force_small_to_zero(pts[2]); |
| curve[3] = force_small_to_zero(pts[3]); |
| verb = SkReduceOrder::Cubic(curve, curve); |
| if (verb == SkPath::kMove_Verb) { |
| continue; // skip degenerate points |
| } |
| break; |
| case SkPath::kClose_Verb: |
| closeContour(curve[0], curveStart); |
| lastCurve = false; |
| continue; |
| case SkPath::kDone_Verb: |
| continue; |
| } |
| *fPathVerbs.append() = verb; |
| int ptCount = SkPathOpsVerbToPoints(verb); |
| fPathPts.append(ptCount, &curve[1]); |
| if (verb == SkPath::kConic_Verb) { |
| *fWeights.append() = *w; |
| } |
| curve[0] = curve[ptCount]; |
| lastCurve = true; |
| } |
| if (!fAllowOpenContours && lastCurve) { |
| closeContour(curve[0], curveStart); |
| } |
| *fPathVerbs.append() = SkPath::kDone_Verb; |
| return fPathVerbs.size() - 1; |
| } |
| |
| bool SkOpEdgeBuilder::close() { |
| complete(); |
| return true; |
| } |
| |
| bool SkOpEdgeBuilder::walk() { |
| uint8_t* verbPtr = fPathVerbs.begin(); |
| uint8_t* endOfFirstHalf = &verbPtr[fSecondHalf]; |
| SkPoint* pointsPtr = fPathPts.begin(); |
| SkScalar* weightPtr = fWeights.begin(); |
| SkPath::Verb verb; |
| SkOpContour* contour = fContourBuilder.contour(); |
| int moveToPtrBump = 0; |
| while ((verb = (SkPath::Verb) *verbPtr) != SkPath::kDone_Verb) { |
| if (verbPtr == endOfFirstHalf) { |
| fOperand = true; |
| } |
| verbPtr++; |
| switch (verb) { |
| case SkPath::kMove_Verb: |
| if (contour && contour->count()) { |
| if (fAllowOpenContours) { |
| complete(); |
| } else if (!close()) { |
| return false; |
| } |
| } |
| if (!contour) { |
| fContourBuilder.setContour(contour = fContoursHead->appendContour()); |
| } |
| contour->init(fGlobalState, fOperand, |
| fXorMask[fOperand] == kEvenOdd_PathOpsMask); |
| pointsPtr += moveToPtrBump; |
| moveToPtrBump = 1; |
| continue; |
| case SkPath::kLine_Verb: |
| fContourBuilder.addLine(pointsPtr); |
| break; |
| case SkPath::kQuad_Verb: |
| { |
| SkVector vec1 = pointsPtr[1] - pointsPtr[0]; |
| SkVector vec2 = pointsPtr[2] - pointsPtr[1]; |
| if (vec1.dot(vec2) < 0) { |
| SkPoint pair[5]; |
| if (SkChopQuadAtMaxCurvature(pointsPtr, pair) == 1) { |
| goto addOneQuad; |
| } |
| if (!SkScalarsAreFinite(&pair[0].fX, std::size(pair) * 2)) { |
| return false; |
| } |
| for (unsigned index = 0; index < std::size(pair); ++index) { |
| pair[index] = force_small_to_zero(pair[index]); |
| } |
| SkPoint cStorage[2][2]; |
| SkPath::Verb v1 = SkReduceOrder::Quad(&pair[0], cStorage[0]); |
| SkPath::Verb v2 = SkReduceOrder::Quad(&pair[2], cStorage[1]); |
| SkPoint* curve1 = v1 != SkPath::kLine_Verb ? &pair[0] : cStorage[0]; |
| SkPoint* curve2 = v2 != SkPath::kLine_Verb ? &pair[2] : cStorage[1]; |
| if (can_add_curve(v1, curve1) && can_add_curve(v2, curve2)) { |
| fContourBuilder.addCurve(v1, curve1); |
| fContourBuilder.addCurve(v2, curve2); |
| break; |
| } |
| } |
| } |
| addOneQuad: |
| fContourBuilder.addQuad(pointsPtr); |
| break; |
| case SkPath::kConic_Verb: { |
| SkVector vec1 = pointsPtr[1] - pointsPtr[0]; |
| SkVector vec2 = pointsPtr[2] - pointsPtr[1]; |
| SkScalar weight = *weightPtr++; |
| if (vec1.dot(vec2) < 0) { |
| // FIXME: max curvature for conics hasn't been implemented; use placeholder |
| SkScalar maxCurvature = SkFindQuadMaxCurvature(pointsPtr); |
| if (0 < maxCurvature && maxCurvature < 1) { |
| SkConic conic(pointsPtr, weight); |
| SkConic pair[2]; |
| if (!conic.chopAt(maxCurvature, pair)) { |
| // if result can't be computed, use original |
| fContourBuilder.addConic(pointsPtr, weight); |
| break; |
| } |
| SkPoint cStorage[2][3]; |
| SkPath::Verb v1 = SkReduceOrder::Conic(pair[0], cStorage[0]); |
| SkPath::Verb v2 = SkReduceOrder::Conic(pair[1], cStorage[1]); |
| SkPoint* curve1 = v1 != SkPath::kLine_Verb ? pair[0].fPts : cStorage[0]; |
| SkPoint* curve2 = v2 != SkPath::kLine_Verb ? pair[1].fPts : cStorage[1]; |
| if (can_add_curve(v1, curve1) && can_add_curve(v2, curve2)) { |
| fContourBuilder.addCurve(v1, curve1, pair[0].fW); |
| fContourBuilder.addCurve(v2, curve2, pair[1].fW); |
| break; |
| } |
| } |
| } |
| fContourBuilder.addConic(pointsPtr, weight); |
| } break; |
| case SkPath::kCubic_Verb: |
| { |
| // Split complex cubics (such as self-intersecting curves or |
| // ones with difficult curvature) in two before proceeding. |
| // This can be required for intersection to succeed. |
| SkScalar splitT[3]; |
| int breaks = SkDCubic::ComplexBreak(pointsPtr, splitT); |
| if (!breaks) { |
| fContourBuilder.addCubic(pointsPtr); |
| break; |
| } |
| SkASSERT(breaks <= (int) std::size(splitT)); |
| struct Splitsville { |
| double fT[2]; |
| SkPoint fPts[4]; |
| SkPoint fReduced[4]; |
| SkPath::Verb fVerb; |
| bool fCanAdd; |
| } splits[4]; |
| SkASSERT(std::size(splits) == std::size(splitT) + 1); |
| SkTQSort(splitT, splitT + breaks); |
| for (int index = 0; index <= breaks; ++index) { |
| Splitsville* split = &splits[index]; |
| split->fT[0] = index ? splitT[index - 1] : 0; |
| split->fT[1] = index < breaks ? splitT[index] : 1; |
| SkDCubic part = SkDCubic::SubDivide(pointsPtr, split->fT[0], split->fT[1]); |
| if (!part.toFloatPoints(split->fPts)) { |
| return false; |
| } |
| split->fVerb = SkReduceOrder::Cubic(split->fPts, split->fReduced); |
| SkPoint* curve = SkPath::kCubic_Verb == split->fVerb |
| ? split->fPts : split->fReduced; |
| split->fCanAdd = can_add_curve(split->fVerb, curve); |
| } |
| for (int index = 0; index <= breaks; ++index) { |
| Splitsville* split = &splits[index]; |
| if (!split->fCanAdd) { |
| continue; |
| } |
| int prior = index; |
| while (prior > 0 && !splits[prior - 1].fCanAdd) { |
| --prior; |
| } |
| if (prior < index) { |
| split->fT[0] = splits[prior].fT[0]; |
| split->fPts[0] = splits[prior].fPts[0]; |
| } |
| int next = index; |
| int breakLimit = std::min(breaks, (int) std::size(splits) - 1); |
| while (next < breakLimit && !splits[next + 1].fCanAdd) { |
| ++next; |
| } |
| if (next > index) { |
| split->fT[1] = splits[next].fT[1]; |
| split->fPts[3] = splits[next].fPts[3]; |
| } |
| if (prior < index || next > index) { |
| split->fVerb = SkReduceOrder::Cubic(split->fPts, split->fReduced); |
| } |
| SkPoint* curve = SkPath::kCubic_Verb == split->fVerb |
| ? split->fPts : split->fReduced; |
| if (!can_add_curve(split->fVerb, curve)) { |
| return false; |
| } |
| fContourBuilder.addCurve(split->fVerb, curve); |
| } |
| } |
| break; |
| case SkPath::kClose_Verb: |
| SkASSERT(contour); |
| if (!close()) { |
| return false; |
| } |
| contour = nullptr; |
| continue; |
| default: |
| SkDEBUGFAIL("bad verb"); |
| return false; |
| } |
| SkASSERT(contour); |
| if (contour->count()) { |
| contour->debugValidate(); |
| } |
| pointsPtr += SkPathOpsVerbToPoints(verb); |
| } |
| fContourBuilder.flush(); |
| if (contour && contour->count() &&!fAllowOpenContours && !close()) { |
| return false; |
| } |
| return true; |
| } |
