| |
| /* |
| * 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 "CurveIntersection.h" |
| #include "LineIntersection.h" |
| #include "SkPath.h" |
| #include "SkRect.h" |
| #include "SkTArray.h" |
| #include "SkTDArray.h" |
| #include "TSearch.h" |
| |
| static int LineIntersect(const SkPoint a[2], const SkPoint b[2], |
| double aRange[2], double bRange[2]) { |
| _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}}; |
| _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}}; |
| return intersect(aLine, bLine, aRange, bRange); |
| } |
| |
| static int LineIntersect(const SkPoint a[2], SkScalar y, double aRange[2]) { |
| _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}}; |
| return horizontalIntersect(aLine, y, aRange); |
| } |
| |
| static SkScalar LineYAtT(const SkPoint a[2], double t) { |
| _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}}; |
| double y; |
| xy_at_t(aLine, t, *(double*) 0, y); |
| return SkDoubleToScalar(y); |
| } |
| |
| static void LineSubDivide(const SkPoint a[2], double startT, double endT, |
| SkPoint sub[2]) { |
| _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}}; |
| _Line dst; |
| sub_divide(aLine, startT, endT, dst); |
| sub[0].fX = SkDoubleToScalar(dst[0].x); |
| sub[0].fY = SkDoubleToScalar(dst[0].y); |
| sub[1].fX = SkDoubleToScalar(dst[1].x); |
| sub[1].fY = SkDoubleToScalar(dst[1].y); |
| } |
| |
| |
| // functions |
| void contourBounds(const SkPath& path, SkTDArray<SkRect>& boundsArray); |
| void simplify(const SkPath& path, bool asFill, SkPath& simple); |
| /* |
| list of edges |
| bounds for edge |
| sort |
| active T |
| |
| if a contour's bounds is outside of the active area, no need to create edges |
| */ |
| |
| /* given one or more paths, |
| find the bounds of each contour, select the active contours |
| for each active contour, compute a set of edges |
| each edge corresponds to one or more lines and curves |
| leave edges unbroken as long as possible |
| when breaking edges, compute the t at the break but leave the control points alone |
| |
| */ |
| |
| void contourBounds(const SkPath& path, SkTDArray<SkRect>& boundsArray) { |
| SkPath::Iter iter(path, false); |
| SkPoint pts[4]; |
| SkPath::Verb verb; |
| SkRect bounds; |
| bounds.setEmpty(); |
| int count = 0; |
| while ((verb = iter.next(pts)) != SkPath::kDone_Verb) { |
| switch (verb) { |
| case SkPath::kMove_Verb: |
| if (!bounds.isEmpty()) { |
| *boundsArray.append() = bounds; |
| } |
| bounds.set(pts[0].fX, pts[0].fY, pts[0].fX, pts[0].fY); |
| count = 0; |
| break; |
| case SkPath::kLine_Verb: |
| count = 1; |
| break; |
| case SkPath::kQuad_Verb: |
| count = 2; |
| break; |
| case SkPath::kCubic_Verb: |
| count = 3; |
| break; |
| case SkPath::kClose_Verb: |
| count = 0; |
| break; |
| default: |
| SkDEBUGFAIL("bad verb"); |
| return; |
| } |
| for (int i = 1; i <= count; ++i) { |
| bounds.growToInclude(pts[i].fX, pts[i].fY); |
| } |
| } |
| } |
| |
| static bool extendLine(const SkPoint line[2], const SkPoint& add) { |
| // FIXME: allow this to extend lines that have slopes that are nearly equal |
| SkScalar dx1 = line[1].fX - line[0].fX; |
| SkScalar dy1 = line[1].fY - line[0].fY; |
| SkScalar dx2 = add.fX - line[0].fX; |
| SkScalar dy2 = add.fY - line[0].fY; |
| return dx1 * dy2 == dx2 * dy1; |
| } |
| |
| struct OutEdge { |
| bool operator<(const OutEdge& rh) const { |
| const SkPoint& first = fPts.begin()[0]; |
| const SkPoint& rhFirst = rh.fPts.begin()[0]; |
| return first.fY == rhFirst.fY |
| ? first.fX < rhFirst.fX |
| : first.fY < rhFirst.fY; |
| } |
| |
| SkTDArray<SkPoint> fPts; |
| SkTDArray<uint8_t> fVerbs; |
| }; |
| |
| // for sorting only |
| class OutBottomEdge : public OutEdge { |
| public: |
| bool operator<(const OutBottomEdge& rh) const { |
| const SkPoint& last = fPts.end()[-1]; |
| const SkPoint& rhLast = rh.fPts.end()[-1]; |
| return last.fY == rhLast.fY |
| ? last.fX < rhLast.fX |
| : last.fY < rhLast.fY; |
| } |
| |
| }; |
| |
| class OutEdgeBuilder { |
| public: |
| OutEdgeBuilder(bool fill) |
| : fFill(fill) { |
| } |
| |
| void addLine(const SkPoint line[2]) { |
| size_t count = fEdges.count(); |
| for (size_t index = 0; index < count; ++index) { |
| SkTDArray<SkPoint>& pts = fEdges[index].fPts; |
| SkPoint* last = pts.end() - 1; |
| if (last[0] == line[0]) { |
| if (extendLine(&last[-1], line[1])) { |
| last[0] = line[1]; |
| } else { |
| *pts.append() = line[1]; |
| } |
| return; |
| } |
| } |
| OutEdge& edge = fEdges.push_back(); |
| *edge.fPts.append() = line[0]; |
| *edge.fPts.append() = line[1]; |
| } |
| |
| void assemble(SkPath& simple) { |
| size_t index = 0; |
| do { |
| SkTDArray<SkPoint>& downArray = fEdges[index].fPts; |
| SkPoint* pts = downArray.begin(); |
| SkPoints* end = downArray.end(); |
| SkPoint firstPt = pts[0]; |
| simple.moveTo(pts[0].fX, pts[0].fY); |
| while (++pts < end) { |
| simple.lineTo(pts->fX, pts->fY); |
| } |
| index = fBottoms[index]; |
| SkTDArray<SkPoint>& upArray = fEdges[index].fPts; |
| pts = upArray.end(); |
| SkPoints* begin = upArray.begin(); |
| while (--pts > begin) { |
| simple.lineTo(pts->fX, pts->fY); |
| } |
| if (pts[0] == firstPt) { |
| simple.close(); |
| closed = true; |
| |
| } else { |
| simple.lineTo(pts->fX, pts->fY); |
| } |
| index = advance > 0 ? fBottoms[index] : fTops[index]; |
| advance = -advance; |
| } while (true); |
| |
| } else { |
| if (firstAdded.fY == pts[0].fY) { |
| advance = -1; |
| pts = ptArray.end(); |
| } |
| } |
| size_t count2 = ptArray.count(); |
| for (size_t inner = 1; inner < count2; ++inner) { |
| pts += advance; |
| simple.lineTo(pts->fX, pts->fY); |
| } |
| if (*pts == *ptArray.begin()) { |
| // lastAdded = *pts; |
| simple.close(); |
| newContour = true; |
| } |
| } |
| } |
| |
| static bool lessThan(const SkTArray<OutEdge>& edges, const int* onePtr, |
| const int* twoPtr) { |
| int one = *onePtr; |
| const OutEdge& oneEdge = edges[(one < 0 ? -one : one) - 1]; |
| const SkPoint* onePt = one < 0 ? oneEdge.fPts.begin() |
| : oneEdge.fPts.end() - 1; |
| int two = *twoPtr; |
| const OutEdge& twoEdge = edges[(two < 0 ? -two : two) - 1]; |
| const SkPoint* twoPt = two < 0 ? twoEdge.fPts.begin() |
| : twoEdge.fPts.end() - 1; |
| return onePt.fY == twoPt.fY ? onePt.fX < twoPt.fX : onePt.fY < twoPt.fY; |
| } |
| |
| void bridge() { |
| size_t index; |
| size_t count = fEdges.count(); |
| if (!count) { |
| return; |
| } |
| SkASSERT(!fFill || (count & 1) == 0); |
| fTops.setCount(count); |
| sk_bzero(fTops.begin(), sizeof(fTops[0]) * count); |
| fBottoms.setCount(count); |
| sk_bzero(fBottoms.begin(), sizeof(fBottoms[0]) * count); |
| for (index = 0; index < count; ++index) { |
| *fList.append() = index + 1; |
| *fList.append() = -index - 1; |
| } |
| Context context; |
| QSort<SkTArray<OutEdge>&, int>(fEdges, fList.begin(), count, lessThan); |
| connectTops(); |
| // sort bottoms |
| SkTDArray<OutBottomEdge*> bottomList; |
| for (index = 0; index < count; ++index) { |
| *bottomList.append() = static_cast<OutBottomEdge*>(&fEdges[index]); |
| fBottoms[index] = -1; |
| } |
| QSort<OutBottomEdge>(bottomList.begin(), count); |
| connectBottoms(bottomList); |
| } |
| |
| protected: |
| void connectTops() { |
| int* lastPtr = fList.end() - 1; |
| int* leftPtr = fList.begin(); |
| for (; leftPtr < lastPtr; ++leftPtr) { |
| OutEdge* left = edges[(*leftPtr < 0 ? -*leftPtr : *leftPtr) - 1]; |
| int* rightPtr = leftPtr + 1; |
| OutEdge* right = edges[(*rightPtr < 0 ? -*rightPtr : *rightPtr) - 1]; |
| start here; |
| // i'm a bit confused right now -- but i'm trying to sort indices |
| // of paired points and then create more indices so assemble() can |
| // look up the next edge and whether to connect the top or bottom |
| int leftIndex = leftPtr - bottomList.begin(); |
| int rightIndex = rightPtr - bottomList.begin(); |
| SkASSERT(!fFill || left->fPts[0].fY == right->fPts[0].fY); |
| if (fFill || left->fPts[0] == right->fPts[0]) { |
| int leftIndex = leftPtr - topList.begin(); |
| int rightIndex = rightPtr - topList.begin(); |
| fTops[leftIndex] = rightIndex; |
| fTops[rightIndex] = leftIndex; |
| ++rightPtr; |
| } |
| leftPtr = rightPtr; |
| } |
| } |
| |
| void connectBottoms(SkTDArray<OutBottomEdge*>& bottomList) { |
| OutBottomEdge** lastPtr = bottomList.end() - 1; |
| OutBottomEdge** leftPtr = bottomList.begin(); |
| size_t leftCount = (*leftPtr)->fPts.count(); |
| for (; leftPtr < lastPtr; ++leftPtr) { |
| OutBottomEdge** rightPtr = leftPtr + 1; |
| size_t rightCount = (*rightPtr)->fPts.count(); |
| SkASSERT(!fFill || (*leftPtr)->fPts[leftCount].fY |
| == (*rightPtr)->fPts[rightCount].fY); |
| if (fFill || (*leftPtr)->fPts[leftCount] |
| == (*rightPtr)->fPts[rightCount]) { |
| int leftIndex = leftPtr - bottomList.begin(); |
| int rightIndex = rightPtr - bottomList.begin(); |
| fBottoms[leftIndex] = rightIndex; |
| fBottoms[rightIndex] = leftIndex; |
| if (++rightPtr < lastPtr) { |
| rightCount = (*rightPtr)->fPts.count(); |
| } |
| } |
| leftPtr = rightPtr; |
| leftCount = rightCount; |
| } |
| } |
| |
| SkTArray<OutEdge> fEdges; |
| SkTDArray<int> fList; |
| bool fFill; |
| }; |
| |
| // Bounds, unlike Rect, does not consider a vertical line to be empty. |
| struct Bounds : public SkRect { |
| static bool Intersects(const Bounds& a, const Bounds& b) { |
| return a.fLeft <= b.fRight && b.fLeft <= a.fRight && |
| a.fTop <= b.fBottom && b.fTop <= a.fBottom; |
| } |
| }; |
| |
| struct Intercepts { |
| SkTDArray<double> fTs; |
| }; |
| |
| struct InEdge { |
| bool operator<(const InEdge& rh) const { |
| return fBounds.fTop == rh.fBounds.fTop |
| ? fBounds.fLeft < rh.fBounds.fLeft |
| : fBounds.fTop < rh.fBounds.fTop; |
| } |
| |
| void add(double* ts, size_t count, int verbIndex) { |
| Intercepts& intercepts = fIntercepts[verbIndex]; |
| // FIXME: in the pathological case where there is a ton of intercepts, binary search? |
| for (size_t index = 0; index < count; ++index) { |
| double t = ts[index]; |
| size_t tCount = intercepts.fTs.count(); |
| for (size_t idx2 = 0; idx2 < tCount; ++idx2) { |
| if (t <= intercepts.fTs[idx2]) { |
| if (t < intercepts.fTs[idx2]) { |
| *intercepts.fTs.insert(idx2) = t; |
| break; |
| } |
| } |
| } |
| if (tCount == 0 || t > intercepts.fTs[tCount - 1]) { |
| *intercepts.fTs.append() = t; |
| } |
| } |
| } |
| |
| bool cached(const InEdge* edge) { |
| // FIXME: in the pathological case where there is a ton of edges, binary search? |
| size_t count = fCached.count(); |
| for (size_t index = 0; index < count; ++index) { |
| if (edge == fCached[index]) { |
| return true; |
| } |
| if (edge < fCached[index]) { |
| *fCached.insert(index) = edge; |
| return false; |
| } |
| } |
| *fCached.append() = edge; |
| return false; |
| } |
| |
| void complete(signed char winding) { |
| SkPoint* ptPtr = fPts.begin(); |
| SkPoint* ptLast = fPts.end(); |
| if (ptPtr == ptLast) { |
| SkDebugf("empty edge\n"); |
| SkASSERT(0); |
| // FIXME: delete empty edge? |
| return; |
| } |
| fBounds.set(ptPtr->fX, ptPtr->fY, ptPtr->fX, ptPtr->fY); |
| ++ptPtr; |
| while (ptPtr != ptLast) { |
| fBounds.growToInclude(ptPtr->fX, ptPtr->fY); |
| ++ptPtr; |
| } |
| fIntercepts.push_back_n(1); |
| if ((fWinding = winding) < 0) { // reverse verbs, pts, if bottom to top |
| size_t index; |
| size_t last = fPts.count() - 1; |
| for (index = 0; index < last; ++index, --last) { |
| SkTSwap<SkPoint>(fPts[index], fPts[last]); |
| } |
| last = fVerbs.count() - 1; |
| for (index = 0; index < last; ++index, --last) { |
| SkTSwap<uint8_t>(fVerbs[index], fVerbs[last]); |
| } |
| } |
| fContainsIntercepts = false; |
| } |
| |
| // temporary data : move this to a separate struct? |
| SkTDArray<const InEdge*> fCached; // list of edges already intercepted |
| SkTArray<Intercepts> fIntercepts; // one per verb |
| |
| // persistent data |
| SkTDArray<SkPoint> fPts; |
| SkTDArray<uint8_t> fVerbs; |
| Bounds fBounds; |
| signed char fWinding; |
| bool fContainsIntercepts; |
| }; |
| |
| class InEdgeBuilder { |
| public: |
| |
| InEdgeBuilder(const SkPath& path, bool ignoreHorizontal, SkTArray<InEdge>& edges) |
| : fPath(path) |
| , fCurrentEdge(NULL) |
| , fEdges(edges) |
| , fIgnoreHorizontal(ignoreHorizontal) |
| { |
| walk(); |
| } |
| |
| protected: |
| |
| void addEdge() { |
| SkASSERT(fCurrentEdge); |
| fCurrentEdge->fPts.append(fPtCount - fPtOffset, &fPts[fPtOffset]); |
| fPtOffset = 1; |
| *fCurrentEdge->fVerbs.append() = fVerb; |
| } |
| |
| int direction(int count) { |
| fPtCount = count; |
| fIgnorableHorizontal = fIgnoreHorizontal && isHorizontal(); |
| if (fIgnorableHorizontal) { |
| return 0; |
| } |
| int last = count - 1; |
| return fPts[0].fY == fPts[last].fY |
| ? fPts[0].fX == fPts[last].fX ? 0 : fPts[0].fX < fPts[last].fX |
| ? 1 : -1 : fPts[0].fY < fPts[last].fY ? 1 : -1; |
| } |
| |
| bool isHorizontal() { |
| SkScalar y = fPts[0].fY; |
| for (int i = 1; i < fPtCount; ++i) { |
| if (fPts[i].fY != y) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| void startEdge() { |
| fCurrentEdge = fEdges.push_back_n(1); |
| fWinding = 0; |
| fPtOffset = 0; |
| } |
| |
| void walk() { |
| SkPath::Iter iter(fPath, true); |
| int winding = 0; |
| while ((fVerb = iter.next(fPts)) != SkPath::kDone_Verb) { |
| switch (fVerb) { |
| case SkPath::kMove_Verb: |
| winding = 0; |
| startEdge(); |
| continue; |
| case SkPath::kLine_Verb: |
| winding = direction(2); |
| break; |
| case SkPath::kQuad_Verb: |
| winding = direction(3); |
| break; |
| case SkPath::kCubic_Verb: |
| winding = direction(4); |
| break; |
| case SkPath::kClose_Verb: |
| SkASSERT(fCurrentEdge); |
| if (fCurrentEdge->fVerbs.count()) { |
| fCurrentEdge->complete(fWinding); |
| fCurrentEdge = NULL; |
| } |
| continue; |
| default: |
| SkDEBUGFAIL("bad verb"); |
| return; |
| } |
| if (fIgnorableHorizontal) { |
| continue; |
| } |
| if (fWinding + winding == 0) { |
| // FIXME: if prior verb or this verb is a horizontal line, reverse |
| // it instead of starting a new edge |
| SkASSERT(fCurrentEdge); |
| fCurrentEdge->complete(fWinding); |
| startEdge(); |
| } |
| fWinding = winding; |
| addEdge(); |
| } |
| if (fCurrentEdge) { |
| fCurrentEdge->complete(fWinding); |
| } |
| } |
| |
| private: |
| const SkPath& fPath; |
| InEdge* fCurrentEdge; |
| SkTArray<InEdge>& fEdges; |
| SkPoint fPts[4]; |
| SkPath::Verb fVerb; |
| int fPtCount; |
| int fPtOffset; |
| int8_t fWinding; |
| bool fIgnorableHorizontal; |
| bool fIgnoreHorizontal; |
| }; |
| |
| struct WorkEdge { |
| SkScalar bottom() const { |
| return fPts[verb()].fY; |
| } |
| |
| void init(const InEdge* edge) { |
| fEdge = edge; |
| fPts = edge->fPts.begin(); |
| fVerb = edge->fVerbs.begin(); |
| } |
| |
| bool next() { |
| SkASSERT(fVerb < fEdge->fVerbs.end()); |
| fPts += *fVerb++; |
| return fVerb != fEdge->fVerbs.end(); |
| } |
| |
| SkPath::Verb verb() const { |
| return (SkPath::Verb) *fVerb; |
| } |
| |
| int verbIndex() const { |
| return fVerb - fEdge->fVerbs.begin(); |
| } |
| |
| int winding() const { |
| return fEdge->fWinding; |
| } |
| |
| const InEdge* fEdge; |
| const SkPoint* fPts; |
| const uint8_t* fVerb; |
| }; |
| |
| // always constructed with SkTDArray because new edges are inserted |
| // this may be a inappropriate optimization, suggesting that a separate array of |
| // ActiveEdge* may be faster to insert and search |
| struct ActiveEdge { |
| void init(const InEdge* edge) { |
| fWorkEdge.init(edge); |
| initT(); |
| } |
| |
| void initT() { |
| fTs = &fWorkEdge.fEdge->fIntercepts[fWorkEdge.verbIndex()].fTs; |
| fTIndex = 0; |
| } |
| |
| bool nextT() { |
| SkASSERT(fTIndex <= fTs->count()); |
| return ++fTIndex == fTs->count() + 1; |
| } |
| |
| bool next() { |
| bool result = fWorkEdge.next(); |
| initT(); |
| return result; |
| } |
| |
| double t() { |
| if (fTIndex == 0) { |
| return 0; |
| } |
| if (fTIndex > fTs->count()) { |
| return 1; |
| } |
| return (*fTs)[fTIndex - 1]; |
| } |
| |
| WorkEdge fWorkEdge; |
| const SkTDArray<double>* fTs; |
| int fTIndex; |
| }; |
| |
| static void addToActive(SkTDArray<ActiveEdge>& activeEdges, const InEdge* edge) { |
| // FIXME: in the pathological case where there is a ton of intercepts, binary search? |
| size_t count = activeEdges.count(); |
| for (size_t index = 0; index < count; ++index) { |
| if (*edge < *activeEdges[index].fWorkEdge.fEdge) { |
| ActiveEdge* active = activeEdges.insert(index); |
| active->init(edge); |
| return; |
| } |
| if (edge == activeEdges[index].fWorkEdge.fEdge) { |
| return; |
| } |
| } |
| ActiveEdge* active = activeEdges.append(); |
| active->init(edge); |
| } |
| |
| // find any intersections in the range of active edges |
| static void addBottomT(InEdge** currentPtr, InEdge** lastPtr, SkScalar bottom) { |
| InEdge** testPtr = currentPtr; |
| InEdge* test = *testPtr; |
| while (testPtr != lastPtr) { |
| if (test->fBounds.fBottom > bottom) { |
| WorkEdge wt; |
| wt.init(test); |
| do { |
| // FIXME: add all curve types |
| // OPTIMIZATION: if bottom intersection does not change |
| // the winding on either side of the split, don't intersect |
| if (wt.verb() == SkPath::kLine_Verb) { |
| double wtTs[2]; |
| int pts = LineIntersect(wt.fPts, bottom, wtTs); |
| if (pts) { |
| test->add(wtTs, pts, wt.verbIndex()); |
| } |
| } |
| } while (wt.next()); |
| } |
| test = *++testPtr; |
| } |
| } |
| |
| static void addIntersectingTs(InEdge** currentPtr, InEdge** lastPtr) { |
| InEdge** testPtr = currentPtr; |
| InEdge* test = *testPtr; |
| while (testPtr != lastPtr - 1) { |
| InEdge* next = *++testPtr; |
| if (!test->cached(next) |
| && Bounds::Intersects(test->fBounds, next->fBounds)) { |
| WorkEdge wt, wn; |
| wt.init(test); |
| wn.init(next); |
| do { |
| // FIXME: add all combinations of curve types |
| if (wt.verb() == SkPath::kLine_Verb |
| && wn.verb() == SkPath::kLine_Verb) { |
| double wtTs[2], wnTs[2]; |
| int pts = LineIntersect(wt.fPts, wn.fPts, wtTs, wnTs); |
| if (pts) { |
| test->add(wtTs, pts, wt.verbIndex()); |
| test->fContainsIntercepts = true; |
| next->add(wnTs, pts, wn.verbIndex()); |
| next->fContainsIntercepts = true; |
| } |
| } |
| } while (wt.bottom() <= wn.bottom() ? wt.next() : wn.next()); |
| } |
| test = next; |
| } |
| } |
| |
| // compute bottom taking into account any intersected edges |
| static void computeInterceptBottom(SkTDArray<ActiveEdge>& activeEdges, |
| SkScalar& bottom) { |
| ActiveEdge* activePtr = activeEdges.begin() - 1; |
| ActiveEdge* lastActive = activeEdges.end(); |
| while (++activePtr != lastActive) { |
| const InEdge* test = activePtr->fWorkEdge.fEdge; |
| if (!test->fContainsIntercepts) { |
| continue; |
| } |
| WorkEdge wt; |
| wt.init(test); |
| do { |
| // FIXME: add all curve types |
| const Intercepts& intercepts = test->fIntercepts[wt.verbIndex()]; |
| const SkTDArray<double>& fTs = intercepts.fTs; |
| size_t count = fTs.count(); |
| for (size_t index = 0; index < count; ++index) { |
| if (wt.verb() == SkPath::kLine_Verb) { |
| SkScalar yIntercept = LineYAtT(wt.fPts, fTs[index]); |
| if (bottom > yIntercept) { |
| bottom = yIntercept; |
| } |
| } |
| } |
| } while (wt.next()); |
| } |
| } |
| |
| static SkScalar findBottom(InEdge** currentPtr, |
| InEdge** edgeListEnd, SkTDArray<ActiveEdge>& activeEdges, SkScalar y, |
| bool asFill, InEdge**& lastPtr) { |
| InEdge* current = *currentPtr; |
| SkScalar bottom = current->fBounds.fBottom; |
| |
| // find the list of edges that cross y |
| InEdge* last = *lastPtr; |
| while (lastPtr != edgeListEnd) { |
| if (bottom <= last->fBounds.fTop) { |
| break; |
| } |
| SkScalar lastTop = last->fBounds.fTop; |
| // OPTIMIZATION: Shortening the bottom is only interesting when filling |
| // and when the edge is to the left of a longer edge. If it's a framing |
| // edge, or part of the right, it won't effect the longer edges. |
| if (lastTop > y) { |
| if (bottom > lastTop) { |
| bottom = lastTop; |
| break; |
| } |
| } else if (bottom > last->fBounds.fBottom) { |
| bottom = last->fBounds.fBottom; |
| } |
| addToActive(activeEdges, last); |
| last = *++lastPtr; |
| } |
| if (asFill && lastPtr - currentPtr <= 1) { |
| SkDebugf("expect 2 or more edges\n"); |
| SkASSERT(0); |
| } |
| return bottom; |
| } |
| |
| static void makeEdgeList(SkTArray<InEdge>& edges, InEdge& edgeSentinel, |
| SkTDArray<InEdge*>& edgeList) { |
| size_t edgeCount = edges.count(); |
| if (edgeCount == 0) { |
| return; |
| } |
| for (size_t index = 0; index < edgeCount; ++index) { |
| *edgeList.append() = &edges[index]; |
| } |
| edgeSentinel.fBounds.set(SK_ScalarMax, SK_ScalarMax, SK_ScalarMax, SK_ScalarMax); |
| *edgeList.append() = &edgeSentinel; |
| ++edgeCount; |
| QSort<InEdge>(edgeList.begin(), edgeCount); |
| } |
| |
| static void removeEdge(SkTDArray<ActiveEdge>& activeEdges, InEdge** currentPtr) { |
| InEdge* current = *currentPtr; |
| ActiveEdge* activePtr = activeEdges.begin() - 1; |
| ActiveEdge* lastActive = activeEdges.end(); |
| while (++activePtr != lastActive) { |
| if (activePtr->fWorkEdge.fEdge == current) { |
| activeEdges.remove(activePtr - activeEdges.begin()); |
| return; |
| } |
| } |
| } |
| |
| // stitch edge and t range that satisfies operation |
| static void stitchEdge(SkTDArray<ActiveEdge>& activeEdges, SkScalar y, |
| SkScalar bottom, int windingMask, OutEdgeBuilder& outBuilder) { |
| int winding = 0; |
| ActiveEdge* activePtr = activeEdges.begin() - 1; |
| ActiveEdge* lastActive = activeEdges.end(); |
| SkDebugf("%s y=%g bottom=%g\n", __FUNCTION__, y, bottom); |
| while (++activePtr != lastActive) { |
| const WorkEdge& wt = activePtr->fWorkEdge; |
| int lastWinding = winding; |
| winding += wt.winding(); |
| if (!(lastWinding & windingMask) && !(winding & windingMask)) { |
| continue; |
| } |
| do { |
| double currentT = activePtr->t(); |
| const SkPoint* points = wt.fPts; |
| bool last; |
| do { |
| last = activePtr->nextT(); |
| double nextT = activePtr->t(); |
| // FIXME: add all combinations of curve types |
| if (wt.verb() == SkPath::kLine_Verb) { |
| SkPoint clippedPts[2]; |
| const SkPoint* clipped; |
| if (currentT * nextT != 0 || currentT + nextT != 1) { |
| LineSubDivide(points, currentT, nextT, clippedPts); |
| clipped = clippedPts; |
| } else { |
| clipped = points; |
| } |
| SkDebugf("%s line %g,%g %g,%g\n", __FUNCTION__, |
| clipped[0].fX, clipped[0].fY, |
| clipped[1].fX, clipped[1].fY); |
| outBuilder.addLine(clipped); |
| if (clipped[1].fY >= bottom) { |
| goto nextEdge; |
| } |
| } |
| currentT = nextT; |
| } while (!last); |
| } while (activePtr->next()); |
| nextEdge: |
| ; |
| } |
| } |
| |
| void simplify(const SkPath& path, bool asFill, SkPath& simple) { |
| // returns 1 for evenodd, -1 for winding, regardless of inverse-ness |
| int windingMask = (path.getFillType() & 1) ? 1 : -1; |
| simple.reset(); |
| simple.setFillType(SkPath::kEvenOdd_FillType); |
| // turn path into list of edges increasing in y |
| // if an edge is a quad or a cubic with a y extrema, note it, but leave it unbroken |
| // once we have a list, sort it, then walk the list (walk edges twice that have y extrema's on top) |
| // and detect crossings -- look for raw bounds that cross over, then tight bounds that cross |
| SkTArray<InEdge> edges; |
| InEdgeBuilder builder(path, asFill, edges); |
| SkTDArray<InEdge*> edgeList; |
| InEdge edgeSentinel; |
| makeEdgeList(edges, edgeSentinel, edgeList); |
| InEdge** currentPtr = edgeList.begin(); |
| // walk the sorted edges from top to bottom, computing accumulated winding |
| SkTDArray<ActiveEdge> activeEdges; |
| OutEdgeBuilder outBuilder(asFill); |
| SkScalar y = (*currentPtr)->fBounds.fTop; |
| do { |
| InEdge** lastPtr = currentPtr; // find the edge below the bottom of the first set |
| SkScalar bottom = findBottom(currentPtr, edgeList.end(), |
| activeEdges, y, asFill, lastPtr); |
| addBottomT(currentPtr, lastPtr, bottom); |
| addIntersectingTs(currentPtr, lastPtr); |
| computeInterceptBottom(activeEdges, bottom); |
| stitchEdge(activeEdges, y, bottom, windingMask, outBuilder); |
| y = bottom; |
| while ((*currentPtr)->fBounds.fBottom <= y) { |
| removeEdge(activeEdges, currentPtr); |
| ++currentPtr; |
| } |
| } while (*currentPtr != &edgeSentinel); |
| // assemble output path from string of pts, verbs |
| outBuilder.bridge(); |
| outBuilder.assemble(simple); |
| } |
| |
| void testSimplify(); |
| |
| void testSimplify() { |
| SkPath path, out; |
| path.setFillType(SkPath::kWinding_FillType); |
| path.addRect(10, 10, 30, 30); |
| path.addRect(20, 20, 40, 40); |
| simplify(path, true, out); |
| path = out; |
| path.addRect(30, 10, 40, 20); |
| path.addRect(10, 30, 20, 40); |
| simplify(path, true, out); |
| path = out; |
| path.addRect(10, 10, 40, 40, SkPath::kCCW_Direction); |
| simplify(path, true, out); |
| if (!out.isEmpty()) { |
| SkDebugf("expected empty\n"); |
| } |
| } |