src/pathops/SkOpSegment.h - platform/external/skqp - Gitiles

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkOpSegment_DEFINE
 #define SkOpSegment_DEFINE

 #include "SkOpAngle.h"
 #include "SkOpSpan.h"
 #include "SkOpTAllocator.h"
 #include "SkPathOpsBounds.h"
 #include "SkPathOpsCubic.h"
 #include "SkPathOpsCurve.h"

 struct SkDCurve;
 class SkOpCoincidence;
 class SkOpContour;
 enum class SkOpRayDir;
 struct SkOpRayHit;
 class SkPathWriter;

 class SkOpSegment {
 public:
     enum AllowAlias {
         kAllowAlias,
         kNoAlias
     };

     bool operator<(const SkOpSegment& rh) const {
         return fBounds.fTop < rh.fBounds.fTop;
     }

     SkOpAngle* activeAngle(SkOpSpanBase* start, SkOpSpanBase** startPtr, SkOpSpanBase** endPtr,
                             bool* done);
     SkOpAngle* activeAngleInner(SkOpSpanBase* start, SkOpSpanBase** startPtr,
                                        SkOpSpanBase** endPtr, bool* done);
     SkOpAngle* activeAngleOther(SkOpSpanBase* start, SkOpSpanBase** startPtr,
                                        SkOpSpanBase** endPtr, bool* done);
     bool activeOp(SkOpSpanBase* start, SkOpSpanBase* end, int xorMiMask, int xorSuMask,
                   SkPathOp op);
     bool activeOp(int xorMiMask, int xorSuMask, SkOpSpanBase* start, SkOpSpanBase* end, SkPathOp op,
                   int* sumMiWinding, int* sumSuWinding);

     bool activeWinding(SkOpSpanBase* start, SkOpSpanBase* end);
     bool activeWinding(SkOpSpanBase* start, SkOpSpanBase* end, int* sumWinding);

     SkOpSegment* addConic(SkPoint pts[3], SkScalar weight, SkOpContour* parent) {
         init(pts, weight, parent, SkPath::kConic_Verb);
         SkDCurve curve;
         curve.fConic.set(pts, weight);
         curve.setConicBounds(pts, weight, 0, 1, &fBounds);
         return this;
     }

     SkOpSegment* addCubic(SkPoint pts[4], SkOpContour* parent) {
         init(pts, 1, parent, SkPath::kCubic_Verb);
         SkDCurve curve;
         curve.fCubic.set(pts);
         curve.setCubicBounds(pts, 1, 0, 1, &fBounds);
         return this;
     }

     void addCurveTo(const SkOpSpanBase* start, const SkOpSpanBase* end, SkPathWriter* path,
                     bool active) const;

     SkOpAngle* addEndSpan(SkChunkAlloc* allocator) {
         SkOpAngle* angle = SkOpTAllocator<SkOpAngle>::Allocate(allocator);
         angle->set(&fTail, fTail.prev());
         fTail.setFromAngle(angle);
         return angle;
     }

     SkOpSegment* addLine(SkPoint pts[2], SkOpContour* parent) {
         init(pts, 1, parent, SkPath::kLine_Verb);
         fBounds.set(pts, 2);
         return this;
     }

     SkOpPtT* addMissing(double t, SkOpSegment* opp, SkChunkAlloc* );

     SkOpAngle* addStartSpan(SkChunkAlloc* allocator) {
         SkOpAngle* angle = SkOpTAllocator<SkOpAngle>::Allocate(allocator);
         angle->set(&fHead, fHead.next());
         fHead.setToAngle(angle);
         return angle;
     }

     SkOpSegment* addQuad(SkPoint pts[3], SkOpContour* parent) {
         init(pts, 1, parent, SkPath::kQuad_Verb);
         SkDCurve curve;
         curve.fQuad.set(pts);
         curve.setQuadBounds(pts, 1, 0, 1, &fBounds);
         return this;
     }

     SkOpPtT* addT(double t, AllowAlias , SkChunkAlloc* );

     void align();

     const SkPathOpsBounds& bounds() const {
         return fBounds;
     }

     void bumpCount() {
         ++fCount;
     }

     void calcAngles(SkChunkAlloc*);
     void checkAngleCoin(SkOpCoincidence* coincidences, SkChunkAlloc* allocator);
     void checkNearCoincidence(SkOpAngle* );
     bool collapsed() const;
     static void ComputeOneSum(const SkOpAngle* baseAngle, SkOpAngle* nextAngle,
                               SkOpAngle::IncludeType );
     static void ComputeOneSumReverse(SkOpAngle* baseAngle, SkOpAngle* nextAngle,
                                      SkOpAngle::IncludeType );
     int computeSum(SkOpSpanBase* start, SkOpSpanBase* end, SkOpAngle::IncludeType includeType);

     SkOpContour* contour() const {
         return fContour;
     }

     int count() const {
         return fCount;
     }

     void debugAddAngle(double startT, double endT, SkChunkAlloc*);
     const SkOpAngle* debugAngle(int id) const;
     SkOpContour* debugContour(int id);

     int debugID() const {
         return SkDEBUGRELEASE(fID, -1);
     }

     SkOpAngle* debugLastAngle();
     const SkOpPtT* debugPtT(int id) const;
     void debugReset();
     const SkOpSegment* debugSegment(int id) const;

 #if DEBUG_ACTIVE_SPANS
     void debugShowActiveSpans() const;
 #endif
 #if DEBUG_MARK_DONE
     void debugShowNewWinding(const char* fun, const SkOpSpan* span, int winding);
     void debugShowNewWinding(const char* fun, const SkOpSpan* span, int winding, int oppWinding);
 #endif

     const SkOpSpanBase* debugSpan(int id) const;
     void debugValidate() const;
     void detach(const SkOpSpan* );
     double distSq(double t, SkOpAngle* opp);

     bool done() const {
         SkASSERT(fDoneCount <= fCount);
         return fDoneCount == fCount;
     }

     bool done(const SkOpAngle* angle) const {
         return angle->start()->starter(angle->end())->done();
     }

     SkDPoint dPtAtT(double mid) const {
         return (*CurveDPointAtT[fVerb])(fPts, fWeight, mid);
     }

     SkDVector dSlopeAtT(double mid) const {
         return (*CurveDSlopeAtT[fVerb])(fPts, fWeight, mid);
     }

     void dump() const;
     void dumpAll() const;
     void dumpAngles() const;
     void dumpCoin() const;
     void dumpPts() const;
     void dumpPtsInner() const;

     SkOpSegment* findNextOp(SkTDArray<SkOpSpanBase*>* chase, SkOpSpanBase** nextStart,
                              SkOpSpanBase** nextEnd, bool* unsortable, SkPathOp op,
                              int xorMiMask, int xorSuMask);
     SkOpSegment* findNextWinding(SkTDArray<SkOpSpanBase*>* chase, SkOpSpanBase** nextStart,
                                   SkOpSpanBase** nextEnd, bool* unsortable);
     SkOpSegment* findNextXor(SkOpSpanBase** nextStart, SkOpSpanBase** nextEnd, bool* unsortable);
     SkOpSpan* findSortableTop(SkOpContour* );
     SkOpGlobalState* globalState() const;

     const SkOpSpan* head() const {
         return &fHead;
     }

     SkOpSpan* head() {
         return &fHead;
     }

     void init(SkPoint pts[], SkScalar weight, SkOpContour* parent, SkPath::Verb verb);

     SkOpSpan* insert(SkOpSpan* prev, SkChunkAlloc* allocator) {
         SkOpSpan* result = SkOpTAllocator<SkOpSpan>::Allocate(allocator);
         SkOpSpanBase* next = prev->next();
         result->setPrev(prev);
         prev->setNext(result);
         SkDEBUGCODE(result->ptT()->fT = 0);
         result->setNext(next);
         if (next) {
             next->setPrev(result);
         }
         return result;
     }

     bool isClose(double t, const SkOpSegment* opp) const;

     bool isHorizontal() const {
         return fBounds.fTop == fBounds.fBottom;
     }

     SkOpSegment* isSimple(SkOpSpanBase** end, int* step) {
         return nextChase(end, step, NULL, NULL);
     }

     bool isVertical() const {
         return fBounds.fLeft == fBounds.fRight;
     }

     bool isVertical(SkOpSpanBase* start, SkOpSpanBase* end) const {
         return (*CurveIsVertical[fVerb])(fPts, fWeight, start->t(), end->t());
     }

     bool isXor() const;

     const SkPoint& lastPt() const {
         return fPts[SkPathOpsVerbToPoints(fVerb)];
     }

     void markAllDone();
     SkOpSpanBase* markAndChaseDone(SkOpSpanBase* start, SkOpSpanBase* end);
     bool markAndChaseWinding(SkOpSpanBase* start, SkOpSpanBase* end, int winding,
             SkOpSpanBase** lastPtr);
     bool markAndChaseWinding(SkOpSpanBase* start, SkOpSpanBase* end, int winding,
             int oppWinding, SkOpSpanBase** lastPtr);
     SkOpSpanBase* markAngle(int maxWinding, int sumWinding, const SkOpAngle* angle);
     SkOpSpanBase* markAngle(int maxWinding, int sumWinding, int oppMaxWinding, int oppSumWinding,
                          const SkOpAngle* angle);
     void markDone(SkOpSpan* );
     bool markWinding(SkOpSpan* , int winding);
     bool markWinding(SkOpSpan* , int winding, int oppWinding);
     bool match(const SkOpPtT* span, const SkOpSegment* parent, double t, const SkPoint& pt) const;
     void missingCoincidence(SkOpCoincidence* coincidences, SkChunkAlloc* allocator);
     void moveMultiples();
     void moveNearby();

     SkOpSegment* next() const {
         return fNext;
     }

     SkOpSegment* nextChase(SkOpSpanBase** , int* step, SkOpSpan** , SkOpSpanBase** last) const;
     bool operand() const;

     static int OppSign(const SkOpSpanBase* start, const SkOpSpanBase* end) {
         int result = start->t() < end->t() ? -start->upCast()->oppValue()
                 : end->upCast()->oppValue();
         return result;
     }

     bool oppXor() const;

     const SkOpSegment* prev() const {
         return fPrev;
     }

     SkPoint ptAtT(double mid) const {
         return (*CurvePointAtT[fVerb])(fPts, fWeight, mid);
     }

     const SkPoint* pts() const {
         return fPts;
     }

     bool ptsDisjoint(const SkOpPtT& span, const SkOpPtT& test) const {
         return ptsDisjoint(span.fT, span.fPt, test.fT, test.fPt);
     }

     bool ptsDisjoint(const SkOpPtT& span, double t, const SkPoint& pt) const {
         return ptsDisjoint(span.fT, span.fPt, t, pt);
     }

     bool ptsDisjoint(double t1, const SkPoint& pt1, double t2, const SkPoint& pt2) const;

     void rayCheck(const SkOpRayHit& base, SkOpRayDir dir, SkOpRayHit** hits,
                   SkChunkAlloc* allocator);

     void resetVisited() {
         fVisited = false;
     }

     void setContour(SkOpContour* contour) {
         fContour = contour;
     }

     void setCubicType(SkDCubic::CubicType cubicType) {
         fCubicType = cubicType;
     }

     void setNext(SkOpSegment* next) {
         fNext = next;
     }

     void setPrev(SkOpSegment* prev) {
         fPrev = prev;
     }

     void setVisited() {
         fVisited = true;
     }

     void setUpWinding(SkOpSpanBase* start, SkOpSpanBase* end, int* maxWinding, int* sumWinding) {
         int deltaSum = SpanSign(start, end);
         *maxWinding = *sumWinding;
         *sumWinding -= deltaSum;
     }

     void setUpWindings(SkOpSpanBase* start, SkOpSpanBase* end, int* sumMiWinding,
                        int* maxWinding, int* sumWinding);
     void setUpWindings(SkOpSpanBase* start, SkOpSpanBase* end, int* sumMiWinding, int* sumSuWinding,
                        int* maxWinding, int* sumWinding, int* oppMaxWinding, int* oppSumWinding);
     void sortAngles();

     static int SpanSign(const SkOpSpanBase* start, const SkOpSpanBase* end) {
         int result = start->t() < end->t() ? -start->upCast()->windValue()
                 : end->upCast()->windValue();
         return result;
     }

     SkOpAngle* spanToAngle(SkOpSpanBase* start, SkOpSpanBase* end) {
         SkASSERT(start != end);
         return start->t() < end->t() ? start->upCast()->toAngle() : start->fromAngle();
     }

     bool subDivide(const SkOpSpanBase* start, const SkOpSpanBase* end, SkDCurve* result) const;
     bool subDivide(const SkOpSpanBase* start, const SkOpSpanBase* end, SkOpCurve* result) const;

     const SkOpSpanBase* tail() const {
         return &fTail;
     }

     SkOpSpanBase* tail() {
         return &fTail;
     }

     void undoneSpan(SkOpSpanBase** start, SkOpSpanBase** end);
     int updateOppWinding(const SkOpSpanBase* start, const SkOpSpanBase* end) const;
     int updateOppWinding(const SkOpAngle* angle) const;
     int updateOppWindingReverse(const SkOpAngle* angle) const;
     int updateWinding(SkOpSpanBase* start, SkOpSpanBase* end);
     int updateWinding(SkOpAngle* angle);
     int updateWindingReverse(const SkOpAngle* angle);

     static bool UseInnerWinding(int outerWinding, int innerWinding);

     SkPath::Verb verb() const {
         return fVerb;
     }

     // look for two different spans that point to the same opposite segment
     bool visited() {
         if (!fVisited) {
             fVisited = true;
             return false;
         }
         return true;
     }

     SkScalar weight() const {
         return fWeight;
     }

     SkOpSpan* windingSpanAtT(double tHit);
     int windSum(const SkOpAngle* angle) const;

     SkPoint* writablePt(bool end) {
         return &fPts[end ? SkPathOpsVerbToPoints(fVerb) : 0];
     }

 private:
     SkOpSpan fHead;  // the head span always has its t set to zero
     SkOpSpanBase fTail;  // the tail span always has its t set to one
     SkOpContour* fContour;
     SkOpSegment* fNext;  // forward-only linked list used by contour to walk the segments
     const SkOpSegment* fPrev;
     SkPoint* fPts;  // pointer into array of points owned by edge builder that may be tweaked
     SkPathOpsBounds fBounds;  // tight bounds
     SkScalar fWeight;
     int fCount;  // number of spans (one for a non-intersecting segment)
     int fDoneCount;  // number of processed spans (zero initially)
     SkPath::Verb fVerb;
     SkDCubic::CubicType fCubicType;
     bool fTopsFound;
     bool fVisited;  // used by missing coincidence check
     SkDEBUGCODE(int fID);
 };

 #endif
	/*
	* Copyright 2012 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/
	#ifndef SkOpSegment_DEFINE
	#define SkOpSegment_DEFINE

	#include "SkOpAngle.h"
	#include "SkOpSpan.h"
	#include "SkOpTAllocator.h"
	#include "SkPathOpsBounds.h"
	#include "SkPathOpsCubic.h"
	#include "SkPathOpsCurve.h"

	struct SkDCurve;
	class SkOpCoincidence;
	class SkOpContour;
	enum class SkOpRayDir;
	struct SkOpRayHit;
	class SkPathWriter;

	class SkOpSegment {
	public:
	enum AllowAlias {
	kAllowAlias,
	kNoAlias
	};

	bool operator<(const SkOpSegment& rh) const {
	return fBounds.fTop < rh.fBounds.fTop;
	}

	SkOpAngle* activeAngle(SkOpSpanBase* start, SkOpSpanBase startPtr, SkOpSpanBase endPtr,
	bool* done);
	SkOpAngle* activeAngleInner(SkOpSpanBase* start, SkOpSpanBase** startPtr,
	SkOpSpanBase** endPtr, bool* done);
	SkOpAngle* activeAngleOther(SkOpSpanBase* start, SkOpSpanBase** startPtr,
	SkOpSpanBase** endPtr, bool* done);
	bool activeOp(SkOpSpanBase* start, SkOpSpanBase* end, int xorMiMask, int xorSuMask,
	SkPathOp op);
	bool activeOp(int xorMiMask, int xorSuMask, SkOpSpanBase* start, SkOpSpanBase* end, SkPathOp op,
	int* sumMiWinding, int* sumSuWinding);

	bool activeWinding(SkOpSpanBase* start, SkOpSpanBase* end);
	bool activeWinding(SkOpSpanBase* start, SkOpSpanBase* end, int* sumWinding);

	SkOpSegment* addConic(SkPoint pts[3], SkScalar weight, SkOpContour* parent) {
	init(pts, weight, parent, SkPath::kConic_Verb);
	SkDCurve curve;
	curve.fConic.set(pts, weight);
	curve.setConicBounds(pts, weight, 0, 1, &fBounds);
	return this;
	}

	SkOpSegment* addCubic(SkPoint pts[4], SkOpContour* parent) {
	init(pts, 1, parent, SkPath::kCubic_Verb);
	SkDCurve curve;
	curve.fCubic.set(pts);
	curve.setCubicBounds(pts, 1, 0, 1, &fBounds);
	return this;
	}

	void addCurveTo(const SkOpSpanBase* start, const SkOpSpanBase* end, SkPathWriter* path,
	bool active) const;

	SkOpAngle* addEndSpan(SkChunkAlloc* allocator) {
	SkOpAngle* angle = SkOpTAllocator<SkOpAngle>::Allocate(allocator);
	angle->set(&fTail, fTail.prev());
	fTail.setFromAngle(angle);
	return angle;
	}

	SkOpSegment* addLine(SkPoint pts[2], SkOpContour* parent) {
	init(pts, 1, parent, SkPath::kLine_Verb);
	fBounds.set(pts, 2);
	return this;
	}

	SkOpPtT* addMissing(double t, SkOpSegment* opp, SkChunkAlloc* );

	SkOpAngle* addStartSpan(SkChunkAlloc* allocator) {
	SkOpAngle* angle = SkOpTAllocator<SkOpAngle>::Allocate(allocator);
	angle->set(&fHead, fHead.next());
	fHead.setToAngle(angle);
	return angle;
	}

	SkOpSegment* addQuad(SkPoint pts[3], SkOpContour* parent) {
	init(pts, 1, parent, SkPath::kQuad_Verb);
	SkDCurve curve;
	curve.fQuad.set(pts);
	curve.setQuadBounds(pts, 1, 0, 1, &fBounds);
	return this;
	}

	SkOpPtT* addT(double t, AllowAlias , SkChunkAlloc* );

	void align();

	const SkPathOpsBounds& bounds() const {
	return fBounds;
	}

	void bumpCount() {
	++fCount;
	}

	void calcAngles(SkChunkAlloc*);
	void checkAngleCoin(SkOpCoincidence* coincidences, SkChunkAlloc* allocator);
	void checkNearCoincidence(SkOpAngle* );
	bool collapsed() const;
	static void ComputeOneSum(const SkOpAngle* baseAngle, SkOpAngle* nextAngle,
	SkOpAngle::IncludeType );
	static void ComputeOneSumReverse(SkOpAngle* baseAngle, SkOpAngle* nextAngle,
	SkOpAngle::IncludeType );
	int computeSum(SkOpSpanBase* start, SkOpSpanBase* end, SkOpAngle::IncludeType includeType);

	SkOpContour* contour() const {
	return fContour;
	}

	int count() const {
	return fCount;
	}

	void debugAddAngle(double startT, double endT, SkChunkAlloc*);
	const SkOpAngle* debugAngle(int id) const;
	SkOpContour* debugContour(int id);

	int debugID() const {
	return SkDEBUGRELEASE(fID, -1);
	}

	SkOpAngle* debugLastAngle();
	const SkOpPtT* debugPtT(int id) const;
	void debugReset();
	const SkOpSegment* debugSegment(int id) const;

	#if DEBUG_ACTIVE_SPANS
	void debugShowActiveSpans() const;
	#endif
	#if DEBUG_MARK_DONE
	void debugShowNewWinding(const char* fun, const SkOpSpan* span, int winding);
	void debugShowNewWinding(const char* fun, const SkOpSpan* span, int winding, int oppWinding);
	#endif

	const SkOpSpanBase* debugSpan(int id) const;
	void debugValidate() const;
	void detach(const SkOpSpan* );
	double distSq(double t, SkOpAngle* opp);

	bool done() const {
	SkASSERT(fDoneCount <= fCount);
	return fDoneCount == fCount;
	}

	bool done(const SkOpAngle* angle) const {
	return angle->start()->starter(angle->end())->done();
	}

	SkDPoint dPtAtT(double mid) const {
	return (*CurveDPointAtT[fVerb])(fPts, fWeight, mid);
	}

	SkDVector dSlopeAtT(double mid) const {
	return (*CurveDSlopeAtT[fVerb])(fPts, fWeight, mid);
	}

	void dump() const;
	void dumpAll() const;
	void dumpAngles() const;
	void dumpCoin() const;
	void dumpPts() const;
	void dumpPtsInner() const;

	SkOpSegment* findNextOp(SkTDArray<SkOpSpanBase> chase, SkOpSpanBase** nextStart,
	SkOpSpanBase** nextEnd, bool* unsortable, SkPathOp op,
	int xorMiMask, int xorSuMask);
	SkOpSegment* findNextWinding(SkTDArray<SkOpSpanBase> chase, SkOpSpanBase** nextStart,
	SkOpSpanBase** nextEnd, bool* unsortable);
	SkOpSegment* findNextXor(SkOpSpanBase nextStart, SkOpSpanBase nextEnd, bool* unsortable);
	SkOpSpan* findSortableTop(SkOpContour* );
	SkOpGlobalState* globalState() const;

	const SkOpSpan* head() const {
	return &fHead;
	}

	SkOpSpan* head() {
	return &fHead;
	}

	void init(SkPoint pts[], SkScalar weight, SkOpContour* parent, SkPath::Verb verb);

	SkOpSpan* insert(SkOpSpan* prev, SkChunkAlloc* allocator) {
	SkOpSpan* result = SkOpTAllocator<SkOpSpan>::Allocate(allocator);
	SkOpSpanBase* next = prev->next();
	result->setPrev(prev);
	prev->setNext(result);
	SkDEBUGCODE(result->ptT()->fT = 0);
	result->setNext(next);
	if (next) {
	next->setPrev(result);
	}
	return result;
	}

	bool isClose(double t, const SkOpSegment* opp) const;

	bool isHorizontal() const {
	return fBounds.fTop == fBounds.fBottom;
	}

	SkOpSegment* isSimple(SkOpSpanBase** end, int* step) {
	return nextChase(end, step, NULL, NULL);
	}

	bool isVertical() const {
	return fBounds.fLeft == fBounds.fRight;
	}

	bool isVertical(SkOpSpanBase* start, SkOpSpanBase* end) const {
	return (*CurveIsVertical[fVerb])(fPts, fWeight, start->t(), end->t());
	}

	bool isXor() const;

	const SkPoint& lastPt() const {
	return fPts[SkPathOpsVerbToPoints(fVerb)];
	}

	void markAllDone();
	SkOpSpanBase* markAndChaseDone(SkOpSpanBase* start, SkOpSpanBase* end);
	bool markAndChaseWinding(SkOpSpanBase* start, SkOpSpanBase* end, int winding,
	SkOpSpanBase** lastPtr);
	bool markAndChaseWinding(SkOpSpanBase* start, SkOpSpanBase* end, int winding,
	int oppWinding, SkOpSpanBase** lastPtr);
	SkOpSpanBase* markAngle(int maxWinding, int sumWinding, const SkOpAngle* angle);
	SkOpSpanBase* markAngle(int maxWinding, int sumWinding, int oppMaxWinding, int oppSumWinding,
	const SkOpAngle* angle);
	void markDone(SkOpSpan* );
	bool markWinding(SkOpSpan* , int winding);
	bool markWinding(SkOpSpan* , int winding, int oppWinding);
	bool match(const SkOpPtT* span, const SkOpSegment* parent, double t, const SkPoint& pt) const;
	void missingCoincidence(SkOpCoincidence* coincidences, SkChunkAlloc* allocator);
	void moveMultiples();
	void moveNearby();

	SkOpSegment* next() const {
	return fNext;
	}

	SkOpSegment* nextChase(SkOpSpanBase** , int* step, SkOpSpan , SkOpSpanBase last) const;
	bool operand() const;

	static int OppSign(const SkOpSpanBase* start, const SkOpSpanBase* end) {
	int result = start->t() < end->t() ? -start->upCast()->oppValue()
	: end->upCast()->oppValue();
	return result;
	}

	bool oppXor() const;

	const SkOpSegment* prev() const {
	return fPrev;
	}

	SkPoint ptAtT(double mid) const {
	return (*CurvePointAtT[fVerb])(fPts, fWeight, mid);
	}

	const SkPoint* pts() const {
	return fPts;
	}

	bool ptsDisjoint(const SkOpPtT& span, const SkOpPtT& test) const {
	return ptsDisjoint(span.fT, span.fPt, test.fT, test.fPt);
	}

	bool ptsDisjoint(const SkOpPtT& span, double t, const SkPoint& pt) const {
	return ptsDisjoint(span.fT, span.fPt, t, pt);
	}

	bool ptsDisjoint(double t1, const SkPoint& pt1, double t2, const SkPoint& pt2) const;

	void rayCheck(const SkOpRayHit& base, SkOpRayDir dir, SkOpRayHit** hits,
	SkChunkAlloc* allocator);

	void resetVisited() {
	fVisited = false;
	}

	void setContour(SkOpContour* contour) {
	fContour = contour;
	}

	void setCubicType(SkDCubic::CubicType cubicType) {
	fCubicType = cubicType;
	}

	void setNext(SkOpSegment* next) {
	fNext = next;
	}

	void setPrev(SkOpSegment* prev) {
	fPrev = prev;
	}

	void setVisited() {
	fVisited = true;
	}

	void setUpWinding(SkOpSpanBase* start, SkOpSpanBase* end, int* maxWinding, int* sumWinding) {
	int deltaSum = SpanSign(start, end);
	maxWinding = sumWinding;
	*sumWinding -= deltaSum;
	}

	void setUpWindings(SkOpSpanBase* start, SkOpSpanBase* end, int* sumMiWinding,
	int* maxWinding, int* sumWinding);
	void setUpWindings(SkOpSpanBase* start, SkOpSpanBase* end, int* sumMiWinding, int* sumSuWinding,
	int* maxWinding, int* sumWinding, int* oppMaxWinding, int* oppSumWinding);
	void sortAngles();

	static int SpanSign(const SkOpSpanBase* start, const SkOpSpanBase* end) {
	int result = start->t() < end->t() ? -start->upCast()->windValue()
	: end->upCast()->windValue();
	return result;
	}

	SkOpAngle* spanToAngle(SkOpSpanBase* start, SkOpSpanBase* end) {
	SkASSERT(start != end);
	return start->t() < end->t() ? start->upCast()->toAngle() : start->fromAngle();
	}

	bool subDivide(const SkOpSpanBase* start, const SkOpSpanBase* end, SkDCurve* result) const;
	bool subDivide(const SkOpSpanBase* start, const SkOpSpanBase* end, SkOpCurve* result) const;

	const SkOpSpanBase* tail() const {
	return &fTail;
	}

	SkOpSpanBase* tail() {
	return &fTail;
	}

	void undoneSpan(SkOpSpanBase start, SkOpSpanBase end);
	int updateOppWinding(const SkOpSpanBase* start, const SkOpSpanBase* end) const;
	int updateOppWinding(const SkOpAngle* angle) const;
	int updateOppWindingReverse(const SkOpAngle* angle) const;
	int updateWinding(SkOpSpanBase* start, SkOpSpanBase* end);
	int updateWinding(SkOpAngle* angle);
	int updateWindingReverse(const SkOpAngle* angle);

	static bool UseInnerWinding(int outerWinding, int innerWinding);

	SkPath::Verb verb() const {
	return fVerb;
	}

	// look for two different spans that point to the same opposite segment
	bool visited() {
	if (!fVisited) {
	fVisited = true;
	return false;
	}
	return true;
	}

	SkScalar weight() const {
	return fWeight;
	}

	SkOpSpan* windingSpanAtT(double tHit);
	int windSum(const SkOpAngle* angle) const;

	SkPoint* writablePt(bool end) {
	return &fPts[end ? SkPathOpsVerbToPoints(fVerb) : 0];
	}

	private:
	SkOpSpan fHead; // the head span always has its t set to zero
	SkOpSpanBase fTail; // the tail span always has its t set to one
	SkOpContour* fContour;
	SkOpSegment* fNext; // forward-only linked list used by contour to walk the segments
	const SkOpSegment* fPrev;
	SkPoint* fPts; // pointer into array of points owned by edge builder that may be tweaked
	SkPathOpsBounds fBounds; // tight bounds
	SkScalar fWeight;
	int fCount; // number of spans (one for a non-intersecting segment)
	int fDoneCount; // number of processed spans (zero initially)
	SkPath::Verb fVerb;
	SkDCubic::CubicType fCubicType;
	bool fTopsFound;
	bool fVisited; // used by missing coincidence check
	SkDEBUGCODE(int fID);
	};

	#endif