pathops version two

src/pathops/SkOpSpan.h

 /*
  * 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 SkOpSpan_DEFINED
 #define SkOpSpan_DEFINED
 
+#include "SkPathOpsDebug.h"
 #include "SkPoint.h"
 
-class SkOpAngle;
+class SkChunkAlloc;
+struct SkOpAngle;
+class SkOpContour;
+class SkOpGlobalState;
 class SkOpSegment;
-
-struct SkOpSpan {
-    SkPoint fPt;  // computed when the curves are intersected
-    double fT;
-    double fOtherT;  // value at fOther[fOtherIndex].fT
-    SkOpSegment* fOther;
-    SkOpAngle* fFromAngle;  // (if t > 0) index into segment's angle array going negative in t
-    SkOpAngle* fToAngle;  // (if t < 1) index into segment's angle array going positive in t
-    int fOtherIndex;  // can't be used during intersection
+class SkOpSpanBase;
+class SkOpSpan;
+
+// subset of op span used by terminal span (when t is equal to one)
+class SkOpPtT {
+public:
+    enum {
+        kIsAlias = 1,
+        kIsDuplicate = 1
+    };
+
+    void addOpp(SkOpPtT* opp) {
+        // find the fOpp ptr to opp
+        SkOpPtT* oppPrev = opp->fNext;
+        if (oppPrev == this) {
+            return;
+        }
+        while (oppPrev->fNext != opp) {
+            oppPrev = oppPrev->fNext;
+             if (oppPrev == this) {
+                 return;
+             }
+        }
+        
+        SkOpPtT* oldNext = this->fNext;
+        SkASSERT(this != opp);
+        this->fNext = opp;
+        SkASSERT(oppPrev != oldNext);
+        oppPrev->fNext = oldNext;
+    }
+
+    bool alias() const;
+    SkOpContour* contour() const;
+
+    int debugID() const {
+        return PATH_OPS_DEBUG_RELEASE(fID, -1);
+    }
+
+    const SkOpAngle* debugAngle(int id) const;
+    SkOpContour* debugContour(int id);
+    int debugLoopLimit(bool report) const;
+    bool debugMatchID(int id) const;
+    const SkOpPtT* debugPtT(int id) const;
+    const SkOpSegment* debugSegment(int id) const;
+    const SkOpSpanBase* debugSpan(int id) const;
+    SkOpGlobalState* globalState() const;
+    void debugValidate() const;
+
+    bool deleted() const {
+        return fDeleted;
+    }
+
+    bool duplicate() const {
+        return fDuplicatePt;
+    }
+
+    void dump() const;  // available to testing only
+    void dumpAll() const;
+    void dumpBase() const;
+
+    void init(SkOpSpanBase* , double t, const SkPoint& , bool dup);
+
+    void insert(SkOpPtT* span) {
+        SkASSERT(span != this);
+        span->fNext = fNext;
+        fNext = span;
+    }
+
+    const SkOpPtT* next() const {
+        return fNext;
+    }
+
+    SkOpPtT* next() {
+        return fNext;
+    }
+
+    bool onEnd() const;
+    SkOpPtT* prev();
+    SkOpPtT* remove();
+    void removeNext(SkOpPtT* kept);
+
+    const SkOpSegment* segment() const;
+    SkOpSegment* segment();
+
+    void setDeleted() {
+        SkASSERT(!fDeleted);
+        fDeleted = true;
+    }
+
+    const SkOpSpanBase* span() const {
+        return fSpan;
+    }
+
+    SkOpSpanBase* span() {
+        return fSpan;
+    }
+
+    double fT; 
+    SkPoint fPt;   // cache of point value at this t
+protected:
+    SkOpSpanBase* fSpan;  // contains winding data
+    SkOpPtT* fNext;  // intersection on opposite curve or alias on this curve
+    bool fDeleted;  // set if removed from span list 
+    bool fDuplicatePt;  // set if identical pt is somewhere in the next loop
+    PATH_OPS_DEBUG_CODE(int fID);
+};
+
+class SkOpSpanBase {
+public:
+    void addSimpleAngle(bool checkFrom , SkChunkAlloc* );
+    void align();
+
+    bool aligned() const {
+        return fAligned;
+    }
+
+    void alignEnd(double t, const SkPoint& pt);
+
+    bool chased() const {
+        return fChased;
+    }
+
+    void clearCoinEnd() {
+        SkASSERT(fCoinEnd != this);
+        fCoinEnd = this;
+    }
+
+    const SkOpSpanBase* coinEnd() const {
+        return fCoinEnd;
+    }
+
+    bool contains(const SkOpSpanBase* ) const;
+    SkOpPtT* contains(const SkOpSegment* );
+
+    bool containsCoinEnd(const SkOpSpanBase* coin) const {
+        SkASSERT(this != coin);
+        const SkOpSpanBase* next = this;
+        while ((next = next->fCoinEnd) != this) {
+            if (next == coin) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    bool containsCoinEnd(const SkOpSegment* ) const;
+    SkOpContour* contour() const;
+
+    int debugBumpCount() {
+        return PATH_OPS_DEBUG_RELEASE(++fCount, -1);
+    }
+
+    int debugID() const {
+        return PATH_OPS_DEBUG_RELEASE(fID, -1);
+    }
+
+    const SkOpAngle* debugAngle(int id) const;
+    bool debugCoinEndLoopCheck() const;
+    SkOpContour* debugContour(int id);
+    const SkOpPtT* debugPtT(int id) const;
+    const SkOpSegment* debugSegment(int id) const;
+    const SkOpSpanBase* debugSpan(int id) const;
+    SkOpGlobalState* globalState() const;
+    void debugValidate() const;
+
+    bool deleted() const {
+        return fPtT.deleted();
+    }
+
+    void dump() const;  // available to testing only
+    void dumpCoin() const;
+    void dumpAll() const;
+    void dumpBase() const;
+
+    bool final() const {
+        return fPtT.fT == 1;
+    }
+
+    SkOpAngle* fromAngle() const {
+        return fFromAngle;
+    }
+
+    void initBase(SkOpSegment* parent, SkOpSpan* prev, double t, const SkPoint& pt);
+
+    void insertCoinEnd(SkOpSpanBase* coin) {
+        if (containsCoinEnd(coin)) {
+            SkASSERT(coin->containsCoinEnd(this));
+            return;
+        }
+        debugValidate();
+        SkASSERT(this != coin);
+        SkOpSpanBase* coinNext = coin->fCoinEnd;
+        coin->fCoinEnd = this->fCoinEnd;
+        this->fCoinEnd = coinNext;
+        debugValidate();
+    }
+
+    void merge(SkOpSpan* span);
+
+    SkOpSpan* prev() const {
+        return fPrev;
+    }
+
+    const SkPoint& pt() const {
+        return fPtT.fPt;
+    }
+
+    const SkOpPtT* ptT() const {
+        return &fPtT;
+    }
+
+    SkOpPtT* ptT() {
+        return &fPtT;
+    }
+
+    SkOpSegment* segment() const {
+        return fSegment;
+    }
+
+    void setChased(bool chased) {
+        fChased = chased;
+    }
+
+    SkOpPtT* setCoinEnd(SkOpSpanBase* oldCoinEnd, SkOpSegment* oppSegment);
+
+    void setFromAngle(SkOpAngle* angle) {
+        fFromAngle = angle;
+    }
+
+    void setPrev(SkOpSpan* prev) {
+        fPrev = prev;
+    }
+
+    bool simple() const {
+        fPtT.debugValidate();
+        return fPtT.next()->next() == &fPtT; 
+    }
+
+    const SkOpSpan* starter(const SkOpSpanBase* end) const {
+        const SkOpSpanBase* result = t() < end->t() ? this : end;
+        return result->upCast();
+    }
+
+    SkOpSpan* starter(SkOpSpanBase* end) {
+        SkASSERT(this->segment() == end->segment());
+        SkOpSpanBase* result = t() < end->t() ? this : end;
+        return result->upCast();
+    }
+
+    SkOpSpan* starter(SkOpSpanBase** endPtr) {
+        SkOpSpanBase* end = *endPtr;
+        SkASSERT(this->segment() == end->segment());
+        SkOpSpanBase* result;
+        if (t() < end->t()) {
+            result = this;
+        } else {
+            result = end;
+            *endPtr = this;
+        }
+        return result->upCast();
+    }
+
+    int step(const SkOpSpanBase* end) const {
+        return t() < end->t() ? 1 : -1;
+    }
+
+    double t() const {
+        return fPtT.fT;
+    }
+
+    void unaligned() {
+        fAligned = false;
+    }
+
+    SkOpSpan* upCast() {
+        SkASSERT(!final());
+        return (SkOpSpan*) this;
+    }
+
+    const SkOpSpan* upCast() const {
+        SkASSERT(!final());
+        return (const SkOpSpan*) this;
+    }
+
+    SkOpSpan* upCastable() {
+        return final() ? NULL : upCast();
+    }
+
+    const SkOpSpan* upCastable() const {
+        return final() ? NULL : upCast();
+    }
+
+private:
+    void alignInner();
+
+protected:  // no direct access to internals to avoid treating a span base as a span
+    SkOpPtT fPtT;  // list of points and t values associated with the start of this span
+    SkOpSegment* fSegment;  // segment that contains this span
+    SkOpSpanBase* fCoinEnd;  // linked list of coincident spans that end here (may point to itself)
+    SkOpAngle* fFromAngle;  // points to next angle from span start to end
+    SkOpSpan* fPrev;  // previous intersection point
+    bool fAligned;
+    bool fChased;  // set after span has been added to chase array
+    PATH_OPS_DEBUG_CODE(int fCount);  // number of pt/t pairs added
+    PATH_OPS_DEBUG_CODE(int fID);
+};
+
+class SkOpSpan : public SkOpSpanBase {
+public:
+    void applyCoincidence(SkOpSpan* opp);
+
+    bool clearCoincident() {
+        SkASSERT(!final());
+        if (fCoincident == this) {
+            return false;
+        }
+        fCoincident = this;
+        return true;
+    }
+
+    bool containsCoincidence(const SkOpSegment* ) const;
+
+    bool containsCoincidence(const SkOpSpan* coin) const {
+        SkASSERT(this != coin);
+        const SkOpSpan* next = this;
+        while ((next = next->fCoincident) != this) {
+            if (next == coin) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    bool debugCoinLoopCheck() const;
+    void detach(SkOpPtT* );
+
+    bool done() const {
+        SkASSERT(!final());
+        return fDone;
+    }
+
+    void dumpCoin() const;
+    bool dumpSpan() const;
+    void init(SkOpSegment* parent, SkOpSpan* prev, double t, const SkPoint& pt);
+
+    void insertCoincidence(SkOpSpan* coin) {
+        if (containsCoincidence(coin)) {
+            SkASSERT(coin->containsCoincidence(this));
+            return;
+        }
+        debugValidate();
+        SkASSERT(this != coin);
+        SkOpSpan* coinNext = coin->fCoincident;
+        coin->fCoincident = this->fCoincident;
+        this->fCoincident = coinNext;
+        debugValidate();
+    }
+
+    bool isCanceled() const {
+        SkASSERT(!final());
+        return fWindValue == 0 && fOppValue == 0;
+    }
+
+    bool isCoincident() const {
+        SkASSERT(!final());
+        return fCoincident != this;
+    }
+
+    SkOpSpanBase* next() const {
+        SkASSERT(!final());
+        return fNext;
+    }
+
+    int oppSum() const {
+        SkASSERT(!final());
+        return fOppSum;
+    }
+
+    int oppValue() const {
+        SkASSERT(!final());
+        return fOppValue;
+    }
+
+    SkOpPtT* setCoinStart(SkOpSpan* oldCoinStart, SkOpSegment* oppSegment);
+
+    void setDone(bool done) {
+        SkASSERT(!final());
+        fDone = done;
+    }
+
+    void setNext(SkOpSpanBase* nextT) {
+        SkASSERT(!final());
+        fNext = nextT;
+    }
+
+    void setOppSum(int oppSum);
+
+    void setOppValue(int oppValue) {
+        SkASSERT(!final());
+        SkASSERT(fOppSum == SK_MinS32);
+        fOppValue = oppValue;
+    }
+
+    void setToAngle(SkOpAngle* angle) {
+        SkASSERT(!final());
+        fToAngle = angle;
+    }
+
+    void setWindSum(int windSum) {
+        SkASSERT(!final());
+        SkASSERT(fWindSum == SK_MinS32 || fWindSum == windSum);
+        SkASSERT(!DEBUG_LIMIT_WIND_SUM || abs(windSum) <= DEBUG_LIMIT_WIND_SUM);
+        fWindSum = windSum;
+    }
+
+    void setWindValue(int windValue) {
+        SkASSERT(!final());
+        SkASSERT(windValue >= 0);
+        SkASSERT(fWindSum == SK_MinS32);
+        fWindValue = windValue;
+    }
+
+    SkOpAngle* toAngle() const {
+        SkASSERT(!final());
+        return fToAngle;
+    }
+
+    int windSum() const {
+        SkASSERT(!final());
+        return fWindSum;
+    }
+
+    int windValue() const {
+        SkASSERT(!final());
+        return fWindValue;
+    }
+
+private:  // no direct access to internals to avoid treating a span base as a span
+    SkOpSpan* fCoincident;  // linked list of spans coincident with this one (may point to itself)
+    SkOpAngle* fToAngle;  // points to next angle from span start to end
+    SkOpSpanBase* fNext;  // next intersection point
     int fWindSum;  // accumulated from contours surrounding this one.
     int fOppSum;  // for binary operators: the opposite winding sum
     int fWindValue;  // 0 == canceled; 1 == normal; >1 == coincident
     int fOppValue;  // normally 0 -- when binary coincident edges combine, opp value goes here
-    bool fChased;  // set after span has been added to chase array
-    bool fCoincident;  // set if span is bumped -- if set additional points aren't inserted
     bool fDone;  // if set, this span to next higher T has been processed
-    bool fLoop;  // set when a cubic loops back to this point
-    bool fMultiple;  // set if this is one of mutiple spans with identical t and pt values
-    bool fNear;  // set if opposite end point is near but not equal to this one
-    bool fSmall;   // if set, consecutive points are almost equal
-    bool fTiny;  // if set, consecutive points are equal but consecutive ts are not precisely equal
-
-    // available to testing only
-    const SkOpSegment* debugToSegment(ptrdiff_t* ) const;
-    void dump() const;
-    void dumpOne() const;
 };
 
 #endif