interpolation of coincidence must be local to a single span

src/pathops/SkOpSegment.cpp

 /*
  * 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 "SkOpCoincidence.h"
 #include "SkOpContour.h"
 #include "SkOpSegment.h"
 #include "SkPathWriter.h"
@@ skipping 240 matching lines @@
     if (this->contains(newT)) {
         return true;
     }
     this->globalState()->resetAllocatedOpSpan();
     SkOpPtT* newPtT = this->addT(newT);
     *startOver |= this->globalState()->allocatedOpSpan();
     if (!newPtT) {
         return false;
     }
     newPtT->fPt = this->ptAtT(newT);
-    // const cast away to change linked list; pt/t values stays unchanged
     SkOpPtT* oppPrev = test->ptT()->oppPrev(newPtT);
     if (oppPrev) {
+        // const cast away to change linked list; pt/t values stays unchanged
         SkOpSpanBase* writableTest = const_cast<SkOpSpanBase*>(test);
         writableTest->mergeMatches(newPtT->span());
         writableTest->ptT()->addOpp(newPtT, oppPrev);
         writableTest->checkForCollapsedCoincidence();
     }
     return true;
 }
 
 // Please keep this in sync with debugAddT()
 SkOpPtT* SkOpSegment::addT(double t) {
@@ skipping 1498 matching lines @@
     int absOut = SkTAbs(outerWinding);
     int absIn = SkTAbs(innerWinding);
     bool result = absOut == absIn ? outerWinding < 0 : absOut < absIn;
     return result;
 }
 
 int SkOpSegment::windSum(const SkOpAngle* angle) const {
     const SkOpSpan* minSpan = angle->start()->starter(angle->end());
     return minSpan->windSum();
 }