look for deleted pts when detecting line/curve coincident edges

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 1101 matching lines @@
     }
     if (this->done()) {
         return;
     }
     SkOpSpan* prior = NULL;
     SkOpSpanBase* spanBase = &fHead;
     do {
         SkOpPtT* ptT = spanBase->ptT(), * spanStopPtT = ptT;
         SkASSERT(ptT->span() == spanBase);
         while ((ptT = ptT->next()) != spanStopPtT) {
+            if (ptT->deleted()) {
+                continue;
+            }
             SkOpSegment* opp = ptT->span()->segment();
             if (opp->verb() == SkPath::kLine_Verb) {
                 continue;
             }
             if (opp->done()) {
                 continue;
             }
             // when opp is encounted the 1st time, continue; on 2nd encounter, look for coincidence
             if (!opp->visited()) {
                 continue;
@@ skipping 10 matching lines @@
             if (spanBase->containsCoinEnd(opp)) {
                 continue;
             } 
             SkOpPtT* priorPtT = NULL, * priorStopPtT;
             // find prior span containing opp segment
             SkOpSegment* priorOpp = NULL;
             SkOpSpan* priorTest = spanBase->prev();
             while (!priorOpp && priorTest) {
                 priorStopPtT = priorPtT = priorTest->ptT();
                 while ((priorPtT = priorPtT->next()) != priorStopPtT) {
+                    if (priorPtT->deleted()) {
+                        continue;
+                    }
                     SkOpSegment* segment = priorPtT->span()->segment();
                     if (segment == opp) {
                         prior = priorTest;
                         priorOpp = opp;
                         break;
                     }
                 }
                 priorTest = priorTest->prev();
             }
             if (!priorOpp) {
@@ skipping 34 matching lines @@
                             oppDxdy.normalize();
                             dxdy.normalize();
                             SkScalar flatness = SkScalarAbs(dxdy.cross(oppDxdy) / FLT_EPSILON);
                             coincident |= flatness < 5000;  // FIXME: replace with tuned value
                         }
                     }
                 }
             }
             if (coincident) {
             // mark coincidence
-                if (!coincidences->extend(priorPtT, ptT, oppStart, oppEnd)) {
+                if (!coincidences->extend(priorPtT, ptT, oppStart, oppEnd)
+                        && !coincidences->extend(oppStart, oppEnd, priorPtT, ptT)) {
                     coincidences->add(priorPtT, ptT, oppStart, oppEnd, allocator);
                 }
                 clear_visited(&fHead);
                 return;
             }
     swapBack:
             if (swapped) {
                 SkTSwap(priorPtT, ptT);
             }
         }
@@ skipping 449 matching lines @@
     int absOut = abs(outerWinding);
     int absIn = abs(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();
 }