path ops work in progress

src/pathops/SkAddIntersections.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 "SkAddIntersections.h"
 #include "SkPathOpsBounds.h"
 
 #if DEBUG_ADD_INTERSECTING_TS
@@ skipping 345 matching lines @@
             }
             if (!foundCommonContour && pts > 0) {
                 test->addCross(next);
                 next->addCross(test);
                 foundCommonContour = true;
             }
             // in addition to recording T values, record matching segment
             if (pts == 2) {
                 if (wn.segmentType() <= SkIntersectionHelper::kLine_Segment
                         && wt.segmentType() <= SkIntersectionHelper::kLine_Segment) {
-                    wt.addCoincident(wn, ts, swap);
-                    continue;
-                }
-                if (wn.segmentType() >= SkIntersectionHelper::kQuad_Segment
+                    if (wt.addCoincident(wn, ts, swap)) {
+                        continue;
+                    }
+                    ts.cleanUpCoincidence();  // prefer (t == 0 or t == 1)
+                    pts = 1;
+                } else if (wn.segmentType() >= SkIntersectionHelper::kQuad_Segment
                         && wt.segmentType() >= SkIntersectionHelper::kQuad_Segment
                         && ts.isCoincident(0)) {
                     SkASSERT(ts.coincidentUsed() == 2);
-                    wt.addCoincident(wn, ts, swap);
-                    continue;
+                    if (wt.addCoincident(wn, ts, swap)) {
+                        continue;
+                    }
+                    ts.cleanUpCoincidence();  // prefer (t == 0 or t == 1)
+                    pts = 1;
                 }
             }
             if (pts >= 2) {
                 for (int pt = 0; pt < pts - 1; ++pt) {
                     const SkDPoint& point = ts.pt(pt);
                     const SkDPoint& next = ts.pt(pt + 1);
                     if (wt.isNear(ts[swap][pt], ts[swap][pt + 1], point, next)
                             && wn.isNear(ts[!swap][pt], ts[!swap][pt + 1], point, next)) {
-                        wt.addPartialCoincident(wn, ts, pt, swap);
+                        if (!wt.addPartialCoincident(wn, ts, pt, swap)) {
+                            // remove extra point if two map to same float values
+                            ts.cleanUpCoincidence();  // prefer (t == 0 or t == 1)
+                            pts = 1;
+                        }
                     }
                 }
             }
             for (int pt = 0; pt < pts; ++pt) {
                 SkASSERT(ts[0][pt] >= 0 && ts[0][pt] <= 1);
                 SkASSERT(ts[1][pt] >= 0 && ts[1][pt] <= 1);
                 SkPoint point = ts.pt(pt).asSkPoint();
                 int testTAt = wt.addT(wn, point, ts[swap][pt], swap && ts.isNear(pt));
                 int nextTAt = wn.addT(wt, point, ts[!swap][pt], !swap && ts.isNear(pt));
                 wt.addOtherT(testTAt, ts[!swap][pt], nextTAt);
@@ skipping 38 matching lines @@
     }
     for (int cIndex = 0; cIndex < contourCount; ++cIndex) {
         SkOpContour* contour = (*contourList)[cIndex];
         contour->calcCoincidentWinding();
     }
     for (int cIndex = 0; cIndex < contourCount; ++cIndex) {
         SkOpContour* contour = (*contourList)[cIndex];
         contour->calcPartialCoincidentWinding();
     }
 }