optimize pathops coverage

src/pathops/SkOpAngle.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 "SkIntersections.h"
 #include "SkOpAngle.h"
 #include "SkOpSegment.h"
 #include "SkPathOpsCurve.h"
@@ skipping 90 matching lines @@
             return COMPARE_RESULT("5 y_ry == 0 && y + ry < 0", y < 0);
         }
         if (y + ry > 0) { // if a y is greater than zero and an x is positive,  non zero is smaller
             return COMPARE_RESULT("6 y_ry == 0 && y + ry > 0", (x + rx > 0) ^ (y == 0));
         }
         // at this point, both y's are zero, so lines are coincident or one is degenerate
         SkASSERT(x * rx != 0);  // and a degenerate line should haven't gotten this far
     }
     // see if either curve can be lengthened before trying the tangent
     if (fSegment->other(fEnd) != rh.fSegment  // tangents not absolutely identical
-            && rh.fSegment->other(rh.fEnd) != fSegment) {  // and not intersecting
+            && rh.fSegment->other(rh.fEnd) != fSegment
+            && y != -DBL_EPSILON 
+            && ry != -DBL_EPSILON) {  // and not intersecting
         SkOpAngle longer = *this;
         SkOpAngle rhLonger = rh;
         if ((longer.lengthen(rh) | rhLonger.lengthen(*this))  // lengthen both
                 && (fUnorderable || !longer.fUnorderable)
                 && (rh.fUnorderable || !rhLonger.fUnorderable)) {
 #if DEBUG_ANGLE
             bugOut.prepend("  ");
 #endif
             return COMPARE_RESULT("10 longer.lengthen(rh) ...", longer < rhLonger);
         }
@@ skipping 302 matching lines @@
     const SkOpSpan& spanMin = fStart < fEnd ? spanStart : spanEnd;
     SkDebugf("id=%d (%1.9g,%1.9g) start=%d (%1.9g) end=%d (%1.9g) sumWind=",
             fSegment->debugID(), fSegment->xAtT(fStart), fSegment->yAtT(fStart),
             fStart, spanStart.fT, fEnd, spanEnd.fT);
     SkPathOpsDebug::WindingPrintf(spanMin.fWindSum);
     SkDebugf(" oppWind=");
     SkPathOpsDebug::WindingPrintf(spanMin.fOppSum),
     SkDebugf(" done=%d\n", spanMin.fDone);
 }
 #endif