path ops work in progress

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 113 matching lines @@
     SkPath::Verb rVerb = rh.fSegment->verb();
     if (y_ry != 0) { // if they aren't coincident, look for a stable cross product
         // at this point, y's are the same sign, neither is zero
         //   and x's are the same sign, or one (or both) is zero
         double x_ry = x * ry;
         double rx_y = rx * y;
         if (!fComputed && !rh.fComputed) {
             if (!SkDLine::NearRay(x, y, rx, ry) && x_ry != rx_y) {
                 return COMPARE_RESULT("7 !fComputed && !rh.fComputed", x_ry < rx_y);
             }
+            if (fSide2 == 0 && rh.fSide2 == 0) {
+                return COMPARE_RESULT("7a !fComputed && !rh.fComputed", x_ry < rx_y);
+            }
         } else {
             // if the vector was a result of subdividing a curve, see if it is stable
             bool sloppy1 = x_ry < rx_y;
             bool sloppy2 = !sloppy1;
             if ((!fComputed || calcSlop(x, y, rx, ry, &sloppy1))
                     && (!rh.fComputed || rh.calcSlop(rx, ry, x, y, &sloppy2))
                     && sloppy1 != sloppy2) {
                 return COMPARE_RESULT("8 CalcSlop(x, y ...", sloppy1);
             }
         }
     }
-    if (fSide2 * rh.fSide2 == 0) {
-//        SkASSERT(fSide2 + rh.fSide2 != 0); // hitting this assert means coincidence was undetected
+    if (fSide2 * rh.fSide2 == 0) {  // one is zero
+#if DEBUG_ANGLE
+        if (fSide2 == rh.fSide2 && y_ry) {  // both is zero; coincidence was undetected
+            SkDebugf("%s coincidence!\n", __FUNCTION__);
+        }
+#endif
         return COMPARE_RESULT("9a fSide2 * rh.fSide2 == 0 ...", fSide2 < rh.fSide2);
     }
     // at this point, the initial tangent line is nearly coincident
     // see if edges curl away from each other
     if (fSide * rh.fSide < 0 && (!approximately_zero(fSide) || !approximately_zero(rh.fSide))) {
         return COMPARE_RESULT("9b fSide * rh.fSide < 0 ...", fSide < rh.fSide);
     }
     if (fUnsortable || rh.fUnsortable) {
         // even with no solution, return a stable sort
         return COMPARE_RESULT("11 fUnsortable || rh.fUnsortable", this < &rh);
@@ skipping 245 matching lines @@
         SkPoint ePt = fSegment->xyAtT(larger);
         SkDebugf("%s unsortable [%d] (%1.9g,%1.9g) [%d] (%1.9g,%1.9g)\n", __FUNCTION__,
                 smaller, iPt.fX, iPt.fY, fEnd, ePt.fX, ePt.fY);
     }
 #endif
     return;
 }
 
 #ifdef SK_DEBUG
 void SkOpAngle::dump() const {
-    SkDebugf("id=%d (%1.9g,%1.9g) start=%d (%1.9g) end=%d (%1.9g)\n", fSegment->debugID(),
-            fSegment->xAtT(fStart), fSegment->yAtT(fStart), fStart, fSegment->span(fStart).fT,
-            fEnd, fSegment->span(fEnd).fT);
+    const SkOpSpan& spanStart = fSegment->span(fStart);
+    const SkOpSpan& spanEnd = fSegment->span(fEnd);
+    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