work in progress

in the middle of switching to sortless version

git-svn-id: http://skia.googlecode.com/svn/trunk@3768 2bbb7eff-a529-9590-31e7-b0007b416f81

25 files changed, 2322 insertions, 400 deletions

diff --git a/experimental/Intersection/ActiveEdge_Test.cpp b/experimental/Intersection/ActiveEdge_Test.cpp
index fe7d664e17..03cb595743 100755
--- a/experimental/Intersection/ActiveEdge_Test.cpp
+++ b/experimental/Intersection/ActiveEdge_Test.cpp
@@ -74,9 +74,9 @@ void ActiveEdge_Test() {
     right.fWorkEdge.fEdge = &rightIn;
     for (size_t x = 0; x < leftRightCount; ++x) {
         left.fAbove = leftRight[x][0];
-        left.fBelow = leftRight[x][1]; 
+        left.fTangent = left.fBelow = leftRight[x][1]; 
         right.fAbove = leftRight[x][2];
-        right.fBelow = leftRight[x][3];
+        right.fTangent = right.fBelow = leftRight[x][3];
         SkASSERT(left < right);
         SkASSERT(operator_less_than(left, right));
         SkASSERT(!(right < left));
diff --git a/experimental/Intersection/CubicBounds.cpp b/experimental/Intersection/CubicBounds.cpp
index 3534425886..5d21be6a9e 100644
--- a/experimental/Intersection/CubicBounds.cpp
+++ b/experimental/Intersection/CubicBounds.cpp
@@ -1,10 +1,63 @@
-/*
- *  CubicBounds.cpp
- *  edge
- *
- *  Created by Cary Clark on 1/27/12.
- *  Copyright 2012 __MyCompanyName__. All rights reserved.
- *
- */
+#include "DataTypes.h"
+#include "Extrema.h"
 
+static int isBoundedByEndPoints(double a, double b, double c, double d)
+{
+    return (a <= b && a <= c && b <= d && c <= d)
+            || (a >= b && a >= c && b >= d && c >= d);
+}
 
+double leftMostT(const Cubic& cubic, double startT, double endT) {
+    double leftTs[2];
+    _Point pt[2];
+    int results = findExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x,
+            leftTs);
+    int best = -1;
+    for (int index = 0; index < results; ++index) {
+        if (startT > leftTs[index] || leftTs[index] > endT) {
+            continue;
+        }
+        if (best < 0) {
+            best = index;
+            continue;
+        }
+        xy_at_t(cubic, leftTs[0], pt[0].x, pt[0].y);
+        xy_at_t(cubic, leftTs[1], pt[1].x, pt[1].y);
+        if (pt[0].x > pt[1].x) {
+            best = 1;
+        }
+    }
+    if (best >= 0) {
+        return leftTs[best];
+    }
+    xy_at_t(cubic, startT, pt[0].x, pt[0].y);
+    xy_at_t(cubic, endT, pt[1].x, pt[1].y);
+    return pt[0].x <= pt[1].x ? startT : endT;
+}
+
+void _Rect::setBounds(const Cubic& cubic) {
+    set(cubic[0]);
+    add(cubic[3]);
+    double tValues[4];
+    int roots = 0;
+    if (!isBoundedByEndPoints(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x)) {
+        roots = findExtrema(cubic[0].x, cubic[1].x, cubic[2].x,
+                cubic[3].x, tValues);
+    }
+    if (!isBoundedByEndPoints(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y)) {
+        roots += findExtrema(cubic[0].y, cubic[1].y, cubic[2].y,
+                cubic[3].y, &tValues[roots]);
+    }
+    for (int x = 0; x < roots; ++x) {
+        _Point result;
+        xy_at_t(cubic, tValues[x], result.x, result.y);
+        add(result);
+    }
+}
+
+void _Rect::setRawBounds(const Cubic& cubic) {
+    set(cubic[0]);
+    for (int x = 1; x < 4; ++x) {
+        add(cubic[x]);
+    }
+}
diff --git a/experimental/Intersection/CubicReduceOrder.cpp b/experimental/Intersection/CubicReduceOrder.cpp
index fee179a5d4..5551026330 100644
--- a/experimental/Intersection/CubicReduceOrder.cpp
+++ b/experimental/Intersection/CubicReduceOrder.cpp
@@ -24,7 +24,7 @@ static int vertical_line(const Cubic& cubic, Cubic& reduction) {
     reduction[1] = cubic[3];
     int smaller = reduction[1].y > reduction[0].y;
     int larger = smaller ^ 1;
-    int roots = SkFindCubicExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y, tValues);
+    int roots = findExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y, tValues);
     for (int index = 0; index < roots; ++index) {
         double yExtrema = interp_cubic_coords(&cubic[0].y, tValues[index]);
         if (reduction[smaller].y > yExtrema) {
@@ -44,7 +44,7 @@ static int horizontal_line(const Cubic& cubic, Cubic& reduction) {
     reduction[1] = cubic[3];
     int smaller = reduction[1].x > reduction[0].x;
     int larger = smaller ^ 1;
-    int roots = SkFindCubicExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, tValues);
+    int roots = findExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, tValues);
     for (int index = 0; index < roots; ++index) {
         double xExtrema = interp_cubic_coords(&cubic[0].x, tValues[index]);
         if (reduction[smaller].x > xExtrema) {
@@ -127,9 +127,9 @@ static int check_linear(const Cubic& cubic, Cubic& reduction,
     double tValues[2];
     int roots;
     if (useX) {
-        roots = SkFindCubicExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, tValues);
+        roots = findExtrema(cubic[0].x, cubic[1].x, cubic[2].x, cubic[3].x, tValues);
     } else {
-        roots = SkFindCubicExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y, tValues);
+        roots = findExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y, tValues);
     }
     for (index = 0; index < roots; ++index) {
         _Point extrema;
diff --git a/experimental/Intersection/CurveIntersection.h b/experimental/Intersection/CurveIntersection.h
index 1da2d9b19b..38d48902fb 100644
--- a/experimental/Intersection/CurveIntersection.h
+++ b/experimental/Intersection/CurveIntersection.h
@@ -6,6 +6,7 @@
 class Intersections;
 
 // unit-testable utilities
+double axialIntersect(const Quadratic& q1, const _Point& p, bool vert);
 bool bezier_clip(const Cubic& cubic1, const Cubic& cubic2, double& minT, double& maxT);
 bool bezier_clip(const Quadratic& q1, const Quadratic& q2, double& minT, double& maxT);
 void chop_at(const Cubic& src, CubicPair& dst, double t);
@@ -34,11 +35,26 @@ int reduceOrder(const Quadratic& quad, Quadratic& reduction);
 int horizontalIntersect(const Cubic& cubic, double y, double tRange[3]);
 int horizontalIntersect(const Cubic& cubic, double left, double right, double y,
         double tRange[3]);
+int horizontalIntersect(const Cubic& cubic, double left, double right, double y,
+        bool flipped, Intersections&);
+int horizontalIntersect(const _Line& line, double left, double right,
+        double y, bool flipped, Intersections& );
 int horizontalIntersect(const Quadratic& quad, double left, double right,
         double y, double tRange[2]);
+int horizontalIntersect(const Quadratic& quad, double left, double right,
+        double y, bool flipped, Intersections& );
 bool intersect(const Cubic& cubic1, const Cubic& cubic2, Intersections& );
 int intersect(const Cubic& cubic, const _Line& line, double cRange[3], double lRange[3]);
 bool intersect(const Quadratic& q1, const Quadratic& q2, Intersections& );
 bool intersect(const Quadratic& quad, const _Line& line, Intersections& );
+double leftMostT(const Cubic& , double startT, double endT);
+double leftMostT(const _Line& , double startT, double endT);
+double leftMostT(const Quadratic& , double startT, double endT);
+int verticalIntersect(const Cubic& cubic, double top, double bottom, double x,
+        bool flipped, Intersections& );
+int verticalIntersect(const _Line& line, double top, double bottom, double x,
+        bool flipped, Intersections& );
+int verticalIntersect(const Quadratic& quad, double top, double bottom,
+        double x, bool flipped, Intersections& );
 
 #endif
diff --git a/experimental/Intersection/EdgeWalker.cpp b/experimental/Intersection/EdgeWalker.cpp
index 1bf3c8bf50..002e84c599 100644
--- a/experimental/Intersection/EdgeWalker.cpp
+++ b/experimental/Intersection/EdgeWalker.cpp
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2012 Google Inc.
  *
@@ -20,9 +19,9 @@
 #define SkASSERT(cond) while (!(cond)) { sk_throw(); }
 
 // FIXME: remove once debugging is complete
-#if 0 // set to 1 for no debugging whatsoever
+#if 01 // set to 1 for no debugging whatsoever
 
-const bool gRunTestsInOneThread = true;
+const bool gRunTestsInOneThread = false;
 
 #define DEBUG_ACTIVE_LESS_THAN 0
 #define DEBUG_ADD 0
@@ -1381,23 +1380,51 @@ struct WorkEdge {
 class ActiveEdge {
 public:
     // this logic must be kept in sync with tooCloseToCall
-    // callers expect this to only read fAbove, fBelow
+    // callers expect this to only read fAbove, fTangent
     bool operator<(const ActiveEdge& rh) const {
-        double topD = fAbove.fX - rh.fAbove.fX;
-        if (rh.fAbove.fY < fAbove.fY) {
-            topD = (rh.fBelow.fY - rh.fAbove.fY) * topD
-                    - (fAbove.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX);
-        } else if (rh.fAbove.fY > fAbove.fY) {
-            topD = (fBelow.fY - fAbove.fY) * topD
-                    + (rh.fAbove.fY - fAbove.fY) * (fBelow.fX - fAbove.fX);
-        }
-        double botD = fBelow.fX - rh.fBelow.fX;
-        if (rh.fBelow.fY > fBelow.fY) {
-            botD = (rh.fBelow.fY - rh.fAbove.fY) * botD
-                    - (fBelow.fY - rh.fBelow.fY) * (rh.fBelow.fX - rh.fAbove.fX);
-        } else if (rh.fBelow.fY < fBelow.fY) {
-            botD = (fBelow.fY - fAbove.fY) * botD
-                    + (rh.fBelow.fY - fBelow.fY) * (fBelow.fX - fAbove.fX);
+        if (fVerb == rh.fVerb) {
+            // FIXME: don't know what to do if verb is quad, cubic
+            return abCompare(fAbove, fBelow, rh.fAbove, rh.fBelow);
+        }
+        // figure out which is quad, line
+        // if cached data says line did not intersect quad, use top/bottom
+        if (fVerb != SkPath::kLine_Verb ? noIntersect(rh) : rh.noIntersect(*this)) {
+            return abCompare(fAbove, fBelow, rh.fAbove, rh.fBelow);
+        }
+        // use whichever of top/tangent tangent/bottom overlaps more 
+        // with line top/bot
+        // assumes quad/cubic can already be upconverted to cubic/cubic
+        const SkPoint* line[2];
+        const SkPoint* curve[4];
+        if (fVerb != SkPath::kLine_Verb) {
+            line[0] = &rh.fAbove;
+            line[1] = &rh.fBelow;
+            curve[0] = &fAbove;
+            curve[1] = &fTangent;
+            curve[2] = &fBelow;
+        } else {
+            line[0] = &fAbove;
+            line[1] = &fBelow;
+            curve[0] = &rh.fAbove;
+            curve[1] = &rh.fTangent;
+            curve[2] = &rh.fBelow;
+        }
+        
+    }
+    
+    bool abCompare(const SkPoint& a1, const SkPoint& a2, const SkPoint& b1,
+            const SkPoint& b2) const {
+        double topD = a1.fX - b1.fX;
+        if (b1.fY < a1.fY) {
+            topD = (b2.fY - b1.fY) * topD - (a1.fY - b1.fY) * (b2.fX - b1.fX);
+        } else if (b1.fY > a1.fY) {
+            topD = (a2.fY - a1.fY) * topD + (b1.fY - a1.fY) * (a2.fX - a1.fX);
+        }
+        double botD = a2.fX - b2.fX;
+        if (b2.fY > a2.fY) {
+            botD = (b2.fY - b1.fY) * botD - (a2.fY - b2.fY) * (b2.fX - b1.fX);
+        } else if (b2.fY < a2.fY) {
+            botD = (a2.fY - a1.fY) * botD + (b2.fY - a2.fY) * (a2.fX - a1.fX);
         }
         // return sign of greater absolute value
         return (fabs(topD) > fabs(botD) ? topD : botD) < 0;
@@ -1477,6 +1504,37 @@ public:
         SkASSERT(!fExplicitTs);
         fTIndex = fTs->count() + 1;
     }
+    
+    void calcAboveBelow(double tAbove, double tBelow) {
+        fVerb = fWorkEdge.verb();
+        switch (fVerb) {
+            case SkPath::kLine_Verb:
+                LineXYAtT(fWorkEdge.fPts, tAbove, &fAbove);
+                LineXYAtT(fWorkEdge.fPts, tBelow, &fTangent);
+                fBelow = fTangent;
+                break;
+            case SkPath::kQuad_Verb:
+                // FIXME: put array in struct to avoid copy?
+                SkPoint quad[3];
+                QuadSubDivide(fWorkEdge.fPts, tAbove, tBelow, quad);
+                fAbove = quad[0];
+                fTangent = quad[0] != quad[1] ? quad[1] : quad[2];
+                fBelow = quad[2];
+                break;
+            case SkPath::kCubic_Verb:
+                SkPoint cubic[3];
+                CubicSubDivide(fWorkEdge.fPts, tAbove, tBelow, cubic);
+                fAbove = cubic[0];
+                // FIXME: can't see how quad logic for how tangent is used
+                // extends to cubic 
+                fTangent = cubic[0] != cubic[1] ? cubic[1]
+                        : cubic[0] != cubic[2] ? cubic[2] : cubic[3];
+                fBelow = cubic[3];
+                break;
+            default:
+                SkASSERT(0);
+        }
+    }
 
     void calcLeft(SkScalar y) {
         // OPTIMIZE: put a kDone_Verb at the end of the verb list?
@@ -1491,29 +1549,14 @@ public:
     }
 
     void calcLeft() {
-        void (*xyAtTFunc)(const SkPoint a[], double t, SkPoint* out);
-        switch (fWorkEdge.verb()) {
-            case SkPath::kLine_Verb:
-                xyAtTFunc = LineXYAtT;
-                break;
-            case SkPath::kQuad_Verb:
-                xyAtTFunc = QuadXYAtT;
-                break;
-            case SkPath::kCubic_Verb:
-                xyAtTFunc = CubicXYAtT;
-                break;
-            default:
-                SkASSERT(0);
-        }
-        // OPTIMIZATION: if fXAbove, fXBelow have already been computed
-        //  for the fTIndex, don't do it again
-        // For identical x, this lets us know which edge is first.
-        // If both edges have T values < 1, check x at next T (fXBelow).
         int add = (fTIndex <= fTs->count() - fExplicitTs) - 1;
         double tAbove = t(fTIndex + add);
-        (*xyAtTFunc)(fWorkEdge.fPts, tAbove, &fAbove);
         double tBelow = t(fTIndex - ~add);
-        (*xyAtTFunc)(fWorkEdge.fPts, tBelow, &fBelow);
+        // OPTIMIZATION: if fAbove, fBelow have already been computed
+        //  for the fTIndex, don't do it again
+        calcAboveBelow(tAbove, tBelow);
+        // For identical x, this lets us know which edge is first.
+        // If both edges have T values < 1, check x at next T (fBelow).
         SkASSERT(tAbove != tBelow);
         // FIXME: this can loop forever
         // need a break if we hit the end
@@ -1523,13 +1566,12 @@ public:
                 add -= 1;
                 SkASSERT(fTIndex + add >= 0);
                 tAbove = t(fTIndex + add);
-                (*xyAtTFunc)(fWorkEdge.fPts, tAbove, &fAbove);
             } else {
                 add += 1;
                 SkASSERT(fTIndex - ~add <= fTs->count() + 1);
                 tBelow = t(fTIndex - ~add);
-                (*xyAtTFunc)(fWorkEdge.fPts, tBelow, &fBelow);
             }
+            calcAboveBelow(tAbove, tBelow);
         }
         fTAbove = tAbove;
         fTBelow = tBelow;
@@ -1541,28 +1583,17 @@ public:
     
     void fixBelow() {
         if (fFixBelow) {
-            switch (fWorkEdge.verb()) {
-                case SkPath::kLine_Verb:
-                    LineXYAtT(fWorkEdge.fPts, nextT(), &fBelow);
-                    break;
-                case SkPath::kQuad_Verb:
-                    QuadXYAtT(fWorkEdge.fPts, nextT(), &fBelow);
-                    break;
-                case SkPath::kCubic_Verb:
-                    CubicXYAtT(fWorkEdge.fPts, nextT(), &fBelow);
-                    break;
-                default:
-                    SkASSERT(0);
-            }
+            fTBelow = nextT();
+            calcAboveBelow(fTAbove, fTBelow);
             fFixBelow = false;
         }
     }
 
     void init(const InEdge* edge) {
         fWorkEdge.init(edge);
+        fDone = false;
         initT();
         fBelow.fY = SK_ScalarMin;
-        fDone = false;
         fYBottom = SK_ScalarMin;
     }
 
@@ -1576,6 +1607,10 @@ public:
   //    fTs = &fWorkEdge.fEdge->fIntercepts[fWorkEdge.verbIndex()].fTs;
   //  but templated arrays don't allow returning a pointer to the end() element
         fTIndex = 0;
+        if (!fDone) {
+            fVerb = fWorkEdge.verb();
+        }
+        SkASSERT(fVerb > SkPath::kMove_Verb);
     }
 
     // OPTIMIZATION: record if two edges are coincident when the are intersected
@@ -1586,13 +1621,10 @@ public:
         if (fAbove != edge->fAbove || fBelow != edge->fBelow) {
             return false;
         }
-        SkPath::Verb verb = fDone ? fWorkEdge.lastVerb() : fWorkEdge.verb();
-        SkPath::Verb edgeVerb = edge->fDone ? edge->fWorkEdge.lastVerb() 
-                : edge->fWorkEdge.verb();
-        if (verb != edgeVerb) {
+        if (fVerb != edge->fVerb) {
             return false;
         }
-        switch (verb) {
+        switch (fVerb) {
             case SkPath::kLine_Verb:
                 return true;
             default:
@@ -1607,13 +1639,18 @@ public:
         return fAbove == edge->fAbove && fBelow == edge->fBelow;
     }
 
-    SkPath::Verb lastVerb() const {
-        return fDone ? fWorkEdge.lastVerb() : fWorkEdge.verb();
-    }
+//    SkPath::Verb lastVerb() const {
+//        return fDone ? fWorkEdge.lastVerb() : fWorkEdge.verb();
+//    }
     
     const SkPoint* lastPoints() const {
         return fDone ? fWorkEdge.lastPoints() : fWorkEdge.points();
     }
+    
+    bool noIntersect(const ActiveEdge& ) const {
+        // incomplete
+        return false;
+    }
 
     // The shortest close call edge should be moved into a position where
     // it contributes if the winding is transitioning to or from zero.
@@ -1654,8 +1691,8 @@ public:
     }
     
     bool swapUnordered(const ActiveEdge* edge, SkScalar bottom) const {
-        SkASSERT(lastVerb() != SkPath::kLine_Verb
-                || edge->lastVerb() != SkPath::kLine_Verb);
+        SkASSERT(fVerb != SkPath::kLine_Verb
+                || edge->fVerb != SkPath::kLine_Verb);
         if (fDone || edge->fDone) {
             return false;
         }
@@ -1670,24 +1707,24 @@ public:
         double t1, t2, b1, b2;
         // This logic must be kept in sync with operator <
         if (edge->fAbove.fY < fAbove.fY) {
-            t1 = (edge->fBelow.fY - edge->fAbove.fY) * (fAbove.fX - edge->fAbove.fX);
-            t2 = (fAbove.fY - edge->fAbove.fY) * (edge->fBelow.fX - edge->fAbove.fX);
+            t1 = (edge->fTangent.fY - edge->fAbove.fY) * (fAbove.fX - edge->fAbove.fX);
+            t2 = (fAbove.fY - edge->fAbove.fY) * (edge->fTangent.fX - edge->fAbove.fX);
         } else if (edge->fAbove.fY > fAbove.fY) {
-            t1 = (fBelow.fY - fAbove.fY) * (fAbove.fX - edge->fAbove.fX);
-            t2 = (fAbove.fY - edge->fAbove.fY) * (fBelow.fX - fAbove.fX);
+            t1 = (fTangent.fY - fAbove.fY) * (fAbove.fX - edge->fAbove.fX);
+            t2 = (fAbove.fY - edge->fAbove.fY) * (fTangent.fX - fAbove.fX);
         } else {
             t1 = fAbove.fX;
             t2 = edge->fAbove.fX;
         }
-        if (edge->fBelow.fY > fBelow.fY) {
-            b1 = (edge->fBelow.fY - edge->fAbove.fY) * (fBelow.fX - edge->fBelow.fX);
-            b2 = (fBelow.fY - edge->fBelow.fY) * (edge->fBelow.fX - edge->fAbove.fX);
-        } else if (edge->fBelow.fY < fBelow.fY) {
-            b1 = (fBelow.fY - fAbove.fY) * (fBelow.fX - edge->fBelow.fX);
-            b2 = (fBelow.fY - edge->fBelow.fY) * (fBelow.fX - fAbove.fX);
+        if (edge->fTangent.fY > fTangent.fY) {
+            b1 = (edge->fTangent.fY - edge->fAbove.fY) * (fTangent.fX - edge->fTangent.fX);
+            b2 = (fTangent.fY - edge->fTangent.fY) * (edge->fTangent.fX - edge->fAbove.fX);
+        } else if (edge->fTangent.fY < fTangent.fY) {
+            b1 = (fTangent.fY - fAbove.fY) * (fTangent.fX - edge->fTangent.fX);
+            b2 = (fTangent.fY - edge->fTangent.fY) * (fTangent.fX - fAbove.fX);
         } else {
-            b1 = fBelow.fX;
-            b2 = edge->fBelow.fX;
+            b1 = fTangent.fX;
+            b2 = edge->fTangent.fX;
         }
         if (fabs(t1 - t2) > fabs(b1 - b2)) {
             ulps = UlpsDiff(t1, t2);
@@ -1701,32 +1738,30 @@ public:
         if (ulps < 0 || ulps > 32) {
             return false;
         }
-        SkPath::Verb verb = lastVerb();
-        SkPath::Verb edgeVerb = edge->lastVerb();
-        if (verb == SkPath::kLine_Verb && edgeVerb == SkPath::kLine_Verb) {
+        if (fVerb == SkPath::kLine_Verb && edge->fVerb == SkPath::kLine_Verb) {
             return true;
         }
-        if (verb != SkPath::kLine_Verb && edgeVerb != SkPath::kLine_Verb) {
+        if (fVerb != SkPath::kLine_Verb && edge->fVerb != SkPath::kLine_Verb) {
             return false;
         }
 
         double ts[2];
         bool isLine = true;
         bool curveQuad = true;
-        if (verb == SkPath::kCubic_Verb) {
+        if (fVerb == SkPath::kCubic_Verb) {
             ts[0] = (fTAbove * 2 + fTBelow) / 3;
             ts[1] = (fTAbove + fTBelow * 2) / 3;
             curveQuad = isLine = false;
-        } else if (edgeVerb == SkPath::kCubic_Verb) {
+        } else if (edge->fVerb == SkPath::kCubic_Verb) {
             ts[0] = (edge->fTAbove * 2 + edge->fTBelow) / 3;
             ts[1] = (edge->fTAbove + edge->fTBelow * 2) / 3;
             curveQuad = false;
-        } else if (verb == SkPath::kQuad_Verb) {
+        } else if (fVerb == SkPath::kQuad_Verb) {
                 ts[0] = fTAbove;
                 ts[1] = (fTAbove + fTBelow) / 2;
                 isLine = false;
         } else {
-            SkASSERT(edgeVerb == SkPath::kQuad_Verb);
+            SkASSERT(edge->fVerb == SkPath::kQuad_Verb);
             ts[0] = edge->fTAbove;
             ts[1] = (edge->fTAbove + edge->fTBelow) / 2;
         }
@@ -1775,10 +1810,10 @@ private:
     // utility used only by swapUnordered
     void extractAboveBelow(ActiveEdge& extracted) const {
         SkPoint curve[4];
-        switch (lastVerb()) {
+        switch (fVerb) {
             case SkPath::kLine_Verb: 
                 extracted.fAbove = fAbove;
-                extracted.fBelow = fBelow;
+                extracted.fTangent = fTangent;
                 return;
             case SkPath::kQuad_Verb:
                 QuadSubDivide(lastPoints(), fTAbove, fTBelow, curve);
@@ -1790,19 +1825,21 @@ private:
                 SkASSERT(0);
         }
         extracted.fAbove = curve[0];
-        extracted.fBelow = curve[1];
+        extracted.fTangent = curve[1];
     }
 
 public:
     WorkEdge fWorkEdge;
     const SkTDArray<double>* fTs;
     SkPoint fAbove;
+    SkPoint fTangent;
     SkPoint fBelow;
     double fTAbove; // OPTIMIZATION: only required if edge has quads or cubics
     double fTBelow;
     SkScalar fYBottom;
     int fCoincident;
     int fTIndex;
+    SkPath::Verb fVerb;
     bool fSkip; // OPTIMIZATION: use bitfields?
     bool fCloseCall;
     bool fDone;
@@ -2253,17 +2290,16 @@ static SkScalar adjustCoincident(SkTDArray<ActiveEdge*>& edgeList,
     for (index = 1; index < edgeCount; ++index) {
         activePtr = nextPtr;
         nextPtr = edgeList[index];
-        if (firstIndex != index - 1 && !activePtr->fSkip) {
-            if (nextPtr->fWorkEdge.verb() == SkPath::kLine_Verb
-                    && activePtr->isUnordered(nextPtr)) {
-                start here;
-                // swap the line with the curve 
-                // back up to the previous edge and retest
-                SkTSwap<ActiveEdge*>(edgeList[index - 1], edgeList[index]);
-                SkASSERT(index > 1);
-                index -= 2;
-                continue;
-            }
+        if (firstIndex != index - 1 && activePtr->fVerb > SkPath::kLine_Verb
+                && nextPtr->fVerb == SkPath::kLine_Verb
+                && activePtr->isUnordered(nextPtr)) {
+            // swap the line with the curve
+            // back up to the previous edge and retest
+            SkTSwap<ActiveEdge*>(edgeList[index - 1], edgeList[index]);
+            SkASSERT(index > 1);
+            index -= 2;
+            nextPtr = edgeList[index];
+            continue;
         }
         bool closeCall = false;
         activePtr->fCoincident = firstIndex;
@@ -2444,9 +2480,9 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
         bool moreToDo, aboveBottom;
         do {
             double currentT = activePtr->t();
-            uint8_t verb = wt.verb();
             const SkPoint* points = wt.fPts;
             double nextT;
+            SkPath::Verb verb = activePtr->fVerb;
             do {
                 nextT = activePtr->nextT();
                 // FIXME: obtuse: want efficient way to say 
@@ -2503,9 +2539,10 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
             // will use these values if they're still valid instead of
             // recomputing
                 if (clipped[verb].fY > activePtr->fBelow.fY
-                        && bottom >= activePtr->fBelow.fY ) {
+                        && bottom >= activePtr->fBelow.fY
+                        && verb == SkPath::kLine_Verb) {
                     activePtr->fAbove = activePtr->fBelow;
-                    activePtr->fBelow = clipped[verb];
+                    activePtr->fBelow = activePtr->fTangent = clipped[verb];
                     activePtr->fTAbove = activePtr->fTBelow < 1
                             ? activePtr->fTBelow : 0;
                     activePtr->fTBelow = nextT;
@@ -2609,6 +2646,17 @@ void simplify(const SkPath& path, bool asFill, SkPath& simple) {
     // if a quadratic or cubic now has an intermediate T value, see if the Ts
     // on either side cause the Y values to monotonically increase. If not, split
     // the curve at the new T.
+
+    // try an alternate approach which does not split curves or stitch edges
+    // (may still need adjustCoincident, though)
+    // the idea is to output non-intersecting contours, then figure out their
+    // respective winding contribution
+    // each contour will need to know whether it is CW or CCW, and then whether
+    // a ray from that contour hits any a contour that contains it. The ray can
+    // move to the left and then arbitrarily move up or down (as long as it never
+    // moves to the right) to find a reference sibling contour or containing 
+    // contour. If the contour is part of an intersection, the companion contour
+    // that is part of the intersection can determine the containership.
     if (builder.containsCurves()) {
         currentPtr = edgeList.begin();
         SkTArray<InEdge> splits;
diff --git a/experimental/Intersection/EdgeWalkerQuadratic4x4_Test.cpp b/experimental/Intersection/EdgeWalkerQuadratic4x4_Test.cpp
new file mode 100644
index 0000000000..75fd9a448d
--- /dev/null
+++ b/experimental/Intersection/EdgeWalkerQuadratic4x4_Test.cpp
@@ -0,0 +1,101 @@
+#include "EdgeWalker_Test.h"
+#include "Intersection_Tests.h"
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include <assert.h>
+
+
+static void* testSimplify4x4QuadraticsMain(void* data)
+{
+    char pathStr[1024];
+    bzero(pathStr, sizeof(pathStr));
+    SkASSERT(data);
+    State4& state = *(State4*) data;
+    int ax = state.a & 0x03;
+    int ay = state.a >> 2;
+    int bx = state.b & 0x03;
+    int by = state.b >> 2;
+    int cx = state.c & 0x03;
+    int cy = state.c >> 2;
+    int dx = state.d & 0x03;
+    int dy = state.d >> 2;
+    for (int e = 0 ; e < 16; ++e) {
+        int ex = e & 0x03;
+        int ey = e >> 2;
+        for (int f = e ; f < 16; ++f) {
+            int fx = f & 0x03;
+            int fy = f >> 2;
+            for (int g = f ; g < 16; ++g) {
+                int gx = g & 0x03;
+                int gy = g >> 2;
+                for (int h = g ; h < 16; ++h) {
+                    int hx = h & 0x03;
+                    int hy = h >> 2;
+                    SkPath path, out;
+                    path.setFillType(SkPath::kWinding_FillType);
+                    path.moveTo(ax, ay);
+                    path.quadTo(bx, by, cx, cy);
+                    path.lineTo(dx, dy);
+                    path.close();
+                    path.moveTo(ex, ey);
+                    path.lineTo(fx, fy);
+                    path.quadTo(gx, gy, hx, hy);
+                    path.close();
+                    if (1) {  // gdb: set print elements 400
+                        char* str = pathStr;
+                        str += sprintf(str, "    path.moveTo(%d, %d);\n", ax, ay);
+                        str += sprintf(str, "    path.quadTo(%d, %d, %d, %d);\n", bx, by, cx, cy);
+                        str += sprintf(str, "    path.lineTo(%d, %d);\n", dx, dy);
+                        str += sprintf(str, "    path.close();\n");
+                        str += sprintf(str, "    path.moveTo(%d, %d);\n", ex, ey);
+                        str += sprintf(str, "    path.lineTo(%d, %d);\n", fx, fy);
+                        str += sprintf(str, "    path.quadTo(%d, %d, %d, %d);\n", gx, gy, hx, hy);
+                        str += sprintf(str, "    path.close();");
+                    }
+                    if (!testSimplify(path, true, out, state.bitmap, state.canvas)) {
+                        SkDebugf("*/\n{ SkPath::kWinding_FillType, %d, %d, %d, %d,"
+                                " %d, %d, %d, %d },\n/*\n", state.a, state.b, state.c, state.d,
+                                e, f, g, h);
+                    }
+                    path.setFillType(SkPath::kEvenOdd_FillType);
+                    if (!testSimplify(path, true, out, state.bitmap, state.canvas)) {
+                        SkDebugf("*/\n{ SkPath::kEvenOdd_FillType, %d, %d, %d, %d,"
+                                " %d, %d, %d, %d },\n/*\n", state.a, state.b, state.c, state.d,
+                                e, f, g, h);
+                    }
+                }
+            }
+        }
+    }
+    return NULL;
+}
+
+const int maxThreads = gRunTestsInOneThread ? 1 : 24;
+
+void Simplify4x4QuadraticsThreaded_Test()
+{
+    State4 threadState[maxThreads];
+    int threadIndex = 0;
+    for (int a = 0; a < 16; ++a) {
+        for (int b = a ; b < 16; ++b) {
+            for (int c = b ; c < 16; ++c) {
+                for (int d = c; d < 16; ++d) {                 
+                    State4* statePtr = &threadState[threadIndex];
+                    statePtr->a = a;
+                    statePtr->b = b;
+                    statePtr->c = c;
+                    statePtr->d = d;
+                    if (maxThreads > 1) {
+                        createThread(statePtr, testSimplify4x4QuadraticsMain);
+                        if (++threadIndex >= maxThreads) {
+                            waitForCompletion(threadState, threadIndex);
+                        }
+                    } else {
+                        testSimplify4x4QuadraticsMain(statePtr);
+                    }
+                }
+            }
+        }
+    }
+    waitForCompletion(threadState, threadIndex);
+}
diff --git a/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp b/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp
index 96ba2f3c5f..f6bf8240f5 100644
--- a/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp
@@ -218,7 +218,22 @@ static void testSimplifyQuadratic16() {
     drawAsciiPaths(path, out, true);
 }
 
+static void testSimplifyQuadratic17() {
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(2, 2);
+    path.close();
+    path.moveTo(0, 1);
+    path.lineTo(0, 1);
+    path.quadTo(2, 1, 3, 3);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
+
 static void (*simplifyTests[])() = {
+    testSimplifyQuadratic17,
     testSimplifyQuadratic16,
     testSimplifyQuadratic15,
     testSimplifyQuadratic14,
@@ -239,7 +254,7 @@ static void (*simplifyTests[])() = {
 
 static size_t simplifyTestsCount = sizeof(simplifyTests) / sizeof(simplifyTests[0]);
 
-static void (*firstTest)() = 0;
+static void (*firstTest)() = testSimplifyQuadratic14;
 static bool skipAll = false;
 
 void SimplifyQuadraticPaths_Test() {
diff --git a/experimental/Intersection/Extrema.cpp b/experimental/Intersection/Extrema.cpp
index 0b850607d4..386f09225a 100644
--- a/experimental/Intersection/Extrema.cpp
+++ b/experimental/Intersection/Extrema.cpp
@@ -1,20 +1,18 @@
 #include "DataTypes.h"
 #include "Extrema.h"
 
-static int valid_unit_divide(double numer, double denom, double* ratio)
+static int validUnitDivide(double numer, double denom, double* ratio)
 {
-    if (numer < 0)
-    {
+    if (numer < 0) {
         numer = -numer;
         denom = -denom;
     }
-
     if (denom == 0 || numer == 0 || numer >= denom)
         return 0;
-
     double r = numer / denom;
-    if (r == 0) // catch underflow if numer <<<< denom
+    if (r == 0) { // catch underflow if numer <<<< denom
         return 0;
+    }
     *ratio = r;
     return 1;
 }
@@ -25,10 +23,10 @@ static int valid_unit_divide(double numer, double denom, double* ratio)
     x1 = Q / A
     x2 = C / Q
 */
-static int SkFindUnitQuadRoots(double A, double B, double C, double roots[2])
+static int findUnitQuadRoots(double A, double B, double C, double roots[2])
 {
     if (A == 0)
-        return valid_unit_divide(-C, B, roots);
+        return validUnitDivide(-C, B, roots);
 
     double* r = roots;
 
@@ -39,8 +37,8 @@ static int SkFindUnitQuadRoots(double A, double B, double C, double roots[2])
     R = sqrt(R);
 
     double Q = (B < 0) ? -(B-R)/2 : -(B+R)/2;
-    r += valid_unit_divide(Q, A, r);
-    r += valid_unit_divide(C, Q, r);
+    r += validUnitDivide(Q, A, r);
+    r += validUnitDivide(C, Q, r);
     if (r - roots == 2 && approximately_equal(roots[0], roots[1])) { // nearly-equal?
         r -= 1; // skip the double root
     }
@@ -51,16 +49,16 @@ static int SkFindUnitQuadRoots(double A, double B, double C, double roots[2])
     A = 3(-a + 3(b - c) + d)
     B = 6(a - 2b + c)
     C = 3(b - a)
-    Solve for t, keeping only those that fit betwee 0 < t < 1
+    Solve for t, keeping only those that fit between 0 < t < 1
 */
-int SkFindCubicExtrema(double a, double b, double c, double d, double tValues[2])
+int findExtrema(double a, double b, double c, double d, double tValues[2])
 {
     // we divide A,B,C by 3 to simplify
     double A = d - a + 3*(b - c);
     double B = 2*(a - b - b + c);
     double C = b - a;
 
-    return SkFindUnitQuadRoots(A, B, C, tValues);
+    return findUnitQuadRoots(A, B, C, tValues);
 }
 
 /** Quad'(t) = At + B, where
@@ -68,10 +66,10 @@ int SkFindCubicExtrema(double a, double b, double c, double d, double tValues[2]
     B = 2(b - a)
     Solve for t, only if it fits between 0 < t < 1
 */
-int SkFindQuadExtrema(double a, double b, double c, double tValue[1])
+int findExtrema(double a, double b, double c, double tValue[1])
 {
     /*  At + B == 0
         t = -B / A
     */
-    return valid_unit_divide(a - b, a - b - b + c, tValue);
+    return validUnitDivide(a - b, a - b - b + c, tValue);
 }
diff --git a/experimental/Intersection/Extrema.h b/experimental/Intersection/Extrema.h
index aae422ea71..0988540957 100644
--- a/experimental/Intersection/Extrema.h
+++ b/experimental/Intersection/Extrema.h
@@ -1,2 +1,2 @@
-int SkFindCubicExtrema(double a, double b, double c, double d, double tValues[2]);
-int SkFindQuadExtrema(double a, double b, double c, double tValue[1]);
+int findExtrema(double a, double b, double c, double d, double tValues[2]);
+int findExtrema(double a, double b, double c, double tValue[1]);
diff --git a/experimental/Intersection/Intersection_Tests.cpp b/experimental/Intersection/Intersection_Tests.cpp
index 0179cb7450..e3c042cf27 100644
--- a/experimental/Intersection/Intersection_Tests.cpp
+++ b/experimental/Intersection/Intersection_Tests.cpp
@@ -4,12 +4,10 @@
 void cubecode_test(int test);
 void testSimplify();
 
-#define TEST_QUADS_FIRST 01
+#define TEST_QUADS_FIRST 0
 
 void Intersection_Tests() {
-#if !TEST_QUADS_FIRST
-    ActiveEdge_Test();
-#endif
+    SimplifyAddIntersectingTs_Test();
 
     cubecode_test(1);
     convert_testx();
@@ -29,8 +27,8 @@ void Intersection_Tests() {
     SimplifyRectangularPaths_Test();
     SimplifyQuadralateralPaths_Test();
 
-#if TEST_QUADS_FIRST
     ActiveEdge_Test();
+#if TEST_QUADS_FIRST
     Simplify4x4QuadraticsThreaded_Test();
 #endif
     SimplifyDegenerate4x4TrianglesThreaded_Test();
diff --git a/experimental/Intersection/Intersection_Tests.h b/experimental/Intersection/Intersection_Tests.h
index e0d892df8c..a2d9df6807 100644
--- a/experimental/Intersection/Intersection_Tests.h
+++ b/experimental/Intersection/Intersection_Tests.h
@@ -12,6 +12,7 @@ void LineCubicIntersection_Test();
 void LineIntersection_Test();
 void LineParameter_Test();
 void LineQuadraticIntersection_Test();
+void SimplifyAddIntersectingTs_Test();
 void SimplifyDegenerate4x4TrianglesThreaded_Test();
 void SimplifyNondegenerate4x4TrianglesThreaded_Test();
 void SimplifyPolygonPaths_Test();
diff --git a/experimental/Intersection/LineCubicIntersection.cpp b/experimental/Intersection/LineCubicIntersection.cpp
index 8517b7e0f8..6f2cf6c5e5 100644
--- a/experimental/Intersection/LineCubicIntersection.cpp
+++ b/experimental/Intersection/LineCubicIntersection.cpp
@@ -109,6 +109,13 @@ int horizontalIntersect(double axisIntercept) {
     return cubicRoots(A, B, C, D, range);
 }
 
+int verticalIntersect(double axisIntercept) {
+    double A, B, C, D;
+    coefficients(&cubic[0].x, A, B, C, D);
+    D -= axisIntercept;
+    return cubicRoots(A, B, C, D, range);
+}
+
 double findLineT(double t) {
     const double* cPtr;
     const double* lPtr;
@@ -158,6 +165,56 @@ int horizontalIntersect(const Cubic& cubic, double left, double right, double y,
     return result;
 }
 
+int horizontalIntersect(const Cubic& cubic, double left, double right, double y,
+        bool flipped, Intersections& intersections) {
+    LineCubicIntersections c(cubic, *((_Line*) 0), intersections.fT[0]);
+    int result = c.horizontalIntersect(y);
+    for (int index = 0; index < result; ) {
+        double x, y;
+        xy_at_t(cubic, intersections.fT[0][index], x, y);
+        if (x < left || x > right) {
+            if (--result > index) {
+                intersections.fT[0][index] = intersections.fT[0][result];
+            }
+            continue;
+        }
+        intersections.fT[0][index] = (x - left) / (right - left);
+        ++index;
+    }
+    if (flipped) {
+        // OPTIMIZATION: instead of swapping, pass original line, use [1].x - [0].x
+        for (int index = 0; index < result; ++index) {
+            intersections.fT[1][index] = 1 - intersections.fT[1][index];
+        }
+    }
+    return result;
+}
+
+int verticalIntersect(const Cubic& cubic, double top, double bottom, double x,
+        bool flipped, Intersections& intersections) {
+    LineCubicIntersections c(cubic, *((_Line*) 0), intersections.fT[0]);
+    int result = c.verticalIntersect(x);
+    for (int index = 0; index < result; ) {
+        double x, y;
+        xy_at_t(cubic, intersections.fT[0][index], x, y);
+        if (y < top || y > bottom) {
+            if (--result > index) {
+                intersections.fT[0][index] = intersections.fT[0][result];
+            }
+            continue;
+        }
+        intersections.fT[0][index] = (y - top) / (bottom - top);
+        ++index;
+    }
+    if (flipped) {
+        // OPTIMIZATION: instead of swapping, pass original line, use [1].x - [0].x
+        for (int index = 0; index < result; ++index) {
+            intersections.fT[1][index] = 1 - intersections.fT[1][index];
+        }
+    }
+    return result;
+}
+
 int intersect(const Cubic& cubic, const _Line& line, double cRange[3], double lRange[3]) {
     LineCubicIntersections c(cubic, line, cRange);
     int roots;
diff --git a/experimental/Intersection/LineIntersection.cpp b/experimental/Intersection/LineIntersection.cpp
index f5128eab2d..40e046cff5 100644
--- a/experimental/Intersection/LineIntersection.cpp
+++ b/experimental/Intersection/LineIntersection.cpp
@@ -1,4 +1,5 @@
 #include "DataTypes.h"
+#include "Intersections.h"
 #include "LineIntersection.h"
 #include <algorithm> // used for std::swap
 
@@ -112,9 +113,9 @@ int horizontalLineIntersect(const _Line& line, double left, double right,
         double y, double tRange[2]) {
     int result = horizontalIntersect(line, y, tRange);
     if (result != 1) {
+        // FIXME: this is incorrect if result == 2
         return result;
     }
-    // FIXME: this is incorrect if result == 2
     double xIntercept = line[0].x + tRange[0] * (line[1].x - line[0].x);
     if (xIntercept > right || xIntercept < left) {
         return 0;
@@ -122,6 +123,116 @@ int horizontalLineIntersect(const _Line& line, double left, double right,
     return result;
 }
 
+int horizontalIntersect(const _Line& line, double left, double right,
+        double y, bool flipped, Intersections& intersections) {
+    int result = horizontalIntersect(line, y, intersections.fT[0]);
+    switch (result) {
+        case 0:
+            break;
+        case 1: {
+            double xIntercept = line[0].x + intersections.fT[0][0]
+                    * (line[1].x - line[0].x);
+            if (xIntercept > right || xIntercept < left) {
+                return 0;
+            }
+            intersections.fT[1][0] = (xIntercept - left) / (right - left);
+            break;
+        }
+        case 2:
+            double lineL = line[0].x;
+            double lineR = line[1].x;
+            if (lineL > lineR) {
+                std::swap(lineL, lineR);
+            }
+            double overlapL = std::max(left, lineL);
+            double overlapR = std::min(right, lineR);
+            if (overlapL > overlapR) {
+                return 0;
+            }
+            if (overlapL == overlapR) {
+                result = 1;
+            }
+            intersections.fT[0][0] = (overlapL - line[0].x) / (line[1].x - line[0].x);
+            intersections.fT[1][0] = (overlapL - left) / (right - left);
+            if (result > 1) {
+                intersections.fT[0][1] = (overlapR - line[0].x) / (line[1].x - line[0].x);
+                intersections.fT[1][1] = (overlapR - left) / (right - left);
+            }
+            break;
+    }
+    if (flipped) {
+        // OPTIMIZATION: instead of swapping, pass original line, use [1].x - [0].x
+        for (int index = 0; index < result; ++index) {
+            intersections.fT[1][index] = 1 - intersections.fT[1][index];
+        }
+    }
+    return result;
+}
+
+int verticalIntersect(const _Line& line, double x, double tRange[2]) {
+    double min = line[0].x;
+    double max = line[1].x;
+    if (min > max) {
+        std::swap(min, max);
+    }
+    if (min > x || max < x) {
+        return 0;
+    }
+    if (approximately_equal(min, max)) {
+        tRange[0] = 0;
+        tRange[1] = 1;
+        return 2;
+    }
+    tRange[0] = (x - line[0].x) / (line[1].x - line[0].x);
+    return 1;
+}
+
+int verticalIntersect(const _Line& line, double top, double bottom,
+        double x, bool flipped, Intersections& intersections) {
+    int result = verticalIntersect(line, x, intersections.fT[0]);
+    switch (result) {
+        case 0:
+            break;
+        case 1: {
+            double yIntercept = line[0].y + intersections.fT[0][0]
+                    * (line[1].y - line[0].y);
+            if (yIntercept > bottom || yIntercept < top) {
+                return 0;
+            }
+            intersections.fT[1][0] = (yIntercept - top) / (bottom - top);
+            break;
+        }
+        case 2:
+            double lineT = line[0].y;
+            double lineB = line[1].y;
+            if (lineT > lineB) {
+                std::swap(lineT, lineB);
+            }
+            double overlapT = std::max(top, lineT);
+            double overlapB = std::min(bottom, lineB);
+            if (overlapT > overlapB) {
+                return 0;
+            }
+            if (overlapT == overlapB) {
+                result = 1;
+            }
+            intersections.fT[0][0] = (overlapT - line[0].y) / (line[1].y - line[0].y);
+            intersections.fT[1][0] = (overlapT - top) / (bottom - top);
+            if (result > 1) {
+                intersections.fT[0][1] = (overlapB - line[0].y) / (line[1].y - line[0].y);
+                intersections.fT[1][1] = (overlapB - top) / (bottom - top);
+            }
+            break;
+    }
+    if (flipped) {
+        // OPTIMIZATION: instead of swapping, pass original line, use [1].y - [0].y
+        for (int index = 0; index < result; ++index) {
+            intersections.fT[1][index] = 1 - intersections.fT[1][index];
+        }
+    }
+    return result;
+}
+
 // from http://www.bryceboe.com/wordpress/wp-content/uploads/2006/10/intersect.py
 // 4 subs, 2 muls, 1 cmp
 static bool ccw(const _Point& A, const _Point& B, const _Point& C) {
diff --git a/experimental/Intersection/LineIntersection.h b/experimental/Intersection/LineIntersection.h
index bb8b4b7d6f..d88e1f4653 100644
--- a/experimental/Intersection/LineIntersection.h
+++ b/experimental/Intersection/LineIntersection.h
@@ -6,6 +6,8 @@
 int horizontalIntersect(const _Line& line, double y, double tRange[2]);
 int horizontalLineIntersect(const _Line& line, double left, double right,
         double y, double tRange[2]);
+int verticalLineIntersect(const _Line& line, double top, double bottom,
+        double x, double tRange[2]);
 int intersect(const _Line& a, const _Line& b, double aRange[2], double bRange[2]);
 bool testIntersect(const _Line& a, const _Line& b);
 
diff --git a/experimental/Intersection/LineQuadraticIntersection.cpp b/experimental/Intersection/LineQuadraticIntersection.cpp
index 737b76749d..1bc831b643 100644
--- a/experimental/Intersection/LineQuadraticIntersection.cpp
+++ b/experimental/Intersection/LineQuadraticIntersection.cpp
@@ -141,6 +141,16 @@ int horizontalIntersect(double axisIntercept) {
     return quadraticRoots(D, E, F, intersections.fT[0]);
 }
 
+int verticalIntersect(double axisIntercept) {
+    double D = quad[2].x; // f
+    double E = quad[1].x; // e
+    double F = quad[0].x; // d
+    D += F - 2 * E; // D = d - 2*e + f
+    E -= F; // E = -(d - e)
+    F -= axisIntercept;
+    return quadraticRoots(D, E, F, intersections.fT[0]);
+}
+
 protected:
     
 double findLineT(double t) {
@@ -167,6 +177,46 @@ bool moreHorizontal;
 
 };
 
+// utility for pairs of coincident quads
+static double horizontalIntersect(const Quadratic& quad, const _Point& pt) {
+    Intersections intersections;
+    LineQuadraticIntersections q(quad, *((_Line*) 0), intersections);
+    int result = q.horizontalIntersect(pt.y);
+    if (result == 0) {
+        return -1;
+    }
+    assert(result == 1);
+    double x, y;
+    xy_at_t(quad, intersections.fT[0][0], x, y);
+    if (approximately_equal(x, pt.x)) {
+        return intersections.fT[0][0];
+    }
+    return -1;
+}
+
+static double verticalIntersect(const Quadratic& quad, const _Point& pt) {
+    Intersections intersections;
+    LineQuadraticIntersections q(quad, *((_Line*) 0), intersections);
+    int result = q.horizontalIntersect(pt.x);
+    if (result == 0) {
+        return -1;
+    }
+    assert(result == 1);
+    double x, y;
+    xy_at_t(quad, intersections.fT[0][0], x, y);
+    if (approximately_equal(y, pt.y)) {
+        return intersections.fT[0][0];
+    }
+    return -1;
+}
+
+double axialIntersect(const Quadratic& q1, const _Point& p, bool vertical) {
+    if (vertical) {
+        return verticalIntersect(q1, p);
+    }
+    return horizontalIntersect(q1, p);
+}
+
 int horizontalIntersect(const Quadratic& quad, double left, double right,
         double y, double tRange[2]) {
     Intersections i;
@@ -184,6 +234,56 @@ int horizontalIntersect(const Quadratic& quad, double left, double right,
     return tCount;
 }
 
+int horizontalIntersect(const Quadratic& quad, double left, double right, double y,
+        bool flipped, Intersections& intersections) {
+    LineQuadraticIntersections q(quad, *((_Line*) 0), intersections);
+    int result = q.horizontalIntersect(y);
+    for (int index = 0; index < result; ) {
+        double x, y;
+        xy_at_t(quad, intersections.fT[0][index], x, y);
+        if (x < left || x > right) {
+            if (--result > index) {
+                intersections.fT[0][index] = intersections.fT[0][result];
+            }
+            continue;
+        }
+        intersections.fT[0][index] = (x - left) / (right - left);
+        ++index;
+    }
+    if (flipped) {
+        // OPTIMIZATION: instead of swapping, pass original line, use [1].x - [0].x
+        for (int index = 0; index < result; ++index) {
+            intersections.fT[1][index] = 1 - intersections.fT[1][index];
+        }
+    }
+    return result;
+}
+
+int verticalIntersect(const Quadratic& quad, double top, double bottom, double x,
+        bool flipped, Intersections& intersections) {
+    LineQuadraticIntersections q(quad, *((_Line*) 0), intersections);
+    int result = q.verticalIntersect(x);
+    for (int index = 0; index < result; ) {
+        double x, y;
+        xy_at_t(quad, intersections.fT[0][index], x, y);
+        if (y < top || y > bottom) {
+            if (--result > index) {
+                intersections.fT[0][index] = intersections.fT[0][result];
+            }
+            continue;
+        }
+        intersections.fT[0][index] = (y - top) / (bottom - top);
+        ++index;
+    }
+    if (flipped) {
+        // OPTIMIZATION: instead of swapping, pass original line, use [1].x - [0].x
+        for (int index = 0; index < result; ++index) {
+            intersections.fT[1][index] = 1 - intersections.fT[1][index];
+        }
+    }
+    return result;
+}
+
 bool intersect(const Quadratic& quad, const _Line& line, Intersections& i) {
     LineQuadraticIntersections q(quad, line, i);
     return q.intersect();
diff --git a/experimental/Intersection/LineQuadraticIntersection_Test.cpp b/experimental/Intersection/LineQuadraticIntersection_Test.cpp
index 017a44ed77..a48f0af128 100644
--- a/experimental/Intersection/LineQuadraticIntersection_Test.cpp
+++ b/experimental/Intersection/LineQuadraticIntersection_Test.cpp
@@ -8,7 +8,9 @@ struct lineQuad {
     Quadratic quad;
     _Line line;
 } lineQuadTests[] = {
-    {{{0, 0}, {0, 1}, {1, 1}}, {{0, 1}, {1, 0}}}
+    {{{2, 0}, {1, 1}, {2, 2}}, {{0, 0}, {0, 2}}},
+    {{{4, 0}, {0, 1}, {4, 2}}, {{3, 1}, {4, 1}}},
+    {{{0, 0}, {0, 1}, {1, 1}}, {{0, 1}, {1, 0}}},
 };
 
 size_t lineQuadTests_count = sizeof(lineQuadTests) / sizeof(lineQuadTests[0]);
diff --git a/experimental/Intersection/LineUtilities.cpp b/experimental/Intersection/LineUtilities.cpp
index 13942252d9..38e1ba0c1f 100644
--- a/experimental/Intersection/LineUtilities.cpp
+++ b/experimental/Intersection/LineUtilities.cpp
@@ -30,3 +30,28 @@ void sub_divide(const _Line& line, double t1, double t2, _Line& dst) {
     dst[1].x = line[0].x - t2 * delta.x;
     dst[1].y = line[0].y - t2 * delta.y;
 }
+
+// may have this below somewhere else already: 
+// copying here because I thought it was clever
+
+// Copyright 2001, softSurfer (www.softsurfer.com)
+// This code may be freely used and modified for any purpose
+// providing that this copyright notice is included with it.
+// SoftSurfer makes no warranty for this code, and cannot be held
+// liable for any real or imagined damage resulting from its use.
+// Users of this code must verify correctness for their application.
+
+// Assume that a class is already given for the object:
+//    Point with coordinates {float x, y;}
+//===================================================================
+
+// isLeft(): tests if a point is Left|On|Right of an infinite line.
+//    Input:  three points P0, P1, and P2
+//    Return: >0 for P2 left of the line through P0 and P1
+//            =0 for P2 on the line
+//            <0 for P2 right of the line
+//    See: the January 2001 Algorithm on Area of Triangles
+float isLeft( _Point P0, _Point P1, _Point P2 )
+{
+    return (P1.x - P0.x)*(P2.y - P0.y) - (P2.x - P0.x)*(P1.y - P0.y);
+}
diff --git a/experimental/Intersection/QuadraticBounds.cpp b/experimental/Intersection/QuadraticBounds.cpp
new file mode 100644
index 0000000000..11591b3c17
--- /dev/null
+++ b/experimental/Intersection/QuadraticBounds.cpp
@@ -0,0 +1,46 @@
+#include "DataTypes.h"
+#include "Extrema.h"
+
+static int isBoundedByEndPoints(double a, double b, double c)
+{
+    return (a <= b && b <= c) || (a >= b && b >= c);
+}
+
+double leftMostT(const Quadratic& quad, double startT, double endT) {
+    double leftT;
+    if (findExtrema(quad[0].x, quad[1].x, quad[2].x, &leftT)
+            && startT <= leftT && leftT <= endT) {
+        return leftT;
+    }
+    _Point startPt;
+    xy_at_t(quad, startT, startPt.x, startPt.y);
+    _Point endPt;
+    xy_at_t(quad, endT, endPt.x, endPt.y);
+    return startPt.x <= endPt.x ? startT : endT;
+}
+
+void _Rect::setBounds(const Quadratic& quad) {
+    set(quad[0]);
+    add(quad[2]);
+    double tValues[2];
+    int roots = 0;
+    if (!isBoundedByEndPoints(quad[0].x, quad[1].x, quad[2].x)) {
+        roots = findExtrema(quad[0].x, quad[1].x, quad[2].x, tValues);
+    }
+    if (!isBoundedByEndPoints(quad[0].y, quad[1].y, quad[2].y)) {
+        roots += findExtrema(quad[0].y, quad[1].y, quad[2].y,
+                &tValues[roots]);
+    }
+    for (int x = 0; x < roots; ++x) {
+        _Point result;
+        xy_at_t(quad, tValues[x], result.x, result.y);
+        add(result);
+    }
+}
+
+void _Rect::setRawBounds(const Quadratic& quad) {
+    set(quad[0]);
+    for (int x = 1; x < 3; ++x) {
+        add(quad[x]);
+    }
+}
diff --git a/experimental/Intersection/QuadraticIntersection.cpp b/experimental/Intersection/QuadraticIntersection.cpp
index f8c43b5e5d..a8e87ef6ea 100644
--- a/experimental/Intersection/QuadraticIntersection.cpp
+++ b/experimental/Intersection/QuadraticIntersection.cpp
@@ -97,7 +97,6 @@ bool intersect(double minT1, double maxT1, double minT2, double maxT2) {
         double newMinT2 = interp(minT2, maxT2, minT);
         double newMaxT2 = interp(minT2, maxT2, maxT);
         split = newMaxT2 - newMinT2 > (maxT2 - minT2) * tClipLimit;
-#define VERBOSE 0
 #if VERBOSE
         printf("%s d=%d s=%d new2=(%g,%g) old2=(%g,%g) split=%d\n", __FUNCTION__, depth,
             splits, newMinT2, newMaxT2, minT2, maxT2, split);
@@ -144,6 +143,35 @@ int splits;
 };
 
 bool intersect(const Quadratic& q1, const Quadratic& q2, Intersections& i) {
+    if (implicit_matches(q1, q2)) {
+        // FIXME: compute T values
+        // compute the intersections of the ends to find the coincident span
+        bool useVertical = fabs(q1[0].x - q1[2].x) < fabs(q1[0].y - q1[2].y);
+        double t;
+        if ((t = axialIntersect(q1, q2[0], useVertical)) >= 0) {
+            i.fT[0][0] = t;
+            i.fT[1][0] = 0;
+            i.fUsed++;
+        }
+        if ((t = axialIntersect(q1, q2[2], useVertical)) >= 0) {
+            i.fT[0][i.fUsed] = t;
+            i.fT[1][i.fUsed] = 1;
+            i.fUsed++;
+        }
+        useVertical = fabs(q2[0].x - q2[2].x) < fabs(q2[0].y - q2[2].y);
+        if ((t = axialIntersect(q2, q1[0], useVertical)) >= 0) {
+            i.fT[0][i.fUsed] = 0;
+            i.fT[1][i.fUsed] = t;
+            i.fUsed++;
+        }
+        if ((t = axialIntersect(q2, q1[2], useVertical)) >= 0) {
+            i.fT[0][i.fUsed] = 1;
+            i.fT[1][i.fUsed] = t;
+            i.fUsed++;
+        }
+        assert(i.fUsed <= 2);
+        return i.fUsed > 0;
+    }
     QuadraticIntersections q(q1, q2, i);
     return q.intersect();
 }
diff --git a/experimental/Intersection/QuadraticReduceOrder.cpp b/experimental/Intersection/QuadraticReduceOrder.cpp
index e6ce04444a..4eef1a7781 100644
--- a/experimental/Intersection/QuadraticReduceOrder.cpp
+++ b/experimental/Intersection/QuadraticReduceOrder.cpp
@@ -21,7 +21,7 @@ static int vertical_line(const Quadratic& quad, Quadratic& reduction) {
     reduction[1] = quad[2];
     int smaller = reduction[1].y > reduction[0].y;
     int larger = smaller ^ 1;
-    if (SkFindQuadExtrema(quad[0].y, quad[1].y, quad[2].y, &tValue)) {
+    if (findExtrema(quad[0].y, quad[1].y, quad[2].y, &tValue)) {
         double yExtrema = interp_quad_coords(quad[0].y, quad[1].y, quad[2].y, tValue);
         if (reduction[smaller].y > yExtrema) {
             reduction[smaller].y = yExtrema;
@@ -38,7 +38,7 @@ static int horizontal_line(const Quadratic& quad, Quadratic& reduction) {
     reduction[1] = quad[2];
     int smaller = reduction[1].x > reduction[0].x;
     int larger = smaller ^ 1;
-    if (SkFindQuadExtrema(quad[0].x, quad[1].x, quad[2].x, &tValue)) {
+    if (findExtrema(quad[0].x, quad[1].x, quad[2].x, &tValue)) {
         double xExtrema = interp_quad_coords(quad[0].x, quad[1].x, quad[2].x, tValue);
         if (reduction[smaller].x > xExtrema) {
             reduction[smaller].x = xExtrema;
@@ -85,9 +85,9 @@ static int check_linear(const Quadratic& quad, Quadratic& reduction,
     double tValue;
     int root;
     if (useX) {
-        root = SkFindQuadExtrema(quad[0].x, quad[1].x, quad[2].x, &tValue);
+        root = findExtrema(quad[0].x, quad[1].x, quad[2].x, &tValue);
     } else {
-        root = SkFindQuadExtrema(quad[0].y, quad[1].y, quad[2].y, &tValue);
+        root = findExtrema(quad[0].y, quad[1].y, quad[2].y, &tValue);
     }
     if (root) {
         _Point extrema;
@@ -146,8 +146,8 @@ int reduceOrder(const Quadratic& quad, Quadratic& reduction) {
             minYSet |= 1 << index;
         }
     }
-    if (minXSet == 0xF) { // test for vertical line
-        if (minYSet == 0xF) { // return 1 if all four are coincident
+    if (minXSet == 0x7) { // test for vertical line
+        if (minYSet == 0x7) { // return 1 if all four are coincident
             return coincident_line(quad, reduction);
         }
         return vertical_line(quad, reduction);
diff --git a/experimental/Intersection/QuadraticUtilities.cpp b/experimental/Intersection/QuadraticUtilities.cpp
index ea4cd851a7..4b4d79417e 100644
--- a/experimental/Intersection/QuadraticUtilities.cpp
+++ b/experimental/Intersection/QuadraticUtilities.cpp
@@ -25,5 +25,3 @@ int quadraticRoots(double A, double B, double C, double t[2]) {
     }
     return foundRoots;
 }
-
-
diff --git a/experimental/Intersection/RectUtilities.cpp b/experimental/Intersection/RectUtilities.cpp
index e7bda028ee..e69de29bb2 100644
--- a/experimental/Intersection/RectUtilities.cpp
+++ b/experimental/Intersection/RectUtilities.cpp
@@ -1,44 +0,0 @@
-#include "DataTypes.h"
-#include "Extrema.h"
-
-void _Rect::setBounds(const Cubic& cubic) {
-    set(cubic[0]);
-    add(cubic[3]);
-    double tValues[4];
-    int roots = SkFindCubicExtrema(cubic[0].x, cubic[1].x, cubic[2].x,
-            cubic[3].x, tValues);
-    roots += SkFindCubicExtrema(cubic[0].y, cubic[1].y, cubic[2].y, cubic[3].y,
-            &tValues[roots]);
-    for (int x = 0; x < roots; ++x) {
-        _Point result;
-        xy_at_t(cubic, tValues[x], result.x, result.y);
-        add(result);
-    }
-}
-
-void _Rect::setRawBounds(const Cubic& cubic) {
-    set(cubic[0]);
-    for (int x = 1; x < 4; ++x) {
-        add(cubic[x]);
-    }
-}
-
-void _Rect::setBounds(const Quadratic& quad) {
-    set(quad[0]);
-    add(quad[2]);
-    double tValues[2];
-    int roots = SkFindQuadExtrema(quad[0].x, quad[1].x, quad[2].x, tValues);
-    roots += SkFindQuadExtrema(quad[0].y, quad[1].y, quad[2].y, &tValues[roots]);
-    for (int x = 0; x < roots; ++x) {
-        _Point result;
-        xy_at_t(quad, tValues[x], result.x, result.y);
-        add(result);
-    }
-}
-
-void _Rect::setRawBounds(const Quadratic& quad) {
-    set(quad[0]);
-    for (int x = 1; x < 3; ++x) {
-        add(quad[x]);
-    }
-}
diff --git a/experimental/Intersection/Simplify.cpp b/experimental/Intersection/Simplify.cpp
new file mode 100644
index 0000000000..5d7209a09d
--- /dev/null
+++ b/experimental/Intersection/Simplify.cpp
@@ -0,0 +1,1213 @@
+/*
+ * 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 "CurveIntersection.h"
+#include "Intersections.h"
+#include "LineIntersection.h"
+#include "SkPath.h"
+#include "SkRect.h"
+#include "SkTArray.h"
+#include "SkTDArray.h"
+#include "ShapeOps.h"
+#include "TSearch.h"
+
+#undef SkASSERT
+#define SkASSERT(cond) while (!(cond)) { sk_throw(); }
+
+// FIXME: remove once debugging is complete
+#if 0 // set to 1 for no debugging whatsoever
+
+//const bool gxRunTestsInOneThread = false;
+
+#define DEBUG_ADD_INTERSECTING_TS 0
+#define DEBUG_BRIDGE 0
+#define DEBUG_DUMP 0
+
+#else
+
+//const bool gRunTestsInOneThread = true;
+
+#define DEBUG_ADD_INTERSECTING_TS 1
+#define DEBUG_BRIDGE 1
+#define DEBUG_DUMP 1
+
+#endif
+
+#if DEBUG_DUMP
+static const char* kLVerbStr[] = {"", "line", "quad", "cubic"};
+static const char* kUVerbStr[] = {"", "Line", "Quad", "Cubic"};
+static int gContourID;
+static int gSegmentID;
+#endif
+
+static int LineIntersect(const SkPoint a[2], const SkPoint b[2],
+        Intersections& intersections) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    const _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}};
+    return intersect(aLine, bLine, intersections.fT[0], intersections.fT[1]);
+}
+
+static int QuadLineIntersect(const SkPoint a[3], const SkPoint b[2],
+        Intersections& intersections) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    const _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}};
+    intersect(aQuad, bLine, intersections);
+    return intersections.fUsed;
+}
+
+static int CubicLineIntersect(const SkPoint a[2], const SkPoint b[3],
+        Intersections& intersections) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    const _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}};
+    return intersect(aCubic, bLine, intersections.fT[0], intersections.fT[1]);
+}
+
+static int QuadIntersect(const SkPoint a[3], const SkPoint b[3],
+        Intersections& intersections) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    const Quadratic bQuad = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}, {b[2].fX, b[2].fY}};
+    intersect(aQuad, bQuad, intersections);
+    return intersections.fUsed;
+}
+
+static int CubicIntersect(const SkPoint a[4], const SkPoint b[4],
+        Intersections& intersections) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    const Cubic bCubic = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}, {b[2].fX, b[2].fY},
+            {b[3].fX, b[3].fY}};
+    intersect(aCubic, bCubic, intersections);
+    return intersections.fUsed;
+}
+
+static int HLineIntersect(const SkPoint a[2], SkScalar left, SkScalar right,
+        SkScalar y, bool flipped, Intersections& intersections) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    return horizontalIntersect(aLine, left, right, y, flipped, intersections);
+}
+
+static int VLineIntersect(const SkPoint a[2], SkScalar left, SkScalar right,
+        SkScalar y, bool flipped, Intersections& intersections) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    return verticalIntersect(aLine, left, right, y, flipped, intersections);
+}
+
+static int HQuadIntersect(const SkPoint a[3], SkScalar left, SkScalar right,
+        SkScalar y, bool flipped, Intersections& intersections) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    return horizontalIntersect(aQuad, left, right, y, flipped, intersections);
+}
+
+static int VQuadIntersect(const SkPoint a[3], SkScalar left, SkScalar right,
+        SkScalar y, bool flipped, Intersections& intersections) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    return verticalIntersect(aQuad, left, right, y, flipped, intersections);
+}
+
+static int HCubicIntersect(const SkPoint a[4], SkScalar left, SkScalar right,
+        SkScalar y, bool flipped, Intersections& intersections) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    return horizontalIntersect(aCubic, left, right, y, flipped, intersections);
+}
+
+static int VCubicIntersect(const SkPoint a[4], SkScalar left, SkScalar right,
+        SkScalar y, bool flipped, Intersections& intersections) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    return verticalIntersect(aCubic, left, right, y, flipped, intersections);
+}
+
+static void LineXYAtT(const SkPoint a[2], double t, SkPoint* out) {
+    const _Line line = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    double x, y;
+    xy_at_t(line, t, x, y);
+    out->fX = SkDoubleToScalar(x);
+    out->fY = SkDoubleToScalar(y);
+}
+
+static void QuadXYAtT(const SkPoint a[3], double t, SkPoint* out) {
+    const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    double x, y;
+    xy_at_t(quad, t, x, y);
+    out->fX = SkDoubleToScalar(x);
+    out->fY = SkDoubleToScalar(y);
+}
+
+static void CubicXYAtT(const SkPoint a[4], double t, SkPoint* out) {
+    const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    double x, y;
+    xy_at_t(cubic, t, x, y);
+    out->fX = SkDoubleToScalar(x);
+    out->fY = SkDoubleToScalar(y);
+}
+
+static void (* const SegmentXYAtT[])(const SkPoint [], double , SkPoint* ) = {
+    NULL,
+    LineXYAtT,
+    QuadXYAtT,
+    CubicXYAtT
+};
+
+static SkScalar LineXAtT(const SkPoint a[2], double t) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    double x;
+    xy_at_t(aLine, t, x, *(double*) 0);
+    return SkDoubleToScalar(x);
+}
+
+static SkScalar QuadXAtT(const SkPoint a[3], double t) {
+    const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    double x;
+    xy_at_t(quad, t, x, *(double*) 0);
+    return SkDoubleToScalar(x);
+}
+
+static SkScalar CubicXAtT(const SkPoint a[4], double t) {
+    const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    double x;
+    xy_at_t(cubic, t, x, *(double*) 0);
+    return SkDoubleToScalar(x);
+}
+
+static SkScalar (* const SegmentXAtT[])(const SkPoint [], double ) = {
+    NULL,
+    LineXAtT,
+    QuadXAtT,
+    CubicXAtT
+};
+
+static SkScalar LineYAtT(const SkPoint a[2], double t) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    double y;
+    xy_at_t(aLine, t, *(double*) 0, y);
+    return SkDoubleToScalar(y);
+}
+
+static SkScalar QuadYAtT(const SkPoint a[3], double t) {
+    const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
+    double y;
+    xy_at_t(quad, t, *(double*) 0, y);
+    return SkDoubleToScalar(y);
+}
+
+static SkScalar CubicYAtT(const SkPoint a[4], double t) {
+    const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
+            {a[3].fX, a[3].fY}};
+    double y;
+    xy_at_t(cubic, t, *(double*) 0, y);
+    return SkDoubleToScalar(y);
+}
+
+static SkScalar (* const SegmentYAtT[])(const SkPoint [], double ) = {
+    NULL,
+    LineYAtT,
+    QuadYAtT,
+    CubicYAtT
+};
+
+static void LineSubDivide(const SkPoint a[2], double startT, double endT,
+        SkPoint sub[2]) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    _Line dst;
+    sub_divide(aLine, startT, endT, dst);
+    sub[0].fX = SkDoubleToScalar(dst[0].x);
+    sub[0].fY = SkDoubleToScalar(dst[0].y);
+    sub[1].fX = SkDoubleToScalar(dst[1].x);
+    sub[1].fY = SkDoubleToScalar(dst[1].y);
+}
+
+static void QuadSubDivide(const SkPoint a[3], double startT, double endT,
+        SkPoint sub[3]) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}};
+    Quadratic dst;
+    sub_divide(aQuad, startT, endT, dst);
+    sub[0].fX = SkDoubleToScalar(dst[0].x);
+    sub[0].fY = SkDoubleToScalar(dst[0].y);
+    sub[1].fX = SkDoubleToScalar(dst[1].x);
+    sub[1].fY = SkDoubleToScalar(dst[1].y);
+    sub[2].fX = SkDoubleToScalar(dst[2].x);
+    sub[2].fY = SkDoubleToScalar(dst[2].y);
+}
+
+static void CubicSubDivide(const SkPoint a[4], double startT, double endT,
+        SkPoint sub[4]) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
+    Cubic dst;
+    sub_divide(aCubic, startT, endT, dst);
+    sub[0].fX = SkDoubleToScalar(dst[0].x);
+    sub[0].fY = SkDoubleToScalar(dst[0].y);
+    sub[1].fX = SkDoubleToScalar(dst[1].x);
+    sub[1].fY = SkDoubleToScalar(dst[1].y);
+    sub[2].fX = SkDoubleToScalar(dst[2].x);
+    sub[2].fY = SkDoubleToScalar(dst[2].y);
+    sub[3].fX = SkDoubleToScalar(dst[3].x);
+    sub[3].fY = SkDoubleToScalar(dst[3].y);
+}
+
+static void QuadSubBounds(const SkPoint a[3], double startT, double endT,
+        SkRect& bounds) {
+    SkPoint dst[3];
+    QuadSubDivide(a, startT, endT, dst);
+    bounds.fLeft = bounds.fRight = dst[0].fX;
+    bounds.fTop = bounds.fBottom = dst[0].fY;
+    for (int index = 1; index < 3; ++index) {
+        bounds.growToInclude(dst[index].fX, dst[index].fY);
+    }
+}
+
+static void CubicSubBounds(const SkPoint a[4], double startT, double endT,
+        SkRect& bounds) {
+    SkPoint dst[4];
+    CubicSubDivide(a, startT, endT, dst);
+    bounds.fLeft = bounds.fRight = dst[0].fX;
+    bounds.fTop = bounds.fBottom = dst[0].fY;
+    for (int index = 1; index < 4; ++index) {
+        bounds.growToInclude(dst[index].fX, dst[index].fY);
+    }
+}
+
+static SkPath::Verb QuadReduceOrder(const SkPoint a[4],
+        SkTDArray<SkPoint>& reducePts) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}};
+    Quadratic dst;
+    int order = reduceOrder(aQuad, dst);
+    for (int index = 0; index < order; ++index) {
+        SkPoint* pt = reducePts.append();
+        pt->fX = SkDoubleToScalar(dst[index].x);
+        pt->fY = SkDoubleToScalar(dst[index].y);
+    }
+    return (SkPath::Verb) (order - 1);
+}
+
+static SkPath::Verb CubicReduceOrder(const SkPoint a[4],
+        SkTDArray<SkPoint>& reducePts) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
+    Cubic dst;
+    int order = reduceOrder(aCubic, dst, kReduceOrder_QuadraticsAllowed);
+    for (int index = 0; index < order; ++index) {
+        SkPoint* pt = reducePts.append();
+        pt->fX = SkDoubleToScalar(dst[index].x);
+        pt->fY = SkDoubleToScalar(dst[index].y);
+    }
+    return (SkPath::Verb) (order - 1);
+}
+
+static SkScalar LineLeftMost(const SkPoint a[2], double startT, double endT) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    double x[2];
+    xy_at_t(aLine, startT, x[0], *(double*) 0);
+    xy_at_t(aLine, endT, x[0], *(double*) 0);
+    return startT < endT ? startT : endT;
+}
+
+static SkScalar QuadLeftMost(const SkPoint a[3], double startT, double endT) {
+    const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}};
+    return leftMostT(aQuad, startT, endT);
+}
+
+static SkScalar CubicLeftMost(const SkPoint a[4], double startT, double endT) {
+    const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
+    return leftMostT(aCubic, startT, endT);
+}
+
+static SkScalar (* const SegmentLeftMost[])(const SkPoint [], double , double) = {
+    NULL,
+    LineLeftMost,
+    QuadLeftMost,
+    CubicLeftMost
+};
+
+static bool IsCoincident(const SkPoint a[2], const SkPoint& above,
+        const SkPoint& below) {
+    const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
+    const _Line bLine = {{above.fX, above.fY}, {below.fX, below.fY}};
+    return implicit_matches_ulps(aLine, bLine, 32);
+}
+
+// Bounds, unlike Rect, does not consider a vertical line to be empty.
+struct Bounds : public SkRect {
+    static bool Intersects(const Bounds& a, const Bounds& b) {
+        return a.fLeft <= b.fRight && b.fLeft <= a.fRight &&
+                a.fTop <= b.fBottom && b.fTop <= a.fBottom;
+    }
+
+    bool isEmpty() {
+        return fLeft > fRight || fTop > fBottom
+                || fLeft == fRight && fTop == fBottom
+                || isnan(fLeft) || isnan(fRight)
+                || isnan(fTop) || isnan(fBottom);
+    }
+
+    void setCubicBounds(const SkPoint a[4]) {
+        _Rect dRect;
+        Cubic cubic  = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+            {a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
+        dRect.setBounds(cubic);
+        set(dRect.left, dRect.top, dRect.right, dRect.bottom);
+    }
+
+    void setQuadBounds(const SkPoint a[3]) {
+        const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
+                {a[2].fX, a[2].fY}};
+        _Rect dRect;
+        dRect.setBounds(quad);
+        set(dRect.left, dRect.top, dRect.right, dRect.bottom);
+    }
+};
+
+class Segment;
+
+struct TEntry {
+    double fT;
+    const Segment* fOther;
+    double fOtherT;
+    bool fCoincident;
+};
+
+class Segment {
+public:
+    Segment() {
+#if DEBUG_DUMP
+        fID = ++gSegmentID;
+#endif
+    }
+    
+    int addT(double newT, const Segment& other) {
+        // FIXME: in the pathological case where there is a ton of intercepts,
+        //  binary search?
+        int insertedAt = -1;
+        TEntry* entry;
+        size_t tCount = fTs.count();
+        double delta;
+        for (size_t idx2 = 0; idx2 < tCount; ++idx2) {
+            if (newT <= fTs[idx2].fT) {
+                insertedAt = idx2;
+                entry = fTs.insert(idx2);
+                goto finish;
+            }
+        }
+        insertedAt = tCount;
+        entry = fTs.append();
+finish:
+        entry->fT = newT;
+        entry->fOther = &other;
+        return insertedAt;
+    }
+    
+    bool addCubic(const SkPoint pts[4]) {
+        fPts = pts;
+        fVerb = SkPath::kCubic_Verb;
+        fBounds.setCubicBounds(pts);
+    }
+
+    bool addLine(const SkPoint pts[2]) {
+        fPts = pts;
+        fVerb = SkPath::kLine_Verb;
+        fBounds.set(pts, 2);
+    }
+    
+    // add 2 to edge or out of range values to get T extremes
+    void addOtherT(int index, double other, bool coincident) {
+        fTs[index].fOtherT = other;
+        fTs[index].fCoincident = coincident;
+    }
+    
+    bool addQuad(const SkPoint pts[3]) {
+        fPts = pts;
+        fVerb = SkPath::kQuad_Verb;
+        fBounds.setQuadBounds(pts);
+    }
+    
+    const Bounds& bounds() const {
+        return fBounds;
+    }
+    
+    int findByT(double t, const Segment* match) const {
+        // OPTIMIZATION: bsearch if count is honkin huge
+        int count = fTs.count();
+        for (int index = 0; index < count; ++index) {
+            const TEntry& entry = fTs[index];
+            if (t == entry.fT && match == entry.fOther) {
+                return index;
+            }
+        }
+        SkASSERT(0); // should never get here
+        return -1;
+    }
+    
+    int findLefty(int tIndex, const SkPoint& base) const {
+        int bestTIndex;
+        SkPoint test;
+        SkScalar bestX = DBL_MAX;
+        int testTIndex = tIndex;
+        while (--testTIndex >= 0) {
+            xyAtT(testTIndex, &test);
+            if (test != base) {
+                continue;
+            }
+            bestX = test.fX;
+            bestTIndex = testTIndex;
+            break;
+        }
+        int count = fTs.count();
+        testTIndex = tIndex;
+        while (++testTIndex < count) {
+            xyAtT(testTIndex, &test);
+            if (test == base) {
+                continue;
+            }
+            return bestX > test.fX ? testTIndex : bestTIndex;
+        }
+        return -1;
+    }
+
+    const Segment* findTop(int& tIndex) const {
+        // iterate through T intersections and return topmost
+        // topmost tangent from y-min to first pt is closer to horizontal
+        int firstT = 0;
+        int lastT = 0;
+        SkScalar topY = fPts[0].fY;
+        int count = fTs.count();
+        int index;
+        for (index = 1; index < count; ++index) {
+            const TEntry& entry = fTs[index];
+            double t = entry.fT;
+            SkScalar yIntercept = (*SegmentYAtT[fVerb])(fPts, t);
+            if (topY > yIntercept) {
+                topY = yIntercept;
+                firstT = lastT = index;
+            } else if (topY == yIntercept) {
+                lastT = index;
+            }
+        }
+        // if a pair of segments go down, choose the higher endpoint
+        if (firstT == lastT && (firstT == 0 || firstT == count - 1)) {
+            tIndex = firstT;
+            return this;
+        }
+        // if the topmost T is not on end, or is three-way or more, find left
+        SkPoint leftBase;
+        xyAtT(firstT, &leftBase);
+        int tLeft = findLefty(firstT, leftBase);
+        SkASSERT(tLeft > 0);
+        const Segment* leftSegment = this;
+        SkScalar left = leftMost(firstT, tLeft);
+        for (index = firstT; index <= lastT; ++index) {
+            const Segment* other = fTs[index].fOther;
+            double otherT = fTs[index].fOtherT;
+            int otherTIndex = other->findByT(otherT, this);
+            // pick companionT closest (but not too close) on either side
+            int otherTLeft = other->findLefty(otherTIndex, leftBase);
+            if (otherTLeft < 0) {
+                continue;
+            }
+            SkScalar otherMost = other->leftMost(otherTIndex, otherTLeft);
+            if (otherMost < left) {
+                leftSegment = other;
+            }
+        }
+        return leftSegment;
+    }
+
+    bool intersected() const {
+        return fTs.count() > 0;
+    }
+
+    bool isHorizontal() const {
+        return fBounds.fTop == fBounds.fBottom;
+    }
+    
+    bool isVertical() const {
+        return fBounds.fLeft == fBounds.fRight;
+    }
+    
+    SkScalar leftMost(int start, int end) const {
+        return (*SegmentLeftMost[fVerb])(fPts, fTs[start].fT, fTs[end].fT);
+    }
+
+    const SkPoint* pts() const {
+        return fPts;
+    }
+    
+    void reset() {
+        fPts = NULL;
+        fVerb = (SkPath::Verb) -1;
+        fBounds.set(SK_ScalarMax, SK_ScalarMax, SK_ScalarMax, SK_ScalarMax);
+        fTs.reset();
+    }
+
+    // OPTIMIZATION: remove this function if it's never called
+    double t(int tIndex) const {
+        return fTs[tIndex].fT;
+    }
+    
+    SkPath::Verb verb() const {
+        return fVerb;
+    }
+    
+    SkScalar xAtT(double t) const {
+        return (*SegmentXAtT[fVerb])(fPts, t);
+    }
+
+    void xyAtT(double t, SkPoint* pt) const {
+        (*SegmentXYAtT[fVerb])(fPts, t, pt);
+    }
+
+#if DEBUG_DUMP
+    void dump() const {
+        const char className[] = "Segment";
+        const int tab = 4;
+        for (int i = 0; i < fTs.count(); ++i) {
+            SkPoint out;
+            (*SegmentXYAtT[fVerb])(fPts, t(i), &out);
+            SkDebugf("%*s [%d] %s.fTs[%d]=%1.9g (%1.9g,%1.9g) other=%d"
+                    " otherT=%1.9g coincident=%d\n",
+                    tab + sizeof(className), className, fID,
+                    kLVerbStr[fVerb], i, fTs[i].fT, out.fX, out.fY,
+                    fTs[i].fOther->fID, fTs[i].fOtherT, fTs[i].fCoincident);
+        }
+        SkDebugf("%*s [%d] fBounds=(l:%1.9g, t:%1.9g r:%1.9g, b:%1.9g)\n",
+                tab + sizeof(className), className, fID,
+                fBounds.fLeft, fBounds.fTop, fBounds.fRight, fBounds.fBottom);
+    }
+#endif
+
+private:
+    const SkPoint* fPts;
+    SkPath::Verb fVerb;
+    Bounds fBounds;
+    SkTDArray<TEntry> fTs;
+#if DEBUG_DUMP
+    int fID;
+#endif
+};
+
+class Contour {
+public:
+    Contour() {
+        reset();
+#if DEBUG_DUMP
+        fID = ++gContourID;
+#endif
+    }
+
+    bool operator<(const Contour& rh) const {
+        return fBounds.fTop == rh.fBounds.fTop
+                ? fBounds.fLeft < rh.fBounds.fLeft
+                : fBounds.fTop < rh.fBounds.fTop;
+    }
+
+    void addCubic(const SkPoint pts[4]) {
+        fSegments.push_back().addCubic(pts);
+        fContainsCurves = true;
+    }
+    void addLine(const SkPoint pts[2]) {
+        fSegments.push_back().addLine(pts);
+    }
+    
+    void addQuad(const SkPoint pts[3]) {
+        fSegments.push_back().addQuad(pts);
+        fContainsCurves = true;
+    }
+    
+    const Bounds& bounds() const { 
+        return fBounds;
+    }
+
+    void complete() {
+        setBounds();
+        fContainsIntercepts = false;
+    }
+    
+    void containsIntercepts() {
+        fContainsIntercepts = true;
+    }
+    
+    void reset() {
+        fSegments.reset();
+        fBounds.set(SK_ScalarMax, SK_ScalarMax, SK_ScalarMax, SK_ScalarMax);
+        fContainsCurves = fContainsIntercepts = false;
+    }
+    
+    Segment& topSegment() {
+        return fSegments[fTopSegment];
+    }
+
+#if DEBUG_DUMP
+    void dump() {
+        int i;
+        const char className[] = "Contour";
+        const int tab = 4;
+        SkDebugf("%s %p (contour=%d)\n", className, this, fID);
+        for (i = 0; i < fSegments.count(); ++i) {
+            SkDebugf("%*s.fSegments[%d]:\n", tab + sizeof(className),
+                    className, i);
+            fSegments[i].dump();
+        }
+        SkDebugf("%*s.fBounds=(l:%1.9g, t:%1.9g r:%1.9g, b:%1.9g)\n",
+                tab + sizeof(className), className,
+                fBounds.fLeft, fBounds.fTop,
+                fBounds.fRight, fBounds.fBottom);
+        SkDebugf("%*s.fTopSegment=%d\n", tab + sizeof(className), className,
+                fTopSegment);
+        SkDebugf("%*s.fContainsIntercepts=%d\n", tab + sizeof(className),
+                className, fContainsIntercepts);
+        SkDebugf("%*s.fContainsCurves=%d\n", tab + sizeof(className),
+                className, fContainsCurves);
+    }
+#endif
+
+protected:
+    void setBounds() {
+        int count = fSegments.count();
+        if (count == 0) {
+            SkDebugf("%s empty contour\n", __FUNCTION__);
+            SkASSERT(0);
+            // FIXME: delete empty contour?
+            return;
+        }
+        fTopSegment = 0;
+        fBounds = fSegments.front().bounds();
+        SkScalar top = fBounds.fTop;
+        for (int index = 1; index < count; ++index) {
+            fBounds.growToInclude(fSegments[index].bounds());
+            if (top > fBounds.fTop) {
+                fTopSegment = index;
+                top = fBounds.fTop;
+            }
+        }
+    }
+    
+public:
+    SkTArray<Segment> fSegments; // not worth accessor functions?
+    
+private:
+    Bounds fBounds;
+    int fTopSegment;
+    bool fContainsIntercepts;
+    bool fContainsCurves;
+#if DEBUG_DUMP
+    int fID;
+#endif
+};
+
+class EdgeBuilder {
+public:
+
+EdgeBuilder(const SkPath& path, SkTArray<Contour>& contours) 
+    : fPath(path)
+    , fCurrentContour(NULL)
+    , fContours(contours)
+{
+#if DEBUG_DUMP
+    gContourID = 0;
+    gSegmentID = 0;
+#endif
+    walk();
+}
+
+protected:
+
+void complete() {
+    if (fCurrentContour && fCurrentContour->fSegments.count()) {
+        fCurrentContour->complete();
+        fCurrentContour = NULL;
+    }
+}
+
+void startContour() {
+    if (!fCurrentContour) {
+        fCurrentContour = fContours.push_back_n(1);
+    }
+}
+
+void walk() {
+    // FIXME:remove once we can access path pts directly
+    SkPath::RawIter iter(fPath); // FIXME: access path directly when allowed
+    SkPoint pts[4];
+    SkPath::Verb verb;
+    do {
+        verb = iter.next(pts);
+        *fPathVerbs.append() = verb;
+        if (verb == SkPath::kMove_Verb) {
+            *fPathPts.append() = pts[0];
+        } else if (verb >= SkPath::kLine_Verb && verb <= SkPath::kCubic_Verb) {
+            fPathPts.append(verb, &pts[1]);
+        }
+    } while (verb != SkPath::kDone_Verb);
+    // FIXME: end of section to remove once path pts are accessed directly
+    
+    SkPath::Verb reducedVerb;
+    uint8_t* verbPtr = fPathVerbs.begin();
+    const SkPoint* pointsPtr = fPathPts.begin();
+    while ((verb = (SkPath::Verb) *verbPtr++) != SkPath::kDone_Verb) {
+        switch (verb) {
+            case SkPath::kMove_Verb:
+                complete();
+                startContour();
+                pointsPtr += 1;
+                continue;
+            case SkPath::kLine_Verb:
+                // skip degenerate points
+                if (pointsPtr[-1].fX != pointsPtr[0].fX
+                        || pointsPtr[-1].fY != pointsPtr[0].fY) {
+                    fCurrentContour->addLine(&pointsPtr[-1]);
+                }
+                break;
+            case SkPath::kQuad_Verb:
+                reducedVerb = QuadReduceOrder(&pointsPtr[-1], fReducePts);
+                if (reducedVerb == 0) {
+                    break; // skip degenerate points
+                }
+                if (reducedVerb == 1) {
+                    fCurrentContour->addLine(fReducePts.end() - 2);
+                    break;
+                }
+                fCurrentContour->addQuad(&pointsPtr[-1]);
+                break;
+            case SkPath::kCubic_Verb:
+                reducedVerb = CubicReduceOrder(&pointsPtr[-1], fReducePts);
+                if (reducedVerb == 0) {
+                    break; // skip degenerate points
+                }
+                if (reducedVerb == 1) {
+                    fCurrentContour->addLine(fReducePts.end() - 2);
+                    break;
+                }
+                if (reducedVerb == 2) {
+                    fCurrentContour->addQuad(fReducePts.end() - 3);
+                    break;
+                }
+                fCurrentContour->addCubic(&pointsPtr[-1]);
+                break;
+            case SkPath::kClose_Verb:
+                SkASSERT(fCurrentContour);
+                complete();
+                continue;
+            default:
+                SkDEBUGFAIL("bad verb");
+                return;
+        }
+        pointsPtr += verb;
+        SkASSERT(fCurrentContour);
+    }
+    complete();
+    if (fCurrentContour && !fCurrentContour->fSegments.count()) {
+        fContours.pop_back();
+    }
+}
+
+private:
+    const SkPath& fPath;
+    SkTDArray<SkPoint> fPathPts; // FIXME: point directly to path pts instead
+    SkTDArray<uint8_t> fPathVerbs; // FIXME: remove 
+    Contour* fCurrentContour;
+    SkTArray<Contour>& fContours;
+    SkTDArray<SkPoint> fReducePts; // segments created on the fly
+};
+
+class Work {
+public:
+    enum SegmentType {
+        kHorizontalLine_Segment = -1,
+        kVerticalLine_Segment = 0,
+        kLine_Segment = SkPath::kLine_Verb,
+        kQuad_Segment = SkPath::kQuad_Verb,
+        kCubic_Segment = SkPath::kCubic_Verb,
+    };
+    
+    void addOtherT(int index, double other, bool coincident) {
+        fContour->fSegments[fIndex].addOtherT(index, other, coincident);
+    }
+    
+    // Avoid collapsing t values that are close to the same since
+    // we walk ts to describe consecutive intersections. Since a pair of ts can
+    // be nearly equal, any problems caused by this should be taken care
+    // of later.
+    // On the edge or out of range values are negative; add 2 to get end
+    int addT(double newT, const Work& other) {
+        fContour->containsIntercepts();
+        return fContour->fSegments[fIndex].addT(newT,
+                other.fContour->fSegments[other.fIndex]);
+    }
+    
+    bool advance() {
+        return ++fIndex < fLast;
+    }
+    
+    SkScalar bottom() const {
+        return bounds().fBottom;
+    }
+    
+    const Bounds& bounds() const {
+        return fContour->fSegments[fIndex].bounds();
+    }
+    
+    const SkPoint* cubic() const {
+        return fCubic;
+    }
+
+    void init(Contour* contour) {
+        fContour = contour;
+        fIndex = 0;
+        fLast = contour->fSegments.count();
+    }
+
+    SkScalar left() const {
+        return bounds().fLeft;
+    }
+    
+    void promoteToCubic() {
+        fCubic[0] = pts()[0];
+        fCubic[2] = pts()[1];
+        fCubic[3] = pts()[2];
+        fCubic[1].fX = (fCubic[0].fX + fCubic[2].fX * 2) / 3;
+        fCubic[1].fY = (fCubic[0].fY + fCubic[2].fY * 2) / 3;
+        fCubic[2].fX = (fCubic[3].fX + fCubic[2].fX * 2) / 3;
+        fCubic[2].fY = (fCubic[3].fY + fCubic[2].fY * 2) / 3;
+    }
+    
+    const SkPoint* pts() const {
+        return fContour->fSegments[fIndex].pts();
+    }
+
+    SkScalar right() const {
+        return bounds().fRight;
+    }
+    
+    ptrdiff_t segmentIndex() const {
+        return fIndex;
+    }
+    
+    SegmentType segmentType() const {
+        const Segment& segment = fContour->fSegments[fIndex];
+        SegmentType type = (SegmentType) segment.verb();
+        if (type != kLine_Segment) {
+            return type;
+        }
+        if (segment.isHorizontal()) {
+            return kHorizontalLine_Segment;
+        }
+        if (segment.isVertical()) {
+            return kVerticalLine_Segment;
+        }
+        return kLine_Segment;
+    }
+    
+    bool startAfter(const Work& after) {
+        fIndex = after.fIndex;
+        return advance();
+    }
+
+    SkScalar top() const {
+        return bounds().fTop;
+    }
+    
+    SkPath::Verb verb() const {
+        return fContour->fSegments[fIndex].verb();
+    }
+    
+    SkScalar x() const {
+        return bounds().fLeft;
+    }
+
+    bool xFlipped() const {
+        return x() != pts()[0].fX;
+    }
+
+    SkScalar y() const {
+        return bounds().fTop;
+    }
+
+    bool yFlipped() const {
+        return y() != pts()[0].fX;
+    }
+
+protected:
+    Contour* fContour;
+    SkPoint fCubic[4];
+    int fIndex;
+    int fLast;
+};
+
+static void debugShowLineIntersection(int pts, const Work& wt,
+        const Work& wn, const double wtTs[2], const double wnTs[2]) {
+#if DEBUG_ADD_INTERSECTING_TS
+    if (!pts) {
+        return;
+    }
+    SkPoint wtOutPt, wnOutPt;
+    LineXYAtT(wt.pts(), wtTs[0], &wtOutPt);
+    LineXYAtT(wn.pts(), wnTs[0], &wnOutPt);
+    SkDebugf("%s wtTs[0]=%g (%g,%g, %g,%g) (%g,%g)\n",
+            __FUNCTION__,
+            wtTs[0], wt.pts()[0].fX, wt.pts()[0].fY,
+            wt.pts()[1].fX, wt.pts()[1].fY, wtOutPt.fX, wtOutPt.fY);
+    if (pts == 2) {
+        SkDebugf("%s wtTs[1]=%g\n", __FUNCTION__, wtTs[1]);
+    }
+    SkDebugf("%s wnTs[0]=%g (%g,%g, %g,%g) (%g,%g)\n",
+            __FUNCTION__,
+            wnTs[0], wn.pts()[0].fX, wn.pts()[0].fY,
+            wn.pts()[1].fX, wn.pts()[1].fY, wnOutPt.fX, wnOutPt.fY);
+    if (pts == 2) {
+        SkDebugf("%s wnTs[1]=%g\n", __FUNCTION__, wnTs[1]);
+    }
+#endif
+}
+
+static bool addIntersectingTs(Contour* test, Contour* next) {
+    if (test != next) {
+        if (test->bounds().fBottom < next->bounds().fTop) {
+            return false;
+        }
+        if (!Bounds::Intersects(test->bounds(), next->bounds())) {
+            return true;
+        }
+    }
+    Work wt, wn;
+    wt.init(test);
+    wn.init(next);
+    do {
+        if (test == next && !wn.startAfter(wt)) {
+            continue;
+        }
+        do {
+            if (!Bounds::Intersects(wt.bounds(), wn.bounds())) {
+                continue;
+            }
+            int pts;
+            Intersections ts;
+            bool swap = false;
+            switch (wt.segmentType()) {
+                case Work::kHorizontalLine_Segment:
+                    swap = true;
+                    switch (wn.segmentType()) {
+                        case Work::kHorizontalLine_Segment:
+                        case Work::kVerticalLine_Segment:
+                        case Work::kLine_Segment: {
+                            pts = HLineIntersect(wn.pts(), wt.left(),
+                                    wt.right(), wt.y(), wt.xFlipped(), ts);
+                            break;
+                        }
+                        case Work::kQuad_Segment: {
+                            pts = HQuadIntersect(wn.pts(), wt.left(),
+                                    wt.right(), wt.y(), wt.xFlipped(), ts);
+                            break;
+                        }
+                        case Work::kCubic_Segment: {
+                            pts = HCubicIntersect(wn.pts(), wt.left(),
+                                    wt.right(), wt.y(), wt.xFlipped(), ts);
+                            break;
+                        }
+                        default:
+                            SkASSERT(0);
+                    }
+                    break;
+                case Work::kVerticalLine_Segment:
+                    swap = true;
+                    switch (wn.segmentType()) {
+                        case Work::kHorizontalLine_Segment:
+                        case Work::kVerticalLine_Segment:
+                        case Work::kLine_Segment: {
+                            pts = VLineIntersect(wn.pts(), wt.top(),
+                                    wt.bottom(), wt.x(), wt.yFlipped(), ts);
+                            break;
+                        }
+                        case Work::kQuad_Segment: {
+                            pts = VQuadIntersect(wn.pts(), wt.top(),
+                                    wt.bottom(), wt.x(), wt.yFlipped(), ts);
+                            break;
+                        }
+                        case Work::kCubic_Segment: {
+                            pts = VCubicIntersect(wn.pts(), wt.top(),
+                                    wt.bottom(), wt.x(), wt.yFlipped(), ts);
+                            break;
+                        }
+                        default:
+                            SkASSERT(0);
+                    }
+                    break;
+                case Work::kLine_Segment:
+                    switch (wn.segmentType()) {
+                        case Work::kHorizontalLine_Segment:
+                            pts = HLineIntersect(wt.pts(), wn.left(),
+                                    wn.right(), wn.y(), wn.xFlipped(), ts);
+                            break;
+                        case Work::kVerticalLine_Segment:
+                            pts = VLineIntersect(wt.pts(), wn.top(),
+                                    wn.bottom(), wn.x(), wn.yFlipped(), ts);
+                            break;
+                        case Work::kLine_Segment: {
+                            pts = LineIntersect(wt.pts(), wn.pts(), ts);
+                            debugShowLineIntersection(pts, wt, wn,
+                                    ts.fT[1], ts.fT[0]);
+                            break;
+                        }
+                        case Work::kQuad_Segment: {
+                            swap = true;
+                            pts = QuadLineIntersect(wn.pts(), wt.pts(), ts);
+                            break;
+                        }
+                        case Work::kCubic_Segment: {
+                            swap = true;
+                            pts = CubicLineIntersect(wn.pts(), wt.pts(), ts);
+                            break;
+                        }
+                        default:
+                            SkASSERT(0);
+                    }
+                    break;
+                case Work::kQuad_Segment:
+                    switch (wn.segmentType()) {
+                        case Work::kHorizontalLine_Segment:
+                            pts = HQuadIntersect(wt.pts(), wn.left(),
+                                    wn.right(), wn.y(), wn.xFlipped(), ts);
+                            break;
+                        case Work::kVerticalLine_Segment:
+                            pts = VQuadIntersect(wt.pts(), wn.top(),
+                                    wn.bottom(), wn.x(), wn.yFlipped(), ts);
+                            break;
+                        case Work::kLine_Segment: {
+                            pts = QuadLineIntersect(wt.pts(), wn.pts(), ts);
+                            break;
+                        }
+                        case Work::kQuad_Segment: {
+                            pts = QuadIntersect(wt.pts(), wn.pts(), ts);
+                            break;
+                        }
+                        case Work::kCubic_Segment: {
+                            wt.promoteToCubic();
+                            pts = CubicIntersect(wt.cubic(), wn.pts(), ts);
+                            break;
+                        }
+                        default:
+                            SkASSERT(0);
+                    }
+                    break;
+                case Work::kCubic_Segment:
+                    switch (wn.segmentType()) {
+                        case Work::kHorizontalLine_Segment:
+                            pts = HCubicIntersect(wt.pts(), wn.left(),
+                                    wn.right(), wn.y(), wn.xFlipped(), ts);
+                            break;
+                        case Work::kVerticalLine_Segment:
+                            pts = VCubicIntersect(wt.pts(), wn.top(),
+                                    wn.bottom(), wn.x(), wn.yFlipped(), ts);
+                            break;
+                        case Work::kLine_Segment: {
+                            pts = CubicLineIntersect(wt.pts(), wn.pts(), ts);
+                            break;
+                        }
+                        case Work::kQuad_Segment: {
+                            wn.promoteToCubic();
+                            pts = CubicIntersect(wt.pts(), wn.cubic(), ts);
+                            break;
+                        }
+                        case Work::kCubic_Segment: {
+                            pts = CubicIntersect(wt.pts(), wn.pts(), ts);
+                            break;
+                        }
+                        default:
+                            SkASSERT(0);
+                    }
+                    break;
+                default:
+                    SkASSERT(0);
+            }
+            // in addition to recording T values, record matching segment
+            bool coincident = pts == 2 && wn.segmentType() <= Work::kLine_Segment
+                    && wt.segmentType() <= Work::kLine_Segment;
+            for (int pt = 0; pt < pts; ++pt) {
+                SkASSERT(ts.fT[0][pt] >= 0 && ts.fT[0][pt] <= 1);
+                SkASSERT(ts.fT[1][pt] >= 0 && ts.fT[1][pt] <= 1);
+                int testTAt = wt.addT(ts.fT[swap][pt], wn);
+                int nextTAt = wn.addT(ts.fT[!swap][pt], wt);
+                wt.addOtherT(testTAt, ts.fT[!swap][pt], coincident);
+                wn.addOtherT(nextTAt, ts.fT[swap][pt], coincident);
+            }
+        } while (wn.advance());
+    } while (wt.advance());
+    return true;
+}
+
+// Each segment may have an inside or an outside. Segments contained within
+// winding may have insides on either side, and form a contour that should be
+// ignored. Segments that are coincident with opposing direction segments may
+// have outsides on either side, and should also disappear.
+// 'Normal' segments will have one inside and one outside. Subsequent connections
+// when winding should follow the intersection direction. If more than one edge
+// is an option, choose first edge that continues the inside.
+ 
+static void bridge(SkTDArray<Contour*>& contourList) {
+    // Start at the top. Above the top is outside, below is inside.
+    Contour* topContour = contourList[0];
+    Segment& topStart = topContour->topSegment();
+    int index;
+    const Segment* topSegment = topStart.findTop(index);
+    start here ;
+    // find span
+    // handle coincident
+    // mark neighbors winding coverage
+    // output span
+    // mark span as processed
+    
+}
+
+static void makeContourList(SkTArray<Contour>& contours, Contour& sentinel,
+        SkTDArray<Contour*>& list) {
+    size_t count = contours.count();
+    if (count == 0) {
+        return;
+    }
+    for (size_t index = 0; index < count; ++index) {
+        *list.append() = &contours[index];
+    }
+    *list.append() = &sentinel;
+    QSort<Contour>(list.begin(), list.end() - 1);
+}
+
+void simplifyx(const SkPath& path, bool asFill, SkPath& simple) {
+    // returns 1 for evenodd, -1 for winding, regardless of inverse-ness
+    int windingMask = (path.getFillType() & 1) ? 1 : -1;
+    simple.reset();
+    simple.setFillType(SkPath::kEvenOdd_FillType);
+
+    // turn path into list of segments
+    SkTArray<Contour> contours;
+    // FIXME: add self-intersecting cubics' T values to segment
+    EdgeBuilder builder(path, contours);
+    SkTDArray<Contour*> contourList;
+    Contour sentinel;
+    sentinel.reset();
+    makeContourList(contours, sentinel, contourList);
+    Contour** currentPtr = contourList.begin();
+    if (!currentPtr) {
+        return;
+    }
+    // find all intersections between segments
+    do {
+        Contour** nextPtr = currentPtr;
+        Contour* current = *currentPtr++;
+        Contour* next;
+        do {
+            next = *nextPtr++;
+        } while (next != &sentinel && addIntersectingTs(current, next));
+    } while (*currentPtr != &sentinel);
+    // construct closed contours
+    bridge(contourList);
+}
+
diff --git a/experimental/Intersection/SimplifyAddIntersectingTs_Test.cpp b/experimental/Intersection/SimplifyAddIntersectingTs_Test.cpp
new file mode 100644
index 0000000000..fff07da646
--- /dev/null
+++ b/experimental/Intersection/SimplifyAddIntersectingTs_Test.cpp
@@ -0,0 +1,132 @@
+#include "CurveIntersection.h"
+#include "Intersections.h"
+#include "LineIntersection.h"
+#include "SkPath.h"
+#include "SkRect.h"
+#include "SkTArray.h"
+#include "SkTDArray.h"
+#include "ShapeOps.h"
+#include "TSearch.h"
+
+namespace SimplifyAddIntersectingTsTest {
+
+#include "Simplify.cpp"
+
+} // end of SimplifyAddIntersectingTsTest namespace
+
+#include "Intersection_Tests.h"
+
+static const SkPoint lines[][2] = {
+    {{ 1,  1}, { 1,  1}},   // degenerate
+    {{ 1,  1}, { 4,  1}},   // horizontal
+    {{ 4,  1}, { 9,  1}},
+    {{ 2,  1}, { 3,  1}},
+    {{ 2,  1}, { 6,  1}},
+    {{ 5,  1}, { 9,  1}},
+    {{ 1,  1}, { 1,  4}},   // vertical
+    {{ 1,  2}, { 1,  3}},
+    {{ 1,  2}, { 1,  6}},
+    {{ 1,  5}, { 1,  9}},
+    {{ 1,  1}, { 3,  3}},   // diagonal
+    {{ 2,  2}, { 4,  4}},
+    {{ 2,  4}, { 4,  2}},
+};
+
+static const size_t lineCount = sizeof(lines) / sizeof(lines[0]);
+
+static const SkPoint quads[][3] = {
+    {{ 1,  1}, { 1,  1}, { 1,  1}},   // degenerate
+    {{ 1,  1}, { 4,  1}, { 5,  1}},   // line
+    {{ 1,  1}, { 4,  1}, { 4,  4}},   // curve
+};
+
+static const size_t quadCount = sizeof(quads) / sizeof(quads[0]);
+
+static const SkPoint cubics[][4] = {
+    {{ 1,  1}, { 1,  1}, { 1,  1}, { 1,  1}},   // degenerate
+    {{ 1,  1}, { 4,  1}, { 5,  1}, { 6,  1}},   // line
+    {{ 1,  1}, { 3,  1}, { 4,  2}, { 4,  4}},   // curve
+};
+
+static const size_t cubicCount = sizeof(cubics) / sizeof(cubics[0]);
+static const size_t testCount = lineCount + quadCount + cubicCount;
+
+static SkPath::Verb setPath(int outer, SkPath& path, const SkPoint*& pts1) {
+    SkPath::Verb c1Type;
+    if (outer < lineCount) {
+        path.moveTo(lines[outer][0].fX, lines[outer][0].fY);
+        path.lineTo(lines[outer][1].fX, lines[outer][1].fY);
+        c1Type = SkPath::kLine_Verb;
+        pts1 = lines[outer];
+    } else {
+        outer -= lineCount;
+        if (outer < quadCount) {
+        path.moveTo(quads[outer][0].fX, quads[outer][0].fY);
+        path.quadTo(quads[outer][1].fX, quads[outer][1].fY,
+                quads[outer][2].fX, quads[outer][2].fY);
+            c1Type = SkPath::kQuad_Verb;
+            pts1 = quads[outer];
+        } else {
+            outer -= quadCount;
+            path.moveTo(cubics[outer][0].fX, cubics[outer][0].fY);
+            path.cubicTo(cubics[outer][1].fX, cubics[outer][1].fY,
+                    cubics[outer][2].fX, cubics[outer][2].fY,
+                    cubics[outer][3].fX, cubics[outer][3].fY);
+            c1Type = SkPath::kCubic_Verb;
+            pts1 = cubics[outer];
+        }
+    }
+    return c1Type;
+}
+
+static void testPath(const SkPath& path, const SkPoint* pts1, SkPath::Verb c1Type,
+        const SkPoint* pts2, SkPath::Verb c2Type) {
+    SkTArray<SimplifyAddIntersectingTsTest::Contour> contour;
+    SimplifyAddIntersectingTsTest::EdgeBuilder builder(path, contour);
+    if (contour.count() < 2) {
+        return;
+    }
+    SimplifyAddIntersectingTsTest::Contour& c1 = contour[0];
+    SimplifyAddIntersectingTsTest::Contour& c2 = contour[1];
+    addIntersectingTs(&c1, &c2);
+    bool c1Intersected = c1.fSegments[0].intersected();
+    bool c2Intersected = c2.fSegments[0].intersected();
+#if DEBUG_DUMP
+    SkDebugf("%s %s (%1.9g,%1.9g %1.9g,%1.9g) %s %s (%1.9g,%1.9g %1.9g,%1.9g)\n",
+            __FUNCTION__, SimplifyAddIntersectingTsTest::kLVerbStr[c1Type],
+            pts1[0].fX, pts1[0].fY, 
+            pts1[c1Type].fX, pts1[c1Type].fY,
+            c1Intersected ? "intersects" : "does not intersect",
+            SimplifyAddIntersectingTsTest::kLVerbStr[c2Type],
+            pts2[0].fX, pts2[0].fY, 
+            pts2[c2Type].fX, pts2[c2Type].fY);
+    if (c1Intersected) {
+        c1.dump();
+        c2.dump();
+    }
+#endif            
+}
+
+static const int firstO = 6;
+static const int firstI = 1;
+
+void SimplifyAddIntersectingTs_Test() {
+    const SkPoint* pts1, * pts2;
+    if (firstO > 0 || firstI > 0) {
+        SkPath path;
+        SkPath::Verb c1Type = setPath(firstO, path, pts1);
+        SkPath path2(path);
+        SkPath::Verb c2Type = setPath(firstI, path2, pts2);
+        testPath(path2, pts1, c1Type, pts2, c2Type);
+    }
+    for (int o = 0; o < testCount; ++o) {
+        SkPath path;
+        SkPath::Verb c1Type = setPath(o, path, pts1);
+        for (int i = 0; i < testCount; ++i) {
+            SkPath path2(path);
+            SkPath::Verb c2Type = setPath(i, path2, pts2);
+            testPath(path2, pts1, c1Type, pts2, c2Type);
+        }
+    }
+}
+
diff --git a/experimental/Intersection/op.htm b/experimental/Intersection/op.htm
index 4f12c91e79..4df4aeb1c1 100644
--- a/experimental/Intersection/op.htm
+++ b/experimental/Intersection/op.htm
@@ -1,184 +1,178 @@
 <html>
 <head>
 <div style="height:0">
-<div id="test_1div">
-path.moveTo(213.673737, 413.292938);
-path.lineTo(225.200134, 343.616821);
-path.lineTo(236.726532, 273.940704);
-path.lineTo(219.386414, 231.373322);
-path.lineTo(213.673737, 413.292938);
-path.close();
-path.moveTo(43.485352, 308.984497);
-path.lineTo(122.610657, 305.950134);
-path.lineTo(201.735962, 302.915802);
-path.lineTo(280.861267, 299.881470);
-path.lineTo(43.485352, 308.984497);
-path.close();
-</div>
-<div id="test_2div">
-path.moveTo(-177.878387, 265.368988);
-path.lineTo(-254.415771, 303.709961);
-path.lineTo(-317.465363, 271.325562);
-path.lineTo(-374.520386, 207.507660);
-path.lineTo(-177.878387, 265.368988);
-path.close();
-path.moveTo(-63.582489, -3.679123);
-path.lineTo(-134.496841, 26.434566);
-path.lineTo(-205.411209, 56.548256);
-path.lineTo(-276.325562, 86.661942);
-path.lineTo(-63.582489, -3.679123);
-path.close();
-path.moveTo(-57.078423, 162.633453);
-path.lineTo(-95.963928, 106.261139);
-path.lineTo(-134.849457, 49.888824);
-path.lineTo(-173.734955, -6.483480);
-path.lineTo(-57.078423, 162.633453);
-path.close();
+
+<div id="testSimplifyQuadratic1">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(1, 0, 1, 1);
+    path.close();
+    path.moveTo(1, 0);
+    path.quadTo(0, 0, 0, 1);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+}
 </div>
-<div id="test_3div">
-path.moveTo(98.666489, -94.295059);
-path.lineTo(156.584320, -61.939133);
-path.lineTo(174.672974, -12.343765);
-path.lineTo(158.622345, 52.028267);
-path.lineTo(98.666489, -94.295059);
-path.close();
-path.moveTo(-133.225616, -48.622055);
-path.lineTo(-73.855499, -10.375397);
-path.lineTo(-14.485367, 27.871277);
-path.lineTo(44.884750, 66.117935);
-path.lineTo(-133.225616, -48.622055);
-path.close();
-path.moveTo( 9.030045, -163.413132);
-path.lineTo(-19.605331, -89.588760);
-path.lineTo(-48.240707, -15.764404);
-path.lineTo(-76.876053, 58.059944);
-path.lineTo( 9.030045, -163.413132);
-path.close();
+
+<div id="testSimplifyQuadratic2">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(20, 0, 20, 20);
+    path.close();
+    path.moveTo(20, 0);
+    path.quadTo(0, 0, 0, 20);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+}
 </div>
-<div id="test_4div">
-path.moveTo(340.41568, -170.97171);
-path.lineTo(418.846893, -142.428329);
-path.lineTo(497.278107, -113.884933);
-path.lineTo(449.18222, -45.6723022);
-path.lineTo(340.41568, -170.97171);
-path.close();
-path.moveTo(326.610535, 34.0393639);
-path.lineTo(371.334595, -14.9620667);
-path.lineTo(416.058624, -63.9634857);
-path.lineTo(460.782654, -112.96492);
-path.lineTo(326.610535, 34.0393639);
-path.close();
+
+<div id="testSimplifyQuadratic3">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(20, 0, 20, 20);
+    path.close();
+    path.moveTo(0, 20);
+    path.quadTo(0, 0, 20, 0);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+}
 </div>
-<div id="test_5div">
-original:
-path.moveTo(0, 0);
-path.quadTo(20, 0, 20, 20);
-path.lineTo(0, 0);
-path.close();
-path.moveTo(0, 20);
-path.quadTo(0, 0, 20, 0);
-path.lineTo(0, 20);
-path.close();
-simplified:
-path.moveTo(0, 0);
-path.lineTo(5, 5);
-path.quadTo(0, 10, 0, 20);
-path.lineTo(20, 20);
-path.quadTo(20, 10, 15, 5);
-path.lineTo(20, 0);
-path.quadTo(14.1421356, 0, 10, 1.71572876);
-path.quadTo(5.85786438, 0, 0, 0);
-path.close();
+
+<div id="testSimplifyQuadratic4">
+    SkPath path, out;
+    path.moveTo(0, 20);
+    path.quadTo(20, 0, 40, 20);
+    path.close();
+    path.moveTo(40, 10);
+    path.quadTo(20, 30, 0, 10);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
-<div id="test_6div">
-original:
-path.moveTo(0, 20);
-path.quadTo(20, 0, 40, 20);
-path.lineTo(0, 20);
-path.close();
-path.moveTo(40, 10);
-path.quadTo(20, 30, 0, 10);
-path.lineTo(40, 10);
-path.close();
-simplified:
-path.moveTo(0, 10);
-path.quadTo(2.92893219, 12.9289322, 5.85786438, 15);
-path.quadTo(2.92893219, 17.0710678, 0, 20);
-path.lineTo(40, 20);
-path.quadTo(37.0710678, 17.0710678, 34.1421356, 15);
-path.quadTo(37.0710678, 12.9289322, 40, 10);
-path.lineTo(0, 10);
-path.close();
+
+<div id="testSimplifyQuadratic5">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(0, 0);
+    path.close();
+    path.moveTo(0, 0);
+    path.lineTo(0, 0);
+    path.quadTo(0, 0, 0, 1);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
-<div id="test_7div">
+
+<div id="testSimplifyQuadratic6">
+    SkPath path, out;
     path.moveTo(0, 0);
     path.quadTo(0, 0, 0, 0);
+    path.lineTo(1, 0);
+    path.close();
+    path.moveTo(0, 0);
     path.lineTo(0, 0);
+    path.quadTo(1, 0, 0, 1);
     path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
+</div>
+
+<div id="testSimplifyQuadratic7">
+    SkPath path, out;
     path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
     path.lineTo(0, 1);
-    path.quadTo(1, 1, 1, 2);
+    path.close();
+    path.moveTo(0, 0);
     path.lineTo(0, 0);
+    path.quadTo(1, 0, 0, 2);
     path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
-<div id="test_8div">
-original:
-path.moveTo(0, 0);
-path.lineTo(3, 1);
-path.lineTo(0, 0);
-path.close();
-path.moveTo(1, 0);
-path.lineTo(0, 1);
-path.quadTo(2, 1, 3, 3);
-path.lineTo(1, 0);
-path.close();
-simplified:
-path.moveTo(1, 0);
-path.lineTo(0, 1);
-path.quadTo(1.42857146, 1, 2.34693885, 2.02040815);
-path.lineTo(1.28571427, 0.428571433);
-path.lineTo(1, 0);
-path.close();
-path.moveTo(2.34693885, 2.02040815);
-path.quadTo(2.71428561, 2.42857146, 3, 3);
-path.lineTo(2.34693885, 2.02040815);
-path.close();
+<div id="testSimplifyQuadratic8">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(0, 0);
+    path.close();
+    path.moveTo(0, 0);
+    path.lineTo(0, 0);
+    path.quadTo(1, 0, 0, 2);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
-<div id="test_9div">
+<div id="testSimplifyQuadratic9">
+    SkPath path, out;
     path.moveTo(0, 0);
     path.quadTo(0, 0, 0, 0);
-    path.lineTo(0, 2);
+    path.lineTo(1, 1);
+    path.close();
+    path.moveTo(0, 0);
     path.lineTo(0, 0);
+    path.quadTo(1, 0, 2, 2);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
+</div>
+
+<div id="testSimplifyQuadratic10">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(0, 0);
+    path.close();
+    path.moveTo(0, 0);
+    path.lineTo(0, 1);
+    path.quadTo(1, 1, 1, 2);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
+</div>
+
+<div id="testSimplifyQuadratic11">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(0, 2);
     path.close();
     path.moveTo(0, 0);
     path.lineTo(2, 1);
     path.quadTo(2, 2, 3, 3);
-    path.lineTo(0, 0);
     path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
-<div id="test_10div">
-original:
-path.moveTo(0, 0);
-path.lineTo(0, 2);
-path.lineTo(0, 0);
-path.close();
-path.moveTo(3, 0);
-path.quadTo(1, 1, 0, 2);
-path.lineTo(3, 0);
-path.close();
-simplified:
-path.moveTo(0, 0);
-path.lineTo(0, 2);
-path.quadTo(1, 1, 3, 0);
-path.lineTo(0, 0);
-path.close();
+<div id="testSimplifyQuadratic12">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.lineTo(0, 2);
+    path.lineTo(0, 0);
+    path.close();
+    path.moveTo(3, 0);
+    path.quadTo(1, 1, 0, 2);
+    path.lineTo(3, 0);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
-<div id="test_11div">
-original:
+<div id="testSimplifyQuadratic13">
+    SkPath path, out;
 path.moveTo(0, 0);
 path.quadTo(0, 0, 1, 0);
 path.lineTo(1, 1);
@@ -188,56 +182,69 @@ path.moveTo(0, 0);
 path.quadTo(3, 0, 1, 1);
 path.lineTo(0, 0);
 path.close();
-simplified:
-path.moveTo(0, 0);
-path.lineTo(1, 1);
-path.lineTo(1, 0);
-path.lineTo(0, 0);
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
-<div id="test_12div">
+<div id="testSimplifyQuadratic14">
+    SkPath path, out;
     path.moveTo(0, 0);
     path.quadTo(0, 0, 0, 0);
     path.lineTo(1, 1);
-    path.lineTo(0, 0);
     path.close();
     path.moveTo(0, 0);
     path.lineTo(0, 0);
     path.quadTo(0, 1, 2, 1);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
+</div>
+
+<div id="testSimplifyQuadratic15">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 1, 3);
+    path.lineTo(3, 3);
+    path.close();
+    path.moveTo(0, 1);
+    path.lineTo(1, 1);
+    path.quadTo(0, 3, 3, 3);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
+</div>
+
+<div id="testSimplifyQuadratic16">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(0, 1);
+    path.close();
+    path.moveTo(0, 0);
     path.lineTo(0, 0);
+    path.quadTo(1, 0, 0, 1);
     path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
-<div id="test_13div">
-original:
-path.moveTo(0, 0);
-path.quadTo(0, 0, 1, 3);
-path.lineTo(3, 3);
-path.lineTo(0, 0);
-path.close();
-path.moveTo(0, 1);
-path.lineTo(1, 1);
-path.quadTo(0, 3, 3, 3);
-path.lineTo(0, 1);
-path.close();
-simplified:
-path.moveTo(0, 0);
-path.lineTo(0.333333343, 1);
-path.lineTo(0, 1);
-path.lineTo(0.428571433, 1.28571427);
-path.lineTo(0.333333343, 1);
-path.lineTo(1, 1);
-path.lineTo(0, 0);
-path.close();
-path.moveTo(1, 1);
-path.quadTo(0.857142866, 1.28571427, 0.795918345, 1.53061223);
-path.lineTo(0.428571433, 1.28571427);
-path.lineTo(1, 3);
-path.lineTo(3, 3);
-path.lineTo(0.795918345, 1.53061223);
-path.quadTo(0.428571433, 3, 3, 3);
-path.lineTo(1, 1);
-path.close();
+<div id="testSimplifyQuadratic17">
+    SkPath path, out;
+    path.moveTo(0, 0);
+    path.quadTo(0, 0, 0, 0);
+    path.lineTo(2, 2);
+    path.close();
+    path.moveTo(0, 1);
+    path.lineTo(0, 1);
+    path.quadTo(2, 1, 3, 3);
+    path.close();
+    testSimplify(path, true, out, bitmap);
+    drawAsciiPaths(path, out, true);
+}
 </div>
 
 </div>
@@ -245,19 +252,23 @@ path.close();
 <script type="text/javascript">
 
 var testDivs = [
-    test_13div,
-    test_12div,
-    test_11div,
-    test_10div,
-    test_9div,
-    test_8div,
-    test_7div,
-    test_6div,
-    test_5div,
-    test_4div,
-    test_3div,
-    test_2div,
-    test_1div,
+    testSimplifyQuadratic17,
+    testSimplifyQuadratic16,
+    testSimplifyQuadratic15,
+    testSimplifyQuadratic14,
+    testSimplifyQuadratic13,
+    testSimplifyQuadratic12,
+    testSimplifyQuadratic11,
+    testSimplifyQuadratic10,
+    testSimplifyQuadratic9,
+    testSimplifyQuadratic8,
+    testSimplifyQuadratic7,
+    testSimplifyQuadratic6,
+    testSimplifyQuadratic5,
+    testSimplifyQuadratic4,
+    testSimplifyQuadratic3,
+    testSimplifyQuadratic2,
+    testSimplifyQuadratic1,
 ];
 
 var scale, columns, rows, xStart, yStart;
@@ -291,8 +302,18 @@ function parse(test) {
             if (pts.length > 0)
                 verbs.push(pts);
         }
-        if (verbs.length > 0)
+        if (verbs.length > 0) {
+            var lastIndex = verbs.length - 1;
+            var lastVerb = verbs[lastIndex];
+            var lastLen = lastVerb.length;
+            if (verbs[0][0] != lastVerb[lastLen - 2] && verbs[0][1] != lastVerb[lastLen - 1]) {
+                var lastPts = [];
+                lastPts.push(verbs[0][0]);
+                lastPts.push(verbs[0][1]);
+                verbs.push(lastPts);
+            }
             contours.push(verbs);
+        }
     }
     if (contours.length > 0)
         tests.push(contours);
@@ -469,23 +490,24 @@ function doKeyPress(evt) {
     case 'n':
         if (++testIndex >= tests.length)
             testIndex = 0;
-    //    insetScale = scale;
+        mouseX = Infinity;
+        drawTop();
+        break;
+    case 'P':
+    case 'p':
+        if (--testIndex < 0)
+            testIndex = tests.length - 1;
         mouseX = Infinity;
         drawTop();
         break;
     case 'T':
     case 't':
-  //      drawTs(testIndex);
         break;
     case '-':
- //       if (--insetScale < 1)
- //           insetScale = 1;
- //       else
             redraw();
         break;
     case '=':
     case '+':
- //       ++insetScale;
         redraw();
         break;
     }