shape ops work in progress

git-svn-id: http://skia.googlecode.com/svn/trunk@3566 2bbb7eff-a529-9590-31e7-b0007b416f81

18 files changed, 546 insertions, 368 deletions

diff --git a/experimental/Intersection/CubicIntersection.h b/experimental/Intersection/CubicIntersection.h
deleted file mode 100644
index b918400d88..0000000000
--- a/experimental/Intersection/CubicIntersection.h
+++ /dev/null
@@ -1,40 +0,0 @@
-#ifndef CubicIntersection_DEFINE
-#define CubicIntersection_DEFINE
-
-#include "DataTypes.h"
-
-class Intersections;
-
-// unit-testable utilities
-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);
-void chop_at(const Quadratic& src, QuadraticPair& dst, double t);
-int convex_hull(const Cubic& cubic, char order[4]);
-bool convex_x_hull(const Cubic& cubic, char connectTo0[2], char connectTo3[2]);
-bool implicit_matches(const Cubic& cubic1, const Cubic& cubic2);
-bool implicit_matches(const Quadratic& quad1, const Quadratic& quad2);
-void sub_divide(const Cubic& src, double t1, double t2, Cubic& dst);
-void sub_divide(const Quadratic& src, double t1, double t2, Quadratic& dst);
-void tangent(const Cubic& cubic, double t, _Point& result);
-void tangent(const Quadratic& cubic, double t, _Point& result);
-
-// utilities used only for unit testing
-bool point_on_parameterized_curve(const Cubic& cubic, const _Point& point);
-bool point_on_parameterized_curve(const Quadratic& quad, const _Point& point);
-
-// main functions
-enum ReduceOrder_Flags {
-    kReduceOrder_NoQuadraticsAllowed,
-    kReduceOrder_QuadraticsAllowed
-};
-int reduceOrder(const Cubic& cubic, Cubic& reduction, ReduceOrder_Flags );
-int reduceOrder(const _Line& line, _Line& reduction);
-int reduceOrder(const Quadratic& quad, Quadratic& reduction);
-//bool intersectStart(const Cubic& cubic1, const Cubic& cubic2, Intersections& );
-bool intersectStartT(const Cubic& cubic1, const Cubic& cubic2, Intersections& );
-bool intersectStart(const Cubic& cubic, const _Line& line, Intersections& );
-bool intersectStart(const Quadratic& q1, const Quadratic& q2, Intersections& );
-bool intersectStart(const Quadratic& quad, const _Line& line, Intersections& );
-
-#endif
diff --git a/experimental/Intersection/CurveIntersection.h b/experimental/Intersection/CurveIntersection.h
index 88316fab7c..25c696c48d 100644
--- a/experimental/Intersection/CurveIntersection.h
+++ b/experimental/Intersection/CurveIntersection.h
@@ -31,6 +31,10 @@ int reduceOrder(const Cubic& cubic, Cubic& reduction, ReduceOrder_Flags );
 int reduceOrder(const _Line& line, _Line& reduction);
 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 Quadratic& quad, double left, double right,
+        double y, double tRange[2]);
 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& );
diff --git a/experimental/Intersection/EdgeWalker.cpp b/experimental/Intersection/EdgeWalker.cpp
index 7f0ddffc01..70fa8e679c 100644
--- a/experimental/Intersection/EdgeWalker.cpp
+++ b/experimental/Intersection/EdgeWalker.cpp
@@ -16,7 +16,7 @@
 #include "ShapeOps.h"
 #include "TSearch.h"
 
-#if 01 // set to 1 for no debugging whatsoever
+#if 0 // set to 1 for no debugging whatsoever
 const bool gShowDebugf = false; // FIXME: remove once debugging is complete
 
 #define DEBUG_DUMP 0
@@ -30,6 +30,7 @@ const bool gShowDebugf = false; // FIXME: remove once debugging is complete
 #define DEBUG_OUT_LESS_THAN 0
 #define DEBUG_ADJUST_COINCIDENT 0
 #define DEBUG_BOTTOM 0
+#define DEBUG_SPLIT 0
 
 #else
 const bool gShowDebugf = true; // FIXME: remove once debugging is complete
@@ -44,7 +45,8 @@ const bool gShowDebugf = true; // FIXME: remove once debugging is complete
 #define DEBUG_OUT 01
 #define DEBUG_OUT_LESS_THAN 0
 #define DEBUG_ADJUST_COINCIDENT 1
-#define DEBUG_BOTTOM 01
+#define DEBUG_BOTTOM 0
+#define DEBUG_SPLIT 1
 
 #endif
 
@@ -59,7 +61,8 @@ 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}};
-    return intersect(aQuad, bLine, intersections);
+    intersect(aQuad, bLine, intersections);
+    return intersections.fUsed;
 }
 
 static int CubicLineIntersect(const SkPoint a[2], const SkPoint b[3],
@@ -67,15 +70,15 @@ static int CubicLineIntersect(const SkPoint a[2], const SkPoint b[3],
     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}};
-    intersections.fUsed = intersect(aCubic, bLine, intersections.fT[0], intersections.fT[1]);
-    return intersections.fUsed;
+    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}};
-    return intersect(aQuad, bQuad, intersections);
+    intersect(aQuad, bQuad, intersections);
+    return intersections.fUsed;
 }
 
 static int CubicIntersect(const SkPoint a[4], const SkPoint b[4],
@@ -84,7 +87,8 @@ static int CubicIntersect(const SkPoint a[4], const SkPoint b[4],
             {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}};
-    return intersect(aCubic, bCubic, intersections);
+    intersect(aCubic, bCubic, intersections);
+    return intersections.fUsed;
 }
 
 static int LineIntersect(const SkPoint a[2], SkScalar left, SkScalar right,
@@ -93,6 +97,19 @@ static int LineIntersect(const SkPoint a[2], SkScalar left, SkScalar right,
     return horizontalLineIntersect(aLine, left, right, y, aRange);
 }
 
+static int QuadIntersect(const SkPoint a[3], SkScalar left, SkScalar right,
+        SkScalar y, double aRange[3]) {
+    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, aRange);
+}
+
+static int CubicIntersect(const SkPoint a[4], SkScalar left, SkScalar right,
+        SkScalar y, double aRange[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}};
+    return horizontalIntersect(aCubic, left, right, y, aRange);
+}
+
 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;
@@ -632,7 +649,25 @@ class Intercepts {
 public:
     Intercepts()
         : fTopIntercepts(0)
-        , fBottomIntercepts(0) {
+        , fBottomIntercepts(0)
+        , fExplicit(false) {
+    }
+    
+    Intercepts& operator=(const Intercepts& src) {
+        fTs = src.fTs;
+        fTopIntercepts = src.fTopIntercepts;
+        fBottomIntercepts = src.fBottomIntercepts;
+    }
+
+    // OPTIMIZATION: remove this function if it's never called
+    double t(int tIndex) const {
+        if (tIndex == 0) {
+            return 0;
+        }
+        if (tIndex > fTs.count()) {
+            return 1;
+        }
+        return fTs[tIndex - 1];
     }
 
 #if DEBUG_DUMP
@@ -657,16 +692,18 @@ public:
             SkDebugf("%*s.fTs[%d]=%1.9g (%1.9g,%1.9g)\n", tab + sizeof(className),
                     className, i, fTs[i], out.fX, out.fY);
         }
-        SkDebugf("%*s.fTopIntercepts=%d\n", tab + sizeof(className),
+        SkDebugf("%*s.fTopIntercepts=%u\n", tab + sizeof(className),
                 className, fTopIntercepts);
-        SkDebugf("%*s.fBottomIntercepts=%d\n", tab + sizeof(className),
+        SkDebugf("%*s.fBottomIntercepts=%u\n", tab + sizeof(className),
                 className, fBottomIntercepts);
     }
 #endif
 
     SkTDArray<double> fTs;
-    int fTopIntercepts;
-    int fBottomIntercepts;
+    unsigned char fTopIntercepts; // 0=init state 1=1 edge >1=multiple edges
+    unsigned char fBottomIntercepts;
+    bool fExplicit; // if set, suppress 0 and 1
+    
 };
 
 struct HorizontalEdge {
@@ -709,13 +746,16 @@ struct InEdge {
         for (size_t index = 0; index < count; ++index) {
             double t = ts[index];
             if (t <= 0) {
+                intercepts.fTopIntercepts <<= 1;
                 fContainsIntercepts |= ++intercepts.fTopIntercepts > 1;
                 continue;
             }
             if (t >= 1) {
+                intercepts.fBottomIntercepts <<= 1;
                 fContainsIntercepts |= ++intercepts.fBottomIntercepts > 1;
                 continue;
             }
+            fIntersected = true;
             foundIntercept = true;
             size_t tCount = intercepts.fTs.count();
             double delta;
@@ -740,6 +780,40 @@ struct InEdge {
         fContainsIntercepts |= foundIntercept;
         return insertedAt;
     }
+    
+    void addPartial(SkTArray<InEdge>& edges, int id, int ptStart, int ptEnd,
+            int verbStart, int verbEnd) {
+        InEdge* edge = edges.push_back_n(1);
+        int verbCount = verbEnd - verbStart;
+        edge->fIntercepts.push_back_n(verbCount);
+        uint8_t* verbs = &fVerbs[verbStart];
+        for (int ceptIdx = 0; ceptIdx < verbCount; ++ceptIdx) {
+            edge->fIntercepts[ceptIdx] = fIntercepts[verbStart + ceptIdx];
+        }
+        edge->fPts.append(ptEnd - ptStart, &fPts[ptStart]);
+        edge->fVerbs.append(verbCount, &fVerbs[verbStart]);
+        edge->setBounds();
+        edge->fID = id + edges.count();
+        edge->fWinding = fWinding;
+        edge->fContainsIntercepts = fContainsIntercepts; // FIXME: may not be correct -- but do we need to know?
+    }
+
+    void addSplit(SkTArray<InEdge>& edges, int id, SkPoint* pts, uint8_t verb,
+            double* ts, int tCount, bool flipped) {
+        InEdge* edge = edges.push_back_n(1);
+        edge->fIntercepts.push_back_n(1);
+        edge->fIntercepts[0].fTs.append(tCount, ts);
+        edge->fIntercepts[0].fExplicit = true;
+        edge->fPts.append(verb, pts);
+        edge->fVerbs.append(1, &verb);
+        edge->setBounds();
+        edge->fID = id + edges.count();
+        edge->fWinding = fWinding;
+        edge->fContainsIntercepts = fContainsIntercepts; // FIXME: may not be correct -- but do we need to know?
+        if (flipped) {
+            flip();
+        }
+    }
 
     bool cached(const InEdge* edge) {
         // FIXME: in the pathological case where there is a ton of edges, binary search?
@@ -758,10 +832,44 @@ struct InEdge {
     }
 
     void complete(signed char winding, int id) {
+        setBounds();
+        fIntercepts.push_back_n(fVerbs.count());
+        if ((fWinding = winding) < 0) { // reverse verbs, pts, if bottom to top
+            flip();
+        }
+        fContainsIntercepts = fIntersected = false;
+        fID = id;
+    }
+    
+     void flip() {
+        size_t index;
+        size_t last = fPts.count() - 1;
+        for (index = 0; index < last; ++index, --last) {
+            SkTSwap<SkPoint>(fPts[index], fPts[last]);
+        }
+        last = fVerbs.count() - 1;
+        for (index = 0; index < last; ++index, --last) {
+            SkTSwap<uint8_t>(fVerbs[index], fVerbs[last]);
+        }
+    }
+
+    void reset() {
+        fCached.reset();
+        fIntercepts.reset();
+        fPts.reset();
+        fVerbs.reset();
+        fBounds.set(SK_ScalarMax, SK_ScalarMax, SK_ScalarMax, SK_ScalarMax);
+        fID = -1;
+        fWinding = 0;
+        fContainsIntercepts = false;
+        fIntersected = false;
+    }
+
+    void setBounds() {
         SkPoint* ptPtr = fPts.begin();
         SkPoint* ptLast = fPts.end();
         if (ptPtr == ptLast) {
-            SkDebugf("empty edge\n");
+            SkDebugf("%s empty edge\n", __FUNCTION__);
             SkASSERT(0);
             // FIXME: delete empty edge?
             return;
@@ -772,20 +880,113 @@ struct InEdge {
             fBounds.growToInclude(ptPtr->fX, ptPtr->fY);
             ++ptPtr;
         }
-        fIntercepts.push_back_n(fVerbs.count());
-        if ((fWinding = winding) < 0) { // reverse verbs, pts, if bottom to top
-            size_t index;
-            size_t last = fPts.count() - 1;
-            for (index = 0; index < last; ++index, --last) {
-                SkTSwap<SkPoint>(fPts[index], fPts[last]);
+    }
+
+    void splitInflectionPts(SkTArray<InEdge>& edges, int idStart) {
+        if (!fIntersected) {
+            return;
+        }
+        uint8_t* verbs = fVerbs.begin();
+        SkPoint* pts = fPts.begin();
+        int lastVerb = 0;
+        int lastPt = 0;
+        uint8_t verb;
+        bool edgeSplit = false;
+        for (int ceptIdx = 0; ceptIdx < fIntercepts.count(); ++ceptIdx, pts += verb) {
+            Intercepts& intercepts = fIntercepts[ceptIdx];
+            verb = *verbs++;
+            if (verb <= SkPath::kLine_Verb) {
+                continue;
+            }
+            size_t tCount = intercepts.fTs.count();
+            if (!tCount) {
+                continue;
+            }
+            size_t tIndex = -1;
+            SkScalar y = pts[0].fY;
+            int lastSplit = 0;
+            int firstSplit = -1;
+            bool curveSplit = false;
+            while (++tIndex < tCount) {
+                double nextT = intercepts.fTs[tIndex];
+                SkScalar nextY = verb == SkPath::kQuad_Verb
+                        ? QuadYAtT(pts, nextT) : CubicYAtT(pts, nextT);
+                if (nextY < y) {
+                    edgeSplit = curveSplit = true;
+                    if (firstSplit < 0) {
+                        firstSplit = tIndex;
+                        int nextPt = pts - fPts.begin();
+                        int nextVerb = verbs - 1 - fVerbs.begin();
+                        if (lastVerb < nextVerb) {
+                            addPartial(edges, idStart, lastPt, nextPt,
+                                    lastVerb, nextVerb);
+            #if DEBUG_SPLIT
+                            SkDebugf("%s addPartial 1 edge=%d\n", __FUNCTION__,
+                                    fID);
+            #endif
+                        }
+                        lastPt = nextPt;
+                        lastVerb = nextVerb;
+                    }
+                } else {
+                    if (firstSplit >= 0) {
+                        if (lastSplit < firstSplit) {
+                            addSplit(edges, idStart, pts, verb,
+                                    &intercepts.fTs[lastSplit],
+                                    firstSplit - lastSplit, false);
+            #if DEBUG_SPLIT
+                            SkDebugf("%s addSplit 1 edge=%d tIndex=%d,%d\n",
+                                    __FUNCTION__, fID, lastSplit, firstSplit);
+            #endif
+                        }
+                        addSplit(edges, idStart, pts, verb,
+                                &intercepts.fTs[firstSplit],
+                                tIndex - firstSplit, true);
+            #if DEBUG_SPLIT
+                        SkDebugf("%s addSplit 2 edge=%d tIndex=%d,%d flip\n",
+                                __FUNCTION__, fID, firstSplit, tIndex);
+            #endif
+                        lastSplit = tIndex;
+                        firstSplit = -1;
+                    }
+                }
+                y = nextY;
+            }
+            if (curveSplit) {
+                if (firstSplit < 0) {
+                    firstSplit = lastSplit;
+                } else {
+                    addSplit(edges, idStart, pts, verb,
+                            &intercepts.fTs[lastSplit], firstSplit - lastSplit,
+                            false);
+            #if DEBUG_SPLIT
+                    SkDebugf("%s addSplit 3 edge=%d tIndex=%d,%d\n", __FUNCTION__,
+                            fID, lastSplit, firstSplit);
+            #endif
+                }
+                addSplit(edges, idStart, pts, verb,
+                        &intercepts.fTs[firstSplit], tIndex - firstSplit,
+                        pts[verb].fY < y);
+            #if DEBUG_SPLIT
+                SkDebugf("%s addSplit 4 edge=%d tIndex=%d,%d %s\n", __FUNCTION__,
+                        fID, firstSplit, tIndex, pts[verb].fY < y ? "flip" : "");
+            #endif
             }
-            last = fVerbs.count() - 1;
-            for (index = 0; index < last; ++index, --last) {
-                SkTSwap<uint8_t>(fVerbs[index], fVerbs[last]);
+        }
+        // collapse remainder -- if there's nothing left, clear it somehow?
+        if (edgeSplit) {
+            int nextVerb = verbs - 1 - fVerbs.begin();
+            if (lastVerb < nextVerb) {
+                int nextPt = pts - fPts.begin();
+                addPartial(edges, idStart, lastPt, nextPt,
+                        lastVerb, nextVerb);
+            #if DEBUG_SPLIT
+                SkDebugf("%s addPartial 2 edge=%d\n", __FUNCTION__, fID);
+            #endif
             }
+            // OPTIMIZATION: reuse the edge instead of marking it empty
+            reset();
         }
-        fContainsIntercepts = false;
-        fID = id;
     }
 
 #if DEBUG_DUMP
@@ -803,7 +1004,6 @@ struct InEdge {
         for (i = 0; i < fIntercepts.count(); ++i) {
             SkDebugf("%*s.fIntercepts[%d]:\n", tab + sizeof(className),
                     className, i);
-            // FIXME: take current verb into consideration
             fIntercepts[i].dump(pts, (SkPath::Verb) *verbs);
             pts += *verbs++;
         }
@@ -822,10 +1022,12 @@ struct InEdge {
                 fWinding);
         SkDebugf("%*s.fContainsIntercepts=%d\n", tab + sizeof(className),
                 className, fContainsIntercepts);
+        SkDebugf("%*s.fIntersected=%d\n", tab + sizeof(className),
+                className, fIntersected);
     }
 #endif
 
-    // temporary data : move this to a separate struct?
+    // FIXME: temporary data : move this to a separate struct?
     SkTDArray<const InEdge*> fCached; // list of edges already intercepted
     SkTArray<Intercepts> fIntercepts; // one per verb
 
@@ -836,6 +1038,7 @@ struct InEdge {
     int fID;
     signed char fWinding;
     bool fContainsIntercepts;
+    bool fIntersected;
 };
 
 class InEdgeBuilder {
@@ -849,10 +1052,19 @@ InEdgeBuilder(const SkPath& path, bool ignoreHorizontal, SkTArray<InEdge>& edges
     , fID(0)
     , fHorizontalEdges(horizontalEdges)
     , fIgnoreHorizontal(ignoreHorizontal)
+    , fContainsCurves(false)
 {
     walk();
 }
 
+bool containsCurves() const {
+    return fContainsCurves;
+}
+
+int nextID() {
+    return ++fID;
+}
+
 protected:
 
 void addEdge() {
@@ -864,7 +1076,7 @@ void addEdge() {
 
 bool complete() {
     if (fCurrentEdge && fCurrentEdge->fVerbs.count()) {
-        fCurrentEdge->complete(fWinding, ++fID);
+        fCurrentEdge->complete(fWinding, nextID());
         fCurrentEdge = NULL;
         return true;
     }
@@ -913,9 +1125,11 @@ void walk() {
                 break;
             case SkPath::kQuad_Verb:
                 winding = direction(3);
+                fContainsCurves = true;
                 break;
             case SkPath::kCubic_Verb:
                 winding = direction(4);
+                fContainsCurves = true;
                 break;
             case SkPath::kClose_Verb:
                 SkASSERT(fCurrentEdge);
@@ -969,6 +1183,7 @@ private:
     int fID;
     int8_t fWinding;
     bool fIgnoreHorizontal;
+    bool fContainsCurves;
 };
 
 struct WorkEdge {
@@ -1134,8 +1349,8 @@ public:
     }
 
     bool advanceT() {
-        SkASSERT(fTIndex <= fTs->count());
-        return ++fTIndex <= fTs->count();
+        SkASSERT(fTIndex <= fTs->count() - fExplicitTs);
+        return ++fTIndex <= fTs->count() - fExplicitTs;
     }
 
     bool advance() {
@@ -1153,6 +1368,7 @@ public:
             SkASSERT(fWorkEdge.fEdge->fPts.begin() <= fWorkEdge.fPts);
         } while (fWorkEdge.fPts[0].fY >= y);
         initT();
+        SkASSERT(!fExplicitTs);
         fTIndex = fTs->count() + 1;
     }
 
@@ -1187,7 +1403,7 @@ public:
         //  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()) - 1;
+        int add = (fTIndex <= fTs->count() - fExplicitTs) - 1;
         double tAbove = t(fTIndex + add);
         (*xyAtTFunc)(fWorkEdge.fPts, tAbove, &fAbove);
         double tBelow = t(fTIndex - ~add);
@@ -1195,6 +1411,7 @@ public:
         SkASSERT(tAbove != tBelow);
         // FIXME: this can loop forever
         // need a break if we hit the end
+        // FIXME: in unit test, figure out how explicit Ts work as well
         while (fAbove.fY == fBelow.fY) {
             if (add < 0 || fTIndex == fTs->count()) {
                 add -= 1;
@@ -1249,7 +1466,8 @@ public:
         const Intercepts& intercepts = fWorkEdge.fEdge->fIntercepts.front();
         SkASSERT(fWorkEdge.verbIndex() <= fWorkEdge.fEdge->fIntercepts.count());
         const Intercepts* interceptPtr = &intercepts + fWorkEdge.verbIndex();
-        fTs = &interceptPtr->fTs; 
+        fTs = &interceptPtr->fTs;
+        fExplicitTs = interceptPtr->fExplicit;
   //  the above is conceptually the same as
   //    fTs = &fWorkEdge.fEdge->fIntercepts[fWorkEdge.verbIndex()].fTs;
   //  but templated arrays don't allow returning a pointer to the end() element
@@ -1379,23 +1597,21 @@ public:
 #endif
         return ulps >= 0 && ulps <= 32;
     }
-
+    
     double nextT() const {
-        SkASSERT(fTIndex <= fTs->count());
+        SkASSERT(fTIndex <= fTs->count() - fExplicitTs);
         return t(fTIndex + 1);
     }
 
     double t() const {
-        if (fTIndex == 0) {
-            return 0;
-        }
-        if (fTIndex > fTs->count()) {
-            return 1;
-        }
-        return (*fTs)[fTIndex - 1];
+        return t(fTIndex);
     }
 
     double t(int tIndex) const {
+        if (fExplicitTs) {
+            SkASSERT(tIndex < fTs->count());
+            return (*fTs)[tIndex];
+        } 
         if (tIndex == 0) {
             return 0;
         }
@@ -1426,6 +1642,7 @@ public:
     bool fCloseCall;
     bool fDone;
     bool fFixBelow;
+    bool fExplicitTs;
 };
 
 static void addToActive(SkTDArray<ActiveEdge>& activeEdges, const InEdge* edge) {
@@ -1462,24 +1679,39 @@ static void addBottomT(InEdge** currentPtr, InEdge** lastPtr,
             HorizontalEdge** sorted = horizontal;
             horzEdge = *sorted;
             do {
-                if (wt.verb() == SkPath::kLine_Verb) {
-                    double wtTs[2];
-                    int pts = LineIntersect(wt.fPts, horzEdge->fLeft,
-                            horzEdge->fRight, horzEdge->fY, wtTs);
-                    if (pts) {
+                double wtTs[4];
+                int pts;
+                uint8_t verb = wt.verb();
+                switch (verb) {
+                    case SkPath::kLine_Verb:
+                        pts = LineIntersect(wt.fPts, horzEdge->fLeft,
+                                horzEdge->fRight, horzEdge->fY, wtTs);
+                        break;
+                    case SkPath::kQuad_Verb:
+                        pts = QuadIntersect(wt.fPts, horzEdge->fLeft,
+                                horzEdge->fRight, horzEdge->fY, wtTs);
+                        break;
+                    case SkPath::kCubic_Verb:
+                        pts = CubicIntersect(wt.fPts, horzEdge->fLeft,
+                                horzEdge->fRight, horzEdge->fY, wtTs);
+                        break;
+                }
+                if (pts) {
 #if DEBUG_ADD_BOTTOM_TS
-                        SkDebugf("%s y=%g wtTs[0]=%g (%g,%g, %g,%g)\n", __FUNCTION__,
-                                horzEdge->fY, wtTs[0], wt.fPts[0].fX, wt.fPts[0].fY,
-                                wt.fPts[1].fX, wt.fPts[1].fY);
-                        if (pts == 2) {
-                            SkDebugf("%s wtTs[1]=%g\n", __FUNCTION__, wtTs[1]);
+                    for (int x = 0; x < pts; ++x) {
+                        SkDebugf("%s y=%g wtTs[0]=%g (%g,%g", __FUNCTION__,
+                                horzEdge->fY, wtTs[x], wt.fPts[0].fX, wt.fPts[0].fY);
+                        for (int y = 0; y < verb; ++y) {
+                            SkDebugf(" %g,%g", wt.fPts[y + 1].fX, wt.fPts[y + 1].fY));
                         }
-#endif
-                        test->add(wtTs, pts, wt.verbIndex());
+                        SkDebugf(")\n");
                     }
-                } else {
-                    // FIXME: add all curve types
-                    SkASSERT(0);
+                    if (pts > verb) {
+                        SkASSERT(0); // FIXME ? should this work?
+                        SkDebugf("%s wtTs[1]=%g\n", __FUNCTION__, wtTs[1]);
+                    }
+#endif
+                    test->add(wtTs, pts, wt.verbIndex());
                 }
                 horzEdge = *++sorted;
             } while (horzEdge->fY == bottom
@@ -1526,6 +1758,9 @@ static void addIntersectingTs(InEdge** currentPtr, InEdge** lastPtr) {
         InEdge** nextPtr = testPtr;
         do {
             InEdge* next = *++nextPtr;
+            // FIXME: this compares against the sentinel sometimes
+            // OPTIMIZATION: this may never be needed since this gets called
+            // in two passes now. Verify that double hits are appropriate.
             if (test->cached(next)) {
                 continue;
             }
@@ -1695,6 +1930,9 @@ static SkScalar computeInterceptBottom(SkTDArray<ActiveEdge>& activeEdges,
             }
         } while (wt.advance());
     }
+#if DEBUG_BOTTOM
+    SkDebugf("%s bottom=%1.9g\n", __FUNCTION__, bottom);
+#endif
     return bottom;
 }
 
@@ -1729,6 +1967,9 @@ static SkScalar findBottom(InEdge** currentPtr,
         }
         test = *++testPtr;
     }
+#if DEBUG_BOTTOM
+    SkDebugf("%s %d bottom=%1.9g\n", __FUNCTION__, activeEdges ? 2 : 1, bottom);
+#endif
     return bottom;
 }
 
@@ -2095,7 +2336,7 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
                     aboveBottom &= !activePtr->fCloseCall;
                 } else {
                     if (activePtr->fSkip || activePtr->fCloseCall) {
-                        SkDebugf("== %1.9g\n", clippedPts[0].fY);
+                        if (gShowDebugf) SkDebugf("== %1.9g\n", clippedPts[0].fY);
                     }
                 }
             } while (moreToDo & aboveBottom);
@@ -2103,6 +2344,16 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
     }
 }
 
+static void dumpEdgeList(const SkTDArray<InEdge*>& edgeList,
+        const InEdge& edgeSentinel) {
+#if DEBUG_DUMP
+    InEdge** debugPtr = edgeList.begin();
+    do {
+        (*debugPtr++)->dump();
+    } while (*debugPtr != &edgeSentinel);
+#endif
+}
+
 void simplify(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;
@@ -2149,14 +2400,24 @@ void simplify(const SkPath& path, bool asFill, SkPath& simple) {
         y = bottom;
         currentPtr = advanceEdges(NULL, currentPtr, lastPtr, y);
     } while (*currentPtr != &edgeSentinel);
-
-#if DEBUG_DUMP
-    InEdge** debugPtr = edgeList.begin();
-    do {
-        (*debugPtr++)->dump();
-    } while (*debugPtr != &edgeSentinel);
-#endif
-
+    // 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.
+    if (builder.containsCurves()) {
+        currentPtr = edgeList.begin();
+        SkTArray<InEdge> splits;
+        do {
+            (*currentPtr)->splitInflectionPts(splits, builder.nextID());
+        } while (*++currentPtr != &edgeSentinel);
+        if (splits.count()) {
+            edges.pop_back(); // pop the sentinel
+            for (int index = 0; index < splits.count(); ++index) {
+                edges.push_back(splits[index]);
+            }
+            makeEdgeList(edges, edgeSentinel, edgeList);
+        }
+    }
+    dumpEdgeList(edgeList, edgeSentinel);
     // walk the sorted edges from top to bottom, computing accumulated winding
     SkTDArray<ActiveEdge> activeEdges;
     OutEdgeBuilder outBuilder(asFill);
@@ -2166,21 +2427,12 @@ void simplify(const SkPath& path, bool asFill, SkPath& simple) {
         InEdge** lastPtr = currentPtr; // find the edge below the bottom of the first set
         SkScalar bottom = findBottom(currentPtr, edgeList.end(),
                 &activeEdges, y, asFill, lastPtr);
-#if DEBUG_BOTTOM
-        SkDebugf("%s findBottom bottom=%1.9g\n", __FUNCTION__, bottom);
-#endif
         if (lastPtr > currentPtr) {
             bottom = computeInterceptBottom(activeEdges, y, bottom);
-#if DEBUG_BOTTOM
-            SkDebugf("%s computeInterceptBottom bottom=%1.9g\n", __FUNCTION__, bottom);
-#endif
             SkTDArray<ActiveEdge*> activeEdgeList;
             sortHorizontal(activeEdges, activeEdgeList, y);
             bottom = adjustCoincident(activeEdgeList, windingMask, y, bottom,
                 outBuilder);
-#if DEBUG_BOTTOM
-            SkDebugf("%s adjustCoincident bottom=%1.9g\n", __FUNCTION__, bottom);
-#endif
             stitchEdge(activeEdgeList, y, bottom, windingMask, asFill, outBuilder);
         }
         y = bottom;
diff --git a/experimental/Intersection/EdgeWalkerPolygon4x4_Test.cpp b/experimental/Intersection/EdgeWalkerPolygon4x4_Test.cpp
index 27ec5be90f..7054683c53 100755
--- a/experimental/Intersection/EdgeWalkerPolygon4x4_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerPolygon4x4_Test.cpp
@@ -1,14 +1,24 @@
 #include "EdgeWalker_Test.h"
 #include "Intersection_Tests.h"
+#include "SkBitmap.h"
+#include "SkCanvas.h"
 #include <assert.h>
 #include <pthread.h>
- 
+
 struct State {
+    State() {
+    bitmap.setConfig(SkBitmap::kARGB_8888_Config, 150 * 2, 100);
+    bitmap.allocPixels();
+    canvas = new SkCanvas(bitmap);
+    }
+
     int a;
     int b;
     int c;
     int d;
     pthread_t threadID;
+    SkCanvas* canvas;
+    SkBitmap bitmap;
     bool abcIsATriangle;
 };
 
@@ -77,13 +87,13 @@ static void* testSimplify4x4QuadralateralsMain(void* data)
                         str += sprintf(str, "    path.lineTo(%d, %d);\n", hx, hy);
                         str += sprintf(str, "    path.close();");
                     }
-                    if (!testSimplify(path, true, out)) {
+                    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)) {
+                    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);
@@ -173,9 +183,9 @@ static void* testSimplify4x4NondegeneratesMain(void* data) {
                     str += sprintf(str, "    path.lineTo(%d, %d);\n", fx, fy);
                     str += sprintf(str, "    path.close();");
                 }
-                testSimplify(path, true, out);
+                testSimplify(path, true, out, state.bitmap, state.canvas);
                 path.setFillType(SkPath::kEvenOdd_FillType);
-                testSimplify(path, true, out);
+                testSimplify(path, true, out, state.bitmap, state.canvas);
             }
         }
     }
@@ -263,9 +273,9 @@ static void* testSimplify4x4DegeneratesMain(void* data) {
                     str += sprintf(str, "    path.lineTo(%d, %d);\n", fx, fy);
                     str += sprintf(str, "    path.close();");
                 }
-                testSimplify(path, true, out);
+                testSimplify(path, true, out, state.bitmap, state.canvas);
                 path.setFillType(SkPath::kEvenOdd_FillType);
-                testSimplify(path, true, out);
+                testSimplify(path, true, out, state.bitmap, state.canvas);
             }
         }
     }
diff --git a/experimental/Intersection/EdgeWalkerPolygons_Mismatches.cpp b/experimental/Intersection/EdgeWalkerPolygons_Mismatches.cpp
index 0054cfbd26..09d6f9347e 100644
--- a/experimental/Intersection/EdgeWalkerPolygons_Mismatches.cpp
+++ b/experimental/Intersection/EdgeWalkerPolygons_Mismatches.cpp
@@ -1,5 +1,6 @@
 #include "EdgeWalker_Test.h"
 #include "Intersection_Tests.h"
+#include "SkBitmap.h"
 
 // edges that didn't match
 struct misMatch {
@@ -1579,6 +1580,7 @@ size_t misMatchCount = sizeof(misMatches) / sizeof(misMatches[0]);
 void TestMismatches();
 
 void TestMismatches() {
+    SkBitmap bitmap;
     for (size_t index = 0; index < misMatchCount; ++index) {
         const misMatch& miss = misMatches[index];
         int ax = miss.a & 0x03;
@@ -1609,6 +1611,6 @@ void TestMismatches() {
         path.lineTo(gx, gy);
         path.lineTo(hx, hy);
         path.close();
-        testSimplify(path, true, out);
+        testSimplify(path, true, out, bitmap);
     }
 }
diff --git a/experimental/Intersection/EdgeWalkerPolygons_Test.cpp b/experimental/Intersection/EdgeWalkerPolygons_Test.cpp
index 7bf6452bee..f3455eec33 100644
--- a/experimental/Intersection/EdgeWalkerPolygons_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerPolygons_Test.cpp
@@ -1,5 +1,8 @@
 #include "EdgeWalker_Test.h"
 #include "Intersection_Tests.h"
+#include "SkBitmap.h"
+
+static SkBitmap bitmap;
 
 static void testSimplifyTriangle() {
     SkPath path, out;
@@ -12,7 +15,7 @@ static void testSimplifyTriangle() {
     path.lineTo(10,30); //                /_|
     path.lineTo(20,30);
     path.close();
-    testSimplify(path, true, out); // expect |\/|
+    testSimplify(path, true, out, bitmap); // expect |\/|
                                    //        |__|         
 }
 
@@ -26,7 +29,7 @@ static void testSimplifyTriangle3() {
     path.lineTo(1, 0);
     path.lineTo(3, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle4() {
@@ -39,7 +42,7 @@ static void testSimplifyTriangle4() {
     path.lineTo(1, 0);
     path.lineTo(2, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle5() {
@@ -52,7 +55,7 @@ static void testSimplifyTriangle5() {
     path.lineTo(1, 1);
     path.lineTo(2, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle6() {
@@ -67,7 +70,7 @@ static void testSimplifyTriangle6() {
     path.lineTo(3, 1);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle7() {
@@ -82,7 +85,7 @@ static void testSimplifyTriangle7() {
     path.lineTo(0, 2);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle8() {
@@ -97,7 +100,7 @@ static void testSimplifyTriangle8() {
     path.lineTo(1, 3);
     path.lineTo(0, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle9() {
@@ -112,7 +115,7 @@ static void testSimplifyTriangle9() {
     path.lineTo(2, 1);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle10() {
@@ -127,7 +130,7 @@ static void testSimplifyTriangle10() {
     path.lineTo(0, 1);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle11() {
@@ -142,7 +145,7 @@ static void testSimplifyTriangle11() {
     path.lineTo(2, 2);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle12() {
@@ -157,7 +160,7 @@ static void testSimplifyTriangle12() {
     path.lineTo(1, 1);
     path.lineTo(2, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle13() {
@@ -172,7 +175,7 @@ static void testSimplifyTriangle13() {
     path.lineTo(1, 1);
     path.lineTo(3, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle14() {
@@ -187,7 +190,7 @@ static void testSimplifyTriangle14() {
     path.lineTo(0, 1);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle15() {
@@ -201,7 +204,7 @@ static void testSimplifyTriangle15() {
     path.lineTo(0, 1);
     path.lineTo(2, 2);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle16() {
@@ -214,7 +217,7 @@ static void testSimplifyTriangle16() {
     path.lineTo(0, 1);
     path.lineTo(1, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle17() {
@@ -227,7 +230,7 @@ static void testSimplifyTriangle17() {
     path.lineTo(1, 3);
     path.lineTo(0, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
     
 static void testSimplifyTriangle18() {
@@ -240,7 +243,7 @@ static void testSimplifyTriangle18() {
     path.lineTo(0, 1);
     path.lineTo(0, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle19() {
@@ -254,7 +257,7 @@ static void testSimplifyTriangle19() {
     path.lineTo(1, 1);
     path.lineTo(2, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle20() {
@@ -267,7 +270,7 @@ static void testSimplifyTriangle20() {
     path.lineTo(3, 2);
     path.lineTo(0, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle21() {
@@ -280,7 +283,7 @@ static void testSimplifyTriangle21() {
     path.lineTo(2, 1);
     path.lineTo(0, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyDegenerateTriangle1() {
@@ -293,7 +296,7 @@ static void testSimplifyDegenerateTriangle1() {
     path.lineTo(0, 0);
     path.lineTo(0, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyDegenerateTriangle2() {
@@ -306,7 +309,7 @@ static void testSimplifyDegenerateTriangle2() {
     path.lineTo(2, 2);
     path.lineTo(3, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyWindingParallelogram() {
@@ -322,7 +325,7 @@ static void testSimplifyWindingParallelogram() {
     path.lineTo(20,30); //               /_/
     path.lineTo(30,10);
     path.close();
-    testSimplify(path, true, out); // expect   _
+    testSimplify(path, true, out, bitmap); // expect   _
                                    //         / \     .       
 }                                  //        /___\    .
 
@@ -339,7 +342,7 @@ static void testSimplifyXorParallelogram() {
     path.lineTo(20,30); //               /_/
     path.lineTo(30,10);
     path.close();
-    testSimplify(path, true, out); // expect   _
+    testSimplify(path, true, out, bitmap); // expect   _
 }                                  //         \ /
 
 static void testSimplifyTriangle2() {
@@ -353,9 +356,10 @@ static void testSimplifyTriangle2() {
     path.lineTo(20,10); //               \ |
     path.lineTo(20,30); //                \|
     path.close();                  //         _
-    testSimplify(path, true, out); // expect | |
+    testSimplify(path, true, out, bitmap); // expect | |
 }                                  //        |_|
 
+#if 0
 static void testPathTriangleRendering() {
     SkPath one, two;
     one.moveTo(0, 0);
@@ -375,10 +379,11 @@ static void testPathTriangleRendering() {
         two.reset();
     }
 }
+#endif
 
 static void simplify(const char* functionName, const SkPath& path,
         bool fill, SkPath& out) {
-    SkDebugf("%s\n", functionName);
+    if (false) SkDebugf("%s\n", functionName);
     simplify(path, fill, out);
 }
 
@@ -525,7 +530,7 @@ static void testSimplifyTriangle22() {
     path.lineTo(0, 2);
     path.lineTo(0, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle23() {
@@ -538,7 +543,7 @@ static void testSimplifyTriangle23() {
     path.lineTo(0, 1);
     path.lineTo(1, 2);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyTriangle24() {
@@ -551,7 +556,7 @@ static void testSimplifyTriangle24() {
     path.lineTo(1, 0);
     path.lineTo(0, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifySkinnyTriangle7() {
@@ -754,7 +759,7 @@ static void (*simplifyTests[])() = {
     testSimplifyTriangle2,
     testSimplifyWindingParallelogram,
     testSimplifyXorParallelogram,
-    testPathTriangleRendering,
+//    testPathTriangleRendering,
 };
 
 static size_t simplifyTestsCount = sizeof(simplifyTests) / sizeof(simplifyTests[0]);
@@ -772,7 +777,7 @@ void SimplifyPolygonPaths_Test() {
     for ( ; index < simplifyTestsCount; ++index) {
         (*simplifyTests[index])();
         if (simplifyTests[index] == testSimplifySkinnyTriangle2) {
-            SkDebugf("%s last fast skinny test\n", __FUNCTION__);
+            if (false) SkDebugf("%s last fast skinny test\n", __FUNCTION__);
         }
         firstTestComplete = true;
     }
diff --git a/experimental/Intersection/EdgeWalkerQuadralaterals_Test.cpp b/experimental/Intersection/EdgeWalkerQuadralaterals_Test.cpp
index a87b37f31b..daf5af77f3 100644
--- a/experimental/Intersection/EdgeWalkerQuadralaterals_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerQuadralaterals_Test.cpp
@@ -1,5 +1,8 @@
 #include "EdgeWalker_Test.h"
 #include "Intersection_Tests.h"
+#include "SkBitmap.h"
+
+static SkBitmap bitmap;
 
 static void testSimplifyQuad1() {
     SkPath path, out;
@@ -13,7 +16,7 @@ static void testSimplifyQuad1() {
     path.lineTo(1, 3);
     path.lineTo(1, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuad2() {
@@ -28,7 +31,7 @@ static void testSimplifyQuad2() {
     path.lineTo(1, 1);
     path.lineTo(0, 2);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuad3() {
@@ -43,7 +46,7 @@ static void testSimplifyQuad3() {
     path.lineTo(2, 1);
     path.lineTo(0, 2);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuad4() {
@@ -58,7 +61,7 @@ static void testSimplifyQuad4() {
     path.lineTo(3, 1);
     path.lineTo(3, 3);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuad5() {
@@ -73,7 +76,7 @@ static void testSimplifyQuad5() {
     path.lineTo(2, 1);
     path.lineTo(0, 2);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuad6() {
@@ -88,7 +91,7 @@ static void testSimplifyQuad6() {
     path.lineTo(1, 1);
     path.lineTo(2, 2);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void (*simplifyTests[])() = {
diff --git a/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp b/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp
index ab4e39b637..584ecdabb3 100644
--- a/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerQuadratics_Test.cpp
@@ -1,5 +1,8 @@
 #include "EdgeWalker_Test.h"
 #include "Intersection_Tests.h"
+#include "SkBitmap.h"
+
+static SkBitmap bitmap;
 
 static void testSimplifyQuadratic1() {
     SkPath path, out;
@@ -9,7 +12,7 @@ static void testSimplifyQuadratic1() {
     path.moveTo(1, 0);
     path.quadTo(0, 0, 0, 1);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuadratic2() {
@@ -20,8 +23,7 @@ static void testSimplifyQuadratic2() {
     path.moveTo(20, 0);
     path.quadTo(0, 0, 0, 20);
     path.close();
-    testSimplify(path, true, out);
-    drawAsciiPaths(path, out, true);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyQuadratic3() {
@@ -32,11 +34,23 @@ static void testSimplifyQuadratic3() {
     path.moveTo(0, 20);
     path.quadTo(0, 0, 20, 0);
     path.close();
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
+}
+
+static void 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);
 }
 
 static void (*simplifyTests[])() = {
+    testSimplifyQuadratic4,
     testSimplifyQuadratic3,
     testSimplifyQuadratic2,
     testSimplifyQuadratic1,
diff --git a/experimental/Intersection/EdgeWalkerRectangles_Test.cpp b/experimental/Intersection/EdgeWalkerRectangles_Test.cpp
index 8dc8627609..a5448e31b6 100644
--- a/experimental/Intersection/EdgeWalkerRectangles_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerRectangles_Test.cpp
@@ -1,5 +1,8 @@
 #include "EdgeWalker_Test.h"
 #include "Intersection_Tests.h"
+#include "SkBitmap.h"
+
+static SkBitmap bitmap;
 
 static void testSimplifyCoincidentInner() {
     SkPath path, out;
@@ -7,7 +10,7 @@ static void testSimplifyCoincidentInner() {
     path.addRect(10, 10, 60, 60, SkPath::kCCW_Direction);
     path.addRect(20, 20, 50, 50, SkPath::kCW_Direction);
     path.addRect(20, 30, 40, 40, SkPath::kCW_Direction);
-    testSimplify(path, true, out);
+    testSimplify(path, true, out, bitmap);
 }
 
 static void testSimplifyCoincidentVertical() {
@@ -304,7 +307,7 @@ static void testSimplifyOverlap() {
                         SkPath path, out;
                         path.addRect(rect1, static_cast<SkPath::Direction>(dir));
                         path.addRect(rect2, static_cast<SkPath::Direction>(dir));
-                        testSimplify(path, true, out);
+                        testSimplify(path, true, out, bitmap);
                     }
                 }
             }
diff --git a/experimental/Intersection/EdgeWalker_Test.h b/experimental/Intersection/EdgeWalker_Test.h
index ac9743699a..1f644a7480 100644
--- a/experimental/Intersection/EdgeWalker_Test.h
+++ b/experimental/Intersection/EdgeWalker_Test.h
@@ -2,9 +2,13 @@
 
 #include "ShapeOps.h"
 
-extern bool comparePaths(const SkPath& one, const SkPath& two);
+class SkBitmap;
+class SkCanvas;
+
+//extern int comparePaths(const SkPath& one, const SkPath& two);
 extern void comparePathsTiny(const SkPath& one, const SkPath& two);
 extern bool drawAsciiPaths(const SkPath& one, const SkPath& two,
         bool drawPaths);
 extern void showPath(const SkPath& path, const char* str = NULL);
-extern bool testSimplify(const SkPath& path, bool fill, SkPath& out);
+extern bool testSimplify(const SkPath& path, bool fill, SkPath& out,
+        SkBitmap& bitmap, SkCanvas* canvas = 0);
diff --git a/experimental/Intersection/EdgeWalker_TestUtility.cpp b/experimental/Intersection/EdgeWalker_TestUtility.cpp
index 2cd01539ba..0b2fd06fbf 100644
--- a/experimental/Intersection/EdgeWalker_TestUtility.cpp
+++ b/experimental/Intersection/EdgeWalker_TestUtility.cpp
@@ -5,7 +5,7 @@
 #include "SkPaint.h"
 
 static bool gShowPath = false;
-static bool gComparePaths = false;
+static bool gComparePaths = true;
 static bool gDrawLastAsciiPaths = true;
 static bool gDrawAllAsciiPaths = false;
 static bool gShowAsciiPaths = false;
@@ -43,17 +43,27 @@ void showPath(const SkPath& path, const char* str) {
     }
 }
 
-static bool pathsDrawTheSame(const SkPath& one, const SkPath& two) {
+static int pathsDrawTheSame(const SkPath& one, const SkPath& two,
+        SkBitmap& bits, SkCanvas* c) {
+    SkCanvas* canvasPtr = c;
+    if (!c) {
+        canvasPtr = new SkCanvas(bits);
+    }
     const SkRect& bounds1 = one.getBounds();
     const SkRect& bounds2 = two.getBounds();
     SkRect larger = bounds1;
     larger.join(bounds2);
-    SkBitmap bits;
     int bitWidth = SkScalarCeil(larger.width()) + 2;
     int bitHeight = SkScalarCeil(larger.height()) + 2;
-    bits.setConfig(SkBitmap::kARGB_8888_Config, bitWidth * 2, bitHeight);
-    bits.allocPixels();
-    SkCanvas canvas(bits);
+    if (bits.width() < bitWidth * 2 || bits.height() < bitHeight) {
+        if (bits.width() >= 200) {
+            SkDebugf("%s bitWidth=%d bitHeight=%d\n", __FUNCTION__, bitWidth, bitHeight);
+        }
+        bits.setConfig(SkBitmap::kARGB_8888_Config, bitWidth * 2, bitHeight);
+        bits.allocPixels();
+        canvasPtr->setBitmapDevice(bits);
+    }
+    SkCanvas& canvas = *canvasPtr;
     canvas.drawColor(SK_ColorWHITE);
     SkPaint paint;
     canvas.save();
@@ -64,17 +74,21 @@ static bool pathsDrawTheSame(const SkPath& one, const SkPath& two) {
     canvas.translate(-bounds1.fLeft + 1 + bitWidth, -bounds1.fTop + 1);
     canvas.drawPath(two, paint);
     canvas.restore();
+    int errors = 0;
     for (int y = 0; y < bitHeight; ++y) {
         uint32_t* addr1 = bits.getAddr32(0, y);
         uint32_t* addr2 = bits.getAddr32(bitWidth, y);
         for (int x = 0; x < bitWidth; ++x) {
-            if (addr1[x] != addr2[x]) {
-                return false;
-                break;
-            }
+            errors += addr1[x] != addr2[x];
         }
     }
-    return true;
+    if (!c) {
+        delete canvasPtr;
+    }
+    return errors;
+}
+
+void bitmapInit(SkBitmap& bits) {
 }
 
 bool drawAsciiPaths(const SkPath& one, const SkPath& two,
@@ -130,8 +144,8 @@ bool drawAsciiPaths(const SkPath& one, const SkPath& two,
     return true;
 }
 
-static bool scaledDrawTheSame(const SkPath& one, const SkPath& two,
-        int a, int b, bool drawPaths) {
+static int scaledDrawTheSame(const SkPath& one, const SkPath& two,
+        int a, int b, bool drawPaths, SkBitmap& bitmap, SkCanvas* canvas) {
     SkMatrix scale;
     scale.reset();
     float aScale = 1.21f;
@@ -140,8 +154,9 @@ static bool scaledDrawTheSame(const SkPath& one, const SkPath& two,
     SkPath scaledOne, scaledTwo;
     one.transform(scale, &scaledOne);
     two.transform(scale, &scaledTwo);
-    if (pathsDrawTheSame(scaledOne, scaledTwo)) {
-        return true;
+    int errors = pathsDrawTheSame(scaledOne, scaledTwo, bitmap, canvas);
+    if (errors == 0) {
+        return 0;
     }
     while (!drawAsciiPaths(scaledOne, scaledTwo, drawPaths)) {
         scale.reset();
@@ -151,28 +166,36 @@ static bool scaledDrawTheSame(const SkPath& one, const SkPath& two,
         one.transform(scale, &scaledOne);
         two.transform(scale, &scaledTwo);
     }
-    return false;
+    return errors;
 }
 
-bool comparePaths(const SkPath& one, const SkPath& two) {
-    if (pathsDrawTheSame(one, two)) {
-        return true;
+static int comparePaths(const SkPath& one, const SkPath& two, SkBitmap& bitmap,
+        SkCanvas* canvas) {
+    int errors = pathsDrawTheSame(one, two, bitmap, canvas);
+    if (errors == 0) {
+        return 0;
     }
     drawAsciiPaths(one, two, gDrawAllAsciiPaths);
     for (int x = 9; x <= 33; ++x) {
-        if (scaledDrawTheSame(one, two, x, x - (x >> 2), gDrawAllAsciiPaths)) {
-            return true;
+        errors = scaledDrawTheSame(one, two, x, x - (x >> 2), gDrawAllAsciiPaths,
+            bitmap, canvas);
+        if (errors == 0) {
+            return 0;
         }
     }
     if (!gDrawAllAsciiPaths) {
-        scaledDrawTheSame(one, two, 9, 7, gDrawLastAsciiPaths);
+        errors = scaledDrawTheSame(one, two, 9, 7, false, bitmap, canvas);
+        if (errors > 4) {
+            scaledDrawTheSame(one, two, 9, 7, true, bitmap, canvas);
+        }
     }
-    if (gComparePathsAssert) {
+    if (errors > 0) SkDebugf("\n%s errors=%d\n", __FUNCTION__, errors); 
+    if (errors > 4 && gComparePathsAssert) {
         showPath(one);
         showPath(two, "simplified:");
         SkASSERT(0);
     }
-    return false;
+    return errors;
 }
 
 // doesn't work yet
@@ -206,7 +229,8 @@ void comparePathsTiny(const SkPath& one, const SkPath& two) {
     }
 }
 
-bool testSimplify(const SkPath& path, bool fill, SkPath& out) {
+bool testSimplify(const SkPath& path, bool fill, SkPath& out, SkBitmap& bitmap,
+        SkCanvas* canvas) {
     if (gShowPath) {
         showPath(path);
     }
@@ -214,5 +238,5 @@ bool testSimplify(const SkPath& path, bool fill, SkPath& out) {
     if (!gComparePaths) {
         return true;
     }
-    return comparePaths(path, out);
+    return comparePaths(path, out, bitmap, canvas) == 0;
 }
diff --git a/experimental/Intersection/LineCubicIntersection.cpp b/experimental/Intersection/LineCubicIntersection.cpp
index 500a91e053..8517b7e0f8 100644
--- a/experimental/Intersection/LineCubicIntersection.cpp
+++ b/experimental/Intersection/LineCubicIntersection.cpp
@@ -139,7 +139,25 @@ int horizontalIntersect(const Cubic& cubic, double y, double tRange[3]) {
     LineCubicIntersections c(cubic, *((_Line*) 0), tRange);
     return c.horizontalIntersect(y);
 }
- 
+
+int horizontalIntersect(const Cubic& cubic, double left, double right, double y,
+        double tRange[3]) {
+    LineCubicIntersections c(cubic, *((_Line*) 0), tRange);
+    int result = c.horizontalIntersect(y);
+    for (int index = 0; index < result; ) {
+        double x, y;
+        xy_at_t(cubic, tRange[index], x, y);
+        if (x < left || x > right) {
+            if (--result > index) {
+                tRange[index] = tRange[result];
+            }
+            continue;
+        }
+        ++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/LineQuadraticIntersection.cpp b/experimental/Intersection/LineQuadraticIntersection.cpp
index 0d6477b085..737b76749d 100644
--- a/experimental/Intersection/LineQuadraticIntersection.cpp
+++ b/experimental/Intersection/LineQuadraticIntersection.cpp
@@ -131,6 +131,16 @@ bool intersect() {
     return roots > 0;
 }
 
+int horizontalIntersect(double axisIntercept) {
+    double D = quad[2].y; // f
+    double E = quad[1].y; // e
+    double F = quad[0].y; // 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) {
@@ -156,7 +166,24 @@ Intersections& intersections;
 bool moreHorizontal;
 
 };
- 
+
+int horizontalIntersect(const Quadratic& quad, double left, double right,
+        double y, double tRange[2]) {
+    Intersections i;
+    LineQuadraticIntersections q(quad, *((_Line*) 0), i);
+    int result = q.horizontalIntersect(y);
+    int tCount = 0;
+    for (int index = 0; index < result; ++index) {
+        double x, y;
+        xy_at_t(quad, i.fT[0][index], x, y);
+        if (x < left || x > right) {
+            continue;
+        }
+        tRange[tCount++] = i.fT[0][index];
+    }
+    return tCount;
+}
+
 bool intersect(const Quadratic& quad, const _Line& line, Intersections& i) {
     LineQuadraticIntersections q(quad, line, i);
     return q.intersect();
diff --git a/experimental/Intersection/QuadraticIntersection.cpp b/experimental/Intersection/QuadraticIntersection.cpp
index 634d083cbd..f8c43b5e5d 100644
--- a/experimental/Intersection/QuadraticIntersection.cpp
+++ b/experimental/Intersection/QuadraticIntersection.cpp
@@ -86,16 +86,22 @@ bool intersect(double minT1, double maxT1, double minT2, double maxT2) {
         double newMinT1 = interp(minT1, maxT1, minT);
         double newMaxT1 = interp(minT1, maxT1, maxT);
         split = (newMaxT1 - newMinT1 > (maxT1 - minT1) * tClipLimit) << 1;
+#define VERBOSE 0
+#if VERBOSE
         printf("%s d=%d s=%d new1=(%g,%g) old1=(%g,%g) split=%d\n", __FUNCTION__, depth,
             splits, newMinT1, newMaxT1, minT1, maxT1, split);
+#endif
         minT1 = newMinT1;
         maxT1 = newMaxT1;
     } else {
         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);
+#endif
         minT2 = newMinT2;
         maxT2 = newMaxT2;
     }
diff --git a/experimental/Intersection/ShapeOpsDemo-Info.plist b/experimental/Intersection/ShapeOpsDemo-Info.plist
deleted file mode 100644
index 5dd4506c0e..0000000000
--- a/experimental/Intersection/ShapeOpsDemo-Info.plist
+++ /dev/null
@@ -1,32 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-<dict>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>English</string>
-	<key>CFBundleExecutable</key>
-	<string>${EXECUTABLE_NAME}</string>
-	<key>CFBundleIconFile</key>
-	<string></string>
-	<key>CFBundleIdentifier</key>
-	<string>com.googlecode.skia.${PRODUCT_NAME:rfc1034identifier}</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleName</key>
-	<string>${PRODUCT_NAME}</string>
-	<key>CFBundlePackageType</key>
-	<string>APPL</string>
-	<key>CFBundleShortVersionString</key>
-	<string>1.0</string>
-	<key>CFBundleSignature</key>
-	<string>????</string>
-	<key>CFBundleVersion</key>
-	<string>1</string>
-	<key>LSMinimumSystemVersion</key>
-	<string>${MACOSX_DEPLOYMENT_TARGET}</string>
-	<key>NSMainNibFile</key>
-	<string>ShapeOpsDemo</string>
-	<key>NSPrincipalClass</key>
-	<string>NSApplication</string>
-</dict>
-</plist>
diff --git a/experimental/Intersection/ShapeOpsDemo.cpp b/experimental/Intersection/ShapeOpsDemo.cpp
deleted file mode 100644
index a2690ea42a..0000000000
--- a/experimental/Intersection/ShapeOpsDemo.cpp
+++ /dev/null
@@ -1,110 +0,0 @@
-#include "EdgeWalker_Test.h"
-#include "ShapeOps.h"
-#include "SkApplication.h"
-#include "SkCanvas.h"
-#include "SkEvent.h"
-#include "SkGraphics.h"
-#include "SkPaint.h"
-
-SkCanvas* canvas = 0;
-SkBitmap* bitmap;
-
-static bool test15(SkCanvas* canvas) {
-    // Three circles bounce inside a rectangle. The circles describe three, four
-    // or five points which in turn describe a polygon. The polygon points
-    // bounce inside the circles. The circles rotate and scale over time. The
-    // polygons are combined into a single path, simplified, and stroked.
-    static int step = 0;
-    const int circles = 3;
-    int scales[circles];
-    int angles[circles];
-    int locs[circles * 2];
-    int pts[circles * 2 * 4];
-    int c, p;
-    for (c = 0; c < circles; ++c) {
-        scales[c] = abs(10 - (step + c * 4) % 21);
-        angles[c] = (step + c * 6) % 600;
-        locs[c * 2] = abs(130 - (step + c * 9) % 261);
-        locs[c * 2 + 1] = abs(170 - (step + c * 11) % 341);
-        for (p = 0; p < 4; ++p) {
-            pts[c * 8 + p * 2] = abs(90 - ((step + c * 121 + p * 13) % 190));
-            pts[c * 8 + p * 2 + 1] = abs(110 - ((step + c * 223 + p * 17) % 230));
-        }
-    }
-    SkPath path, out;
-    for (c = 0; c < circles; ++c) {
-        for (p = 0; p < 4; ++p) {
-            SkScalar x = pts[c * 8 + p * 2];
-            SkScalar y = pts[c * 8 + p * 2 + 1];
-            x *= 3 + scales[c] / 10.0f;
-            y *= 3 + scales[c] / 10.0f;
-            SkScalar angle = angles[c] * 3.1415f * 2 / 600;
-            SkScalar temp = x * cos(angle) - y * sin(angle);
-            y = x * sin(angle) + y * cos(angle);
-            x = temp;
-            x += locs[c * 2] * 200 / 130.0f;
-            y += locs[c * 2 + 1] * 200 / 170.0f;
-            x += 50;
-    //        y += 200;
-            if (p == 0) {
-                path.moveTo(x, y);
-            } else {
-                path.lineTo(x, y);
-            }
-        }
-        path.close();
-    }
-    showPath(path, "original:");
-    simplify(path, true, out);
-    showPath(out, "simplified:");
-    SkPaint paint;
-    paint.setAntiAlias(true);
-    paint.setStyle(SkPaint::kStroke_Style);
-    paint.setStrokeWidth(3);
-    paint.setColor(0x3F007fbF);
-    canvas->drawPath(path, paint);
-    paint.setColor(0xFF60FF00);
-    paint.setStrokeWidth(1);
-    canvas->drawPath(out, paint);
-    ++step;
-    return true;
-}
-
-static bool (*tests[])(SkCanvas* ) = {
-    test15,
-};
-
-static size_t testsCount = sizeof(tests) / sizeof(tests[0]);
-
-static bool (*firstTest)(SkCanvas*) = test15;
-
-extern "C" void* getPixels(bool* animate);
-extern "C" void unlockPixels();
-
-extern "C" void* getPixels(bool* animate) {
-	if (!canvas) {
-		canvas = new SkCanvas();
-		bitmap = new SkBitmap();
-		SkBitmap::Config config = SkBitmap::kARGB_8888_Config;
-		
-		bitmap->setConfig(config, 1100, 630);
-		bitmap->allocPixels();
-        bitmap->setIsOpaque(true);
-		canvas->setBitmapDevice(*bitmap);
-	}
-	canvas->drawColor(SK_ColorWHITE);
-    size_t index = 0;
-    if (index == 0 && firstTest) {
-        while (index < testsCount && tests[index] != firstTest) {
-            ++index;
-        }
-    }
-	*animate = (tests[index])(canvas);
-	bitmap->lockPixels();
-	return bitmap->getPixels();
-}
-
-extern "C" void unlockPixels() {
-	bitmap->unlockPixels();
-}
-
diff --git a/experimental/Intersection/edge-Info.plist b/experimental/Intersection/edge-Info.plist
deleted file mode 100644
index f696cb233e..0000000000
--- a/experimental/Intersection/edge-Info.plist
+++ /dev/null
@@ -1,32 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-<dict>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>English</string>
-	<key>CFBundleExecutable</key>
-	<string>${EXECUTABLE_NAME}</string>
-	<key>CFBundleIconFile</key>
-	<string></string>
-	<key>CFBundleIdentifier</key>
-	<string>com.yourcompany.${PRODUCT_NAME:rfc1034identifier}</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleName</key>
-	<string>${PRODUCT_NAME}</string>
-	<key>CFBundlePackageType</key>
-	<string>APPL</string>
-	<key>CFBundleShortVersionString</key>
-	<string>1.0</string>
-	<key>CFBundleSignature</key>
-	<string>????</string>
-	<key>CFBundleVersion</key>
-	<string>1</string>
-	<key>LSMinimumSystemVersion</key>
-	<string>${MACOSX_DEPLOYMENT_TARGET}</string>
-	<key>NSMainNibFile</key>
-	<string>MainMenu</string>
-	<key>NSPrincipalClass</key>
-	<string>NSApplication</string>
-</dict>
-</plist>
diff --git a/experimental/Intersection/thingsToDo.txt b/experimental/Intersection/thingsToDo.txt
new file mode 100644
index 0000000000..a1d8ac01f2
--- /dev/null
+++ b/experimental/Intersection/thingsToDo.txt
@@ -0,0 +1,20 @@
+add unit test for quadratic horizontal intersection
+add unit test for cubic horizontal intersection with left/right
+add unit test for ActiveEdge::calcLeft (can currently loop forever)
+does ActiveEdge::isCoincidentWith need to support quad, cubic?
+figure out why variation in ActiveEdge::tooCloseToCall isn't better
+why does 'lastPtr - 2' in addIntersectingTs break testSimplifyTriangle22?
+add code to promote quad to cubic, or add quad/cubic intersection
+figure out why testSimplifySkinnyTriangle13 fails
+
+for quadratics and cubics, once various T values are added, see if consecutive
+Ts have ys that go up instead of down. If so, the edge needs to be broken.
+
+when splitting curves at inflection pts, should I retain the original curve
+data and note that the first/last T are no longer 0/1 ?
+I need to figure this out before I can proceed
+
+would it make sense to leave the InEdge alone, and add multiple copies of
+ActiveEdge, pointing to the same InEdge, where the copy has only the subset
+of Ts that need to be walked in reverse order?
+