work in progress

git-svn-id: http://skia.googlecode.com/svn/trunk@3471 2bbb7eff-a529-9590-31e7-b0007b416f81

6 files changed, 561 insertions, 112 deletions

diff --git a/experimental/Intersection/EdgeWalker.cpp b/experimental/Intersection/EdgeWalker.cpp
index e33fd94681..94d6e5a2a9 100644
--- a/experimental/Intersection/EdgeWalker.cpp
+++ b/experimental/Intersection/EdgeWalker.cpp
@@ -22,13 +22,14 @@ static bool gShowDebugf = false; // FIXME: remove once debugging is complete
 #define DEBUG_ADD_INTERSECTING_TS 0
 #define DEBUG_ADD_BOTTOM_TS 0
 #define COMPARE_DOUBLE 0
-#define ASSERT_ON_ULPS 0
 #define DEBUG_ABOVE_BELOW 0
 #define DEBUG_ACTIVE_LESS_THAN 0
 #define DEBUG_SORT_HORIZONTAL 0
 #define DEBUG_OUT 0
 #define DEBUG_OUT_LESS_THAN 0
 #define DEBUG_ADJUST_COINCIDENT 0
+#define DEBUG_BOTTOM 0
+
 #else
 static bool gShowDebugf = true; // FIXME: remove once debugging is complete
 
@@ -36,14 +37,15 @@ static bool gShowDebugf = true; // FIXME: remove once debugging is complete
 #define DEBUG_ADD 01
 #define DEBUG_ADD_INTERSECTING_TS 0
 #define DEBUG_ADD_BOTTOM_TS 0
-#define COMPARE_DOUBLE 0
-#define ASSERT_ON_ULPS 0
+#define COMPARE_DOUBLE 01
 #define DEBUG_ABOVE_BELOW 01
-#define DEBUG_ACTIVE_LESS_THAN 0
+#define DEBUG_ACTIVE_LESS_THAN 01
 #define DEBUG_SORT_HORIZONTAL 01
 #define DEBUG_OUT 01
 #define DEBUG_OUT_LESS_THAN 0
 #define DEBUG_ADJUST_COINCIDENT 1
+#define DEBUG_BOTTOM 01
+
 #endif
 
 // FIXME: not wild about this -- min delta should be based on size of curve, not t
@@ -193,7 +195,7 @@ struct OutEdge {
                 ? first.fX < rhFirst.fX
                 : first.fY < rhFirst.fY;
     }
-    
+
     SkPoint fPts[4];
     int fID; // id of edge generating data
     uint8_t fVerb; // FIXME: not read from everywhere
@@ -214,7 +216,7 @@ public:
         newEdge.fID = id;
         newEdge.fCloseCall = closeCall;
     }
-    
+
     bool trimLine(SkScalar y, int id) {
         size_t count = fEdges.count();
         while (count-- != 0) {
@@ -349,7 +351,7 @@ public:
             } while (edgeIndex);
         } while (true);
     }
-    
+
     // sort points by y, then x
     // if x/y is identical, sort bottoms before tops
     // if identical and both tops/bottoms, sort by angle
@@ -504,7 +506,7 @@ struct Bounds : public SkRect {
         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
@@ -519,7 +521,7 @@ public:
         : fTopIntercepts(0)
         , fBottomIntercepts(0) {
     }
-    
+
 #if DEBUG_DUMP
     // FIXME: pass current verb as parameter
     void dump(const SkPoint* pts) {
@@ -528,7 +530,7 @@ public:
         for (int i = 0; i < fTs.count(); ++i) {
             SkPoint out;
             LineXYAtT(pts, fTs[i], &out);
-            SkDebugf("%*s.fTs[%d]=%g (%g,%g)\n", tab + sizeof(className),
+            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),
@@ -553,9 +555,9 @@ struct HorizontalEdge {
     void dump() {
         const char className[] = "HorizontalEdge";
         const int tab = 4;
-        SkDebugf("%*s.fLeft=%g\n", tab + sizeof(className), className, fLeft);
-        SkDebugf("%*s.fRight=%g\n", tab + sizeof(className), className, fRight);
-        SkDebugf("%*s.fY=%g\n", tab + sizeof(className), className, fY);
+        SkDebugf("%*s.fLeft=%1.9g\n", tab + sizeof(className), className, fLeft);
+        SkDebugf("%*s.fRight=%1.9g\n", tab + sizeof(className), className, fRight);
+        SkDebugf("%*s.fY=%1.9g\n", tab + sizeof(className), className, fY);
     }
 #endif
 
@@ -682,14 +684,14 @@ struct InEdge {
             pts += *verbs++;
         }
         for (i = 0; i < fPts.count(); ++i) {
-            SkDebugf("%*s.fPts[%d]=(%g,%g)\n", tab + sizeof(className),
+            SkDebugf("%*s.fPts[%d]=(%1.9g,%1.9g)\n", tab + sizeof(className),
                     className, i, fPts[i].fX, fPts[i].fY);
         }
         for (i = 0; i < fVerbs.count(); ++i) {
             SkDebugf("%*s.fVerbs[%d]=%d\n", tab + sizeof(className),
                     className, i, fVerbs[i]);
         }
-        SkDebugf("%*s.fBounds=(%g. %g, %g, %g)\n", tab + sizeof(className),
+        SkDebugf("%*s.fBounds=(%1.9g. %1.9g, %1.9g, %1.9g)\n", tab + sizeof(className),
                 className, fBounds.fLeft, fBounds.fTop,
                 fBounds.fRight, fBounds.fBottom);
         SkDebugf("%*s.fWinding=%d\n", tab + sizeof(className), className,
@@ -861,7 +863,7 @@ struct WorkEdge {
         fPts += *fVerb++;
         return fVerb != fEdge->fVerbs.end();
     }
-    
+
     SkPath::Verb lastVerb() const {
         SkASSERT(fVerb > fEdge->fVerbs.begin());
         return (SkPath::Verb) fVerb[-1];
@@ -875,7 +877,7 @@ struct WorkEdge {
     ptrdiff_t verbIndex() const {
         return fVerb - fEdge->fVerbs.begin();
     }
-    
+
     int winding() const {
         return fEdge->fWinding;
     }
@@ -903,12 +905,6 @@ public:
             const SkPoint& check = rh.fBelow.fY <= fBelow.fY
                     && fBelow != rh.fBelow ? rh.fBelow :
                     rh.fAbove;
-        #if COMPARE_DOUBLE
-            SkASSERT(((check.fY - fAbove.fY) * (fBelow.fX - fAbove.fX)
-                < (fBelow.fY - fAbove.fY) * (check.fX - fAbove.fX))
-                == ((check.fY - fDAbove.y) * (fDBelow.x - fDAbove.x)
-                < (fDBelow.y - fDAbove.y) * (check.fX - fDAbove.x)));
-        #endif
         #if DEBUG_ACTIVE_LESS_THAN
             SkDebugf("%s 1 %c %cthis (edge=%d) {%g,%g %g,%g}"
                     " < rh (edge=%d) {%g,%g %g,%g} upls=(%d)\n", __FUNCTION__,
@@ -920,10 +916,11 @@ public:
                     UlpsDiff((check.fY - fAbove.fY) * (fBelow.fX - fAbove.fX),
                         (fBelow.fY - fAbove.fY) * (check.fX - fAbove.fX)));
         #endif
-        #if ASSERT_ON_ULPS
-            int ulps = UlpsDiff((check.fY - fAbove.fY) * (fBelow.fX - fAbove.fX),
-                            (fBelow.fY - fAbove.fY) * (check.fX - fAbove.fX));
-            SkASSERT((unsigned) ulps == 0x80000000 || ulps == 0 || ulps > 32);
+        #if COMPARE_DOUBLE
+            SkASSERT(((check.fY - fAbove.fY) * (fBelow.fX - fAbove.fX)
+                < (fBelow.fY - fAbove.fY) * (check.fX - fAbove.fX))
+                == ((check.fY - fDAbove.y) * (fDBelow.x - fDAbove.x)
+                < (fDBelow.y - fDAbove.y) * (check.fX - fDAbove.x)));
         #endif
             return (check.fY - fAbove.fY) * (fBelow.fX - fAbove.fX)
                     < (fBelow.fY - fAbove.fY) * (check.fX - fAbove.fX);
@@ -931,32 +928,28 @@ public:
         // FIXME: need to compute distance, not check for points equal
         const SkPoint& check = fBelow.fY <= rh.fBelow.fY 
                 && fBelow != rh.fBelow ? fBelow : fAbove;
-    #if COMPARE_DOUBLE
-        SkASSERT(((rh.fBelow.fY - rh.fAbove.fY) * (check.fX - rh.fAbove.fX)
-                < (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX))
-                == ((rh.fDBelow.y - rh.fDAbove.y) * (check.fX - rh.fDAbove.x)
-                < (check.fY - rh.fDAbove.y) * (rh.fDBelow.x - rh.fDAbove.x)));
-    #endif
     #if DEBUG_ACTIVE_LESS_THAN
         SkDebugf("%s 2 %c %cthis (edge=%d) {%g,%g %g,%g}"
-                " < rh (edge=%d) {%g,%g %g,%g} upls=(%d)\n", __FUNCTION__,
-                fBelow.fY <= rh.fBelow.fY & fBelow != rh.fBelow ? 'B' : 'A',
+                " < rh (edge=%d) {%g,%g %g,%g} upls=(%d) (%d,%d)\n", __FUNCTION__,
+                fBelow.fY <= rh.fBelow.fY && fBelow != rh.fBelow ? 'B' : 'A',
                 (rh.fBelow.fY - rh.fAbove.fY) * (check.fX - rh.fAbove.fX)
                 < (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX) 
                 ? ' ' : '!', ID(), fAbove.fX, fAbove.fY, fBelow.fX, fBelow.fY,
                 rh.ID(), rh.fAbove.fX, rh.fAbove.fY, rh.fBelow.fX, rh.fBelow.fY,
                 UlpsDiff((rh.fBelow.fY - rh.fAbove.fY) * (check.fX - rh.fAbove.fX),
-                    (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX)));
+                    (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX)),
+                UlpsDiff(fBelow.fX, rh.fBelow.fX), UlpsDiff(fBelow.fY, rh.fBelow.fY));
     #endif
-    #if ASSERT_ON_ULPS
-        int ulps = UlpsDiff((rh.fBelow.fY - rh.fAbove.fY) * (check.fX - rh.fAbove.fX),
-                        (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX));
-        SkASSERT((unsigned) ulps == 0x80000000 || ulps == 0 || ulps > 32);
+    #if COMPARE_DOUBLE
+        SkASSERT(((rh.fBelow.fY - rh.fAbove.fY) * (check.fX - rh.fAbove.fX)
+                < (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX))
+                == ((rh.fDBelow.y - rh.fDAbove.y) * (check.fX - rh.fDAbove.x)
+                < (check.fY - rh.fDAbove.y) * (rh.fDBelow.x - rh.fDAbove.x)));
     #endif
         return (rh.fBelow.fY - rh.fAbove.fY) * (check.fX - rh.fAbove.fX)
                 < (check.fY - rh.fAbove.fY) * (rh.fBelow.fX - rh.fAbove.fX);
     }
-    
+
     // If a pair of edges are nearly coincident for some span, add a T in the
     // edge so it can be shortened to match the other edge. Note that another
     // approach is to trim the edge after it is added to the OutBuilder list --
@@ -969,7 +962,7 @@ public:
         addTatYInner(y);
         fFixBelow = true;
     }
-    
+
     void addTatYAbove(SkScalar y) {
         if (fBelow.fY <= y) {
             return;
@@ -978,12 +971,15 @@ public:
     }
 
     void addTatYInner(SkScalar y) {
-        double ts[2];
+        if (fWorkEdge.fPts[0].fY > y) {
+            backup(y);
+        }
         SkScalar left = fWorkEdge.fPts[0].fX;
         SkScalar right = fWorkEdge.fPts[1].fX;
         if (left > right) {
             SkTSwap(left, right);
         }
+        double ts[2];
         int pts = LineIntersect(fWorkEdge.fPts, left, right, y, ts);
         SkASSERT(pts == 1);
         // An ActiveEdge or WorkEdge has no need to modify the T values computed
@@ -993,6 +989,9 @@ public:
         // an additional t value must be added, requiring the cast below.
         InEdge* writable = const_cast<InEdge*>(fWorkEdge.fEdge);
         int insertedAt = writable->add(ts, pts, fWorkEdge.verbIndex());
+    #if DEBUG_ADJUST_COINCIDENT
+        SkDebugf("%s edge=%d y=%1.9g t=%1.9g\n", __FUNCTION__, ID(), y, ts[0]);
+    #endif
         if (insertedAt >= 0) {
             if (insertedAt + 1 < fTIndex) {
                 SkASSERT(insertedAt + 2 == fTIndex);
@@ -1013,15 +1012,29 @@ public:
         initT();
         return result;
     }
-    
+
+    void backup(SkScalar y) {
+        do {
+            SkASSERT(fWorkEdge.fEdge->fVerbs.begin() < fWorkEdge.fVerb);
+            fWorkEdge.fPts -= *--fWorkEdge.fVerb;
+            SkASSERT(fWorkEdge.fEdge->fPts.begin() <= fWorkEdge.fPts);
+        } while (fWorkEdge.fPts[0].fY >= y);
+        initT();
+        fTIndex = fTs->count() + 1;
+    }
+
     void calcLeft(SkScalar y) {
         // OPTIMIZE: put a kDone_Verb at the end of the verb list?
         if (fDone || fBelow.fY > y) {
             return; // nothing to do; use last
         }
         calcLeft();
+        if (fAbove.fY == fBelow.fY) {
+            SkDebugf("%s edge=%d fAbove.fY != fBelow.fY %1.9g\n", __FUNCTION__,
+                    ID(), fAbove.fY);
+        }
     }
-    
+
     void calcLeft() {
         switch (fWorkEdge.verb()) {
             case SkPath::kLine_Verb: {
@@ -1036,14 +1049,19 @@ public:
                 double tBelow = t(fTIndex - ~add);
                 LineXYAtT(fWorkEdge.fPts, tBelow, &fBelow);
             SkASSERT(tAbove != tBelow);
-// maybe the following is the right sort of thing to do, but it's fragile and
-// it breaks testSimplifySkinnyTriangle4
-#if 0
-            if (fAbove == fBelow && !add) {
-                tBelow = t(fTIndex - ~add + 1);
-                LineXYAtT(fWorkEdge.fPts, tBelow, &fBelow);
+            while (fAbove.fY == fBelow.fY) {
+                if (add < 0) {
+                    add -= 1;
+                    SkASSERT(fTIndex + add >= 0);
+                    tAbove = t(fTIndex + add);
+                    LineXYAtT(fWorkEdge.fPts, tAbove, &fAbove);
+                } else {
+                    add += 1;
+                    SkASSERT(fTIndex - ~add <= fTs->count() + 1);
+                    tBelow = t(fTIndex - ~add);
+                    LineXYAtT(fWorkEdge.fPts, tBelow, &fBelow);
+                }
             }
-#endif
             #if COMPARE_DOUBLE
                 LineXYAtT(fWorkEdge.fPts, tAbove, &fDAbove);
                 LineXYAtT(fWorkEdge.fPts, tBelow, &fDBelow);
@@ -1060,10 +1078,10 @@ public:
         }
     }
 
-    bool done(SkScalar y) const {
-        return fDone || fYBottom > y;
+    bool done(SkScalar bottom) const {
+        return fDone || fYBottom >= bottom;
     }
-    
+
     void fixBelow() {
         if (fFixBelow) {
             LineXYAtT(fWorkEdge.fPts, nextT(), &fBelow);
@@ -1078,7 +1096,7 @@ public:
         fDone = false;
         fYBottom = SK_ScalarMin;
     }
-    
+
     void initT() {
         const Intercepts& intercepts = fWorkEdge.fEdge->fIntercepts.front();
         SkASSERT(fWorkEdge.verbIndex() <= fWorkEdge.fEdge->fIntercepts.count());
@@ -1089,13 +1107,13 @@ public:
   //  but templated arrays don't allow returning a pointer to the end() element
         fTIndex = 0;
     }
-    
+
     // OPTIMIZATION: record if two edges are coincident when the are intersected
     // It's unclear how to do this -- seems more complicated than recording the
     // t values, since the same t values could exist intersecting non-coincident
     // edges.
     bool isCoincidentWith(const ActiveEdge* edge, SkScalar y) const {
-        
+
         if (!fAbove.equalsWithinTolerance(edge->fAbove, MIN_PT_DELTA)
                 || !fBelow.equalsWithinTolerance(edge->fBelow, MIN_PT_DELTA)) {
             return false;
@@ -1116,7 +1134,7 @@ public:
         }
         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.
     bool swapClose(const ActiveEdge* next, int prev, int wind, int mask) const {
@@ -1129,7 +1147,7 @@ public:
         }
         return false;
     }
-    
+
     bool swapCoincident(const ActiveEdge* edge, SkScalar bottom) const {
         if (fBelow.fY >= bottom || fDone || edge->fDone) {
             return false;
@@ -1149,7 +1167,7 @@ public:
         }
         return false;
     }
-    
+
     bool tooCloseToCall(const ActiveEdge* edge) const {
         int ulps;
         // FIXME: don't compare points for equality
@@ -1200,7 +1218,7 @@ public:
     }
 
     // FIXME: debugging only
-    int ID() {
+    int ID() const {
         return fWorkEdge.fEdge->fID;
     }
 
@@ -1288,6 +1306,9 @@ static void addBottomT(InEdge** currentPtr, InEdge** lastPtr,
 
 static void addIntersectingTs(InEdge** currentPtr, InEdge** lastPtr) {
     InEdge** testPtr = currentPtr - 1;
+    // FIXME: lastPtr should be past the point of interest, so
+    // test below should be  lastPtr - 2
+    // that breaks testSimplifyTriangle22, so further investigation is needed
     while (++testPtr != lastPtr - 1) {
         InEdge* test = *testPtr;
         InEdge** nextPtr = testPtr;
@@ -1423,7 +1444,7 @@ static SkScalar findBottom(InEdge** currentPtr,
         bool asFill, InEdge**& testPtr) {
     InEdge* current = *currentPtr;
     SkScalar bottom = current->fBounds.fBottom;
-    
+
     // find the list of edges that cross y
     InEdge* test = *testPtr;
     while (testPtr != edgeListEnd) {
@@ -1487,8 +1508,14 @@ static void skipCoincidence(int lastWinding, int winding, int windingMask,
     } 
     // FIXME: ? shouldn't this be if (lastWinding & windingMask) ?
     if (lastWinding) {
+#if DEBUG_ADJUST_COINCIDENT
+        SkDebugf("%s edge=%d 1 set skip=false\n", __FUNCTION__, activePtr->ID());
+#endif
         activePtr->fSkip = false;
     } else {
+#if DEBUG_ADJUST_COINCIDENT
+        SkDebugf("%s edge=%d 2 set skip=false\n", __FUNCTION__, firstCoincident->ID());
+#endif
         firstCoincident->fSkip = false;
     }
 }
@@ -1613,21 +1640,37 @@ static SkScalar adjustCoincident(SkTDArray<ActiveEdge*>& edgeList,
                 // coincident edge, trim it back to the top of this span
                 if (outBuilder.trimLine(y, activePtr->ID())) {
                     activePtr->addTatYAbove(y);
+            #if DEBUG_ADJUST_COINCIDENT
+                    SkDebugf("%s 1 edge=%d y=%1.9g (was fYBottom=%1.9g)\n",
+                            __FUNCTION__, activePtr->ID(), y, activePtr->fYBottom);
+            #endif
                     activePtr->fYBottom = y;
                 }
                 if (outBuilder.trimLine(y, nextPtr->ID())) {
                     nextPtr->addTatYAbove(y);
+            #if DEBUG_ADJUST_COINCIDENT
+                    SkDebugf("%s 2 edge=%d y=%1.9g (was fYBottom=%1.9g)\n",
+                            __FUNCTION__, nextPtr->ID(), y, nextPtr->fYBottom);
+            #endif
                     nextPtr->fYBottom = y;
                 }
                 // add missing t values so edges can be the same length
                 SkScalar testY = activePtr->fBelow.fY;
                 nextPtr->addTatYBelow(testY);
                 if (bottom > testY && testY > y) {
+            #if DEBUG_ADJUST_COINCIDENT
+                    SkDebugf("%s 3 edge=%d bottom=%1.9g (was bottom=%1.9g)\n",
+                            __FUNCTION__, activePtr->ID(), testY, bottom);
+            #endif
                     bottom = testY;
                 }
                 testY = nextPtr->fBelow.fY;
                 activePtr->addTatYBelow(testY);
                 if (bottom > testY && testY > y) {
+            #if DEBUG_ADJUST_COINCIDENT
+                    SkDebugf("%s 4 edge=%d bottom=%1.9g (was bottom=%1.9g)\n",
+                            __FUNCTION__, nextPtr->ID(), testY, bottom);
+            #endif
                     bottom = testY;
                 }
             }
@@ -1654,7 +1697,7 @@ static SkScalar adjustCoincident(SkTDArray<ActiveEdge*>& edgeList,
 
 // stitch edge and t range that satisfies operation
 static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
-        SkScalar bottom, int windingMask, OutEdgeBuilder& outBuilder) {
+        SkScalar bottom, int windingMask, bool fill, OutEdgeBuilder& outBuilder) {
     int winding = 0;
     ActiveEdge** activeHandle = edgeList.begin() - 1;
     ActiveEdge** lastActive = edgeList.end();
@@ -1680,31 +1723,12 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
 #endif
                     );
         }
-        if (activePtr->done(y)) {
-            if (activePtr->fCloseCall) {
-                // if the top has already advanced, trim the last edge add
-                // FIXME: not so simple
-                outBuilder.trimLine(y, activePtr->ID());
-                activePtr->fYBottom = y;
-            }
-            // FIXME: if this is successful, rewrite done to take bottom as well
-            if (activePtr->fDone) {
-                if (gShowDebugf) {
-                    SkDebugf("%*s activePtr->fDone\n", tab, "");
-                }
-                continue;
-            }
-            if (activePtr->fYBottom >= bottom) {
-                if (gShowDebugf) {
-                    SkDebugf("%*s activePtr->fYBottom=%1.9g >= bottom\n", tab, "",
-                            activePtr->fYBottom);
-                }
-                continue;
-            }
-            if (0) {
-                SkDebugf("%s bot %1.9g,%1.9g\n", __FUNCTION__, activePtr->fYBottom,
-                        bottom);
+        if (activePtr->done(bottom)) {
+            if (gShowDebugf) {
+                SkDebugf("%*s fDone=%d || fYBottom=%1.9g >= bottom\n", tab, "",
+                        activePtr->fDone, activePtr->fYBottom);
             }
+            continue;
         }
         int opener = (lastWinding & windingMask) == 0;
         bool closer = (winding & windingMask) == 0;
@@ -1748,7 +1772,8 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
                         dClipped = dPoints;
                 #endif
                     }
-                    if (inWinding && !activePtr->fSkip) {
+                    if (inWinding && !activePtr->fSkip && (fill ? clipped[0].fY
+                            != clipped[1].fY : clipped[0] != clipped[1])) {
                         if (gShowDebugf) {
                             SkDebugf("%*s line %1.9g,%1.9g %1.9g,%1.9g edge=%d"
                                     " v=%d t=(%1.9g,%1.9g)\n", tab, "",
@@ -1759,8 +1784,9 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
                                     - activePtr->fWorkEdge.fEdge->fVerbs.begin(),
                                     currentT, nextT);
                         }
-                        outBuilder.addLine(clipped, activePtr->fWorkEdge.fEdge->fID,
-                            activePtr->fCloseCall);
+                        outBuilder.addLine(clipped,
+                                activePtr->fWorkEdge.fEdge->fID,
+                                activePtr->fCloseCall);
                     } else {
                         if (gShowDebugf) {
                             SkDebugf("%*s skip %1.9g,%1.9g %1.9g,%1.9g"
@@ -1819,8 +1845,16 @@ static void stitchEdge(SkTDArray<ActiveEdge*>& edgeList, SkScalar y,
                 // FIXME: initialized in sortHorizontal, cleared here as well so
                 // that next edge is not skipped -- but should skipped edges ever
                 // continue? (probably not)
-                aboveBottom = clipped[verb].fY < bottom && !activePtr->fCloseCall; // TEST: added close call
-                activePtr->fSkip = activePtr->fCloseCall = false;
+                aboveBottom = clipped[verb].fY < bottom;
+                if (clipped[0].fY != clipped[verb].fY) {
+                    activePtr->fSkip = false;
+                    activePtr->fCloseCall = false;
+                    aboveBottom &= !activePtr->fCloseCall;
+                } else {
+                    if (activePtr->fSkip || activePtr->fCloseCall) {
+                        SkDebugf("== %1.9g\n", clippedPts[0].fY);
+                    }
+                }
             } while (moreToDo & aboveBottom);
         } while ((moreToDo || activePtr->advance()) & aboveBottom);
     }
@@ -1872,14 +1906,14 @@ 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
-    
+
     // walk the sorted edges from top to bottom, computing accumulated winding
     SkTDArray<ActiveEdge> activeEdges;
     OutEdgeBuilder outBuilder(asFill);
@@ -1889,13 +1923,22 @@ 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);
-            stitchEdge(activeEdgeList, y, bottom, windingMask, outBuilder);
+#if DEBUG_BOTTOM
+            SkDebugf("%s adjustCoincident bottom=%1.9g\n", __FUNCTION__, bottom);
+#endif
+            stitchEdge(activeEdgeList, y, bottom, windingMask, asFill, outBuilder);
         }
         y = bottom;
         // OPTIMIZATION: as edges expire, InEdge allocations could be released
diff --git a/experimental/Intersection/EdgeWalkerPolygons_Test.cpp b/experimental/Intersection/EdgeWalkerPolygons_Test.cpp
index 9a740e996b..3cc1b5d982 100644
--- a/experimental/Intersection/EdgeWalkerPolygons_Test.cpp
+++ b/experimental/Intersection/EdgeWalkerPolygons_Test.cpp
@@ -500,6 +500,12 @@ static void testPathTriangleRendering() {
     }
 }
 
+static void simplify(const char* functionName, const SkPath& path,
+        bool fill, SkPath& out) {
+    SkDebugf("%s\n", functionName);
+    simplify(path, fill, out);
+}
+
 static void testSimplifySkinnyTriangle1() {
     for (int x = 1; x < 255; ++x) {
         SkPath path, out;
@@ -518,7 +524,7 @@ static void testSimplifySkinnyTriangle1() {
         path.lineTo((x * 71) % 30, 2000);
         path.lineTo((x * 51) % 30, 3000);
         path.close();
-    testSimplify(path, true, out);
+        simplify(path, true, out);
     }
 }
 
@@ -546,7 +552,7 @@ path.lineTo(196.621033, 394.917633);
 //path.lineTo(289.392517, 517.138489);
 path.close();
 #endif
-    testSimplify(path, true, out);
+    simplify(__FUNCTION__, path, true, out);
 }
 
 static void testSimplifySkinnyTriangle3() {
@@ -561,7 +567,7 @@ static void testSimplifySkinnyTriangle3() {
         path.lineTo(416, 486.978577);
         path.lineTo(465, 430.970581);
         path.close();
-    testSimplify(path, true, out);
+    simplify(__FUNCTION__, path, true, out);
 }
 
 static void testSimplifySkinnyTriangle4() {
@@ -584,7 +590,7 @@ path.lineTo(210.344177, 437.315125);
 path.lineTo(197.019455, 383.794556);
 path.lineTo(278.742737, 508.065643);
 path.close();
-    testSimplify(path, true, out);
+    simplify(__FUNCTION__, path, true, out);
 }
 
 static void testSimplifySkinnyTriangle5() {
@@ -607,9 +613,31 @@ path.lineTo(203.059692, 441.332336);
 path.lineTo(195.994370, 386.856506);
 path.lineTo(271.998901, 521.301025);
 path.close();
-    testSimplify(path, true, out);
+    simplify(__FUNCTION__, path, true, out);
 }
 
+static void testSimplifySkinnyTriangle6() {
+        SkPath path, out;
+path.moveTo(591.091064, 627.534851);
+path.lineTo(541.088135, 560.707642);
+path.lineTo(491.085175, 493.880310);
+path.lineTo(441.082214, 427.053101);
+path.lineTo(591.091064, 627.534851);
+path.close();
+path.moveTo(317.093445, 592.013306);
+path.lineTo(366.316162, 542.986572);
+path.lineTo(416.051514, 486.978577);
+path.lineTo(465.786865, 430.970581);
+path.lineTo(317.093445, 592.013306);
+path.close();
+path.moveTo(289.392517, 517.138489);
+path.lineTo(249.886078, 508.598022);
+path.lineTo(217.110916, 450.916443);
+path.lineTo(196.621033, 394.917633);
+path.lineTo(289.392517, 517.138489);
+path.close();
+    simplify(__FUNCTION__, path, true, out);
+}
 
 static void testSimplifyTriangle22() {
     SkPath path, out;
@@ -650,7 +678,107 @@ static void testSimplifyTriangle24() {
     testSimplify(path, true, out);
 }
 
+static void testSimplifySkinnyTriangle7() {
+        SkPath path, out;
+path.moveTo(487.502319, 550.811279);
+path.lineTo(448.826050, 491.720123);
+path.lineTo(410.149780, 432.628967);
+path.lineTo(371.473572, 373.537781);
+path.lineTo(487.502319, 550.811279);
+path.close();
+path.moveTo(295.817108, 532.655579);
+path.lineTo(342.896271, 485.912292);
+path.lineTo(389.975433, 439.169006);
+path.lineTo(437.054596, 392.425781);
+path.lineTo(295.817108, 532.655579);
+path.close();
+path.moveTo(239.726822, 575.025269);
+path.lineTo(204.117569, 521.429688);
+path.lineTo(171.275452, 454.110382);
+path.lineTo(193.328583, 397.859497);
+path.lineTo(239.726822, 575.025269);
+path.close();
+    simplify(__FUNCTION__, path, true, out);
+}
+
+static void testSimplifySkinnyTriangle8() {
+        SkPath path, out;
+path.moveTo(441.943115, 511.678040);
+path.lineTo(408.487549, 456.880920);
+path.lineTo(375.031952, 402.083801);
+path.lineTo(341.576385, 347.286682);
+path.lineTo(441.943115, 511.678040);
+path.close();
+path.moveTo(297.548492, 557.246704);
+path.lineTo(350.768494, 507.627014);
+path.lineTo(403.988525, 458.007385);
+path.lineTo(457.208527, 408.387695);
+path.lineTo(297.548492, 557.246704);
+path.close();
+path.moveTo(209.857895, 615.802979);
+path.lineTo(178.249481, 534.230347);
+path.lineTo(144.905640, 460.056824);
+path.lineTo(192.953125, 404.972900);
+path.lineTo(209.857895, 615.802979);
+path.close();
+    simplify(__FUNCTION__, path, true, out);
+}
+
+static void testSimplifySkinnyTriangle9() {
+        SkPath path, out;
+path.moveTo(439.867065, 528.291931);
+path.lineTo(405.413025, 469.107178);
+path.lineTo(370.958954, 409.922363);
+path.lineTo(336.504883, 350.737610);
+path.lineTo(439.867065, 528.291931);
+path.close();
+path.moveTo(298.922455, 573.251953);
+path.lineTo(356.360962, 521.905090);
+path.lineTo(413.799438, 470.558228);
+path.lineTo(471.237915, 419.211365);
+path.lineTo(298.922455, 573.251953);
+path.close();
+path.moveTo(187.200775, 643.035156);
+path.lineTo(159.713165, 540.993774);
+path.lineTo(126.257164, 462.198517);
+path.lineTo(193.534012, 409.266235);
+path.lineTo(187.200775, 643.035156);
+path.close();
+path.close();
+    simplify(__FUNCTION__, path, true, out);
+}
+
+static void testSimplifySkinnyTriangle10() {
+        SkPath path, out;
+#if 0
+path.moveTo(99.270325, 239.365234);
+path.lineTo(105.967056, 173.361206);
+path.lineTo(148.821381, 141.309891);
+path.lineTo(159.101013, 189.235138);
+path.lineTo(99.270325, 239.365234);
+path.close();
+#endif
+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();
+    simplify(__FUNCTION__, path, true, out);
+}
+
 static void (*simplifyTests[])() = {
+    testSimplifySkinnyTriangle10,
+    testSimplifySkinnyTriangle9,
+    testSimplifySkinnyTriangle8,
+    testSimplifySkinnyTriangle7,
+    testSimplifySkinnyTriangle6,
     testSimplifySkinnyTriangle5,
     testSimplifySkinnyTriangle4,
     testSimplifySkinnyTriangle3,
@@ -691,7 +819,7 @@ static void (*simplifyTests[])() = {
 
 static size_t simplifyTestsCount = sizeof(simplifyTests) / sizeof(simplifyTests[0]);
 
-static void (*firstTest)() = testSimplifySkinnyTriangle4;
+static void (*firstTest)() = 0;
 
 void SimplifyPolygonPaths_Test() {
     size_t index = 0;
@@ -703,6 +831,9 @@ void SimplifyPolygonPaths_Test() {
     bool firstTestComplete = false;
     for ( ; index < simplifyTestsCount; ++index) {
         (*simplifyTests[index])();
+        if (simplifyTests[index] == testSimplifySkinnyTriangle2) {
+            SkDebugf("%s last fast skinny test\n", __FUNCTION__);
+        }
         firstTestComplete = true;
     }
 }
diff --git a/experimental/Intersection/EdgeWalker_Test.h b/experimental/Intersection/EdgeWalker_Test.h
index c449d1a4d8..c7f405b19d 100644
--- a/experimental/Intersection/EdgeWalker_Test.h
+++ b/experimental/Intersection/EdgeWalker_Test.h
@@ -5,7 +5,7 @@
 extern void contourBounds(const SkPath& path, SkTDArray<SkRect>& boundsArray);
 extern bool comparePaths(const SkPath& one, const SkPath& two);
 extern void comparePathsTiny(const SkPath& one, const SkPath& two);
-extern void drawAsciiPaths(const SkPath& one, const SkPath& two,
+extern bool drawAsciiPaths(const SkPath& one, const SkPath& two,
         bool drawPaths);
 extern void simplify(const SkPath& path, bool asFill, SkPath& simple);
 extern void showPath(const SkPath& path, const char* str = NULL);
diff --git a/experimental/Intersection/EdgeWalker_TestUtility.cpp b/experimental/Intersection/EdgeWalker_TestUtility.cpp
index 84ca87fce3..fc69516c40 100644
--- a/experimental/Intersection/EdgeWalker_TestUtility.cpp
+++ b/experimental/Intersection/EdgeWalker_TestUtility.cpp
@@ -5,13 +5,14 @@
 #include "SkPaint.h"
 
 static bool gShowPath = false;
-static bool gDrawLastAsciiPaths = false;
+static bool gComparePaths = false;
+static bool gDrawLastAsciiPaths = true;
 static bool gDrawAllAsciiPaths = false;
 static bool gShowAsciiPaths = false;
-static bool gComparePathsAssert = false;
+static bool gComparePathsAssert = true;
 
 void showPath(const SkPath& path, const char* str) {
-    SkDebugf("%s\n", str ? "original:" : str);
+    SkDebugf("%s\n", !str ? "original:" : str);
     SkPath::Iter iter(path, true);
     uint8_t verb;
     SkPoint pts[4];
@@ -76,10 +77,10 @@ static bool pathsDrawTheSame(const SkPath& one, const SkPath& two) {
     return true;
 }
 
-void drawAsciiPaths(const SkPath& one, const SkPath& two,
+bool drawAsciiPaths(const SkPath& one, const SkPath& two,
         bool drawPaths) {
     if (!drawPaths) {
-        return;
+        return true;
     }
     if (gShowAsciiPaths) {
         showPath(one, "one:");
@@ -90,8 +91,15 @@ void drawAsciiPaths(const SkPath& one, const SkPath& two,
     SkRect larger = bounds1;
     larger.join(bounds2);
     SkBitmap bits;
+    char out[256];
     int bitWidth = SkScalarCeil(larger.width()) + 2;
+    if (bitWidth * 2 + 1 >= (int) sizeof(out)) {
+        return false;
+    }
     int bitHeight = SkScalarCeil(larger.height()) + 2;
+    if (bitHeight >= (int) sizeof(out)) {
+        return false;
+    }
     bits.setConfig(SkBitmap::kARGB_8888_Config, bitWidth * 2, bitHeight);
     bits.allocPixels();
     SkCanvas canvas(bits);
@@ -105,8 +113,6 @@ void drawAsciiPaths(const SkPath& one, const SkPath& two,
     canvas.translate(-bounds2.fLeft + 1 + bitWidth, -bounds2.fTop + 1);
     canvas.drawPath(two, paint);
     canvas.restore();
-    char out[1024];
-    SkASSERT(bitWidth * 2 + 1 < (int) sizeof(out));
     for (int y = 0; y < bitHeight; ++y) {
         uint32_t* addr1 = bits.getAddr32(0, y);
         int x;
@@ -121,20 +127,30 @@ void drawAsciiPaths(const SkPath& one, const SkPath& two,
         *outPtr++ = '\0';
         SkDebugf("%s\n", out);
     }
+    return true;
 }
 
 static bool scaledDrawTheSame(const SkPath& one, const SkPath& two,
         int a, int b, bool drawPaths) {
     SkMatrix scale;
     scale.reset();
-    scale.preScale(a * 1.21f, b * 1.11f);
+    float aScale = 1.21f;
+    float bScale = 1.11f;
+    scale.preScale(a * aScale, b * bScale);
     SkPath scaledOne, scaledTwo;
     one.transform(scale, &scaledOne);
     two.transform(scale, &scaledTwo);
     if (pathsDrawTheSame(scaledOne, scaledTwo)) {
         return true;
     }
-    drawAsciiPaths(scaledOne, scaledTwo, drawPaths);
+    while (!drawAsciiPaths(scaledOne, scaledTwo, drawPaths)) {
+        scale.reset();
+        aScale *= 0.5f;
+        bScale *= 0.5f;
+        scale.preScale(a * aScale, b * bScale);
+        one.transform(scale, &scaledOne);
+        two.transform(scale, &scaledTwo);
+    }
     return false;
 }
 
@@ -195,5 +211,8 @@ bool testSimplify(const SkPath& path, bool fill, SkPath& out) {
         showPath(path);
     }
     simplify(path, fill, out);
+    if (!gComparePaths) {
+        return true;
+    }
     return comparePaths(path, out);
 }
diff --git a/experimental/Intersection/edge.xcodeproj/project.pbxproj b/experimental/Intersection/edge.xcodeproj/project.pbxproj
index 1b520f199e..0cd951e386 100644
--- a/experimental/Intersection/edge.xcodeproj/project.pbxproj
+++ b/experimental/Intersection/edge.xcodeproj/project.pbxproj
@@ -26,6 +26,9 @@
 		FE7413AE14F689E700056D7B /* libopts.a in Frameworks */ = {isa = PBXBuildFile; fileRef = FEF87C2C13E0410900335C58 /* libopts.a */; };
 		FE7413D414F6915A00056D7B /* EdgeWalkerPolygons_Test.cpp in Sources */ = {isa = PBXBuildFile; fileRef = FE7413D314F6915A00056D7B /* EdgeWalkerPolygons_Test.cpp */; };
 		FE7413D814F691C200056D7B /* EdgeWalker_TestUtility.cpp in Sources */ = {isa = PBXBuildFile; fileRef = FE7413D714F691C200056D7B /* EdgeWalker_TestUtility.cpp */; };
+		FE99AE40151B4ED10072AA0D /* tempskinny4.txt in Resources */ = {isa = PBXBuildFile; fileRef = FE99AE3F151B4ED10072AA0D /* tempskinny4.txt */; };
+		FE99AE44151B4EE70072AA0D /* xtempskinny4.txt in Resources */ = {isa = PBXBuildFile; fileRef = FE99AE43151B4EE70072AA0D /* xtempskinny4.txt */; };
+		FE99AEBE151B64ED0072AA0D /* op.htm in Resources */ = {isa = PBXBuildFile; fileRef = FE99AEBD151B64ED0072AA0D /* op.htm */; };
 		FEA5F4E21498000C005052F9 /* libports.a in Frameworks */ = {isa = PBXBuildFile; fileRef = FEA5F4E11497FFF6005052F9 /* libports.a */; };
 		FEA61B0014EF589900B736CB /* libanimator.a in Frameworks */ = {isa = PBXBuildFile; fileRef = FEED7268144DD3EA0059E97B /* libanimator.a */; };
 		FEA61B2C14F2AF6600B736CB /* EdgeWalkerRectangles_Test.cpp in Sources */ = {isa = PBXBuildFile; fileRef = FEA61B2B14F2AF6600B736CB /* EdgeWalkerRectangles_Test.cpp */; };
@@ -258,6 +261,9 @@
 		FE7413D314F6915A00056D7B /* EdgeWalkerPolygons_Test.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = EdgeWalkerPolygons_Test.cpp; sourceTree = "<group>"; };
 		FE7413D714F691C200056D7B /* EdgeWalker_TestUtility.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = EdgeWalker_TestUtility.cpp; sourceTree = "<group>"; };
 		FE7413DB14F6926D00056D7B /* EdgeWalker_Test.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = EdgeWalker_Test.h; sourceTree = "<group>"; };
+		FE99AE3F151B4ED10072AA0D /* tempskinny4.txt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = tempskinny4.txt; sourceTree = "<group>"; };
+		FE99AE43151B4EE70072AA0D /* xtempskinny4.txt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = xtempskinny4.txt; sourceTree = "<group>"; };
+		FE99AEBD151B64ED0072AA0D /* op.htm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.html; path = op.htm; sourceTree = "<group>"; };
 		FEA5F4D91497FFF6005052F9 /* ports.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = ports.xcodeproj; path = ../../out/gyp/ports.xcodeproj; sourceTree = SOURCE_ROOT; };
 		FEA61B2B14F2AF6600B736CB /* EdgeWalkerRectangles_Test.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = EdgeWalkerRectangles_Test.cpp; sourceTree = "<group>"; };
 		FEA670F013C49E2200FE6FC1 /* SkAntiEdge.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = SkAntiEdge.cpp; sourceTree = "<group>"; };
@@ -386,6 +392,7 @@
 		29B97314FDCFA39411CA2CEA /* edge */ = {
 			isa = PBXGroup;
 			children = (
+				FE99AEBD151B64ED0072AA0D /* op.htm */,
 				FEA670EF13C49D7600FE6FC1 /* views */,
 				FEC123A7149001B20086BF1F /* AntiEdge */,
 				29B97315FDCFA39411CA2CEA /* Intersection */,
@@ -481,6 +488,8 @@
 		FE71354F14D305FD0008E392 /* ShapeOps */ = {
 			isa = PBXGroup;
 			children = (
+				FE99AE43151B4EE70072AA0D /* xtempskinny4.txt */,
+				FE99AE3F151B4ED10072AA0D /* tempskinny4.txt */,
 				FE3DBAFD150E4A680006ADF4 /* junk.htm */,
 				FE3DB8C9150A48320006ADF4 /* junk.txt */,
 				FE71358514D309E90008E392 /* EdgeWalker.cpp */,
@@ -899,6 +908,9 @@
 				1DDD58160DA1D0A300B32029 /* MainMenu.xib in Resources */,
 				FEED72B0144DD5710059E97B /* SampleApp.xib in Resources */,
 				FE3DBAFE150E4A680006ADF4 /* junk.htm in Resources */,
+				FE99AE40151B4ED10072AA0D /* tempskinny4.txt in Resources */,
+				FE99AE44151B4EE70072AA0D /* xtempskinny4.txt in Resources */,
+				FE99AEBE151B64ED0072AA0D /* op.htm in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/experimental/Intersection/op.htm b/experimental/Intersection/op.htm
new file mode 100644
index 0000000000..dcfb654c35
--- /dev/null
+++ b/experimental/Intersection/op.htm
@@ -0,0 +1,244 @@
+<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>
+
+<script type="text/javascript">
+
+var testDivs = [
+    test_1div,
+];
+
+var scale, columns, rows, xStart, yStart;
+
+var ticks = 0.1;
+var at_x = 13 + 0.5;
+var at_y = 13 + 0.5;
+
+var tests = [];
+var testIndex = 0;
+
+var ctx;
+
+function parse(test) {
+    var contours = [];
+    var contourStrs = test.split("path.close();");
+    var pattern = /\d+\.*\d*/g;
+    for (var c in contourStrs) {
+        var points = contourStrs[c].match(pattern);
+        var pts = [];
+        for (var wd in points) {
+            var num = parseFloat(points[wd]);
+            if (isNaN(num)) continue;
+            pts.push(num );
+        }
+        contours.push(pts);
+    }
+    tests.push(contours);
+}
+
+function init(test) {
+    var canvas = document.getElementById('canvas');
+    if (!canvas.getContext) return;
+    ctx = canvas.getContext('2d');
+    var xmin = Infinity;
+    var xmax = -Infinity;
+    var ymin = Infinity;
+    var ymax = -Infinity;
+    for (pts in test) {
+        var pt = test[pts];
+        for (i = 0; i < pt.length; i += 2) {
+            xmin = Math.min(xmin, pt[i]);
+            ymin = Math.min(ymin, pt[i + 1]);
+            xmax = Math.max(xmax, pt[i]);
+            ymax = Math.max(ymax, pt[i + 1]);
+        }
+    }
+    var subscale = 1;
+    while ((xmax - xmin) * subscale < 0.1 && (ymax - ymin) * subscale < 0.1) {
+        subscale *= 10;
+    }
+    columns = Math.ceil(xmax) - Math.floor(xmin) + 1;
+    rows = Math.ceil(ymax) - Math.floor(ymin) + 1;
+    xStart = Math.floor(xmin);
+    yStart = Math.floor(ymin);
+    var hscale = ctx.canvas.width / columns / ticks;
+    var vscale = ctx.canvas.height / rows / ticks;
+    scale = Math.floor(Math.min(hscale, vscale)) * subscale;
+}
+
+function drawPoint(px, py, xoffset, yoffset, unit) {
+    var label = px + "=" + px.toFixed(3) + ", " + py + "=" + py.toFixed(3);
+    var _px = px * unit + xoffset;
+    var _py = py * unit + yoffset;
+    ctx.beginPath();
+    ctx.arc(_px, _py, 3, 0, Math.PI*2, true);
+    ctx.closePath();
+    ctx.fill();
+    ctx.fillText(label, _px + 5, _py);
+}
+
+function draw(test, _at_x, _at_y, scale) {
+    var unit = scale * ticks;
+    ctx.lineWidth = 1;
+    var i;
+    for (i = 0; i <= rows * ticks; ++i) {
+        ctx.strokeStyle = (i % ticks) != 0 ? "rgb(160,160,160)" : "black";
+        ctx.beginPath();
+        ctx.moveTo(_at_x + 0, _at_y + i * scale);
+        ctx.lineTo(_at_x + unit * columns, _at_y + i * scale);
+        ctx.stroke();
+    }
+    for (i = 0; i <= columns * ticks; ++i) {
+        ctx.strokeStyle = (i % ticks) != 0 ? "rgb(160,160,160)" : "black";
+        ctx.beginPath();
+        ctx.moveTo(_at_x + i * scale, _at_y + 0);
+        ctx.lineTo(_at_x + i * scale, _at_y + unit * rows);
+        ctx.stroke();
+    }
+ 
+    var xoffset = xStart * -unit + _at_x;
+    var yoffset = yStart * -unit + _at_y;
+
+    ctx.fillStyle = "rgb(40,80,60)"
+    for (i = 0; i <= columns; i += (1 / ticks))
+    {
+        num = (xoffset - _at_x) / -unit + i; 
+        ctx.fillText(num.toFixed(0), i * unit + _at_y - 5, 10);
+    }
+    for (i = 0; i <= rows; i += (1 / ticks))
+    {
+        num = (yoffset - _at_x) / -unit + i; 
+        ctx.fillText(num.toFixed(0), 0, i * unit + _at_y + 0);
+    }
+    ctx.strokeStyle = "red";
+    for (pts in test) {
+        var pt = test[pts];
+        var x = pt[0];
+        var y = pt[1];
+        ctx.beginPath();
+        ctx.moveTo(xoffset + x * unit, yoffset + y * unit);
+        for (i = 2; i < pt.length; i += 2) {
+            x = pt[i];
+            y = pt[i + 1];
+            ctx.lineTo(xoffset + x * unit, yoffset + y * unit);
+        }
+        ctx.stroke();
+    }
+    
+    ctx.fillStyle="blue";
+    for (pts in test) {
+        var pt = test[pts];
+        for (i = 0; i < pt.length; i += 2) {
+            x = pt[i];
+            y = pt[i + 1];
+            drawPoint(x, y, xoffset, yoffset, unit);
+        }
+    }
+}
+
+var mouseX = Infinity, mouseY;
+
+function calcXY() {
+    var e = window.event;
+	var tgt = e.target || e.srcElement;
+    var left = tgt.offsetLeft;
+    var top = tgt.offsetTop;
+    var unit = scale * ticks;
+    mouseX = (e.clientX - left - Math.ceil(at_x) + 1) / unit + xStart;
+    mouseY = (e.clientY - top - Math.ceil(at_y)) / unit + yStart;
+}
+
+function handleMouseOver() {
+    calcXY();
+    var num = mouseX.toFixed(3) + ", " + mouseY.toFixed(3);
+    ctx.beginPath();
+    ctx.rect(300,100,200,10);
+    ctx.fillStyle="white";
+    ctx.fill();
+    ctx.fillStyle="black";
+    ctx.fillText(num, 300, 108);
+}
+
+function handleMouseClick() {
+    calcXY();
+//    drawInset();
+}
+
+function drawTop() {
+    init(tests[testIndex]);
+    redraw();
+}
+
+function redraw() {
+    ctx.beginPath();
+    ctx.rect(0, 0, ctx.canvas.width, ctx.canvas.height);
+    ctx.fillStyle="white";
+    ctx.fill();
+    draw(tests[testIndex], at_x, at_y, scale);
+//    if (insetScale != scale && mouseX != Infinity)
+//        drawInset();
+}
+
+function doKeyPress(evt) {
+    var char = String.fromCharCode(evt.charCode);
+    switch (char) {
+    case 'N':
+    case 'n':
+        if (++testIndex >= tests.length)
+            testIndex = 0;
+    //    insetScale = scale;
+        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;
+    }
+}
+
+function start() {
+    for (i = 0; i < testDivs.length; ++i) {
+        var str = testDivs[i].firstChild.data;
+        parse(str);
+    }
+    drawTop();
+    window.addEventListener('keypress', doKeyPress, true);
+}
+
+</script>
+</head>
+
+<body onLoad="start();">
+<canvas id="canvas" width="1500" height="1000"
+    onmousemove="handleMouseOver()"
+    onclick="handleMouseClick()"
+    ></canvas >
+</body>
+</html>