path ops work in progress

src/pathops/SkIntersections.h

Index: src/pathops/SkIntersections.h
diff --git a/src/pathops/SkIntersections.h b/src/pathops/SkIntersections.h
index 389098d84e67136dff4160f9d2635879e7fc4c71..f63a023ef0a5ef26c21c42ecfc8bd5b0c2a88fc3 100644
--- a/src/pathops/SkIntersections.h
+++ b/src/pathops/SkIntersections.h
@@ -25,6 +25,7 @@ public:
         sk_bzero(fIsCoincident, sizeof(fIsCoincident));
         sk_bzero(&fIsNear, sizeof(fIsNear));
         reset();
+        fMax = 0;  // require that the caller set the max
     }
 
     class TArray {
@@ -43,6 +44,7 @@ public:
         memcpy(fIsCoincident, i.fIsCoincident, sizeof(fIsCoincident));
         memcpy(&fIsNear, &i.fIsNear, sizeof(fIsNear));
         fUsed = i.fUsed;
+        fMax = i.fMax;
         fSwap = i.fSwap;
         SkDEBUGCODE(fDepth = i.fDepth);
     }
@@ -54,6 +56,7 @@ public:
     int cubic(const SkPoint a[4]) {
         SkDCubic cubic;
         cubic.set(a);
+        fMax = 1;  // self intersect
         return intersect(cubic);
     }
 
@@ -62,6 +65,7 @@ public:
         aCubic.set(a);
         SkDCubic bCubic;
         bCubic.set(b);
+        fMax = 9;
         return intersect(aCubic, bCubic);
     }
 
@@ -69,12 +73,14 @@ public:
                         bool flipped) {
         SkDCubic cubic;
         cubic.set(a);
+        fMax = 3;
         return horizontal(cubic, left, right, y, flipped);
     }
 
     int cubicVertical(const SkPoint a[4], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
         SkDCubic cubic;
         cubic.set(a);
+        fMax = 3;
         return vertical(cubic, top, bottom, x, flipped);
     }
 
@@ -83,6 +89,7 @@ public:
         cubic.set(a);
         SkDLine line;
         line.set(b);
+        fMax = 3;
         return intersect(cubic, line);
     }
 
@@ -91,6 +98,7 @@ public:
         cubic.set(a);
         SkDQuad quad;
         quad.set(b);
+        fMax = 6;
         return intersect(cubic, quad);
     }
 
@@ -119,12 +127,14 @@ public:
                        bool flipped) {
         SkDLine line;
         line.set(a);
+        fMax = 2;
         return horizontal(line, left, right, y, flipped);
     }
 
     int lineVertical(const SkPoint a[2], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
         SkDLine line;
         line.set(a);
+        fMax = 2;
         return vertical(line, top, bottom, x, flipped);
     }
 
@@ -132,6 +142,7 @@ public:
         SkDLine aLine, bLine;
         aLine.set(a);
         bLine.set(b);
+        fMax = 2;
         return intersect(aLine, bLine);
     }
 
@@ -143,12 +154,14 @@ public:
                        bool flipped) {
         SkDQuad quad;
         quad.set(a);
+        fMax = 2;
         return horizontal(quad, left, right, y, flipped);
     }
 
     int quadVertical(const SkPoint a[3], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
         SkDQuad quad;
         quad.set(a);
+        fMax = 2;
         return vertical(quad, top, bottom, x, flipped);
     }
 
@@ -157,6 +170,7 @@ public:
         quad.set(a);
         SkDLine line;
         line.set(b);
+        fMax = 2;
         return intersect(quad, line);
     }
 
@@ -165,18 +179,23 @@ public:
         aQuad.set(a);
         SkDQuad bQuad;
         bQuad.set(b);
+        fMax = 4;
         return intersect(aQuad, bQuad);
     }
 
     int quadRay(const SkPoint pts[3], const SkDLine& line);
     void removeOne(int index);
 
-    // leaves flip, swap alone
+    // leaves flip, swap, max alone
     void reset() {
         fAllowNear = true;
         fUsed = 0;
     }
 
+    void setMax(int max) {
+        fMax = max;
+    }
+
     void swap() {
         fSwap ^= true;
     }
@@ -200,6 +219,7 @@ public:
     }
 
     static double Axial(const SkDQuad& , const SkDPoint& , bool vertical);
+    void cleanUpCoincidence();
     int coincidentUsed() const;
     int cubicRay(const SkPoint pts[4], const SkDLine& line);
     void flip();
@@ -246,7 +266,11 @@ public:
     }
 
 private:
-    int computePoints(const SkDLine& line, int used);
+    bool cubicCheckCoincidence(const SkDCubic& c1, const SkDCubic& c2);
+    bool cubicExactEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2);
+    void cubicNearEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2, const SkDRect& );
+    void cleanUpParallelLines(bool parallel);
+    void computePoints(const SkDLine& line, int used);
     // used by addCoincident to remove ordinary intersections in range
  //   void remove(double one, double two, const SkDPoint& startPt, const SkDPoint& endPt);
 
@@ -255,6 +279,7 @@ private:
     uint16_t fIsCoincident[2];  // bit set for each curve's coincident T
     uint16_t fIsNear;  // bit set for each T if 2nd curve's point is near but not equal to 1st
     unsigned char fUsed;
+    unsigned char fMax;
     bool fAllowNear;
     bool fSwap;
 #ifdef SK_DEBUG