path ops work in progress

src/pathops/SkIntersections.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkIntersections_DEFINE
 #define SkIntersections_DEFINE
 
 #include "SkPathOpsCubic.h"
 #include "SkPathOpsLine.h"
 #include "SkPathOpsPoint.h"
 #include "SkPathOpsQuad.h"
 
 class SkIntersections {
 public:
     SkIntersections()
         : fSwap(0)
 #ifdef SK_DEBUG
         , fDepth(0)
 #endif
     {
         sk_bzero(fPt, sizeof(fPt));
         sk_bzero(fT, sizeof(fT));
         sk_bzero(fIsCoincident, sizeof(fIsCoincident));
         sk_bzero(&fIsNear, sizeof(fIsNear));
         reset();
+        fMax = 0;  // require that the caller set the max
     }
 
     class TArray {
     public:
         explicit TArray(const double ts[9]) : fTArray(ts) {}
         double operator[](int n) const {
             return fTArray[n];
         }
         const double* fTArray;
     };
     TArray operator[](int n) const { return TArray(fT[n]); }
 
     void set(const SkIntersections& i) {
         memcpy(fPt, i.fPt, sizeof(fPt));
         memcpy(fT, i.fT, sizeof(fT));
         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);
     }
 
     void allowNear(bool nearAllowed) {
         fAllowNear = nearAllowed;
     }
 
     int cubic(const SkPoint a[4]) {
         SkDCubic cubic;
         cubic.set(a);
+        fMax = 1;  // self intersect
         return intersect(cubic);
     }
 
     int cubicCubic(const SkPoint a[4], const SkPoint b[4]) {
         SkDCubic aCubic;
         aCubic.set(a);
         SkDCubic bCubic;
         bCubic.set(b);
+        fMax = 9;
         return intersect(aCubic, bCubic);
     }
 
     int cubicHorizontal(const SkPoint a[4], SkScalar left, SkScalar right, SkScalar y,
                         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);
     }
 
     int cubicLine(const SkPoint a[4], const SkPoint b[2]) {
         SkDCubic cubic;
         cubic.set(a);
         SkDLine line;
         line.set(b);
+        fMax = 3;
         return intersect(cubic, line);
     }
 
     int cubicQuad(const SkPoint a[4], const SkPoint b[3]) {
         SkDCubic cubic;
         cubic.set(a);
         SkDQuad quad;
         quad.set(b);
+        fMax = 6;
         return intersect(cubic, quad);
     }
 
     bool hasT(double t) const {
         SkASSERT(t == 0 || t == 1);
         return fUsed > 0 && (t == 0 ? fT[0][0] == 0 : fT[0][fUsed - 1] == 1);
     }
 
     int insertSwap(double one, double two, const SkDPoint& pt) {
         if (fSwap) {
             return insert(two, one, pt);
         } else {
             return insert(one, two, pt);
         }
     }
 
     bool isCoincident(int index) {
         return (fIsCoincident[0] & 1 << index) != 0;
     }
 
     bool isNear(int index) {
         return (fIsNear & 1 << index) != 0;
     }
 
     int lineHorizontal(const SkPoint a[2], SkScalar left, SkScalar right, SkScalar y,
                        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);
     }
 
     int lineLine(const SkPoint a[2], const SkPoint b[2]) {
         SkDLine aLine, bLine;
         aLine.set(a);
         bLine.set(b);
+        fMax = 2;
         return intersect(aLine, bLine);
     }
 
     const SkDPoint& pt(int index) const {
         return fPt[index];
     }
 
     int quadHorizontal(const SkPoint a[3], SkScalar left, SkScalar right, SkScalar y,
                        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);
     }
 
     int quadLine(const SkPoint a[3], const SkPoint b[2]) {
         SkDQuad quad;
         quad.set(a);
         SkDLine line;
         line.set(b);
+        fMax = 2;
         return intersect(quad, line);
     }
 
     int quadQuad(const SkPoint a[3], const SkPoint b[3]) {
         SkDQuad aQuad;
         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;
     }
 
     void swapPts();
 
     bool swapped() const {
         return fSwap;
     }
 
     int used() const {
         return fUsed;
     }
 
     void downDepth() {
         SkASSERT(--fDepth >= 0);
     }
 
     void upDepth() {
         SkASSERT(++fDepth < 16);
     }
 
     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();
     int horizontal(const SkDLine&, double y);
     int horizontal(const SkDLine&, double left, double right, double y, bool flipped);
     int horizontal(const SkDQuad&, double left, double right, double y, bool flipped);
     int horizontal(const SkDQuad&, double left, double right, double y, double tRange[2]);
     int horizontal(const SkDCubic&, double y, double tRange[3]);
     int horizontal(const SkDCubic&, double left, double right, double y, bool flipped);
     int horizontal(const SkDCubic&, double left, double right, double y, double tRange[3]);
@@ skipping 26 matching lines @@
 
     int depth() const {
 #ifdef SK_DEBUG
         return fDepth;
 #else
         return 0;
 #endif
     }
 
 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);
 
     SkDPoint fPt[9];  // FIXME: since scans store points as SkPoint, this should also
     double fT[2][9];
     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
     int fDepth;
 #endif
 };
 
 extern int (SkIntersections::*CurveRay[])(const SkPoint[], const SkDLine& );
 extern int (SkIntersections::*CurveVertical[])(const SkPoint[], SkScalar top, SkScalar bottom,
             SkScalar x, bool flipped);
 
 #endif