Add base types for path ops

src/pathops/SkPathOpsQuad.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 SkPathOpsQuad_DEFINED
+#define SkPathOpsQuad_DEFINED
+
+#include "SkPathOpsPoint.h"
+
+struct SkDQuadPair {
+    const SkDQuad& first() const { return (const SkDQuad&) pts[0]; }
+    const SkDQuad& second() const { return (const SkDQuad&) pts[2]; }
+    SkDPoint pts[5];
+};
+
+struct SkDQuad {
+    SkDPoint fPts[3];
+
+    void set(const SkPoint pts[3]) {
+        fPts[0] = pts[0];
+        fPts[1] = pts[1];
+        fPts[2] = pts[2];
+    }
+
+    const SkDPoint& operator[](int n) const { SkASSERT(n >= 0 && n < 3); return fPts[n]; }
+    SkDPoint& operator[](int n) { SkASSERT(n >= 0 && n < 3); return fPts[n]; }
+
+    static int AddValidTs(double s[], int realRoots, double* t);
+    SkDQuadPair chopAt(double t) const;
+    SkDVector dxdyAtT(double t) const;
+    static int FindExtrema(double a, double b, double c, double tValue[1]);
+    bool isLinear(int startIndex, int endIndex) const;
+    bool monotonicInY() const;
+    double nearestT(const SkDPoint&) const;
+    bool pointInHull(const SkDPoint&) const;
+    static int RootsReal(double A, double B, double C, double t[2]);
+    static int RootsValidT(const double A, const double B, const double C, double s[2]);
+    static void SetABC(const double* quad, double* a, double* b, double* c);
+    SkDQuad subDivide(double t1, double t2) const;
+    static SkDQuad SubDivide(const SkPoint a[3], double t1, double t2) {
+        SkDQuad quad;
+        quad.set(a);
+        return quad.subDivide(t1, t2);
+    }
+    SkDPoint subDivide(const SkDPoint& a, const SkDPoint& c, double t1, double t2) const;
+    static SkDPoint SubDivide(const SkPoint pts[3], const SkDPoint& a, const SkDPoint& c,
+                              double t1, double t2) {
+        SkDQuad quad;
+        quad.set(pts);
+        return quad.subDivide(a, c, t1, t2);
+    }
+    SkDCubic toCubic() const;
+    SkDPoint top(double startT, double endT) const;
+    SkDPoint xyAtT(double t) const;
+private:
+//  static double Tangent(const double* quadratic, double t); // uncalled
+};
+
+#endif