1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkPathOpsCubic_DEFINED
9#define SkPathOpsCubic_DEFINED
10
11#include "SkPath.h"
12#include "SkPathOpsPoint.h"
13#include "SkTArray.h"
14
15struct SkDCubicPair {
16    const SkDCubic& first() const { return (const SkDCubic&) pts[0]; }
17    const SkDCubic& second() const { return (const SkDCubic&) pts[3]; }
18    SkDPoint pts[7];
19};
20
21struct SkDCubic {
22    SkDPoint fPts[4];
23
24    void set(const SkPoint pts[4]) {
25        fPts[0] = pts[0];
26        fPts[1] = pts[1];
27        fPts[2] = pts[2];
28        fPts[3] = pts[3];
29    }
30
31    static const int gPrecisionUnit;
32
33    const SkDPoint& operator[](int n) const { SkASSERT(n >= 0 && n < 4); return fPts[n]; }
34    SkDPoint& operator[](int n) { SkASSERT(n >= 0 && n < 4); return fPts[n]; }
35
36    void align(int endIndex, int ctrlIndex, SkDPoint* dstPt) const;
37    double calcPrecision() const;
38    SkDCubicPair chopAt(double t) const;
39    bool clockwise() const;
40    static void Coefficients(const double* cubic, double* A, double* B, double* C, double* D);
41    bool controlsContainedByEnds() const;
42    SkDVector dxdyAtT(double t) const;
43    bool endsAreExtremaInXOrY() const;
44    static int FindExtrema(double a, double b, double c, double d, double tValue[2]);
45    int findInflections(double tValues[]) const;
46
47    static int FindInflections(const SkPoint a[4], double tValues[]) {
48        SkDCubic cubic;
49        cubic.set(a);
50        return cubic.findInflections(tValues);
51    }
52
53    int findMaxCurvature(double tValues[]) const;
54    bool isLinear(int startIndex, int endIndex) const;
55    bool monotonicInY() const;
56    SkDPoint ptAtT(double t) const;
57    static int RootsReal(double A, double B, double C, double D, double t[3]);
58    static int RootsValidT(const double A, const double B, const double C, double D, double s[3]);
59    bool serpentine() const;
60    SkDCubic subDivide(double t1, double t2) const;
61
62    static SkDCubic SubDivide(const SkPoint a[4], double t1, double t2) {
63        SkDCubic cubic;
64        cubic.set(a);
65        return cubic.subDivide(t1, t2);
66    }
67
68    void subDivide(const SkDPoint& a, const SkDPoint& d, double t1, double t2, SkDPoint p[2]) const;
69
70    static void SubDivide(const SkPoint pts[4], const SkDPoint& a, const SkDPoint& d, double t1,
71                          double t2, SkDPoint p[2]) {
72        SkDCubic cubic;
73        cubic.set(pts);
74        cubic.subDivide(a, d, t1, t2, p);
75    }
76
77    SkDPoint top(double startT, double endT) const;
78    void toQuadraticTs(double precision, SkTArray<double, true>* ts) const;
79    SkDQuad toQuad() const;
80
81#ifdef SK_DEBUG
82    void dump();
83#endif
84};
85
86#endif
87