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    enum SearchAxis {
23        kXAxis,
24        kYAxis
25    };
26
27    const SkDPoint& operator[](int n) const { SkASSERT(n >= 0 && n < 4); return fPts[n]; }
28    SkDPoint& operator[](int n) { SkASSERT(n >= 0 && n < 4); return fPts[n]; }
29
30    void align(int endIndex, int ctrlIndex, SkDPoint* dstPt) const;
31    double binarySearch(double min, double max, double axisIntercept, SearchAxis xAxis) const;
32    double calcPrecision() const;
33    SkDCubicPair chopAt(double t) const;
34    bool clockwise() const;
35    static void Coefficients(const double* cubic, double* A, double* B, double* C, double* D);
36    bool controlsContainedByEnds() const;
37    SkDVector dxdyAtT(double t) const;
38    bool endsAreExtremaInXOrY() const;
39    static int FindExtrema(double a, double b, double c, double d, double tValue[2]);
40    int findInflections(double tValues[2]) const;
41
42    static int FindInflections(const SkPoint a[4], double tValues[2]) {
43        SkDCubic cubic;
44        cubic.set(a);
45        return cubic.findInflections(tValues);
46    }
47
48    int findMaxCurvature(double tValues[]) const;
49    bool isLinear(int startIndex, int endIndex) const;
50    bool monotonicInY() const;
51    SkDPoint ptAtT(double t) const;
52    static int RootsReal(double A, double B, double C, double D, double t[3]);
53    static int RootsValidT(const double A, const double B, const double C, double D, double s[3]);
54
55    int searchRoots(double extremes[6], int extrema, double axisIntercept,
56                    SearchAxis xAxis, double* validRoots) const;
57    bool serpentine() const;
58
59    void set(const SkPoint pts[4]) {
60        fPts[0] = pts[0];
61        fPts[1] = pts[1];
62        fPts[2] = pts[2];
63        fPts[3] = pts[3];
64    }
65
66    SkDCubic subDivide(double t1, double t2) const;
67
68    static SkDCubic SubDivide(const SkPoint a[4], double t1, double t2) {
69        SkDCubic cubic;
70        cubic.set(a);
71        return cubic.subDivide(t1, t2);
72    }
73
74    void subDivide(const SkDPoint& a, const SkDPoint& d, double t1, double t2, SkDPoint p[2]) const;
75
76    static void SubDivide(const SkPoint pts[4], const SkDPoint& a, const SkDPoint& d, double t1,
77                          double t2, SkDPoint p[2]) {
78        SkDCubic cubic;
79        cubic.set(pts);
80        cubic.subDivide(a, d, t1, t2, p);
81    }
82
83    SkDPoint top(double startT, double endT) const;
84    void toQuadraticTs(double precision, SkTArray<double, true>* ts) const;
85    SkDQuad toQuad() const;
86
87    // utilities callable by the user from the debugger when the implementation code is linked in
88    void dump() const;
89    void dumpNumber() const;
90
91    static const int gPrecisionUnit;
92
93    SkDPoint fPts[4];
94};
95
96#endif
97