QuadraticUtilities.h revision c83c70e911a38aea03db4af8dd9841d0d77bd129 
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#if !defined QUADRATIC_UTILITIES_H
9#define QUADRATIC_UTILITIES_H
10
11#include "DataTypes.h"
12
13int add_valid_ts(double s[], int realRoots, double* t);
14void chop_at(const Quadratic& src, QuadraticPair& dst, double t);
15double dx_at_t(const Quadratic& , double t);
16double dy_at_t(const Quadratic& , double t);
17void dxdy_at_t(const Quadratic& , double t, _Point& xy);
18double nearestT(const Quadratic& , const _Point& );
19bool point_in_hull(const Quadratic& , const _Point& );
20
21/* Parameterization form, given A*t*t + 2*B*t*(1-t) + C*(1-t)*(1-t)
22 *
23 * a = A - 2*B +   C
24 * b =     2*B - 2*C
25 * c =             C
26 */
27inline void set_abc(const double* quad, double& a, double& b, double& c) {
28    a = quad[0];     // a = A
29    b = 2 * quad[2]; // b =     2*B
30    c = quad[4];     // c =             C
31    b -= c;          // b =     2*B -   C
32    a -= b;          // a = A - 2*B +   C
33    b -= c;          // b =     2*B - 2*C
34}
35
36int quadraticRootsReal(double A, double B, double C, double t[2]);
37int quadraticRootsValidT(const double A, const double B, const double C, double s[2]);
38void sub_divide(const Quadratic& src, double t1, double t2, Quadratic& dst);
39_Point sub_divide(const Quadratic& src, const _Point& a, const _Point& c, double t1, double t2);
40void toCubic(const Quadratic& , Cubic& );
41_Point top(const Quadratic& , double startT, double endT);
42void xy_at_t(const Quadratic& , double t, double& x, double& y);
43_Point xy_at_t(const Quadratic& , double t);
44
45#endif
46