1 /*
2 * bezier.h
3 *
4 * Copyright 2007 MenTaLguY <mental@rydia.net>
5 * Copyright 2007 Michael Sloan <mgsloan@gmail.com>
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it either under the terms of the GNU Lesser General Public
9 * License version 2.1 as published by the Free Software Foundation
10 * (the "LGPL") or, at your option, under the terms of the Mozilla
11 * Public License Version 1.1 (the "MPL"). If you do not alter this
12 * notice, a recipient may use your version of this file under either
13 * the MPL or the LGPL.
14 *
15 * You should have received a copy of the LGPL along with this library
16 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 * You should have received a copy of the MPL along with this library
19 * in the file COPYING-MPL-1.1
20 *
21 * The contents of this file are subject to the Mozilla Public License
22 * Version 1.1 (the "License"); you may not use this file except in
23 * compliance with the License. You may obtain a copy of the License at
24 * http://www.mozilla.org/MPL/
25 *
26 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
27 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
28 * the specific language governing rights and limitations.
29 *
30 */
32 #ifndef SEEN_BEZIER_H
33 #define SEEN_BEZIER_H
35 #include "coord.h"
36 #include "isnan.h"
37 #include "bezier-to-sbasis.h"
39 namespace Geom {
41 template <unsigned order>
42 class Bezier {
43 private:
44 Coord c_[order+1];
46 protected:
47 Bezier(Coord c[]) {
48 std::copy(c, c+order+1, c_);
49 }
51 public:
52 template <unsigned required_order>
53 static void assert_order(Bezier<required_order> const *) {}
55 Bezier() {}
57 //Construct an order-0 bezier (constant Bézier)
58 explicit Bezier(Coord c0) {
59 assert_order<0>(this);
60 c_[0] = c0;
61 }
63 //Construct an order-1 bezier (linear Bézier)
64 Bezier(Coord c0, Coord c1) {
65 assert_order<1>(this);
66 c_[0] = c0; c_[1] = c1;
67 }
69 //Construct an order-2 bezier (quadratic Bézier)
70 Bezier(Coord c0, Coord c1, Coord c2) {
71 assert_order<2>(this);
72 c_[0] = c0; c_[1] = c1; c_[2] = c2;
73 }
75 //Construct an order-3 bezier (cubic Bézier)
76 Bezier(Coord c0, Coord c1, Coord c2, Coord c3) {
77 assert_order<3>(this);
78 c_[0] = c0; c_[1] = c1; c_[2] = c2; c_[3] = c3;
79 }
81 inline unsigned degree() const { return order; }
83 //IMPL: FragmentConcept
84 typedef Coord output_type;
85 inline bool isZero() const {
86 for(int i = 0; i <= order; i++) {
87 if(c_[i] != 0) return false;
88 }
89 return true;
90 }
91 inline bool isFinite() const {
92 for(int i = 0; i <= order; i++) {
93 if(!is_finite(c_[i])) return false;
94 }
95 return true;
96 }
97 inline Coord at0() const { return c_[0]; }
98 inline Coord at1() const { return c_[order]; }
100 inline SBasis toSBasis() const { return bezier_to_sbasis<order>(c_); }
102 inline Interval bounds_fast() const { return Interval::fromArray(c_, order+1); }
103 //TODO: better bounds exact
104 inline Interval bounds_exact() const { return toSBasis().bounds_exact(); }
105 inline Interval bounds_local(double u, double v) const { return toSBasis().bounds_local(u, v); }
107 //Only mutator
108 inline Coord &operator[](int index) { return c_[index]; }
109 inline Coord const &operator[](int index) const { return c_[index]; }
111 Maybe<int> winding(Point p) const {
112 return sbasis_winding(toSBasis(), p);
113 }
115 Point pointAndDerivativesAt(Coord t, unsigned n_derivs, Point *derivs) const {
116 //TODO
117 return Point(0,0);
118 }
119 };
121 template<unsigned order>
122 Bezier<order> reverse(const Bezier<order> & a) {
123 Bezier<order> result;
124 for(int i = 0; i <= order; i++)
125 result[i] = a[order - i];
126 return result;
127 }
129 template<unsigned order>
130 vector<Point> bezier_points(const D2<Bezier<order> > & a) {
131 vector<Point> result;
132 for(int i = 0; i <= order; i++) {
133 Point p;
134 for(unsigned d = 0; d < 2; d++) p[d] = a[d][i];
135 result[i] = p;
136 }
137 return result;
138 }
140 }
141 #endif //SEEN_BEZIER_H