COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/bezier.h @ 1081:c0ad2673b11f

Last change on this file since 1081:c0ad2673b11f was 1073:bedab8bd915f, checked in by Alpar Juttner, 16 years ago

graph_to_eps mission accomplished.

  • lemon/graph_to_eps.h header created
  • lemon/bezier.h: Tools to compute with bezier curves (unclean and undocumented interface, used internally by graph_to_eps.h)
  • demo/graph_to_eps_demo.cc: a simple demo for lemon/graph_to_eps.h
File size: 3.3 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/bezier.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_BEZIER_H
18#define LEMON_BEZIER_H
19
20///\ingroup misc
21///\file
22///\brief Classes to compute with Bezier curves.
23///
24///Up to now this file is internally used by \ref graph_to_eps.h
25///
26///\author Alpar Juttner
27
28#include<lemon/xy.h>
29
30namespace lemon {
31
32class BezierBase {
33public:
34  typedef xy<double> xy;
35protected:
36  static xy conv(xy x,xy y,double t) {return (1-t)*x+t*y;}
37};
38
39class Bezier1 : public BezierBase
40{
41public:
42  xy p1,p2;
43
44  Bezier1() {}
45  Bezier1(xy _p1, xy _p2) :p1(_p1), p2(_p2) {}
46 
47  xy operator()(double t) const
48  {
49    //    return conv(conv(p1,p2,t),conv(p2,p3,t),t);
50    return conv(p1,p2,t);
51  }
52  Bezier1 before(double t) const
53  {
54    return Bezier1(p1,conv(p1,p2,t));
55  }
56 
57  Bezier1 after(double t) const
58  {
59    return Bezier1(conv(p1,p2,t),p2);
60  }
61  Bezier1 operator()(double a,double b) { return before(b).after(a/b); } 
62};
63
64class Bezier2 : public BezierBase
65{
66public:
67  xy p1,p2,p3;
68
69  Bezier2() {}
70  Bezier2(xy _p1, xy _p2, xy _p3) :p1(_p1), p2(_p2), p3(_p3) {}
71  Bezier2(const Bezier1 &b) : p1(b.p1), p2(conv(b.p1,b.p2,.5)), p3(b.p2) {}
72  xy operator()(double t) const
73  {
74    //    return conv(conv(p1,p2,t),conv(p2,p3,t),t);
75    return ((1-t)*(1-t))*p1+(2*(1-t)*t)*p2+(t*t)*p3;
76  }
77  Bezier2 before(double t) const
78  {
79    xy q(conv(p1,p2,t));
80    xy r(conv(p2,p3,t));
81    return Bezier2(p1,q,conv(q,r,t));
82  }
83 
84  Bezier2 after(double t) const
85  {
86    xy q(conv(p1,p2,t));
87    xy r(conv(p2,p3,t));
88    return Bezier2(conv(q,r,t),r,p3);
89  }
90  Bezier2 operator()(double a,double b) { return before(b).after(a/b); }
91 
92};
93
94class Bezier3 : public BezierBase
95{
96public:
97  xy p1,p2,p3,p4;
98
99  Bezier3() {}
100  Bezier3(xy _p1, xy _p2, xy _p3, xy _p4) :p1(_p1), p2(_p2), p3(_p3), p4(_p4) {}
101  Bezier3(const Bezier1 &b) : p1(b.p1), p2(conv(b.p1,b.p2,1.0/3.0)),
102                              p3(conv(b.p1,b.p2,2.0/3.0)), p4(b.p2) {}
103  Bezier3(const Bezier2 &b) : p1(b.p1), p2(conv(b.p1,b.p2,2.0/3.0)),
104                              p3(conv(b.p2,b.p3,1.0/3.0)), p4(b.p3) {}
105 
106  xy operator()(double t) const
107    {
108      //    return Bezier2(conv(p1,p2,t),conv(p2,p3,t),conv(p3,p4,t))(t);
109      return ((1-t)*(1-t)*(1-t))*p1+(3*t*(1-t)*(1-t))*p2+
110        (3*t*t*(1-t))*p3+(t*t*t)*p4;
111    }
112  Bezier3 before(double t) const
113    {
114      xy p(conv(p1,p2,t));
115      xy q(conv(p2,p3,t));
116      xy r(conv(p3,p4,t));
117      xy a(conv(p,q,t));
118      xy b(conv(q,r,t));
119      xy c(conv(a,b,t));
120      return Bezier3(p1,p,a,c);
121    }
122 
123  Bezier3 after(double t) const
124    {
125      xy p(conv(p1,p2,t));
126      xy q(conv(p2,p3,t));
127      xy r(conv(p3,p4,t));
128      xy a(conv(p,q,t));
129      xy b(conv(q,r,t));
130      xy c(conv(a,b,t));
131      return Bezier3(c,b,r,p4);
132    }
133  Bezier3 operator()(double a,double b) { return before(b).after(a/b); }
134 
135};
136
137} //END OF NAMESPACE LEMON
138
139#endif // LEMON_BEZIER_H
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