1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
// Copyright (c) 2000 Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.2-branch/Intersections_2/include/CGAL/Segment_2_Line_2_intersection.h $
// $Id: Segment_2_Line_2_intersection.h 31166 2006-05-17 16:30:56Z spion $
//
//
// Author(s) : Geert-Jan Giezeman
#ifndef CGAL_SEGMENT_2_LINE_2_INTERSECTION_H
#define CGAL_SEGMENT_2_LINE_2_INTERSECTION_H
#include <CGAL/Line_2.h>
#include <CGAL/Segment_2.h>
#include <CGAL/Point_2.h>
#include <CGAL/kernel_assertions.h>
#include <CGAL/number_utils.h>
#include <CGAL/Object.h>
#include <CGAL/Line_2_Line_2_intersection.h>
CGAL_BEGIN_NAMESPACE
namespace CGALi {
template <class K>
class Segment_2_Line_2_pair {
public:
enum Intersection_results {NO_INTERSECTION, POINT, SEGMENT};
Segment_2_Line_2_pair() ;
Segment_2_Line_2_pair(typename K::Segment_2 const *seg,
typename K::Line_2 const *line);
Intersection_results intersection_type() const;
bool intersection(typename K::Point_2 &result) const;
bool intersection(typename K::Segment_2 &result) const;
protected:
typename K::Segment_2 const*_seg;
typename K::Line_2 const * _line;
mutable bool _known;
mutable Intersection_results _result;
mutable typename K::Point_2 _intersection_point;
};
template <class K>
inline bool do_intersect(
const typename CGAL_WRAP(K)::Segment_2 &p1,
const typename CGAL_WRAP(K)::Line_2 &p2,
const K&)
{
typedef Segment_2_Line_2_pair<K> pair_t;
pair_t pair(&p1, &p2);
return pair.intersection_type() != pair_t::NO_INTERSECTION;
}
template <class K>
Object
intersection(const typename CGAL_WRAP(K)::Segment_2 &seg,
const typename CGAL_WRAP(K)::Line_2 &line,
const K&)
{
typedef Segment_2_Line_2_pair<K> is_t;
is_t ispair(&seg, &line);
switch (ispair.intersection_type()) {
case is_t::NO_INTERSECTION:
default:
return Object();
case is_t::POINT: {
typename K::Point_2 pt;
ispair.intersection(pt);
return make_object(pt);
}
case is_t::SEGMENT:
return make_object(seg);
}
}
template <class K>
Object
intersection(const typename CGAL_WRAP(K)::Line_2 &line,
const typename CGAL_WRAP(K)::Segment_2 &seg,
const K& k)
{
return CGALi::intersection(seg, line, k);
}
template <class K>
class Line_2_Segment_2_pair: public Segment_2_Line_2_pair<K> {
public:
Line_2_Segment_2_pair(
typename K::Line_2 const *line,
typename K::Segment_2 const *seg) :
Segment_2_Line_2_pair<K>(seg, line) {}
};
template <class K>
inline bool do_intersect(
const typename CGAL_WRAP(K)::Line_2 &p1,
const typename CGAL_WRAP(K)::Segment_2 &p2,
const K&)
{
typedef Line_2_Segment_2_pair<K> pair_t;
pair_t pair(&p1, &p2);
return pair.intersection_type() != pair_t::NO_INTERSECTION;
}
template <class K>
Segment_2_Line_2_pair<K>::Segment_2_Line_2_pair()
{
_seg = 0;
_line = 0;
_known = false;
}
template <class K>
Segment_2_Line_2_pair<K>::Segment_2_Line_2_pair(
typename K::Segment_2 const *seg, typename K::Line_2 const *line)
{
_seg = seg;
_line = line;
_known = false;
}
template <class K>
typename Segment_2_Line_2_pair<K>::Intersection_results
Segment_2_Line_2_pair<K>::intersection_type() const
{
if (_known)
return _result;
// The non const this pointer is used to cast away const.
_known = true;
const typename K::Line_2 &l1 = _seg->supporting_line();
Line_2_Line_2_pair<K> linepair(&l1, _line);
switch ( linepair.intersection_type()) {
case Line_2_Line_2_pair<K>::NO_INTERSECTION:
_result = NO_INTERSECTION;
break;
case Line_2_Line_2_pair<K>::POINT:
linepair.intersection(_intersection_point);
_result = (_seg->collinear_has_on(_intersection_point) )
? POINT : NO_INTERSECTION;
break;
case Line_2_Line_2_pair<K>::LINE:
_result = SEGMENT;
break;
}
return _result;
}
template <class K>
bool
Segment_2_Line_2_pair<K>::intersection(typename K::Point_2 &result) const
{
if (!_known)
intersection_type();
if (_result != POINT)
return false;
result = _intersection_point;
return true;
}
template <class K>
bool
Segment_2_Line_2_pair<K>::intersection(typename K::Segment_2 &result) const
{
if (!_known)
intersection_type();
if (_result != SEGMENT)
return false;
result = *_seg;
return true;
}
} // namespace CGALi
template <class K>
inline bool
do_intersect(const Segment_2<K> &seg, const Line_2<K> &line)
{
typedef typename K::Do_intersect_2 Do_intersect;
return Do_intersect()(seg, line);
}
template <class K>
inline bool
do_intersect(const Line_2<K> &line, const Segment_2<K> &seg)
{
typedef typename K::Do_intersect_2 Do_intersect;
return Do_intersect()(line, seg);
}
template <class K>
inline Object
intersection(const Line_2<K> &line, const Segment_2<K> &seg)
{
typedef typename K::Intersect_2 Intersect;
return Intersect()(seg, line);
}
template <class K>
inline Object
intersection(const Segment_2<K> &seg, const Line_2<K> &line)
{
typedef typename K::Intersect_2 Intersect;
return Intersect()(line, seg);
}
CGAL_END_NAMESPACE
#endif
|
