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1 | <HTML> | |
2 | <!-- Copyright 2007 Aaron Windsor | |
3 | ||
4 | Distributed under the Boost Software License, Version 1.0. | |
5 | (See accompanying file LICENSE_1_0.txt or copy at | |
6 | http://www.boost.org/LICENSE_1_0.txt) | |
7 | ||
8 | --> | |
9 | <HEAD> | |
10 | <TITLE>Planar Face Visitor Concept</TITLE> | |
11 | </HEAD> | |
12 | <BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" | |
13 | ALINK="#ff0000"> | |
14 | <IMG SRC="../../../boost.png" | |
15 | ALT="C++ Boost" width="277" height="86"> | |
16 | ||
17 | <BR Clear> | |
18 | ||
19 | <H1>Planar Face Visitor Concept</H1> | |
20 | ||
21 | This concept defines the visitor interface for | |
22 | <a href="./planar_face_traversal.html"><tt>planar_face_traversal</tt></a>. | |
23 | Users can define a class with the Planar Face Visitor interface and pass an | |
24 | object of the class to <tt>planar_face_traversal</tt>, thereby augmenting the | |
25 | actions taken during the traversal. Note that objects passed to | |
26 | <tt>planar_face_traversal</tt> are passed by reference. | |
27 | ||
28 | <h3>Notation</h3> | |
29 | ||
30 | <table> | |
31 | <tbody><tr> | |
32 | <td><tt>V</tt></td> | |
33 | <td>A type that is a model of Planar Face Visitor.</td> | |
34 | </tr> | |
35 | ||
36 | <tr> | |
37 | <td><tt>vis</tt></td> | |
38 | <td>An object of type <tt>V</tt>.</td> | |
39 | </tr> | |
40 | ||
41 | <tr> | |
42 | <td><tt>G</tt></td> | |
43 | <td>A type that is a model of Graph.</td> | |
44 | </tr> | |
45 | ||
46 | <tr> | |
47 | <td><tt>e</tt></td> | |
48 | <td>An object of type <tt>boost::graph_traits<G>::edge_descriptor</tt>. | |
49 | </td> | |
50 | </tr> | |
51 | ||
52 | <tr> | |
53 | <td><tt>v</tt></td> | |
54 | <td>An object of type <tt>boost::graph_traits<G>::vertex_descriptor</tt>. | |
55 | </td> | |
56 | </tr> | |
57 | ||
58 | </tbody></table> | |
59 | ||
60 | ||
61 | <h3>Valid Expressions</h3> | |
62 | ||
63 | <table border="1"> | |
64 | <tbody><tr> | |
65 | <th>Name</th><th>Expression</th><th>Return Type</th><th>Description</th> | |
66 | </tr> | |
67 | ||
68 | <tr> | |
69 | <td>Begin Traversal</td> | |
70 | <td><tt>vis.begin_traversal()</tt></td> | |
71 | <td><tt>void</tt></td> | |
72 | <td> | |
73 | This is invoked once per traversal, before the traversal begins. | |
74 | </td> | |
75 | </tr> | |
76 | ||
77 | <tr> | |
78 | <td>Begin Face</td> | |
79 | <td><tt>vis.begin_face()</tt></td> | |
80 | <td><tt>void</tt></td> | |
81 | <td> | |
82 | This is invoked once for each face, before any vertices or edges on the face | |
83 | are visited. | |
84 | </td> | |
85 | </tr> | |
86 | ||
87 | <tr> | |
88 | <td>Next Vertex</td> | |
89 | <td><tt>vis.next_vertex(v)</tt></td> | |
90 | <td><tt>void</tt></td> | |
91 | <td> | |
92 | This is invoked when a vertex is encountered while traversing a face. | |
93 | </td> | |
94 | </tr> | |
95 | ||
96 | ||
97 | <tr> | |
98 | <td>Next Edge</td> | |
99 | <td><tt>vis.next_edge(e)</tt></td> | |
100 | <td><tt>void</tt></td> | |
101 | <td> | |
102 | This is invoked when an edge is encountered while traversing a face. | |
103 | </td> | |
104 | </tr> | |
105 | ||
106 | <tr> | |
107 | <td>End Face</td> | |
108 | <td><tt>vis.end_face()</tt></td> | |
109 | <td><tt>void</tt></td> | |
110 | <td> | |
111 | This is invoked once for each face, after all vertices and edges on the face | |
112 | are visited. | |
113 | </td> | |
114 | </tr> | |
115 | ||
116 | ||
117 | <tr> | |
118 | <td>End Traversal</td> | |
119 | <td><tt>vis.end_traversal()</tt></td> | |
120 | <td><tt>void</tt></td> | |
121 | <td> | |
122 | This is invoked once per traversal, after the traversal ends. | |
123 | </td> | |
124 | </tr> | |
125 | ||
126 | </tbody></table> | |
127 | ||
128 | <h3>Models</h3> | |
129 | ||
130 | <ul> | |
131 | <li> The file <a href="../../../boost/graph/planar_face_traversal.hpp"> | |
132 | <tt>planar_face_traversal.hpp</tt></a> contains a class | |
133 | <tt>planar_face_traversal_visitor</tt> that implements empty actions for | |
134 | all event points of a Planar Face Visitor. In the case where only a few of the | |
135 | event points of Planar Face Visitor need to be implemented, one can derive from | |
136 | <tt>planar_face_traversal_visitor</tt> and only implement the necessary event | |
137 | points. <li> The implementation of <a href="./make_maximal_planar.html"> | |
138 | <tt>make_maximal_planar</tt></a> uses a <tt>triangulation_visitor</tt> that is | |
139 | a model of Planar Face Visitor. | |
140 | </li> | |
141 | </ul> | |
142 | ||
143 | <br> | |
144 | <HR> | |
145 | Copyright © 2007 Aaron Windsor (<a href="mailto:aaron.windsor@gmail.com"> | |
146 | aaron.windsor@gmail.com</a>) | |
147 | </BODY> | |
148 | </HTML> |