source: NonGTP/Boost/boost/graph/circle_layout.hpp @ 857

Revision 857, 1.8 KB checked in by igarcia, 19 years ago (diff)
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[857]1// Copyright 2004 The Trustees of Indiana University.
2
3// Use, modification and distribution is subject to the Boost Software
4// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
5// http://www.boost.org/LICENSE_1_0.txt)
6
7//  Authors: Douglas Gregor
8//           Andrew Lumsdaine
9#ifndef BOOST_GRAPH_CIRCLE_LAYOUT_HPP
10#define BOOST_GRAPH_CIRCLE_LAYOUT_HPP
11#include <cmath>
12#include <utility>
13#include <boost/graph/graph_traits.hpp>
14
15namespace boost {
16  /**
17   * \brief Layout the graph with the vertices at the points of a regular
18   * n-polygon.
19   *
20   * The distance from the center of the polygon to each point is
21   * determined by the @p radius parameter. The @p position parameter
22   * must be an Lvalue Property Map whose value type is a class type
23   * containing @c x and @c y members that will be set to the @c x and
24   * @c y coordinates.
25   */
26  template<typename VertexListGraph, typename PositionMap, typename Radius>
27  void
28  circle_graph_layout(const VertexListGraph& g, PositionMap position,
29                      Radius radius)
30  {
31    const double pi = 3.14159;
32
33#ifndef BOOST_NO_STDC_NAMESPACE
34    using std::sin;
35    using std::cos;
36#endif // BOOST_NO_STDC_NAMESPACE
37
38    typedef typename graph_traits<VertexListGraph>::vertices_size_type
39      vertices_size_type;
40
41    vertices_size_type n = num_vertices(g);
42   
43    typedef typename graph_traits<VertexListGraph>::vertex_iterator
44      vertex_iterator;
45
46    vertices_size_type i = 0;
47    for(std::pair<vertex_iterator, vertex_iterator> v = vertices(g);
48        v.first != v.second; ++v.first, ++i) {
49      position[*v.first].x = radius * cos(i * 2 * pi / n);
50      position[*v.first].y = radius * sin(i * 2 * pi / n);
51    }
52  }
53} // end namespace boost
54
55#endif // BOOST_GRAPH_CIRCLE_LAYOUT_HPP
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