#### /Src/Dependencies/Boost/boost/graph/circle_layout.hpp

C++ Header | 58 lines | 34 code | 8 blank | 16 comment | 0 complexity | 2d05a0b737a72f8d2ff0c494e396c2e2 MD5 | raw file
``` 1// Copyright 2004 The Trustees of Indiana University.
2
4// (See accompanying file LICENSE_1_0.txt or copy at
6
7//  Authors: Douglas Gregor
8//           Andrew Lumsdaine
9#ifndef BOOST_GRAPH_CIRCLE_LAYOUT_HPP
10#define BOOST_GRAPH_CIRCLE_LAYOUT_HPP
11#include <boost/config/no_tr1/cmath.hpp>
12#include <boost/math/constants/constants.hpp>
13#include <utility>
14#include <boost/graph/graph_traits.hpp>
15#include <boost/graph/iteration_macros.hpp>
16#include <boost/graph/topology.hpp>
17#include <boost/static_assert.hpp>
18
19namespace boost {
20  /**
21   * \brief Layout the graph with the vertices at the points of a regular
22   * n-polygon.
23   *
24   * The distance from the center of the polygon to each point is
25   * determined by the @p radius parameter. The @p position parameter
26   * must be an Lvalue Property Map whose value type is a class type
27   * containing @c x and @c y members that will be set to the @c x and
28   * @c y coordinates.
29   */
30  template<typename VertexListGraph, typename PositionMap, typename Radius>
31  void
32  circle_graph_layout(const VertexListGraph& g, PositionMap position,
34  {
35    BOOST_STATIC_ASSERT (property_traits<PositionMap>::value_type::dimensions >= 2);
36    const double pi = boost::math::constants::pi<double>();
37
38#ifndef BOOST_NO_STDC_NAMESPACE
39    using std::sin;
40    using std::cos;
41#endif // BOOST_NO_STDC_NAMESPACE
42
43    typedef typename graph_traits<VertexListGraph>::vertices_size_type
44      vertices_size_type;
45
46    vertices_size_type n = num_vertices(g);
47
48    vertices_size_type i = 0;
49    double two_pi_over_n = 2. * pi / n;
50    BGL_FORALL_VERTICES_T(v, g, VertexListGraph) {
51      position[v][0] = radius * cos(i * two_pi_over_n);
52      position[v][1] = radius * sin(i * two_pi_over_n);
53      ++i;
54    }
55  }
56} // end namespace boost
57
58#endif // BOOST_GRAPH_CIRCLE_LAYOUT_HPP
```