libs/graph/example/planar_face_traversal.cpp
//=======================================================================
// Copyright 2007 Aaron Windsor
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
#include <iostream>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/properties.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/ref.hpp>
#include <vector>
#include <boost/graph/planar_face_traversal.hpp>
#include <boost/graph/boyer_myrvold_planar_test.hpp>
using namespace boost;
// Some planar face traversal visitors that will
// print the vertices and edges on the faces
struct output_visitor : public planar_face_traversal_visitor
{
void begin_face() { std::cout << "New face: "; }
void end_face() { std::cout << std::endl; }
};
struct vertex_output_visitor : public output_visitor
{
template <typename Vertex>
void next_vertex(Vertex v)
{
std::cout << v << " ";
}
};
struct edge_output_visitor : public output_visitor
{
template <typename Edge>
void next_edge(Edge e)
{
std::cout << e << " ";
}
};
int main(int argc, char** argv)
{
typedef adjacency_list
< vecS,
vecS,
undirectedS,
property<vertex_index_t, int>,
property<edge_index_t, int>
>
graph;
// Create a graph - this is a biconnected, 3 x 3 grid.
// It should have four small (four vertex/four edge) faces and
// one large face that contains all but the interior vertex
graph g(9);
add_edge(0,1,g);
add_edge(1,2,g);
add_edge(3,4,g);
add_edge(4,5,g);
add_edge(6,7,g);
add_edge(7,8,g);
add_edge(0,3,g);
add_edge(3,6,g);
add_edge(1,4,g);
add_edge(4,7,g);
add_edge(2,5,g);
add_edge(5,8,g);
// Initialize the interior edge index
property_map<graph, edge_index_t>::type e_index = get(edge_index, g);
graph_traits<graph>::edges_size_type edge_count = 0;
graph_traits<graph>::edge_iterator ei, ei_end;
for(tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
put(e_index, *ei, edge_count++);
// Test for planarity - we know it is planar, we just want to
// compute the planar embedding as a side-effect
typedef std::vector< graph_traits<graph>::edge_descriptor > vec_t;
std::vector<vec_t> embedding(num_vertices(g));
if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
boyer_myrvold_params::embedding =
&embedding[0]
)
)
std::cout << "Input graph is planar" << std::endl;
else
std::cout << "Input graph is not planar" << std::endl;
std::cout << std::endl << "Vertices on the faces: " << std::endl;
vertex_output_visitor v_vis;
planar_face_traversal(g, &embedding[0], v_vis);
std::cout << std::endl << "Edges on the faces: " << std::endl;
edge_output_visitor e_vis;
planar_face_traversal(g, &embedding[0], e_vis);
return 0;
}