144 lines
4.5 KiB
C++
144 lines
4.5 KiB
C++
//=======================================================================
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// Copyright 2007 Aaron Windsor
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//=======================================================================
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#include <iostream>
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#include <boost/graph/adjacency_list.hpp>
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#include <boost/graph/properties.hpp>
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#include <boost/graph/graph_traits.hpp>
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#include <boost/property_map/property_map.hpp>
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#include <boost/ref.hpp>
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#include <vector>
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#include <boost/graph/make_biconnected_planar.hpp>
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#include <boost/graph/make_maximal_planar.hpp>
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#include <boost/graph/planar_face_traversal.hpp>
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#include <boost/graph/boyer_myrvold_planar_test.hpp>
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// This example shows how to start with a connected planar graph
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// and add edges to make the graph maximal planar (triangulated.)
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// Any maximal planar simple graph on n vertices has 3n - 6 edges and
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// 2n - 4 faces, a consequence of Euler's formula.
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using namespace boost;
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// This visitor is passed to planar_face_traversal to count the
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// number of faces.
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struct face_counter : public planar_face_traversal_visitor
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{
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face_counter() : count(0) {}
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void begin_face() { ++count; }
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int count;
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};
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int main(int argc, char** argv)
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{
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typedef adjacency_list
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< vecS,
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vecS,
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undirectedS,
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property<vertex_index_t, int>,
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property<edge_index_t, int>
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>
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graph;
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// Create the graph - a straight line
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graph g(10);
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add_edge(0,1,g);
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add_edge(1,2,g);
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add_edge(2,3,g);
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add_edge(3,4,g);
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add_edge(4,5,g);
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add_edge(5,6,g);
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add_edge(6,7,g);
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add_edge(7,8,g);
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add_edge(8,9,g);
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std::cout << "Since the input graph is planar with " << num_vertices(g)
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<< " vertices," << std::endl
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<< "The output graph should be planar with "
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<< 3*num_vertices(g) - 6 << " edges and "
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<< 2*num_vertices(g) - 4 << " faces." << std::endl;
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//Initialize the interior edge index
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property_map<graph, edge_index_t>::type e_index = get(edge_index, g);
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graph_traits<graph>::edges_size_type edge_count = 0;
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graph_traits<graph>::edge_iterator ei, ei_end;
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for(boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
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put(e_index, *ei, edge_count++);
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//Test for planarity; compute the planar embedding as a side-effect
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typedef std::vector< graph_traits<graph>::edge_descriptor > vec_t;
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std::vector<vec_t> embedding(num_vertices(g));
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if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
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boyer_myrvold_params::embedding =
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&embedding[0]
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)
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)
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std::cout << "Input graph is planar" << std::endl;
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else
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std::cout << "Input graph is not planar" << std::endl;
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make_biconnected_planar(g, &embedding[0]);
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// Re-initialize the edge index, since we just added a few edges
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edge_count = 0;
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for(boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
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put(e_index, *ei, edge_count++);
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//Test for planarity again; compute the planar embedding as a side-effect
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if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
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boyer_myrvold_params::embedding =
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&embedding[0]
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)
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)
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std::cout << "After calling make_biconnected, the graph is still planar"
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<< std::endl;
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else
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std::cout << "After calling make_biconnected, the graph is not planar"
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<< std::endl;
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make_maximal_planar(g, &embedding[0]);
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// Re-initialize the edge index, since we just added a few edges
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edge_count = 0;
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for(boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
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put(e_index, *ei, edge_count++);
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// Test for planarity one final time; compute the planar embedding as a
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// side-effect
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std::cout << "After calling make_maximal_planar, the final graph ";
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if (boyer_myrvold_planarity_test(boyer_myrvold_params::graph = g,
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boyer_myrvold_params::embedding =
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&embedding[0]
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)
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)
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std::cout << "is planar." << std::endl;
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else
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std::cout << "is not planar." << std::endl;
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std::cout << "The final graph has " << num_edges(g)
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<< " edges." << std::endl;
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face_counter count_visitor;
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planar_face_traversal(g, &embedding[0], count_visitor);
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std::cout << "The final graph has " << count_visitor.count << " faces."
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<< std::endl;
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return 0;
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}
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