手动为 boost 的图表着色

我正在努力尝试使用 boost 手动为图的顶点着色。我写了下面的代码，但我不明白为什么生成的文件没有任何颜色。

int main(int,char*[]) {
    typedef property<edge_name_t, string> EdgeProperties;
    typedef property<vertex_name_t, string, property<vertex_color_t, default_color_type>> VertexProperties;
    typedef adjacency_list<vecS, vecS, directedS, VertexProperties, EdgeProperties> Graph;
    typedef graph_traits<Graph>::vertex_descriptor Vertex;
    typedef graph_traits<Graph>::edge_descriptor Edge;

    Graph g;
    property_map<Graph, vertex_name_t>::type vertex_label = get(vertex_name, g);
    property_map<Graph, vertex_color_t>::type color_map = get(vertex_color, g);
    property_map<Graph, edge_name_t>::type edge_label = get(edge_name, g);

    Vertex v1 = add_vertex(g);
    vertex_label[v1] = "v1";

    put(color_map, v1, boost::red_color);

    std::ofstream outf("example.gv");
    write_graphviz(outf, g,
                   make_label_writer(vertex_label),
                   make_label_writer(edge_label)
                   );
    return 0;
}

顶点着色实际上是一个算法细节。据我所知，没有“自动”规定可以将其转换为 graphviz。

不过，您可以添加自定义属性。

我通常会更改它以使用动态属性：

std::ofstream outf("example.gv");

dynamic_properties dp;
dp.property("node_id", get(vertex_index, g));
dp.property("label", vertex_label);
dp.property("label", edge_label);

write_graphviz_dp(outf, g, dp);

现在就像向动态集中添加新的顶点属性一样简单：

dp.property("color", make_transform_value_property_map(&color_to_string, color_map));

唯一的复杂之处是您需要提供以下转换：default_color_type到文本。这是彩色图通常不用于表示目的这一事实的另一个症状。这是一个完整的工作示例：

Live On Coliru

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphviz.hpp>
#include <iostream>
using namespace boost;

inline char const* color_to_string(default_color_type c) {
    switch(c) {
        case default_color_type::red_color:   return "red";
        case default_color_type::green_color: return "green";
        case default_color_type::gray_color:  return "gray";
        case default_color_type::white_color: return "white";
        case default_color_type::black_color: return "black";
    }
    return ""; // not known
}


int main() {
    typedef property<edge_name_t, std::string> EdgeProperties;
    typedef property<vertex_name_t, std::string, property<vertex_color_t, default_color_type>> VertexProperties;
    typedef adjacency_list<vecS, vecS, directedS, VertexProperties, EdgeProperties> Graph;
    typedef graph_traits<Graph>::vertex_descriptor Vertex;

    Graph g;
    property_map<Graph, vertex_name_t>::type vertex_label = get(vertex_name, g);
    property_map<Graph, vertex_color_t>::type color_map = get(vertex_color, g);
    property_map<Graph, edge_name_t>::type edge_label = get(edge_name, g);

    Vertex v1 = add_vertex(g);
    vertex_label[v1] = "v1";

    put(color_map, v1, boost::red_color);

    dynamic_properties dp;
    dp.property("node_id", get(vertex_index, g));
    dp.property("label", vertex_label);
    dp.property("label", edge_label);
    dp.property("color", make_transform_value_property_map(&color_to_string, color_map));

    write_graphviz_dp(std::cout, g, dp);
}

Prints:

digraph G {
0 [color=red, label=v1];
}