four-block-tree.cpp

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#include <ogdf/basic/GraphAttributes.h>
#include <ogdf/basic/GraphList.h>
#include <ogdf/basic/Graph.h>
#include <ogdf/basic/graph_generators/randomized.h>
#include <ogdf/basic/graphics.h>
#include <ogdf/decomposition/FourBlockTree.h>
#include <ogdf/fileformats/GraphIO.h>
#include <ogdf/planarlayout/PlanarStraightLayout.h>
#include <memory>
#include <string>
 
using namespace ogdf;
 
int main(void) {
    Graph g;
    constexpr int n = 16;
    randomPlanarConnectedGraph(g, n, 3 * n - 6);
    const adjEntry externalFace = g.firstNode()->firstAdj()->cyclicSucc();
 
    const auto fbt = FourBlockTree::construct(g, externalFace);
 
    PlanarStraightLayout layout;
    {
        GraphAttributes ga(g,
                ogdf::GraphAttributes::nodeLabel | ogdf::GraphAttributes::nodeGraphics
                        | ogdf::GraphAttributes::nodeStyle | ogdf::GraphAttributes::edgeGraphics
                        | ogdf::GraphAttributes::edgeStyle);
        ga.directed() = false;
        layout.callFixEmbed(ga, externalFace);
        for (const node v : g.nodes) {
            ga.label(v) = std::to_string(v->index());
            ga.fillColor(v) = Color::Name::White;
        }
        GraphIO::write(ga, "output-g.svg", GraphIO::drawSVG);
    }
    int i = 0;
    fbt->preorder([&](const FourBlockTree& treeNode) -> void {
        GraphAttributes ga(*treeNode.g,
                ogdf::GraphAttributes::nodeLabel | ogdf::GraphAttributes::nodeGraphics
                        | ogdf::GraphAttributes::nodeStyle | ogdf::GraphAttributes::edgeGraphics
                        | ogdf::GraphAttributes::edgeStyle);
        ga.directed() = false;
        layout.callFixEmbed(ga, treeNode.externalFace);
        for (const node v : treeNode.g->nodes) {
            ga.label(v) = std::to_string(treeNode.originalNodes[v]->index());
            ga.fillColor(v) = Color::Name::White;
        }
        GraphIO::write(ga, std::string("output-node-") + std::to_string(i++) + ".svg",
                GraphIO::drawSVG);
    });
    return 0;
}