JUNG 实现图Graph可视化

本文介绍利用Java的第三方API JUNG 实现图的可视化

通过对示例代码分析，解析可视化方法。

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JUNG 下载地址

https://sourceforge.net/projects/jung/files/

JUNG api参考文档：

http://jung.sourceforge.net/doc/api/overview-summary.html

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预处理

JUNG 中的图可视化方法基于JUNG内置图类，本文基于自定义图呈现可视化图，故需要先将自定义图转存为JUNG图对象。

JUNG 提供 泛型接口，进行转化或创建时利用自定义边类型与节点类型即可。

以以下代码为例：

/**
     * 将graph.Graph 转为 JUNG.graph.Graph 过滤掉超边.
     * 
     * @param g - 基于 graph.Graph
     * @return edu.uci.ics.jung.graph.Graph
     */
    public static edu.uci.ics.jung.graph.Graph<Vertex, Edge> graphTransform(Graph<Vertex, Edge> g) {
        edu.uci.ics.jung.graph.Graph<Vertex, Edge> graph = new SparseGraph<>(); // 稀疏图
        for (Vertex vertex : g.vertices()) {
            graph.addVertex(vertex);
        }
        for (Edge edge : g.edges()) {
            if (edge.sourceVertices().size() == 0) {
                // 超边
                continue;
            }
            if (edge.sourceVertices().size() == 1) {
                // 有向边
                graph.addEdge(edge, getVertex(edge.sourceVertices()),
                        getVertex(edge.targetVertices()), EdgeType.DIRECTED);
            } else {
                // 无向边
                Vertex existV = getVertex(edge.vertices());
                graph.addEdge(edge, existV, getVertexExcept(edge.vertices(), existV),
                        EdgeType.UNDIRECTED);
            }
        }

        return graph;
    }

如此，获得一个jung 图对象。

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类成员属性：

public class GraphVisualizationHelper {
    SparseGraph<Vertex, Edge> graph; // 稀疏图对象
    BasicVisualizationServer<Vertex, Edge> vv; // 简单可视化类
    Transformer<Vertex, Paint> vertexPaint;
    Transformer<Edge, Stroke> edgeStrokeTransformer;
    Transformer<Vertex, Shape> vertexShape;
    JFrame frame; // JFrame 框架展现图
……

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构造方法

通过调用具体方法，工厂化构件图。

    /**
     * constructor to create the graph.
     * @param originGraph - user-defined graph.
     */
    public GraphVisualizationHelper(graph.Graph<Vertex, Edge> originGraph) {
        createWindow(); // 初始化窗口
        createGraph(originGraph); // 图转换:自定义图对象 - jung图对象
        createTransformers(); // 设置图变换器
        showGraph(); // 设置图参数 ，呈现图信息
    }

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1.createWindow() 方法 初始化窗口

    private void createWindow() {
        frame = new JFrame("Simple Graph View");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

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2.createGraph(originGraph) 方法 转化图：自定义图对象 - jung图对象

    private void createGraph(graph.Graph<Vertex, Edge> originGraph) {
        // Graph<V, E> where V is the type of the vertices and E is the type of
        // the edges
        graph = (SparseGraph<Vertex, Edge>) helper.Transformer.graphTransform(originGraph);
    }

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3.createTransformers() 方法 设置图变换器

具体信息见代码注释：

    private void createTransformers() {
        // Setup up a new vertex to paint transformer...
        // Transformer <V,Paint>
        vertexPaint = new Transformer<Vertex, Paint>() {
            @Override
            public Paint transform(Vertex s) {
                if (s.getLabel().equals("John")) {
                    return Color.GREEN;
                } else {
                    return Color.YELLOW;
                }
            }
        };

        // 设置顶点形状的显示尺寸为：字符数*8+16
        Transformer<Vertex, Integer> vst = new Transformer<Vertex, Integer>() {
            @Override
            public Integer transform(Vertex i) {
                int len = i.toString().length();
                if (len < 10) {
                    len = 10;
                }
                return new Integer(len * 10);
            }
        };
        // 高宽比变换器
        Transformer<Vertex, Float> vart = i -> {
            int len = i.toString().length();
            if (len < 5) {
                len = 5;
            }
            return new Float(10 / len);
        };
        // 构造顶点形状工厂
        final VertexShapeFactory<Vertex> vsf = new VertexShapeFactory<Vertex>(vst, vart);
        // 设置顶点形状变换器
        vertexShape = new Transformer<Vertex, Shape>() {
            @Override
            public Shape transform(Vertex s) {
                return vsf.getEllipse(s);
            }
        };

        // Set up a new stroke Transformer for the edges
        float[] dash = {10.0f};
        // (width of line, , )
        final Stroke edgeStroke = new BasicStroke(2.0f, BasicStroke.CAP_BUTT,
                BasicStroke.JOIN_MITER, 10.0f, dash, 0.0f);
        // Transformer <E,Stroke>
        edgeStrokeTransformer = new Transformer<Edge, Stroke>() {
            @Override
            public Stroke transform(Edge s) {
                return edgeStroke;
            }
        };

    }

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4.showGraph() 方法 设置图参数，呈现图信息

具体信息见代码注释：

    private void showGraph() {

        // The Layout<V, E> is parameterized by the vertex and edge types
        Layout<Vertex, Edge> layout = new CircleLayout<>(graph);
        layout.setSize(new Dimension(1440, 1440)); // sets the initial size of the
        // space
        // The BasicVisualizationServer<V,E> is parameterized by the edge types
        vv = new BasicVisualizationServer<Vertex, Edge>(layout);
        // ( width , height)
        vv.setPreferredSize(new Dimension(1920, 1920)); // Sets the viewing area
        // size

        // 修改顶点字体大小
        vv.getRenderContext().setVertexFontTransformer(new Transformer<Vertex, Font>() {
            @Override
            public Font transform(Vertex i) {
                return new Font("宋体", Font.PLAIN, 32);
            }
        });

        // 修改边字体大小
        vv.getRenderContext().setEdgeFontTransformer(new Transformer<Edge, Font>() {
            @Override
            public Font transform(Edge i) {
                return new Font("宋体", Font.PLAIN, 24);
            }
        });

        // apply transformers
        vv.getRenderContext().setVertexShapeTransformer(vertexShape);
        vv.getRenderContext().setVertexFillPaintTransformer(vertexPaint);
        vv.getRenderContext().setEdgeStrokeTransformer(edgeStrokeTransformer);
        vv.getRenderContext().setVertexLabelTransformer(new ToStringLabeller<Vertex>());
        vv.getRenderContext().setEdgeLabelTransformer(new ToStringLabeller<Edge>());
        vv.getRenderer().getVertexLabelRenderer().setPosition(Position.CNTR);

        frame.getContentPane().add(vv);
        frame.pack();
        frame.setVisible(true);
    }