在 Prefuse 中创建数据

Question

我是 Prefuse 的新手。演示示例都是从文件/数据库加载的数据。有没有办法动态创建数据而不是从文件加载。例如，我想创建一个树数据结构并将其可视化。任何简单的工作示例都会对我很有帮助。

Answer 1

我刚刚一直在解决这个问题。这是 Example.java 的调整版本，它展示了实现这一目标的一种方法。

我不是从 socialnet.xml 加载数据，而是以编程方式生成数据（基于 Aggregate.java 但没有聚合内容）并向每个 添加一个字段节点和每个边。 Node 字段是一个简单的布尔标志，用于控制其渲染的颜色； Edge 字段是一个标签 - 但它还没有被渲染。我还在研究那个！ :-)

特定于问题的代码位于 makeGraph() 中。基本方法是创建一个表（节点和边各一个），并向这些表中添加列来定义数据的形状；然后当您添加节点和边时，您可以添加相应的数据。一个问题是，对于边，您必须包含边的源/目标节点的列 - 有关更多详细信息，请参阅Graph 和Table 文档。还有其他方法可以做到这一点（例如涉及Schema），但我还没有弄清楚它们。

希望这有帮助。

import javax.swing.JFrame;

import prefuse.Constants;
import prefuse.Display;
import prefuse.Visualization;
import prefuse.action.ActionList;
import prefuse.action.RepaintAction;
import prefuse.action.assignment.ColorAction;
import prefuse.action.assignment.DataColorAction;
import prefuse.action.layout.graph.ForceDirectedLayout;
import prefuse.activity.Activity;
import prefuse.controls.DragControl;
import prefuse.controls.PanControl;
import prefuse.controls.ZoomControl;
import prefuse.data.Edge;
import prefuse.data.Graph;
import prefuse.data.Node;
import prefuse.data.Table;
import prefuse.render.DefaultRendererFactory;
import prefuse.render.EdgeRenderer;
import prefuse.render.Renderer;
import prefuse.render.ShapeRenderer;
import prefuse.util.ColorLib;
import prefuse.visual.VisualItem;

public class Example extends Display {

    private Graph makeGraph() {

        // Create tables for node and edge data, and configure their columns.
        Table nodeData = new Table();
        Table edgeData = new Table(0,1);
        nodeData.addColumn("flag", boolean.class);
        edgeData.addColumn(Graph.DEFAULT_SOURCE_KEY, int.class);
        edgeData.addColumn(Graph.DEFAULT_TARGET_KEY, int.class);
        edgeData.addColumn("label", String.class);
        // Need more data in your nodes or edges?  Just add more
        // columns.

        // Create Graph backed by those tables.  Note that I'm
        // creating a directed graph here also.
        Graph g = new Graph(nodeData, edgeData, true);

        // Create some nodes and edges, each carrying some data.
        // There are surely prettier ways to do this, but for the
        // example it gets the job done.
        for ( int i=0; i<3; ++i ) {
            Node n1 = g.addNode();
            Node n2 = g.addNode();
            Node n3 = g.addNode();
            n1.setBoolean("flag", false);
            n2.setBoolean("flag", true);
            n3.setBoolean("flag", true);
            Edge e1 = g.addEdge(n1, n2);
            Edge e2 = g.addEdge(n1, n3);
            Edge e3 = g.addEdge(n2, n3);
            e1.setString("label", "a");
            e2.setString("label", "a");
            e3.setString("label", "a");
        }
        Edge e4 = g.getEdge(g.addEdge(0, 3));
        Edge e5 = g.getEdge(g.addEdge(3, 6));
        Edge e6 = g.getEdge(g.addEdge(6, 0));
        e4.setString("label", "b");
        e5.setString("label", "b");
        e6.setString("label", "b");
        return g;
    }

    public Example() {

        super(new Visualization());

        Graph graph = makeGraph();

        m_vis.addGraph("graph", graph);
        m_vis.setInteractive("graph.edges", null, false);
        m_vis.setValue("graph.nodes", null, VisualItem.SHAPE,
                new Integer(Constants.SHAPE_ELLIPSE));

        Renderer nodeR = new ShapeRenderer(20);
        EdgeRenderer edgeR = new EdgeRenderer(prefuse.Constants.EDGE_TYPE_CURVE, prefuse.Constants.EDGE_ARROW_FORWARD);

        DefaultRendererFactory drf = new DefaultRendererFactory();
        drf.setDefaultRenderer(nodeR);
        drf.setDefaultEdgeRenderer(edgeR);
        m_vis.setRendererFactory(drf);

        int[] palette = new int[] {
            ColorLib.rgb(255,180,180), ColorLib.rgb(190,190,255)
        };
        ColorAction nStroke = new ColorAction("graph.nodes", VisualItem.STROKECOLOR);
        nStroke.setDefaultColor(ColorLib.gray(100));

        DataColorAction nFill = new DataColorAction("graph.nodes", "flag",
            Constants.NOMINAL, VisualItem.FILLCOLOR, palette);
        ColorAction edges = new ColorAction("graph.edges",
            VisualItem.STROKECOLOR, ColorLib.gray(200));
        ColorAction arrow = new ColorAction("graph.edges",
            VisualItem.FILLCOLOR, ColorLib.gray(200));
        ActionList color = new ActionList();
        color.add(nStroke);
        color.add(nFill);
        color.add(edges);
        color.add(arrow);

        ActionList layout = new ActionList(Activity.INFINITY);
        layout.add(new ForceDirectedLayout("graph"));
        layout.add(new RepaintAction());

        m_vis.putAction("color", color);
        m_vis.putAction("layout", layout);

        setSize(720, 500); // set display size
        pan(360, 250);
        setHighQuality(true);
        addControlListener(new DragControl());
        addControlListener(new PanControl());
        addControlListener(new ZoomControl());

        m_vis.run("color");
        m_vis.run("layout");

    }

    public static void main(String[] argv) {
        Example ex = new Example();
        JFrame frame = new JFrame("prefuse example");
        frame.getContentPane().add(ex);
        frame.pack();           // layout components in window
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true); // show the window
    }

}