Creating Data in Prefuse

Question

I am new to Prefuse. Demo examples are all downloaded data from a file / database. Is there a way to dynamically create data instead of loading from a file. For example, I want to create a tree data structure and visualize this. Any simple working example would be really helpful for me.

Answer 1

I just attacked this problem. Here's a modified version of Example.java that shows one way to do this.

Instead of loading data from socialnet.xml , I generate it programmatically (based on Aggregate.java , but without aggregation) and adding one field to each Node and each Edge . The Node field is a simple Boolean flag that controls the color that it displays; the Edge field is a label, but it is not yet displayed. I'm still working on it !:-)

The code for a specific question is in makeGraph() . The main approach is to create a Table (well, one for nodes and edges) and add columns to those tables that define the data form; then when you add your nodes and edges, you can add the corresponding data. One of them is that for edges you should include columns for end nodes / target nodes - for more information see the Graph and Table documentation. There are other ways to do this (for example, involving Schema ), but I have not discussed them yet.

Hope this helps.

 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 } }