How to manually set the zoom on a Jung visualisation?

Question

I have a jung tree displayed in a JPanel. The constructor of my tree looks like this:

  Forest<String, Integer> graph = new DelegateForest<String, Integer>();
  static GraphZoomScrollPane panel = null;
  static DefaultModalGraphMouse graphMouse = null;
  static JComboBox modeBox = null;
  static ScalingControl scaler;

  public PanelTree(List<Cluster> clist) {
    setBounds(215, 10, 550, 550);
    updateData(clist); // adds vertex and edges to graph

    treeLayout = new TreeLayout<String, Integer>(graph);
    vv = new VisualizationViewer<String, Integer>(treeLayout, new Dimension(500, 500));
    vv.setBackground(Color.white);
    vv.getRenderContext().setEdgeShapeTransformer(new EdgeShape.Line());
    vv.getRenderContext().setVertexLabelTransformer(new ToStringLabeller());
    // add a listener for ToolTips
    vv.setVertexToolTipTransformer(new ToStringLabeller());
    vv.getRenderContext()
            .setArrowFillPaintTransformer(new ConstantTransformer(Color.lightGray));

    panel = new GraphZoomScrollPane(vv);
    add(panel);

    graphMouse = new DefaultModalGraphMouse();

    vv.setGraphMouse(graphMouse);

    modeBox = graphMouse.getModeComboBox();
    modeBox.addItemListener(graphMouse.getModeListener());
    graphMouse.setMode(ModalGraphMouse.Mode.TRANSFORMING);

    scaler = new CrossoverScalingControl();
}

But the tree is quite large. So I want to know is there is a way to either automatically zoom out so the tree fits in the windows, and otherwise just set a default zoom that is less than the default one. How can I do that ?

score 2 · Answer 1 · answered Aug 29 '13 at 22:59

ScalingControl is not good method if you use Mouse Transformer.

Try to:

// for zoom:
vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.LAYOUT).setScale(scale_x1, scale_y1, vv.getCenter());
// for out:
vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.VIEW).setScale(scale_x2, scale_y2, vv.getCenter());

score 2 · Answer 2 · answered Mar 23 '12 at 14:18

ScalingControl scaler = new CrossoverScalingControl();

public void zoomIn() {
    setZoom(1);
}

public void zoomOut() {
    setZoom(-1);
}

private void setZoom(int amount) {
    scaler.scale(vv, amount > 0 ? 1.1f : 1 / 1.1f, vv.getCenter());
}

To fits the graph on the window, you can calculate the diference between the graph size and the panel size, and call the setZoom() method passing the factor of diference.

How to manually set the zoom on a Jung visualisation?

2 Answers2

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