How to get a vertex coordinate in JUNG?

问题

Is there a way to get the vertex coordinate when using the EditingModalGraphMouse in Jung ?? I've made a class for the vertex with the coordinate setter and getter but i don't kown how to set the vertex with its specific coordinate ? (i've user a transformer : Transformer)

回答1:

The following gives you an idea on how to obtain the Cartesian coordinates on a Jung VisualizationViewer instance...

Create an inner class as follows:

protected class MyGraphMousePlugin extends TranslatingGraphMousePlugin implements MouseListener {

    @Override
    public void mouseMoved(MouseEvent e) {
        final VisualizationViewer<GeoLocationData.Station,GeoLocationData.Link> vv =
        (VisualizationViewer<GeoLocationData.Station,GeoLocationData.Link>)e.getSource();
        Point2D p = e.getPoint();//vv.getRenderContext().getBasicTransformer().inverseViewTransform(e.getPoint());
        GraphElementAccessor<GeoLocationData.Station,GeoLocationData.Link> pickSupport = vv.getPickSupport();
        if(pickSupport != null) {               
            vv.setToolTipText ("<html>x: "+p.getX()+"<br>y: "+p.getY());
        }
    }

    public MyGraphMousePlugin(int modifiers) {
        super(modifiers);
        // TODO Auto-generated constructor stub
    }

    public MyGraphMousePlugin() {
        super();
    }
}

Add the plugin to your GraphMouse instance:

graphMouse = new DefaultModalGraphMouse<Object, Object>();
vv.setGraphMouse(graphMouse);
vv.addKeyListener(graphMouse.getModeKeyListener());
graphMouse.add(new MyGraphMousePlugin());

Edited:

Next modification will give you the Cartesian coordinates that take into account the translation made upon a Jung graph layout:

protected class MyGraphMousePlugin extends TranslatingGraphMousePlugin implements MouseListener {

    @Override
    public void mouseMoved(final MouseEvent e) {

        SwingUtilities.invokeLater(
                new Runnable() {
                    public void run() {
                        final VisualizationViewer<GeoLocationData.Station,GeoLocationData.Link> vv =
                            (VisualizationViewer<GeoLocationData.Station,GeoLocationData.Link>)e.getSource();
                        Point2D p = e.getPoint();//vv.getRenderContext().getBasicTransformer().inverseViewTransform(e.getPoint());
                        GraphElementAccessor<GeoLocationData.Station,GeoLocationData.Link> pickSupport = vv.getPickSupport();
                        if(pickSupport != null) {

                            AffineTransform lat =
                                vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.LAYOUT).getTransform();
                            //AffineTransform vat =
                            //  vv.getRenderContext().getMultiLayerTransformer().getTransformer(Layer.VIEW).getTransform();
                            //AffineTransform at = new AffineTransform();

                            double x = p.getX() - lat.getTranslateX(); //;
                            double y = p.getY() - lat.getTranslateY(); //;

                            vv.setToolTipText ("<html>x: "+x+"<br>y: "+y);
                        }

                    }
                }
        );
    }

    public MyGraphMousePlugin(int modifiers) {
        super(modifiers);
        // TODO Auto-generated constructor stub
    }

    public MyGraphMousePlugin() {
        super();
    }
}

It is still not perfect since it omits the scale factor, but you will get the idea...

You need to calculate from the screen coordinate system to the view coordinate system to the model coordinate system to get the model's coordinates.

The generic types in the above codes should be changed to your own version :)

Edited

Haha, the clue is already there and it is the correct way...no need to calculate! http://sourceforge.net/projects/jung/forums/forum/252062/topic/3040266?message=6522779

    @Override
    public void mouseMoved(final MouseEvent e) {

        SwingUtilities.invokeLater(
                new Runnable() {
                    public void run() {
                        final VisualizationViewer<GeoLocationData.Station,GeoLocationData.Link> vv =
                            (VisualizationViewer<GeoLocationData.Station,GeoLocationData.Link>)e.getSource();
                        Point2D p = vv.getRenderContext().getMultiLayerTransformer().inverseTransform(e.getPoint());

                        double x = p.getX();
                        double y = p.getY();

                        vv.setToolTipText ("<html>x: "+(int)x+"<br>y: "+(int)y);
                    }
                }
        );
    }

来源：https://stackoverflow.com/questions/5663897/how-to-get-a-vertex-coordinate-in-jung

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