JFreeChart connect one point to all other around

Question

is it possible to connect one point to all others around in JFreeChart
here how it should looks

Answer 1

You'll need a custom renderer. This minimal example overrides the XYLineAndShapeRenderer method drawPrimaryLine(). It draws the lines relative to the item having anchor as its series index. You'll need to recapitulate the existing implementation, replacing the lines shown below.

Addendum: The example simply passes anchor as a constructor parameter, but you can extend XYDataset to include a unique value for each series.

MyRenderer r = new MyRenderer(8);
XYPlot plot = new XYPlot(dataset, new NumberAxis("X"), new NumberAxis("Y"), r);
JFreeChart chart = new JFreeChart(plot);
…
private static class MyRenderer extends XYLineAndShapeRenderer {

    private final int anchor;

    public MyRenderer(int acnchor) {
        this.anchor = acnchor;
    }

    @Override
    protected void drawPrimaryLine(XYItemRendererState state, Graphics2D g2,
        XYPlot plot, XYDataset dataset, int pass, int series, int item,
        ValueAxis domainAxis, ValueAxis rangeAxis, Rectangle2D dataArea) {
        if (item == anchor) {
            return;
        }
        …
        double x0 = dataset.getXValue(series, anchor);
        double y0 = dataset.getYValue(series, anchor);
        …
    }
}