JFreechart Polar Chart shape annotation

Question

I am trying to color different region of a polar chart with different colors. e.g coloring the region between the angle 20 and 60 and between the radii 2 and 4. How can I do this? I was thinking of using a shape annotation and from there drawing an arc, but it seems there is no shape annotation for polar plots. Any ideas? Thank you

import java.awt.Color;
import java.awt.Dimension;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.axis.NumberTick;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.plot.PolarPlot;
import org.jfree.chart.renderer.DefaultPolarItemRenderer;
import org.jfree.chart.renderer.PolarItemRenderer;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.TextAnchor;

public class test2 extends JFrame {

    private static final String title = "Archimedes' Spiral";

    public test2(String title) {
        super(title);
        JFreeChart chart = createChart(createDataset());
        ChartPanel panel = new ChartPanel(chart);
        panel.setPreferredSize(new Dimension(500, 500));
        panel.setMouseZoomable(false);
        this.add(panel);
    }

    private static XYDataset createDataset() {
        XYSeriesCollection result = new XYSeriesCollection();
        XYSeries series = new XYSeries(title);
        XYSeries ser = new XYSeries("test");
        for (int t = 0; t <= 1 * 360; t++) {
            series.add(90 - t, t);
        }

        for (int t = 0; t <= 1 * 120; t++) {
            ser.add(90 - t, 40);
            ser.add(90 - t, 120);
        }
        result.addSeries(series);
        result.addSeries(ser);
        return result;
    }

    private static JFreeChart createChart(XYDataset dataset) {
        ValueAxis radiusAxis = new NumberAxis();
        radiusAxis.setTickLabelsVisible(false);
        PolarItemRenderer renderer = new DefaultPolarItemRenderer();
        PolarPlot plot = new PolarPlot(dataset, radiusAxis, renderer) {

            @Override
            protected List refreshAngleTicks() {
                List<NumberTick> ticks = new ArrayList<NumberTick>();
                int delta = (int) this.getAngleTickUnit().getSize();
                for (int t = 0; t < 360; t += delta) {
                    int tp = (360 + 90 - t) % 360;
                    NumberTick tick = new NumberTick(
                        Double.valueOf(t), String.valueOf(tp),
                        TextAnchor.CENTER, TextAnchor.CENTER, 0.0);
                    ticks.add(tick);
                }
                return ticks;
            }
        };
        plot.setBackgroundPaint(new Color(0x00f0f0f0));
        plot.setRadiusGridlinePaint(Color.gray);
        plot.addCornerTextItem("r(θ) = θ; 0 < θ < 6π");
        DefaultPolarItemRenderer ren = new DefaultPolarItemRenderer();
        ren.setSeriesFilled(0, true);
        ren.setSeriesFilled(1, true);
        plot.setRenderer(ren);
        JFreeChart chart = new JFreeChart(
            title, JFreeChart.DEFAULT_TITLE_FONT, plot, true);
        chart.setBackgroundPaint(Color.white);
        return chart;
    }

    public static void main(String[] args) {
        test2 demo = new test2(title);
        demo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        demo.pack();
        demo.setLocationRelativeTo(null);
        demo.setVisible(true);
    }
}

score 1 · Accepted Answer · edited May 23 '17 at 12:30

1

The DefaultPolarItemRenderer typically used in a PolarPlot has the method setSeriesFilled(), which controls whether a series is filled. The renderer specifies the AlphaComposite.SRC_OVER mode with a value of 50%, so overlapping fills look especially nice.

Addendum: To create the chart seen below, start with this example and reduce the data set's domain from 6π to 2π in createDataset():

for (int t = 0; t <= 1 * 360; t++) { ...

Then make the series filled in createChart():

...
DefaultPolarItemRenderer renderer = new DefaultPolarItemRenderer();
renderer.setSeriesFilled(0, true);
...

enter image description here

edited May 23 '17 at 12:30

Community

1
1

answered Jun 30 '11 at 21:50

trashgod

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Thank you. Do you please have an example? – jpo Jun 30 '11 at 23:04
Oops, I forgot to change the upper limit in the corner text item. – trashgod Jul 01 '11 at 03:42
Thanks again. SO, if I getting right, you suggest creating XYseries and defining the shape of the series with the intervals over which I want to apply the colors. If this is so, is there no other way of doing this without creating series? – jpo Jul 01 '11 at 22:11
Thank you again. One last thing(hopefully): I am trying to set the series colors. I used setSeriesFilled(0, true) and setSeriesPaint(0, Color.black); But this does not work as nice when more than one series is involved. The first series has transparent color(which is great), but subsequent series have stripes over them. Would you please tell me how to set series with a transparent fill color? – jpo Jul 02 '11 at 22:50
`Color.black` has an alpha of 100%. Let `JFreeChart` choose the series paint, or specify a suitable value when constructing the desired `Color`. – trashgod Jul 03 '11 at 01:24
Sorry, for bring this up again, but my series fill is not as nice as yours. It looks like this: http://s1122.photobucket.com/albums/l539/jpo2/?action=view&current=polar.gif Do you have any idea why this will be? ...Just in case this happened to you before. – jpo Jul 07 '11 at 04:34
It looks like an inadvertently large multiple of 2π, but I'm guessing. – trashgod Jul 07 '11 at 04:39
Oh... Same thing happens when I add a filled series to your previous example. Please see above for code. Than you – jpo Jul 07 '11 at 05:18
Yes, I see a similar appearance. You might also enjoy trying a few [rose curves](http://en.wikipedia.org/wiki/Rose_curve). – trashgod Jul 07 '11 at 05:25
But, how is the code different from that you have in http://stackoverflow.com/questions/6576911/jfreechart-loop-through-polar-chart-sectors/6577977#6577977? Do you knwo how I can fix it for it to look like what you produce in http://stackoverflow.com/questions/6576911/jfreechart-loop-through-polar-chart-sectors/6577977#6577977? – jpo Jul 07 '11 at 05:28
It's the same as [this](http://stackoverflow.com/questions/6576911/jfreechart-loop-through-polar-chart-sectors/6585876#6585876) with _i_ = 6. – trashgod Jul 07 '11 at 05:34

JFreechart Polar Chart shape annotation

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