JFreeChart select an area without zooming

Question

I recently started using JFreeChart and there is something i would like to do but i\'m not sure if it\'s possible. My program is supposed to draw a spectrogram (a sound grap

Answer 1

Don't do this by zooming, use a MouseListener added to your ChartPanel to add a Marker to the Domain axis.

In this example I have subclassed MouseAdapter so that when you press the mouse down the domain value is captured (markerStart) and when you release the mouse end postition is updated ('markerEnd') and a Marker is added to the plot (updateMarker)

You will then get a chart like this:

Note that in this example I've actually turned off the zooming.

import java.awt.Color;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;

import javax.swing.JFrame;
import javax.swing.JPanel;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.IntervalMarker;
import org.jfree.chart.plot.Marker;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.Layer;


public class MouseMarkerDemo extends JFrame {


    public MouseMarkerDemo(String title) {
        super(title);
        JPanel chartPanel = createDemoPanel();
        chartPanel.setPreferredSize(new java.awt.Dimension(500, 270));
        setContentPane(chartPanel);
    }


    private final static class  MouseMarker extends MouseAdapter{
        private Marker marker;
        private Double markerStart = Double.NaN;
        private Double markerEnd = Double.NaN;
        private final XYPlot plot;
        private final JFreeChart chart;
        private  final ChartPanel panel;


        public MouseMarker(ChartPanel panel) {
            this.panel = panel;
            this.chart = panel.getChart();
            this.plot = (XYPlot) chart.getPlot();
        }

        private void updateMarker(){
            if (marker != null){
                plot.removeDomainMarker(marker,Layer.BACKGROUND);
            }
            if (!( markerStart.isNaN() && markerEnd.isNaN())){
                if ( markerEnd > markerStart){
                    marker = new IntervalMarker(markerStart, markerEnd);
                    marker.setPaint(new Color(0xDD, 0xFF, 0xDD, 0x80));
                    marker.setAlpha(0.5f);
                    plot.addDomainMarker(marker,Layer.BACKGROUND);
                }
            }
        }

        private Double getPosition(MouseEvent e){
            Point2D p = panel.translateScreenToJava2D( e.getPoint());
            Rectangle2D plotArea = panel.getScreenDataArea();
            XYPlot plot = (XYPlot) chart.getPlot();
            return plot.getDomainAxis().java2DToValue(p.getX(), plotArea, plot.getDomainAxisEdge());
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            markerEnd = getPosition(e);
            updateMarker();
        }

        @Override
        public void mousePressed(MouseEvent e) {
            markerStart = getPosition(e);
        }
    }

    private static XYDataset createDataset() {

        XYSeries series1 = new XYSeries("Data");
        series1.add(1.0, 1.0);
        series1.add(2.0, 4.0);
        series1.add(3.0, 3.0);
        series1.add(4.0, 5.0);
        series1.add(5.0, 5.0);
        series1.add(6.0, 7.0);
        series1.add(7.0, 7.0);
        series1.add(8.0, 8.0);

        XYSeriesCollection dataset = new XYSeriesCollection();
        dataset.addSeries(series1);
        return dataset;

    }


    private static JFreeChart createChart(XYDataset dataset) {

        JFreeChart chart = ChartFactory.createXYLineChart(
            "Mouse Marker",
            "X",
            "Y",
            dataset,
            PlotOrientation.VERTICAL,
            true,
            true,
            false
        );
        XYPlot plot = (XYPlot) chart.getPlot();
        plot.setDomainPannable(true);
        plot.setRangePannable(true);
        XYLineAndShapeRenderer renderer
                = (XYLineAndShapeRenderer) plot.getRenderer();
        renderer.setBaseShapesVisible(true);
        renderer.setBaseShapesFilled(true);
        return chart;
    }

    public static JPanel createDemoPanel() {
        final JFreeChart chart = createChart(createDataset());
        final ChartPanel panel = new ChartPanel(chart);
        panel.setRangeZoomable(false);
        panel.setDomainZoomable(false);
        panel.addMouseListener(new MouseMarker(panel));
        return panel;
    }

    public static void main(String[] args) {
        MouseMarkerDemo demo = new MouseMarkerDemo("JFreeChart: MouseMarkerDemo.java");
        demo.pack();
        demo.setVisible(true);
    }

}