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 graph) from a wav file. So i managed to get the data from my wav file in a double arraylist and to display it in a chart. But now i would like to be able to select an area of my spectrogram (with the same tool used for zooming) without zooming and to be able to play only the selected part on my sound. But i simply can't find any way to succeed. Here is my code of my chart:

    package classes;

import java.awt.Color;
import java.awt.Paint;
import java.awt.Rectangle;
import java.io.File;
import java.io.IOException;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.Plot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.RectangleInsets;

public class Chart{
    JFreeChart chart;
    Plot plot;

    //Constructeur de la classe Chart
    public Chart(double[][] bs, int channel, int framesLength, float frameRate)
    {
        // Création d'un XY chart
        XYSeries series = new XYSeries("XYGraph");
        int i=0,j=0;
        float k=0;
        //Ajout de tous les points du tableau de 16 bytes dans le chart
        for( i=0; i <channel;i++)
        {
            for(j=0; j< framesLength;j++)
            {
                //Division des valeurs par 2^15 pour être entre 1 et -1
                series.add(k, (bs[i][j]/32768));
                //Echelle de X
                k+=(1/frameRate);
            }
        }
        // Ajoute la série au dataset
        XYSeriesCollection dataset = new XYSeriesCollection();
        dataset.addSeries(series);
        // Génération du graphe
        chart = ChartFactory.createXYLineChart(
        "Ajouter titre à la fonction de génération", // Titre
        "Temps (s)", // Nom de l'axe X
        "y-axis", // Nom de l'axe Y
        dataset, // Dataset
        PlotOrientation.VERTICAL, // Plot Orientation
        true, // Show Legend
        false, // Use tooltips
        false // Configure chart to generate URLs?
        );
        plot= (XYPlot) chart.getPlot();

    }
    //Renvoie le chart
    public JFreeChart getChart()
    {
        return chart;
    }

    public void color(Color c)
    {
        plot.setBackgroundPaint(c);
    }
}

And here i'm calling the Chart class and using it:

Chart chartUn= new Chart(bs, channels  , frameLength , frameRate);
        chartUn.color(Color.pink);
        vue.setChartPanelUn(new ChartPanel(chartUn.getChart(), false));
        vue.getChartPanelUn().setRangeZoomable(false);
        vue.getChartPanelUn().setMouseWheelEnabled(true);

vue.getChartPanelUn() returns a ChartPanel. Would you have an idée how to solve my problem? Thanks a lot (And sorry if my english is not always exact :/)

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);
    }

}