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JFreeChart format Y-axis to show values in Power


How to format y-axis to show values as 5*10^5, 1*10^6, 2*10^6... instead of 500,000,1,000,000, 2,000,000... and which are divisible by 5 or 10?

enter image description here


Solution

  • A LogAxis with the default tick units seems to work. This related example uses integer tick units.

    image

    import java.awt.Dimension;
    import java.awt.EventQueue;
    import javax.swing.JFrame;
    import org.jfree.chart.ChartPanel;
    import org.jfree.chart.JFreeChart;
    import org.jfree.chart.axis.LogAxis;
    import org.jfree.chart.axis.NumberAxis;
    import org.jfree.chart.plot.XYPlot;
    import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
    import org.jfree.data.xy.XYSeries;
    import org.jfree.data.xy.XYSeriesCollection;
    
    /**
     * @see https://stackoverflow.com/a/22450677/230513
     * @see https://stackoverflow.com/a/10353270/230513
     */
    public class Test {
    
        private static final int N = 7;
    
        private void display() {
            XYSeries series = new XYSeries("Series");
            for (int i = 0; i <= N; i++) {
                series.add(i, Math.pow(10, i));
            }
            NumberAxis xAxis = new NumberAxis("X");
            xAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
            LogAxis yAxis = new LogAxis("Y");
            XYPlot plot = new XYPlot(new XYSeriesCollection(series),
                xAxis, yAxis, new XYLineAndShapeRenderer(true, false));
            JFreeChart chart = new JFreeChart(
                "Chart", JFreeChart.DEFAULT_TITLE_FONT, plot, false);
    
            JFrame f = new JFrame("Test");
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            f.add(new ChartPanel(chart) {
    
                @Override
                public Dimension getPreferredSize() {
                    return new Dimension(480, 240);
                }
            });
            f.pack();
            f.setLocationRelativeTo(null);
            f.setVisible(true);
        }
    
        public static void main(String[] args) {
            EventQueue.invokeLater(new Runnable() {
    
                @Override
                public void run() {
                    new Test().display();
                }
            });
        }
    }