Jfreechart optimize X axis labels

Question

In JFreechart I have an X axis with dates (and times).

How can I ask JFreechart to optimize them and make the most out of it?

Right now it contains more label th

Answer 1

Your updated example creates a CategoryDataset and uses the ChartFactory method, createLineChart(), to create a CategoryPlot. You can adjust the label positions for readability as shown here and below. Moreover,

it would be nice to have a vertical grid line only when the label is visible and hide all other grid lines.

plot.getDomainAxis().setCategoryLabelPositions(
    CategoryLabelPositions.UP_45);
plot.setDomainGridlinesVisible(true);
plot.setRangeGridlinesVisible(false);

More generally, create a TimeSeries and use the corresponding ChartFactory method, createTimeSeriesChart(). The resulting DateAxis will automatically adjust the labels when the enclosing chart is resized. In addition,

• You can adjust the date format as shown here.

• To establish the chart's initial size, override getPreferredSize(), as suggested here.

• When using setRange(), query the underlying dataset, as shown below.

• Construct and manipulate Swing GUI objects only on the event dispatch thread.

import java.awt.Dimension;
import java.awt.EventQueue;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.ui.ApplicationFrame;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.time.Day;
import org.jfree.data.time.Hour;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;

public class TempChart extends ApplicationFrame {

    public TempChart(String applicationTitle, String chartTitle) {
        super(applicationTitle);
        TimeSeries s = createSeries();
        JFreeChart chart = ChartFactory.createTimeSeriesChart(
            chartTitle, "Date", "Temperature", new TimeSeriesCollection(s));

        XYPlot plot = (XYPlot) chart.getPlot();
        plot.getRangeAxis().setRange(Math.floor(s.getMinY()), Math.ceil(s.getMaxY()));

        ChartPanel chartPanel = new ChartPanel(chart) {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(560, 367);
            }
        };
        add(chartPanel);
    }

    private TimeSeries createSeries() {
        TimeSeries series = new TimeSeries("Temperature");

        series.add(new Hour(0, new Day()), 26.44);
        series.add(new Hour(1, new Day()), 26.2);
        series.add(new Hour(2, new Day()), 25.93);
        series.add(new Hour(3, new Day()), 25.71);
        series.add(new Hour(4, new Day()), 25.54);
        series.add(new Hour(5, new Day()), 25.42);
        series.add(new Hour(6, new Day()), 25.25);
        series.add(new Hour(7, new Day()), 25.19);
        series.add(new Hour(8, new Day()), 25.25);
        series.add(new Hour(9, new Day()), 25.36);
        series.add(new Hour(10, new Day()), 25.52);
        series.add(new Hour(11, new Day()), 25.86);
        series.add(new Hour(12, new Day()), 26.51);
        series.add(new Hour(13, new Day()), 26.82);

        return series;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                TempChart chart = new TempChart(
                    "Temperature demo", "Time Axis labels adjust on resize");
                chart.pack();
                chart.setLocationRelativeTo(null);
                chart.setVisible(true);
            }
        });
    }
}