java JFreeChart x 轴刻度
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JFreeChart x axis scale
提问by Biscuit128
I have a JFree XY Line chart which always starts at x = 0. Then based on user defined settings from a properties file, the application increments based on that number (this represents the time in minutes).
我有一个 JFree XY 折线图，它总是从 x = 0 开始。然后根据用户定义的属性文件设置，应用程序根据该数字递增（这表示以分钟为单位的时间）。
For example, x = 0 to start the user defined setting is 5 so the scale goes 0, 5, 10, 15, 20…, or the user setting is 3 so it goes 0, 3, 6, 9, 12… Pretty simple.
例如，x = 0 开始用户定义的设置为 5，因此比例变为 0、5、10、15、20……，或者用户设置为 3，因此变为 0、3、6、9、12……非常简单.
The issue I am having is the way in which the graph starts. If I start at 0, then 0 is in the middle of the graph rather than at the bottom left with -0.0000005, -0.000004, -0.000003… 0.000000 , 0.000001 , 0.000002… 0.000005
我遇到的问题是图表开始的方式。如果我从 0 开始，那么 0 位于图表的中间而不是左下角 -0.0000005, -0.000004, -0.000003… 0.000000 , 0.000001 , 0.000002… 0.000005
How can I just manually add the scale at the bottom, i.e. define it should be increments of 2 and then maintain it?
我怎样才能在底部手动添加比例，即定义它应该是 2 的增量然后保持它？
回答by obourgain
You should use NumberAxis, which contains a lot of methods to define the scale of your chart.
您应该使用NumberAxis，它包含许多定义图表比例的方法。
Example :
例子 ：
// Create an XY Line chart
XYSeries series = new XYSeries("Random Data");
series.add(1.0, 500.2);
series.add(10.0, 694.1);
XYSeriesCollection data = new XYSeriesCollection(series);
JFreeChart chart = ChartFactory.createXYLineChart("XY Series Demo", "X", "Y", data,
PlotOrientation.VERTICAL,
true, true, false);
// Create an NumberAxis
NumberAxis xAxis = new NumberAxis();
xAxis.setTickUnit(new NumberTickUnit(2));
// Assign it to the chart
XYPlot plot = (XYPlot) chart.getPlot();
plot.setDomainAxis(xAxis);
回答by trashgod
Based on this example, here's an ssccethat uses setTickUnit()to adjust the domain axis tick unit dynamically, starting from the value 5.
基于这个例子，这里有一个sscce用于setTickUnit()动态调整域轴刻度单位，从值开始5。
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.axis.NumberTickUnit;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
/** @see https://stackoverflow.com/a/14167983/230513 */
public class SSCCE {
private static final int COUNT = 100;
private static final int UNITS = 5;
private static final Random r = new Random();
public static void main(String[] args) {
XYSeries series = new XYSeries("Data");
for (int i = 0; i < COUNT; i++) {
series.add(i, r.nextGaussian());
}
XYSeriesCollection data = new XYSeriesCollection(series);
final JFreeChart chart = ChartFactory.createXYLineChart("TickUnits",
"X", "Y", data, PlotOrientation.VERTICAL, true, true, false);
XYPlot plot = (XYPlot) chart.getPlot();
final NumberAxis xAxis = (NumberAxis) plot.getDomainAxis();
xAxis.setTickUnit(new NumberTickUnit(UNITS));
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame f = new JFrame("TickUnitDemo");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new ChartPanel(chart));
final JSpinner spinner = new JSpinner(
new SpinnerNumberModel(UNITS, 1, COUNT, 1));
spinner.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
JSpinner s = (JSpinner) e.getSource();
Number n = (Number) s.getValue();
xAxis.setTickUnit(new NumberTickUnit(n.intValue()));
}
});
JPanel p = new JPanel();
p.add(new JLabel(chart.getTitle().getText()));
p.add(spinner);
f.add(p, BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
});
}
}
