我正在使用JFreeChart 1.0.14绘制XYSeries。我确实可以访问所有元素（ChartPanel、JFreeChart、XYSeriesCollection、XYSeries）。不时有新的数据要绘制，所以我更新了我的系列（为了简单起见，我们假设只有一个系列）：
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
XYSeries xyData = new XYSeries("Trace");
for (int i = 0; i < n; i++)
xyData.add(data[0][i], data[1][i], false);
collection.removeAllSeries();
collection.addSeries(xyData);
chart.getXYPlot().setRangeAxis(createNewAxis());
}
});
这一切都很好。但我有一个问题。用户可以通过在绘图中拖动进行缩放。每次更新数据时，都会重置此缩放。这很有道理，因为我创建了新的轴。如何保留用户缩放状态？由于用户也可以选择自动范围/范围，我不想对这些（Axis#setRange/setAutoRange）进行某种破解。我发现了一些关于ChartPanel#getScaleX()的东西。但在上述CCD_ 10的开始处，这始终是CCD_。我也找不到任何ChartPanel.setScaleX。
我是做错了什么，还是有其他方法可以在不改变轴的范围/自动范围行为的情况下保持用户缩放状态？
BTW:I有来重新创建轴，因为它们也可以在logscale和linscale之间切换。
我不认为每次添加新点或调用removeAllSeries() 时都需要创建新的XYSeries xyData
此示例显示如何将动态数据添加到XYSeriesCollection
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JPanel;
import org.jfree.chart.ChartFactory;
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.axis.ValueAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.time.Millisecond;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;
/**
* A demonstration application showing a XYseries chart where you can
* dynamically add (random) data by clicking on a button.
*/
public class DynamicDataDemo1 extends ApplicationFrame {
/**
* Constructs a new demonstration application.
*
* @param title
* the frame title.
*/
public DynamicDataDemo1(String title) {
super(title);
MyDemoPanel demoPanel = new MyDemoPanel();
setContentPane(demoPanel);
}
static class MyDemoPanel extends DemoPanel implements ActionListener {
/** The time series data. */
/** The most recent value added. */
private double lastValue1 = 200.0;
private double lastValue2 = 200.0;
private XYPlot plot;
private boolean logAxis = false;
private String lastSeries = "";
private final XYSeriesCollection dataset;
private static String SERIES_NAME = "Random Data ";
private static int seriesNumber = 0;
/**
* Creates a new instance.
*/
public MyDemoPanel() {
super(new BorderLayout());
lastSeries = SERIES_NAME + (seriesNumber++);
XYSeries series = new XYSeries(lastSeries);
dataset = new XYSeriesCollection(series);
ChartPanel chartPanel = new ChartPanel(createChart(dataset));
chartPanel.setPreferredSize(new java.awt.Dimension(500, 270));
addChart(chartPanel.getChart());
JPanel buttonPanel = new JPanel();
buttonPanel.setBorder(BorderFactory.createEmptyBorder(4, 4, 4, 4));
JButton button = new JButton("Add New Data Item");
button.setActionCommand("ADD_DATA");
button.addActionListener(this);
buttonPanel.add(button);
{
JButton button2 = new JButton("Switch Axis");
button2.setActionCommand("SWITCH_AXIS");
button2.addActionListener(this);
buttonPanel.add(button2);
}
{
JButton button2 = new JButton("Add Series");
button2.setActionCommand("ADD_SERIES");
button2.addActionListener(this);
buttonPanel.add(button2);
}
add(chartPanel);
add(buttonPanel, BorderLayout.SOUTH);
}
private JFreeChart createChart(XYDataset dataset) {
JFreeChart result = ChartFactory.createXYLineChart("Dynamic Data Demo", "Time", "Value", dataset, PlotOrientation.VERTICAL, true, true, false);
plot = (XYPlot) result.getPlot();
ValueAxis domainAxis = plot.getDomainAxis();
domainAxis.setAutoRange(true);
final ValueAxis rangeAxis = plot.getRangeAxis();
rangeAxis.setAutoRange(true);
return result;
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("ADD_DATA")) {
double factor1 = 0.90 + 0.2 * Math.random();
double factor2 = 0.90 + 0.2 * Math.random();
this.lastValue1 = this.lastValue1 * factor1;
this.lastValue2 = this.lastValue2 * factor2;
Millisecond now = new Millisecond();
System.out.println("Now = " + now.toString());
XYSeries series = dataset.getSeries(lastSeries);
series.add(this.lastValue2, this.lastValue1);
} else if (e.getActionCommand().equals("SWITCH_AXIS")) {
if (!logAxis) {
LogAxis xAxis = new LogAxis("X");
LogAxis yAxis = new LogAxis("Y");
updateZoom(xAxis,yAxis);
logAxis = true;
} else {
NumberAxis xAxis = new NumberAxis("X");
NumberAxis yAxis = new NumberAxis("Y");
updateZoom(xAxis,yAxis);
logAxis = false;
}
} else if (e.getActionCommand().equals("ADD_SERIES")) {
lastSeries = SERIES_NAME + (seriesNumber++);
XYSeries series = new XYSeries(lastSeries);
dataset.addSeries(series);
}
}
private void (ValueAxis xAxis, ValueAxis yAxis) {
double domainMin = plot.getDomainAxis().getRange().getLowerBound();
double domainMax = plot.getDomainAxis().getRange().getUpperBound();
System.out.println(domainMin + "," + domainMax);
double rangeMin = plot.getRangeAxis().getRange().getLowerBound();
double rangeMax = plot.getRangeAxis().getRange().getUpperBound();
System.out.println(rangeMin + "," + rangeMax);
xAxis.setRange(domainMin, domainMax);
plot.setDomainAxis(xAxis);
yAxis.setRange(rangeMin, rangeMax);
plot.setRangeAxis(yAxis);
}
}
public static JPanel createDemoPanel() {
return new DynamicDataDemo1.MyDemoPanel();
}
public static void main(String[] args) {
DynamicDataDemo1 demo = new DynamicDataDemo1("JFreeChart: Dynamic XYSeries");
demo.pack();
RefineryUtilities.centerFrameOnScreen(demo);
demo.setVisible(true);
}
}
此示例基于JFreeChart:DynamicDataDemo1.java。每次单击"添加新数据项"都会添加一个新点。在本例中，添加数据点时将保留"缩放"，但更改轴时不会保留。
要在将轴从法线更改为对数刻度时保持缩放，反之亦然，请使用两个轴的当前上限和下限，并设置新轴的Range，如updateZoom 所示
我不知道如何将"用户缩放状态"从一个轴转移到另一个轴。因此，如果不需要，我确保不刷新轴（=对数/线性之间没有刻度变化）。如果发生更改，用户缩放状态将丢失，这是不幸的。但这种情况并不经常发生，而且是由用户控制的，所以用户可能可以重置缩放状态。