我正在使用JFreeChart 1.0.14来绘制XYSeries。我可以访问所有元素（ChartPanel，JFreeChart，XYSeriesCollection，XYSeries）。有时会有新的数据要绘制，所以我更新了我的系列（为简单起见，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());
}
});
这一切都很棒。但我有一个问题。用户可以通过拖动绘图进行缩放。每次重置此缩放，数据都会更新。这是有道理的，因为我创造了新的轴。如何保留用户缩放状态？由于用户也可以选择自动量程/范围，我不想对那些（Axis#setRange/setAutoRange）进行某种破解。我找到了ChartPanel#getScaleX()的内容。但在上述1.0的开头，这始终是invokeLater。我也找不到任何ChartPanel.setScaleX。
我是做错了还是有其他方法可以保留用户缩放状态而不改变轴的范围/自动量程行为？
BTW：我有重新创建轴，因为它们也可以在logscale和linscale之间切换。
答案 0 :(得分：1)
每次添加新点或致电XYSeries xyData
removeAllSeries()
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”时，都会添加一个新点。在此示例中，当您添加数据点时，将保留缩放，但在您移动轴时则不会。
在将轴从正常刻度更改为对数刻度时保持变焦，反之亦然使用两个轴的当前上限和下限并设置新轴的Range，如updateZoom所示< / p>
答案 1 :(得分：0)
我没弄明白如何将“用户缩放状态”从一个轴接管到另一个轴。因此，如果不需要，我确保不刷新轴（=对数/线性之间没有比例变化）。如果有更改，用户缩放状态将丢失，这是不幸的。但这种情况经常发生并且不受用户控制，因此用户可能无法重置缩放状态。