我使用 JFreeChart 编写了一个简单的抛物线图。当按下鼠标按钮时，我得到图形点坐标，当释放鼠标按钮时，我也想得到图形点坐标。 但图表鼠标移动按下鼠标按钮时不起作用。如何解决我的问题并在释放鼠标按钮后获取图形坐标？
这是我的代码：
package parabolademo;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartMouseEvent;
import org.jfree.chart.ChartMouseListener;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.entity.ChartEntity;
import org.jfree.chart.entity.XYItemEntity;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.function.Function2D;
import org.jfree.data.function.PolynomialFunction2D;
import org.jfree.data.general.DatasetUtilities;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;
public class ParabolaDemo extends ApplicationFrame {
/*
* @param title the frame title.
*/
int flag = 0;
double delta = 0;
double px = 0.0, py = 0.0, prx = 0.0, pry = 0.0, chartpx = 0.0, chartpy = 0.0,
chartX = 0.0, chartY = 0.0;
int windowheight = 270;
public ParabolaDemo(final String title) {
super(title);
double[] a = {0.0, 0.0, 1.0};
Function2D p = new PolynomialFunction2D(a);
double lrange = -20.0;
double rrange = 20.0;
XYDataset dataset = DatasetUtilities.sampleFunction2D(p, lrange, rrange, 1000, "y = f(x)");
double max = 0.0;
if (a[2] < 0) {
max = p.getValue(-a[1] / 2*a[2]);
}
else {
if (p.getValue(lrange) > p.getValue(rrange))
max = p.getValue(lrange);
else
max = p.getValue(rrange);
}
System.out.println("max = " + max);
delta = max / 16.4;
final JFreeChart chart = ChartFactory.createXYLineChart(
"Parabola",
"X",
"Y",
dataset,
PlotOrientation.VERTICAL,
true,
true,
false
);
final ChartPanel chartPanel = new ChartPanel(chart);
chartPanel.addMouseListener(new CustomListener());
chartPanel.addChartMouseListener(new ChartMouseListener() {
@Override
public void chartMouseClicked(ChartMouseEvent cme) {
}
@Override
public void chartMouseMoved(ChartMouseEvent cme) {
ChartEntity ce = cme.getEntity();
if (ce instanceof XYItemEntity) {
XYItemEntity e = (XYItemEntity) ce;
XYDataset d = ((XYItemEntity) ce).getDataset();
int i = ((XYItemEntity) ce).getItem();
chartpx = d.getXValue(0, i);
chartpy = d.getYValue(0, i);
//System.out.println("X:" + chartpx + ", Y:" + chartpy);
}
Point2D po = chartPanel.translateScreenToJava2D(cme.getTrigger().getPoint());
Rectangle2D plotArea = chartPanel.getScreenDataArea();
XYPlot plot = (XYPlot) chart.getPlot(); // your plot
chartX = plot.getDomainAxis().java2DToValue(po.getX(), plotArea, plot.getDomainAxisEdge());
chartY = plot.getRangeAxis().java2DToValue(po.getY(), plotArea, plot.getRangeAxisEdge());
System.out.println("X:" + chartX + ", Y:" + chartY);
}
});
chartPanel.setPreferredSize(new java.awt.Dimension(500, windowheight));
chartPanel.setDomainZoomable(false);
chartPanel.setRangeZoomable(false);
setContentPane(chartPanel);
}
public static void main(final String[] args) {
final ParabolaDemo demo = new ParabolaDemo("Parabola Plot Demo");
demo.pack();
RefineryUtilities.centerFrameOnScreen(demo);
demo.setVisible(true);
}
public class CustomListener implements MouseListener {
public void mouseClicked(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
flag = 1;
px = chartpx;
py = chartpy;
System.out.println("Mouse Pressed! xpos = " + px + "; py = " + py);
}
public void mouseReleased(MouseEvent e) {
flag = 1;
prx = chartX;
pry = chartY;
System.out.println("Mouse Released! xpos = " + prx + "; py = " + pry);
}
}
}
提前致谢！
如图所示here, ChartPanel使用单击-拖动-释放手势来处理缩放；setMouseZoomable(false)并没有改变这一点。
根据显示的建议进行工作here，下面的完整示例打印任何单击点的坐标。我放大了系列形状，以便更容易看到效果。另外，应该构造和操作 Swing GUI 对象only on the 事件派发线程.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Rectangle;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartMouseEvent;
import org.jfree.chart.ChartMouseListener;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.entity.ChartEntity;
import org.jfree.chart.entity.XYItemEntity;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.function.Function2D;
import org.jfree.data.function.PolynomialFunction2D;
import org.jfree.data.general.DatasetUtilities;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;
import org.jfree.util.ShapeUtilities;
public class ParabolaDemo extends ApplicationFrame {
/*
* @see https://stackoverflow.com/a/20107935/230513
* @see https://stackoverflow.com/q/20081801/230513
*/
public ParabolaDemo(final String title) {
super(title);
double[] a = {0.0, 0.0, 3.0};
Function2D p = new PolynomialFunction2D(a);
XYDataset dataset = DatasetUtilities.sampleFunction2D(
p, -20.0, 20.0, 20, "y = 3x² {-20…20}");
final JFreeChart chart = ChartFactory.createXYLineChart("Parabola",
"X", "Y", dataset, PlotOrientation.VERTICAL, true, true, false);
final XYPlot plot = (XYPlot) chart.getPlot();
XYLineAndShapeRenderer r = (XYLineAndShapeRenderer) plot.getRenderer();
r.setBaseShapesVisible(true);
r.setSeriesShape(0, ShapeUtilities.createTranslatedShape(
new Rectangle(12, 12), -6, -6));
final ChartPanel chartPanel = new ChartPanel(chart) {
@Override
public Dimension getPreferredSize() {
return new Dimension(640, 480);
}
};
chartPanel.addChartMouseListener(new ChartMouseListener() {
@Override
public void chartMouseClicked(ChartMouseEvent cme) {
report(cme);
}
@Override
public void chartMouseMoved(ChartMouseEvent cme) {
//report(cme);
}
private void report(ChartMouseEvent cme) {
ChartEntity ce = cme.getEntity();
if (ce instanceof XYItemEntity) {
XYItemEntity e = (XYItemEntity) ce;
XYDataset d = e.getDataset();
int s = e.getSeriesIndex();
int i = e.getItem();
System.out.println("X:" + d.getX(s, i) + ", Y:" + d.getY(s, i));
}
}
});
setContentPane(chartPanel);
}
public static void main(final String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
final ParabolaDemo demo = new ParabolaDemo("Parabola Demo");
demo.pack();
RefineryUtilities.centerFrameOnScreen(demo);
demo.setVisible(true);
}
});
}
}