Java - 如何在鼠标按钮释放后接收点坐标 (JFreeChart) [英] Java - how to receive point coordinates after mouse button release (JFreeChart)

问题描述

我使用 JFreeChart 编写了一个简单的抛物线图.我得到图形点坐标，当鼠标按钮按下时，我也想得到图形点坐标，当鼠标按钮释放时.但是 chartMouseMoved 在按下鼠标按钮时不起作用.释放鼠标按钮后如何解决我的问题并获取图形坐标?

I wrote a simple parabola plot using JFreeChart. I get graphic point coordinates, when mouse button pressed and i also want to get graphic point coordinates, when mouse button released. But chartMouseMoved don't work while mouse button pressing. How can I solve my problem and get graphic coordinates after mouse button releasing?

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！

推荐答案

如图 这里，ChartPanel 使用点击-拖动-释放手势来处理缩放；setMouseZoomable(false) 不会改变这一点.

As shown here, ChartPanel uses the click-drag-release gesture to handle zooming; setMouseZoomable(false) doesn't change that.

根据此处所示的建议，下面的完整示例打印任何点击点的坐标.我已经放大了系列形状，以便更容易看到效果.此外，Swing GUI 对象应该仅在 事件调度线程.

Working from the suggestion shown here, the complete example below prints the coordinates of any clicked point. I've enlarged the series shape to make it easier to see the effect. In addition, Swing GUI objects should be constructed and manipulated only on the event dispatch thread.

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);
            }
        });
    }
}

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