在鼠标附近显示鼠标坐标，以作为鼠标移动的提示 [英] Display mouse coordinates near mouse as hints on mouse move

问题描述

在XYPlot上，我希望鼠标的坐标显示为靠近鼠标的提示，但是仅当(鼠标)在图表上移动时才显示！换句话说，当十字准线移动到另一个点时，坐标值的定位也将跟随十字准线移动.

On an XYPlot, I want the coordinates of mouse displayed as hint near to mouse, but only when (the mouse) move on chart! In another words, when the crosshair moves to another point, the positioning of the coordinate values would move too, following the crosshair.

还将绘制1条水平线和1条垂直线，它们在鼠标悬停时特别相交.

Also 1 horizontal line and 1 vertical line will be drawn, that intersects specifically at the point that mouse is over on.

这可能吗? 到目前为止，我可以使用ChartMouseListener和chartMouseMoved方法获取坐标并打印在控制台上.

Is this possible? Until now I can get the coordinates and printed on console using ChartMouseListener and chartMouseMoved method.

这是我的项目，也是我想用鼠标成为图表的方式.

This is my project and how I want to be the chart with mouse.

推荐答案

JFreeChart对十字线有相当灵活的支持.要执行您描述的操作，我将在ChartPanel上使用一个Overlay，并从ChartMouseListener中更新十字线.这是一个独立的示例(我将把它添加到我们随 JFreeChart开发人员指南一起提供的演示集中.):

JFreeChart has quite flexible support for crosshairs. To do what you described I would use an Overlay on the ChartPanel, and update the crosshairs from your ChartMouseListener. Here is a self-contained example (which I'll add to the collection of demos that we ship with the JFreeChart Developer Guide):

package org.jfree.chart.demo;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
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.axis.ValueAxis;
import org.jfree.chart.panel.CrosshairOverlay;
import org.jfree.chart.plot.Crosshair;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.general.DatasetUtilities;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.RectangleEdge;

/**
 * A demo showing crosshairs that follow the data points on an XYPlot.
 */
public class CrosshairOverlayDemo1 extends JFrame implements ChartMouseListener {

    private ChartPanel chartPanel;

    private Crosshair xCrosshair;

    private Crosshair yCrosshair;

    public CrosshairOverlayDemo1(String title) {
        super(title);
        setContentPane(createContent());
    }

    private JPanel createContent() {
        JFreeChart chart = createChart(createDataset());
        this.chartPanel = new ChartPanel(chart);
        this.chartPanel.addChartMouseListener(this);
        CrosshairOverlay crosshairOverlay = new CrosshairOverlay();
        this.xCrosshair = new Crosshair(Double.NaN, Color.GRAY, new BasicStroke(0f));
        this.xCrosshair.setLabelVisible(true);
        this.yCrosshair = new Crosshair(Double.NaN, Color.GRAY, new BasicStroke(0f));
        this.yCrosshair.setLabelVisible(true);
        crosshairOverlay.addDomainCrosshair(xCrosshair);
        crosshairOverlay.addRangeCrosshair(yCrosshair);
        chartPanel.addOverlay(crosshairOverlay);
        return chartPanel;
    }

    private JFreeChart createChart(XYDataset dataset) {
        JFreeChart chart = ChartFactory.createXYLineChart("Crosshair Demo", 
                "X", "Y", dataset);
        return chart;
    }

    private XYDataset createDataset() {
        XYSeries series = new XYSeries("S1");
        for (int x = 0; x < 10; x++) {
            series.add(x, x + Math.random() * 4.0);
        }
        XYSeriesCollection dataset = new XYSeriesCollection(series);
        return dataset;
    }

    @Override
    public void chartMouseClicked(ChartMouseEvent event) {
        // ignore
    }

    @Override
    public void chartMouseMoved(ChartMouseEvent event) {
        Rectangle2D dataArea = this.chartPanel.getScreenDataArea();
        JFreeChart chart = event.getChart();
        XYPlot plot = (XYPlot) chart.getPlot();
        ValueAxis xAxis = plot.getDomainAxis();
        double x = xAxis.java2DToValue(event.getTrigger().getX(), dataArea, 
                RectangleEdge.BOTTOM);
        double y = DatasetUtilities.findYValue(plot.getDataset(), 0, x);
        this.xCrosshair.setValue(x);
        this.yCrosshair.setValue(y);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                CrosshairOverlayDemo1 app = new CrosshairOverlayDemo1(
                        "JFreeChart: CrosshairOverlayDemo1.java");
                app.pack();
                app.setVisible(true);
            }
        });
    }

}

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