矩形选择JFreeChart

Question

我尝试使用mousePressed，mouseDragged和mouseReleased在XYLineChart中进行矩形选择。 因此，当我按下按钮时，它允许我执行此操作：

private DeltaOnAreaSelected d;
d = new DeltaOnAreaSelected(this);
monChartPanel.addMouseListener(d);
monChartPanel.addMouseMotionListener(d);

现在，这里是我按下按钮的DeltaOnAreaSelected类：

public class DeltaOnAreaSelected implements MouseMotionListener, MouseListener{

private SpectrumController control;  
private ChartPanel panel;
private JFreeChart chart;
private SpectrumPanel specPanel;
private SpectrumDataset dataset;
private Rectangle selection;
private Point anchor;
private Double freqMin = Double.NaN;
private Double freqMax = Double.NaN;
private Double powerMin = Double.NaN;
private Double powerMax = Double.NaN;
private Double powerPointMin = Double.NaN;
private Double powerPointMax = Double.NaN;
private Graphics2D g2d;

    public DeltaOnAreaSelected(SpectrumController c){
        control = c;
        panel = c.getSpectrumChartPanel().getChartPanel();
        chart = c.getSpectrumChartPanel().getChartPanel().getChart();
        specPanel = c.getSpectrumPanel();
        dataset = c.getSpectrumChartPanel().getSpectrumDataset();
    }

    private Double getPositionFreq(MouseEvent e){
        Point2D p = panel.translateScreenToJava2D(e.getPoint());
        Rectangle2D plotArea = panel.getScreenDataArea();
        XYPlot plot = (XYPlot) chart.getPlot();

        return plot.getDomainAxis().java2DToValue(p.getX(), plotArea, plot.getDomainAxisEdge());
    }

    private Double getPositionPower(MouseEvent e){
        Point2D p = panel.translateScreenToJava2D(e.getPoint());
        Rectangle2D plotArea = panel.getScreenDataArea();
        XYPlot plot = (XYPlot) chart.getPlot();

        return plot.getRangeAxis().java2DToValue(p.getY(), plotArea, plot.getRangeAxisEdge());
    }

    @Override
    public void mousePressed(MouseEvent e) {
        freqMin = getPositionFreq(e);
        powerMax = getPositionPower(e);
        anchor = e.getPoint();
        selection = new Rectangle(anchor);
        g2d = (Graphics2D)panel.getGraphics();
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        selection.setBounds( (int)Math.min(anchor.x,e.getX()), (int)Math.min(anchor.y,e.getY()),
                (int)Math.abs(e.getX()-anchor.x), (int)Math.abs(e.getY()-anchor.y));
        if (selection!=null){
            g2d.setColor(Color.red);
            g2d.draw(selection);
        }
        panel.repaint();
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        freqMax = getPositionFreq(e);
        powerMin = getPositionPower(e);
        selection = null;
        panel.repaint();

        powerPointMin = dataset.getCurveData().getMinY(freqMin, freqMax, powerMin, powerMax).getY();
        powerPointMax = dataset.getCurveData().getMaxY(freqMin, freqMax, powerMin, powerMax).getY();

        //Round the variables at 3 numbers
        BigDecimal centerFreq = new BigDecimal((freqMax + freqMin)/2);
        centerFreq = centerFreq.setScale(3, BigDecimal.ROUND_DOWN);
        BigDecimal deltaFreq = new BigDecimal(freqMax-freqMin);
        deltaFreq = deltaFreq.setScale(3, BigDecimal.ROUND_DOWN);
        BigDecimal deltaPower = new BigDecimal(powerPointMax-powerPointMin);
        deltaPower = deltaPower.setScale(3, BigDecimal.ROUND_DOWN);

        //Display the delta on area selected
        specPanel.getInfoPanel().getDeltaOnAreaText()
                .setText("DELTA ON AREA SELECTED : \n"
                        + "Center freq. (Hz) : " + centerFreq.doubleValue() + "\n"
                        + "Delta freq. (Hz) : " + deltaFreq.doubleValue() + "\n"
                        + "Delta power (dB) : " + deltaPower.doubleValue());
        specPanel.getInfoPanel().getDeltaOnAreaText().setVisible(true);
    }

    @Override
    public void mouseExited(MouseEvent e){
        panel.removeMouseListener(this);
        panel.removeMouseMotionListener(this);
    }

    @Override
    public void mouseMoved(MouseEvent e) {}
    @Override
    public void mouseClicked(MouseEvent e) {}
    @Override
    public void mouseEntered(MouseEvent e) {}
}

我的问题是矩形显示为生涩，并且不会停留在释放鼠标的位置。 你有什么想法帮助我吗？

谢谢！