Question

我有一个动态的区域图表，我想在我的图表显示的最后一个点上添加一个绿点（我的图表上的最近值）。例如，显示线条边框我想要一个大绿点显示在我的区域图表上？我正在使用示例shown here。

怎么做？这是我的代码：

 public class essaijfree2 extends ApplicationFrame {

private static final String TITLE = "Dynamic Series";
private static final String START = "Start";
private static final String STOP = "Stop";
private static final float MINMAX = 100;
private static final int COUNT = 2 * 60;
private static final int FAST = 100;
private static final int SLOW = FAST * 5;
private static final Random random = new Random();
private Timer timer;

public essaijfree2(final String title) {
    super(title);
    final DynamicTimeSeriesCollection dataset =
        new DynamicTimeSeriesCollection(1, COUNT, new Second());
    dataset.setTimeBase(new Second(0, 0, 0, 1, 1, 2011));
    dataset.addSeries(gaussianData(), 0, "Gaussian data");
    JFreeChart chart = createChart(dataset);
    XYPlot xyPlot = (XYPlot) chart.getPlot();
    XYDifferenceRenderer r = new XYDifferenceRenderer(Color.green,Color.red, true);
    xyPlot.setRenderer(r);



    final JComboBox combo = new JComboBox();
    combo.addItem("Fast");
    combo.addItem("Slow");
    combo.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            if ("Fast".equals(combo.getSelectedItem())) {
                timer.setDelay(FAST);
            } else {
                timer.setDelay(SLOW);
            }
        }
    });

    this.add(new ChartPanel(chart), BorderLayout.CENTER);
    JPanel btnPanel = new JPanel(new FlowLayout());

    btnPanel.add(combo);
    this.add(btnPanel, BorderLayout.SOUTH);

    timer = new Timer(FAST, new ActionListener() {

        float[] newData = new float[1];

        @Override
        public void actionPerformed(ActionEvent e) {
            newData[0] = randomValue();
            dataset.advanceTime();
            dataset.appendData(newData);
        }
    });
}

private float randomValue() {

    return (float) (random.nextGaussian() * MINMAX / 3);
}

private float[] gaussianData() {
    float[] a = new float[COUNT];
    for (int i = 0; i < a.length; i++) {
        a[i] = randomValue();
    }
    return a;
}

private JFreeChart createChart(final XYDataset dataset) {
    final JFreeChart result = ChartFactory.createXYAreaChart(
        TITLE, "hh:mm:ss", "milliVolts", dataset,PlotOrientation.VERTICAL, true, true, false);
    final XYPlot plot = result.getXYPlot();
    ValueAxis domain = plot.getDomainAxis();
    domain.setAutoRange(true);

    ValueAxis range = plot.getRangeAxis();
    range.setRange(-MINMAX, MINMAX);
    return result;
}

public void start() {
    timer.start();
}

public static void main(final String[] args) {
    EventQueue.invokeLater(new Runnable() {

        @Override
        public void run() {
            essaijfree2 demo = new essaijfree2(TITLE);
            demo.pack();
            RefineryUtilities.centerFrameOnScreen(demo);
            demo.setVisible(true);
            demo.start();
        }
    });
}

Answer 1

我会看到位于最后添加的基准坐标处的XYShapeAnnotation。可以看到一些例子here。您可以使用具有不同 alpha 的RadialGradientPaint来获得光环效果。我从未尝试动态执行此操作，但XYPlot包含方法addAnnotation()和removeAnnotation();都通知所有注册的听众。

Answer 2

我建议您创建自己的XYAnnotation，a）不使用预定义的x和y值，而是从数据集中选择它们，b）使用在Java2D空间中定义边界的形状，以便形状大小保持不变当你放大。这是一个例子：

Item Annotation Demo

public class ItemAnnotationDemo {

    public static void main(String[] args) {
        int count = 20;
        double[][] data = new double[2][count];
        for(int i = 0; i < count; i++){
            data[0][i] = i;
            data[1][i] = i;
        }
        DefaultXYDataset dataset = new DefaultXYDataset();
        dataset.addSeries("Values", data);
        NumberAxis xAxis = new NumberAxis("x axis");
        NumberAxis yAxis = new NumberAxis("y axis");
        XYItemRenderer renderer = new XYLineAndShapeRenderer(true, true);
        renderer.addAnnotation(new XYItemAnnotation(
            new Rectangle2D.Double(-10, -8, 20, 16),
            new Color(128,128,128,128),
            new BasicStroke(3.0f),
            Color.RED,0,Integer.MAX_VALUE));
        XYPlot plot = new XYPlot(dataset, xAxis, yAxis, renderer);
        JFreeChart chart = new JFreeChart(plot);
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new ChartPanel(chart));
        frame.pack();
        frame.setVisible(true);

    }
}
class XYItemAnnotation extends AbstractXYAnnotation{
    private Shape shape;
    private Paint outline;
    private Paint fill;
    private Stroke stroke;
    private int si;
    private int ii;
    public XYItemAnnotation(Shape shape, Paint fillPaint, Stroke outlineStroke, Paint outlinePaint, int seriesIndex, int itemIndex){
        super();
        this.shape = shape;
        this.fill = fillPaint;
        this.stroke = outlineStroke;
        this.outline = outlinePaint;
        this.si = seriesIndex;
        this.ii = itemIndex;
    }
    public void draw(Graphics2D g2, XYPlot plot, Rectangle2D dataArea, ValueAxis domainAxis, ValueAxis rangeAxis, int datasetIndex, PlotRenderingInfo info){
        XYDataset dataset = plot.getDataset(datasetIndex);
        if(dataset == null) return;
        if(si > dataset.getSeriesCount() - 1 ) return;
        int item = Math.max(0, ii);
        item = Math.min(item, dataset.getItemCount(si) - 1);
        double dx = dataset.getXValue(si, item);
        double dy = dataset.getYValue(si, item);
        if(Double.isNaN(dx) || Double.isNaN(dy)) return;
        if(!domainAxis.getRange().contains(dx) || !rangeAxis.getRange().contains(dy)) return;
        PlotOrientation orientation = plot.getOrientation();
        RectangleEdge domainEdge = Plot.resolveDomainAxisLocation(
                plot.getDomainAxisLocation(), orientation);
        RectangleEdge rangeEdge = Plot.resolveRangeAxisLocation(
                plot.getRangeAxisLocation(), orientation);

        double jx = domainAxis.valueToJava2D(dx, dataArea, domainEdge);
        double jy = rangeAxis.valueToJava2D(dy, dataArea, rangeEdge);
        if (orientation == PlotOrientation.HORIZONTAL) {
            double temp = jx;
            jx = jy;
            jy = temp;
        }
        Shape trans = ShapeUtilities.createTranslatedShape(shape, jx, jy);
        g2.setPaint(fill);
        g2.fill(trans);
        g2.setPaint(outline);
        g2.setStroke(stroke);
        g2.draw(trans);

    }
}

面积图JFreechart上的图形点

2 个答案: