如何更改/自定义JFreeChart的十字线叠图? [英] How to change/customize Crosshair Overlays for JFreeChart?

问题描述

我正在尝试将十字线叠加层用于XYPlot.尽管我想更改标签的绘制方式，但效果很好.这是我当前的代码段:

I am trying to use a crosshair overlay for an XYPlot. This works quite well, though I would like to change the way the label is drawn. This is my current snippet:

// add crosshair
final CrosshairOverlay crosshairOverlay = new CrosshairOverlay();
final Crosshair xCrosshair = new Crosshair(Double.NaN, Color.DARK_GRAY, new BasicStroke(0f));
xCrosshair.setLabelBackgroundPaint(new Color(1f, 1f, 1f, 0f));
xCrosshair.setLabelOutlineVisible(false);
xCrosshair.setLabelVisible(true);
xCrosshair.setLabelGenerator(new CrosshairLabelGenerator() {
    @Override
    public String generateLabel(final Crosshair ch) {
        return UnitConverter.freq2Str(ch.getValue());
    }
});

final Crosshair yCrosshair = new Crosshair(Double.NaN, Color.DARK_GRAY, new BasicStroke(0f));
yCrosshair.setLabelBackgroundPaint(new Color(1f, 1f, 1f, 0f));
yCrosshair.setLabelVisible(true);
yCrosshair.setLabelOutlineVisible(false);
yCrosshair.setLabelGenerator(new CrosshairLabelGenerator() {
    @Override
    public String generateLabel(final Crosshair ch) {
        return UnitConverter.val2Str(ch.getValue(), 5, "dBc/Hz");
    }
});

crosshairOverlay.addDomainCrosshair(xCrosshair);
crosshairOverlay.addRangeCrosshair(yCrosshair);
this.addOverlay(crosshairOverlay);
this.addChartMouseListener(new ChartMouseListener() {
    @Override
    public void chartMouseMoved(final ChartMouseEvent event) {
        final Rectangle2D dataArea = APChartPanel.this.getScreenDataArea();
        final XYPlot plot = (XYPlot) event.getChart().getPlot();
        final double x = plot.getDomainAxis().java2DToValue(event.getTrigger().getX(), dataArea, RectangleEdge.BOTTOM);
        final double y = plot.getRangeAxis().java2DToValue(event.getTrigger().getY(), dataArea, RectangleEdge.LEFT);
        xCrosshair.setValue(x);
        yCrosshair.setValue(y);
    }

    @Override
    public void chartMouseClicked(final ChartMouseEvent arg0) {}
});

这将产生以下标签:

首先，我想删除文本周围的框，并希望控制字体大小和字体.但是使用Crosshair#setLabelOutlineVisible(boolean)也会删除文本，并且Crosshair#setLabelFont(Font)完全不会更改字体.这仍在进行中还是我在这里做错了什么?

As a start, I would like to remove the box around the text and would like to control the font size and family. But using Crosshair#setLabelOutlineVisible(boolean) will also remove the text and Crosshair#setLabelFont(Font) doesn't change the font at all. Is this still work in progress or am I doing something wrong here?

我得到了以下解决方案:

I got to the following solution:

通过使用@trashgod的建议扩展CrosshairOverlay并将此代码用于单个十字准线:

by extending CrosshairOverlay with the suggestions of @trashgod and using this code for an individual crosshair:

final Crosshair yCrosshair = new Crosshair(Double.NaN, Color.GRAY, new BasicStroke(0f));
yCrosshair.setLabelBackgroundPaint(new Color(1f, 1f, 1f, 0.7f));
yCrosshair.setLabelPaint(Color.GRAY);
yCrosshair.setLabelVisible(true);
yCrosshair.setLabelOutlineVisible(false);
yCrosshair.setLabelFont(yCrosshair.getLabelFont().deriveFont(11f));
yCrosshair.setLabelGenerator(new CrosshairLabelGenerator() {
    @Override
    public String generateLabel(final Crosshair ch) {
        return UnitConverter.val2Str(ch.getValue(), 5, "dBc/Hz");
    }
});

推荐答案

此处，但以前既未使用Crosshair::isLabelOutlineVisible也未使用Crosshair::getLabelFont.您可以尝试这样的事情:

The CrosshairOverlay method drawVerticalCrosshair() renders the crosshair label, as shown here, but it previously used neither Crosshair::isLabelOutlineVisible nor Crosshair::getLabelFont. You might try something like this:

if (crosshair.isLabelOutlineVisible()) { g2.draw(hotspot); }
g2.setFont(crosshair.getLabelFont());
TextUtilities.drawAlignedString(label, g2, xx, yy, alignPt);

从这个示例开始，我进行了以下更改以显示结果.

Starting from this example, I made the following changes to get the result shown.

xCrosshair.setLabelFont(xCrosshair.getLabelFont().deriveFont(20f));
xCrosshair.setLabelBackgroundPaint(new Color(1f, 1f, 1f, 0f));
xCrosshair.setLabelOutlineVisible(false);

drawHorizontalCrosshair()中的类似代码也应更新；保存和还原图形上下文的字体也可能是必要的.

Similar code in drawHorizontalCrosshair() should also be updated; saving and restoring the graphics context's font may also be warranted.

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