防止JFreeChart DialPlot包含大值？ [英] Prevent JFreeChart DialPlot wrapping around with large values?

问题描述

我的数据值可以在0到100之间变化。我想显示一个显示范围0-30的JFreeChart DialPlot，其中大于30的值通过将针固定在30但显示在表盘上的真实值显示。

My data value can vary between 0-100. I would like to display a JFreeChart DialPlot showing the range 0-30, where values larger than 30 are displayed by having the needle fixed at 30 but the true value displayed on the dial.

下图显示了我的示例代码目前产生的代码：

The image below shows what my example code currently produces:

当前输出

我在这里展示价值50.表盘已经缠绕到14点。我希望它设置为最大值（30），就像燃料表盘一样：

Here I am displaying the value 50. The dial has wrapped around to point at 14. I would prefer it to be set to the maximum (30), much like with a fuel dial:

所需输出

JFreeChart可以实现吗？下面的SSCCE代码。

Is this possible with JFreeChart? SSCCE code below.

public class DemoChartProblem {

  private final DefaultValueDataset dataset = new DefaultValueDataset(50);
  private final JFrame frame = new JFrame();

  public static void main(String[] args) throws Exception {
    new DemoChartProblem();
  }

  public DemoChartProblem() {
    frame.setPreferredSize(new Dimension(300, 300));
    frame.add(buildDialPlot(0, 30, 5));
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

    SwingUtilities.invokeLater(new Runnable() {
      @Override
      public void run() {
        frame.setVisible(true);
      }
    });
  }

  private ChartPanel buildDialPlot(int minimumValue, int maximumValue,
      int majorTickGap) {

    DialPlot plot = new DialPlot(dataset);
    plot.setDialFrame(new StandardDialFrame());
    plot.addLayer(new DialValueIndicator(0));
    plot.addLayer(new DialPointer.Pointer());

    StandardDialScale scale = new StandardDialScale(minimumValue, maximumValue,
        -120, -300, majorTickGap, majorTickGap - 1);
    scale.setTickRadius(0.88);
    scale.setTickLabelOffset(0.20);
    plot.addScale(0, scale);

    return new ChartPanel(new JFreeChart(plot));
  }
}

推荐答案

我我只是想出了一个解决方法，但我很想知道是否有更好的方法。

I've just figured out a work-around answer, but I would be interested to hear if there are better methods.

在这个解决方案中，我维持两个 DefaultValueDataset 对象。一个包含实际值，一个包含约束值，不大于我的拨号限制。针与约束集关联，拨号值与实际值相关联。

In this solution, I maintain two DefaultValueDataset objects. One contains the real value and one contains a constrained value, no larger than my dial limit. The needle is associated with the constrained set and the dial value is linked to the real value.

public class DemoChartProblem {

  private static final int DISPLAY_MAX = 30;
  private final DefaultValueDataset dataset = new DefaultValueDataset();
  private final DefaultValueDataset displayDataset = new DefaultValueDataset();
  private final JFrame frame = new JFrame();

  public static void main(String[] args) throws Exception {
    new DemoChartProblem();
  }

  public DemoChartProblem() {
    frame.setPreferredSize(new Dimension(300, 300));
    frame.add(buildDialPlot(0, DISPLAY_MAX, 5));
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

    setValue(50);

    SwingUtilities.invokeLater(new Runnable() {
      @Override
      public void run() {
        frame.setVisible(true);
      }
    });
  }

  private void setValue(int value) {
    dataset.setValue(value);
    displayDataset.setValue(Math.min(DISPLAY_MAX, value));
  }

  private ChartPanel buildDialPlot(int minimumValue, int maximumValue,
      int majorTickGap) {

    DialPlot plot = new DialPlot();
    plot.setDataset(0, dataset);
    plot.setDataset(1, displayDataset);

    plot.setDialFrame(new StandardDialFrame());

    // value indicator uses the real data set
    plot.addLayer(new DialValueIndicator(0));

    // needle uses constrained data set
    plot.addLayer(new DialPointer.Pointer(1));

    StandardDialScale scale = new StandardDialScale(minimumValue, maximumValue,
        -120, -300, majorTickGap, majorTickGap - 1);
    scale.setTickRadius(0.88);
    scale.setTickLabelOffset(0.20);
    plot.addScale(0, scale);

    return new ChartPanel(new JFreeChart(plot));
  }
}

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