JFreeChart 折线图，每个点都有文本 [英] JFreeChart line chart with text at each point

问题描述

我想在折线图中绘制的每个点上放置文字.

I would like put text over each point I plotted in a line chart.

这是我能做的:

这就是我需要的(点的名称是绿色的):

And this is what I need (names of point are in green):

推荐答案

StandardXYItemLabelGenerator 应该可以工作；有一个例子这里.

The StandardXYItemLabelGenerator should work; there's an example here.

附录:你在图片中看到的标签在一个单独的字符串数组中.

此类标签可以合并到 XYDataset 中，如下面的 LabeledXYDataset 所示.由于没有使用 StandardXYItemLabelGenerator 的任何功能，XYItemLabelGenerator 的自定义实现就足够了.XYItemRenderer 控制标签的颜色、大小和相对位置.

Such labels may be incorporated in the XYDataset, as shown in LabeledXYDataset below. Because none of the features of StandardXYItemLabelGenerator are used, a custom implementation of XYItemLabelGenerator is sufficient. The XYItemRenderer controls the color, size and relative position of the labels.

附录:如何添加工具提示?

由 ChartFactory.createXYLineChart()，只需为渲染器指定一个 XYToolTipGenerator.默认格式，见这里，是系列:(x, y).

Guided by ChartFactory.createXYLineChart(), simply specify a XYToolTipGenerator to the renderer. The default format, seen here, is Series: (x, y).

renderer.setBaseToolTipGenerator(new StandardXYToolTipGenerator());

import java.awt.Color;
import java.awt.Dimension;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import org.jfree.chart.*;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.labels.ItemLabelAnchor;
import org.jfree.chart.labels.ItemLabelPosition;
import org.jfree.chart.labels.XYItemLabelGenerator;
import org.jfree.chart.labels.StandardXYToolTipGenerator;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.xy.AbstractXYDataset;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.TextAnchor;

/** @see https://stackoverflow.com/a/14459322/230513 */
public class UnitPrice {

    private static XYDataset createDataset() {
        LabeledXYDataset ds = new LabeledXYDataset();
        ds.add(11,  0, "");
        ds.add(12, 68, "A");
        ds.add(13, 65, "B");
        ds.add(14, 67, "C");
        ds.add(15, 69, "D");
        ds.add(16, 60, "F");
        ds.add(17, 83, "G");
        ds.add(18, 86, "H");
        ds.add(19, 70, "I");
        ds.add(20, 60, "J");
        ds.add(21, 55, "K");
        ds.add(22, 54, "L");
        ds.add(23, 50, "M");
        return ds;
    }

    private static class LabeledXYDataset extends AbstractXYDataset {

        private static final int N = 26;
        private List<Number> x = new ArrayList<Number>(N);
        private List<Number> y = new ArrayList<Number>(N);
        private List<String> label = new ArrayList<String>(N);

        public void add(double x, double y, String label){
            this.x.add(x);
            this.y.add(y);
            this.label.add(label);
        }

        public String getLabel(int series, int item) {
            return label.get(item);
        }

        @Override
        public int getSeriesCount() {
            return 1;
        }

        @Override
        public Comparable getSeriesKey(int series) {
            return "Unit";
        }

        @Override
        public int getItemCount(int series) {
            return label.size();
        }

        @Override
        public Number getX(int series, int item) {
            return x.get(item);
        }

        @Override
        public Number getY(int series, int item) {
            return y.get(item);
        }
    }

    private static class LabelGenerator implements XYItemLabelGenerator {

        @Override
        public String generateLabel(XYDataset dataset, int series, int item) {
            LabeledXYDataset labelSource = (LabeledXYDataset) dataset;
            return labelSource.getLabel(series, item);
        }

    }

    private static JFreeChart createChart(final XYDataset dataset) {
        NumberAxis domain = new NumberAxis("Unit");
        NumberAxis range = new NumberAxis("Price");
        domain.setAutoRangeIncludesZero(false);
        XYItemRenderer renderer = new XYLineAndShapeRenderer(true, false);
        renderer.setBaseItemLabelGenerator(new LabelGenerator());
        renderer.setBaseItemLabelPaint(Color.green.darker());
        renderer.setBasePositiveItemLabelPosition(
            new ItemLabelPosition(ItemLabelAnchor.CENTER, TextAnchor.CENTER));
        renderer.setBaseItemLabelFont(
            renderer.getBaseItemLabelFont().deriveFont(14f));
        renderer.setBaseItemLabelsVisible(true);
        renderer.setBaseToolTipGenerator(new StandardXYToolTipGenerator());
        XYPlot plot = new XYPlot(dataset, domain, range, renderer);
        JFreeChart chart = new JFreeChart(
            "Unit Price", JFreeChart.DEFAULT_TITLE_FONT, plot, false);
        return chart;
    }

    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        XYDataset dataset = createDataset();
        JFreeChart chart = createChart(dataset);
        ChartPanel chartPanel = new ChartPanel(chart) {

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(400, 320);
            }
        };
        f.add(chartPanel);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

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