JFreeChart StackedXYAreaRenderer导致“卷曲".在图表中

本文介绍了JFreeChart StackedXYAreaRenderer导致“卷曲".在图表中的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在使用JFreeChart显示一段时间内两组数据的堆叠折线图，在此示例中为狗和猫.

I'm using JFreeChart to show a stacked line chart of two sets of data over time, in this example dogs and cats.

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JFrame;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.StackedXYAreaRenderer;
import org.jfree.data.time.Minute;
import org.jfree.data.time.TimeTableXYDataset;

public class ChartTest {

    public ChartTest() throws ParseException{

        TimeTableXYDataset chartData = createChartData();
        JFreeChart chart = createChart(chartData);
        ChartPanel chartPanel = new ChartPanel(chart);

        JFrame frame = new JFrame("Chart Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(chartPanel);
        frame.setSize(500,  500);

        frame.setVisible(true);
    }

    private TimeTableXYDataset createChartData() throws ParseException {

        int[] dogs = {14, 81, 99, 89, 151, 263, 396, 548, 822, 1410, 2180, 3134, 4065, 5016, 6019, 7648, 9323, 11059, 12252, 13432, 15238, 17559, 19796, 21853, 23971, 26414, 28694, 31371, 34233, 37353, 40451, 44081, 47978, 52040, 56024, 60486, 64881, 69663, 74320, 79391, 84840, 91228, 96383, 102061, 107832, 114244, 119992, 126207, 132894, 139146, 144727, 150896, 156503, 161960, 167724, 174172, 180121, 185929, 191375, 196050, 200768, 205208, 208727, 212329, 216439, 221102, 224284, 226944, 230307, 233075, 234814, 236220, 237733, 239158, 240311, 241267};
        int[] cats = {244, 360, 363, 644, 1075, 1516, 2241, 3160, 3591, 4661, 5633, 6990, 7889, 9059, 10510, 11743, 12506, 13540, 14557, 15705, 16969, 18350, 20197, 21659, 23160, 24840, 26394, 28109, 29742, 31428, 33021, 34514, 35822, 37339, 38784, 40258, 41568, 42921, 44180, 45454, 46710, 48084, 49418, 50712, 51920, 53014, 53923, 54830, 55756, 56573, 57554, 58352, 59064, 59874, 60933, 61948, 62762, 63299, 63772, 64243, 64789, 65206, 65693, 66016, 66391, 66859, 67432, 67919, 68400, 68677, 68944, 69211, 69511, 69786, 69990, 70279};

        final TimeTableXYDataset chartData = new TimeTableXYDataset();

        long start = new SimpleDateFormat("MM/dd/yyyy HH:mm").parse("11/08/2016 08:00").getTime();

        for (int t = 0; t < dogs.length; t++) {
            Minute m = new Minute(new Date(start + 15*t*60*1000));
            chartData.add(m, dogs[t], "Dogs");
            chartData.add(m, cats[t], "Cats");
        }

        return chartData;
    }

    private JFreeChart createChart(TimeTableXYDataset chartData) {

        JFreeChart chart = ChartFactory.createStackedXYAreaChart("Dogs and Cats", "Time", "Count", chartData, PlotOrientation.VERTICAL, false, true, false);

        StackedXYAreaRenderer chartRenderer = new StackedXYAreaRenderer();
        XYPlot plot = (XYPlot)chart.getPlot();
        plot.setRenderer(chartRenderer);

        DateAxis dateAxis = new DateAxis();
        dateAxis.setDateFormatOverride(new SimpleDateFormat("HH:mm"));
        dateAxis.setTickLabelFont(dateAxis.getTickLabelFont().deriveFont(20f));

        plot.setDomainAxis(dateAxis);

        return chart;
    }

    public static void main(String... args) throws ParseException{
        new ChartTest();
    }
}

但是，这会导致图表的cats部分出现卷曲":

However, this results in a "crimp" in the cats section of the chart:

我查看了我的数据，它不包含负值或任何可能使图表偏离的奇怪值.

I've looked my data over, and it doesn't contain negative values or anything strange that might throw the chart off.

通过一些shot弹枪调试，我意识到，如果我从createChart()函数中删除了这段代码:

Through some shotgun debugging, I realized that if I remove this section of code from the createChart() function:

    StackedXYAreaRenderer chartRenderer = new StackedXYAreaRenderer();
    XYPlot plot = (XYPlot)chart.getPlot();
    plot.setRenderer(chartRenderer);

    DateAxis dateAxis = new DateAxis();
    dateAxis.setDateFormatOverride(new SimpleDateFormat("HH:mm"));
    dateAxis.setTickLabelFont(dateAxis.getTickLabelFont().deriveFont(20f));

    plot.setDomainAxis(dateAxis);

然后我得到了一个更合理的堆积线图:

Then I get a more reasonable stacked line chart:

但是后来我丢失了格式正确的日期.

But then I lose my nicely formatted dates.

我的问题是:

是什么原因导致图表的cats部分出现卷曲"以及两个堆栈之间的空间?

What is causing the "crimp" in the cats section of the chart, and the space between the two stacks?

是否有另一种方式格式化不引起这种行为的日期?

Is there a different way to format the dates that doesn't cause this behavior?

推荐答案

ChartFactory.createStackedXYAreaChart() 实例化 StackedXYAreaRenderer2 可以避免此问题.您的示例将其替换为 StackedXYAreaRenderer .要么

ChartFactory.createStackedXYAreaChart() instantiates StackedXYAreaRenderer2 to avoid this problem. Your example replaces it with an instance of StackedXYAreaRenderer. Either,

使用工厂的渲染器和自定义的DateAxis.

private JFreeChart createChart(TimeTableXYDataset chartData) {
    JFreeChart chart = ChartFactory.createStackedXYAreaChart(
        "Dogs and Cats", "Time", "Count", chartData,
        PlotOrientation.VERTICAL, false, true, false);
    DateAxis dateAxis = new DateAxis();
    dateAxis.setDateFormatOverride(new SimpleDateFormat("HH:mm"));
    dateAxis.setTickLabelFont(dateAxis.getTickLabelFont().deriveFont(20f));
    XYPlot plot = (XYPlot) chart.getPlot();
    plot.setDomainAxis(dateAxis);
    return chart;
}

在您的createChart()方法中，如此处所示，重现工厂.

Recapitulate the factory, as shown here, in your createChart() method.

private JFreeChart createChart(TimeTableXYDataset chartData) {
    DateAxis dateAxis = new DateAxis("Time");
    dateAxis.setDateFormatOverride(new SimpleDateFormat("HH:mm"));
    dateAxis.setTickLabelFont(dateAxis.getTickLabelFont().deriveFont(20f));
    NumberAxis yAxis = new NumberAxis("Count");
    XYToolTipGenerator toolTipGenerator = new StandardXYToolTipGenerator();
    StackedXYAreaRenderer2 renderer = new StackedXYAreaRenderer2(
        toolTipGenerator, null);
    renderer.setOutline(true);
    XYPlot plot = new XYPlot(chartData, dateAxis, yAxis, renderer);
    plot.setOrientation(PlotOrientation.VERTICAL);
    plot.setRangeAxis(yAxis);  // forces recalculation of the axis range
    JFreeChart chart = new JFreeChart("Dogs and Cats",
        JFreeChart.DEFAULT_TITLE_FONT, plot, false);
    new StandardChartTheme("JFree").apply(chart);
    return chart;
}

作者撰写，"使用不同的绘制方法，为每个数据点计算一个多边形并填充它."相反，StackedXYAreaRenderer似乎是通过将端点与直线连接而关闭了一个Shape.

The author writes, "StackedXYAreaRenderer2 uses a different drawing approach, calculating a polygon for each data point and filling that." In contrast, StackedXYAreaRenderer appears to close a single Shape by connecting the endpoints with a straight line.

这篇关于JFreeChart StackedXYAreaRenderer导致“卷曲".在图表中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！