Jfree：堆积面积图在零值处重叠

Question

I am having a problem in jfree chart - StackedAreaChart.

The problem is I want to show one positive value and another negative value. The positive value ends on year say 2011 and negative starts from 2012. But in stacked area chart it overlaps for some distance on the scale. See the image for problem and required solution.

Does anybody knows the solution for this. Any help will be appreciated.

Answer 1

Try using a TimeTableXYDataset to hold the series data and a second StackedXYAreaRenderer to show the negatives. This might solve your problem:

import java.io.File;
import java.io.IOException;
import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.StackedXYAreaRenderer;
import org.jfree.data.time.TimeTableXYDataset;
import org.jfree.data.time.Year;
import org.jfree.data.xy.TableXYDataset;

public class StackedAreaChart2 {

    public StackedAreaChart2() {
        TimeTableXYDataset[] dataset = createDataset();
        createChart(dataset);
    }

    public TimeTableXYDataset[] createDataset() {
        TimeTableXYDataset dataSet1 = new TimeTableXYDataset();

        dataSet1.add(new Year(2001), 1.0,"Series1");
        dataSet1.add(new Year(2002), 2.0,"Series1");
        dataSet1.add(new Year(2003),3.0,"Series1");
        dataSet1.add(new Year(2004),4.0,"Series1");
        dataSet1.add(new Year(2005),5.0,"Series1");
        dataSet1.add(new Year(2006),0,"Series1");

        dataSet1.add(new Year(2001), 6.0,"Series2");
        dataSet1.add(new Year(2002),3.0,"Series2");
        dataSet1.add(new Year(2003),4.0,"Series2");
        dataSet1.add(new Year(2004),3.0,"Series2");
        dataSet1.add(new Year(2005),9.0,"Series2");
        dataSet1.add(new Year(2006),0,"Series2");

        TimeTableXYDataset dataSet2 = new TimeTableXYDataset();
        dataSet2.add(new Year(2006),-2,"Series3");
        dataSet2.add(new Year(2007),-3,"Series3");
        dataSet2.add(new Year(2008),-4,"Series3");  

        return new TimeTableXYDataset[] {dataSet1,dataSet2};
    }

    public JFreeChart createChart(TableXYDataset[]  dataset) {
        final JFreeChart chart = ChartFactory.createStackedXYAreaChart("","","",dataset[0],PlotOrientation.VERTICAL,true,true,false);
        XYPlot plot = (XYPlot) chart.getPlot();        
        StackedXYAreaRenderer renderer2 = new StackedXYAreaRenderer();
        plot.setDataset(1, dataset[1]);
        plot.setRenderer(1, renderer2);
        NumberAxis axis = (NumberAxis) plot.getDomainAxis();
        axis.setNumberFormatOverride(new NumberFormat(){

            @Override
            public StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition pos) {
                  SimpleDateFormat format = new SimpleDateFormat("YYYY");   
                  return toAppendTo.append(format.format(new Date((long) number)));
                }

            @Override
            public StringBuffer format(long number, StringBuffer toAppendTo, FieldPosition pos) {
                return new StringBuffer(String.format("%s", number));
            }

            @Override
            public Number parse(String source, ParsePosition parsePosition) {
                return null;
            }
        });
        return chart;
    }

    public void saveChart(JFreeChart chart, String fileLocation) {
        String fileName = fileLocation;
        try {
            ChartUtilities.saveChartAsPNG(new File(fileName), chart, 1000, 600);
        } catch (IOException e) {
            e.printStackTrace();
            System.err.println("Problem occurred creating chart.");
        }
    }

    public static void main(final String[] args) {
        final StackedAreaChart2 demo = new StackedAreaChart2();
        TableXYDataset[] categoryDataset = demo.createDataset();
        JFreeChart chart = demo.createChart(categoryDataset);
        String fileLocation = "StackAreaChart.png";
        demo.saveChart(chart, fileLocation);
        System.out.println("Pie Chart has been created successfully");
        System.out.println("Chart has been saved to: " + fileLocation);
    }

}