Question

JFreeChart has a class called LineFunction2D(double YIntercept, double Slope). I can get the JFreeChart examples to work, but I can’t get LineFunction2D to work. How can I add the line graph to a JFreeChart object?

LineFunction2D line = new LineFunction2D(.03125, (.125 - .03125));

//missing code goes here

JFreeChart chart = new JFreeChart(Plot plot);
ChartPanel panel = new ChartPanel(chart);

Thanks!

(I’m working on the sscce, and will post it soon.)

Answer 1

I think that the code you are looking for is the call to DatasetUtilities.sampleFunction2D to convert the dataset into am XYDataset that you can add to your plot

private static final double A = 5 / 16d;
private static final double B = 1 / 8d - A;
private double start = 1;
private double end = 10;
private int samples = 4;
private Comparable<String> seriesKey = "Regression";

…

        XYPlot plot = new XYPlot(this.data1, xAxis, yAxis, renderer1);
        LineFunction2D line = new LineFunction2D(A, B);
        XYDataset lineDS = DatasetUtilities.sampleFunction2D(line,start,end,samples,seriesKey );
        plot.setDataset(plot.getDatasetCount() + 1, lineDS);