Grid line issues when using AxesChartStyler.setPlotGridLinesStroke

[wborn]

Since XChart 3.3.0 the grid lines appear multiple times when customizing them with AxesChartStyler.setPlotGridLinesStroke.

It can be reproduced using the small example program below:

package example;

import java.awt.BasicStroke;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;
import javax.swing.JPanel;

import org.knowm.xchart.XYChart;
import org.knowm.xchart.XYChartBuilder;

public class ChartTest {

    private static class ChartPanel extends JPanel {

        private static final long serialVersionUID = 1L;

        @Override
        public void paint(Graphics g) {
            XYChart chart = new XYChartBuilder().width(getWidth()).height(getHeight()).build();
            chart.getStyler().setPlotGridLinesStroke(new BasicStroke((float) 3.125, BasicStroke.CAP_BUTT,
                    BasicStroke.JOIN_BEVEL, 10, new float[] { 6.25f, 6.25f }, 0));
            chart.paint((Graphics2D) g, chart.getWidth(), chart.getHeight());
        }
    }

    public static void main(String s[]) {
        JFrame frame = new JFrame();
        frame.getContentPane().add("Center", new ChartPanel());
        frame.pack();
        frame.setSize(new Dimension(500, 300));
        frame.setVisible(true);
        frame.setTitle("Chart Test");
        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }

}

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These are the resulting grid lines when running this program using XChart 3.8.1:

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If I run the same program using XChart 3.1.0 the grid lines look normal:

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It seems the issues started with XChart 3.2.0 where the grid lines are not filled:

The change log also mentions there was a fix for this in 3.3.0, but it looks like the fix had some side effects.

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I've tested this on Java 11, Ubuntu 20.04.3