This is pretty easy to replicate by creating a background gradient fill for the dial chart as follows:
Code: Select all
GradientPaint gp = new GradientPaint(new Point(),
new Color(255, 255, 102), new Point(),
new Color(255, 128, 0));
DialBackground db = new DialBackground(gp);
db.setGradientPaintTransformer(new StandardGradientPaintTransformer(GradientPaintTransformType.VERTICAL));
plot.setBackground(db);