@Override
	protected void paintFocusBorder( Component c, Graphics2D g ) {
		// the outer focus border is painted outside of the icon
		float wh = ICON_SIZE + (focusWidth * 2);
		g.fill( new Ellipse2D.Float( -focusWidth, -focusWidth, wh, wh ) );
	}
Icon for {@link javax.swing.JRadioButton}.
<p>
<strong>Note</strong>:
      If Component.focusWidth is greater than zero, then the outer focus border
      is painted outside of the icon bounds. Make sure that the radiobutton
      has margins, which are equal or greater than focusWidth.

@uiDefault RadioButton.icon.style					String	optional; "outlined"/null (default) or "filled"
@uiDefault RadioButton.icon.centerDiameter			int or float

@author Karl Tauber
flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatRadioButtonIcon.java