private double startAngle;
    
    /** The extent of the scale display. */
    private double extent;
    
    /** 
     * The factor (in the range 0.0 to 1.0) that determines the outside limit
     * of the tick marks.
     */
    private double tickRadius;

    /**
     * The increment (in data units) between major tick marks. 
     */
    private double majorTickIncrement;