public boolean getShapesVisible() {
        return this.shapesVisible;
    }

    /**
     * Sets a flag that controls whether or not shapes are drawn for each 
     * data value, and sends a {@link RendererChangeEvent} to all registered
     * listeners.
     * 
     * @param flag  the flag.
     * 
     * @see #getShapesVisible()
     */
    public void setShapesVisible(boolean flag) {
        this.shapesVisible = flag;
        fireChangeEvent();