@Override public void drawBackground(Graphics2D g2,Rectangle2D area){
  fillBackground(g2,area,this.orientation);
  drawBackgroundImage(g2,area);
}

@ Override public void drawBackground ( Graphics2D g2 , Rectangle2D area ) { fillBackground ( g2 , area , this . orientation ) ; drawBackgroundImage ( g2 , area ) ; }
draws the plot background ( the background color and / or image ) . < p > this method will be called during the chart drawing process and is declared public so that it can be accessed by the renderers used by certain subclasses . you shouldn ' t need to call this method directly .
