protected void drawZeroDomainBaseline(Graphics2D g2,Rectangle2D area){
  if (isDomainZeroBaselineVisible()) {
    XYItemRenderer r=getRenderer();
    if (r instanceof AbstractXYItemRenderer) {
      AbstractXYItemRenderer renderer=(AbstractXYItemRenderer)r;
      renderer.drawDomainLine(g2,this,getDomainAxis(),area,0.0,this.domainZeroBaselinePaint,this.domainZeroBaselineStroke);
    }
  }
}

protected void drawZeroDomainBaseline ( Graphics2D g2 , Rectangle2D area ) { if ( isDomainZeroBaselineVisible ( ) ) { XYItemRenderer r = getRenderer ( ) ; if ( r instanceof AbstractXYItemRenderer ) { AbstractXYItemRenderer renderer = ( AbstractXYItemRenderer ) r ; renderer . drawDomainLine ( g2 , this , getDomainAxis ( ) , area , 0.0 , this . domainZeroBaselinePaint , this . domainZeroBaselineStroke ) ; } } }
draws a base line across the chart at value zero on the domain axis .
