if( start==null || end==null )
return;
if( showMouseOver && tracker.getCurrentPoint()!=null ){
MinFinder finder=new MinFinder(tracker.getCurrentPoint());
graphics.setColor(PreferenceUtil.instance().getDrawVertexFillColor());
if( start!=null && end!=null && finder.dist(start)<radius ){
graphics.fill(new Rectangle(start.getX()-radius, start.getY()-radius, radius*2, radius*2 ));
graphics.fill(new Rectangle(end.getX()-radius, end.getY()-radius, radius*2, radius*2 ));
}
if( start!=null && end !=null && finder.dist(end)<radius ){
graphics.fill(new Rectangle(start.getX()-radius, start.getY()-radius, radius*2, radius*2 ));
graphics.fill(new Rectangle(end.getX()-radius, end.getY()-radius, radius*2, radius*2 ));
}
}