public bool EndsAfter(FPoint ev)
{
return(endPt.X > ev.X || endPt.X == ev.X && endPt.Y > ev.Y);
}
public double CrossProduct(FPoint pt)
{
return((endPt.X - startPt.X) * (pt.Y - startPt.Y) - (endPt.Y - startPt.Y) * (pt.X - startPt.X));
}