public static Point Add(Point pt, Size sz)
{
return new Point(pt.X + sz.Width, pt.Y + sz.Height);
}
public static Point Subtract(Point pt, Size sz)
{
return new Point(pt.X - sz.Width, pt.Y - sz.Height);
}
public void Offset(Point p)
{
Offset(p.X, p.Y);
}
