public Rectangle(Point lowerleft, Size size)
 {
     this.Left = lowerleft.X;
     this.Bottom = lowerleft.Y;
     this.Right = lowerleft.X + size.Width;
     this.Top = lowerleft.Y + size.Height;
 }
 public Rectangle(Point lowerleft, Point upperright)
 {
     this.Left = lowerleft.X;
     this.Bottom = lowerleft.Y;
     this.Right = upperright.X;
     this.Top = upperright.Y;
 }