public DVector2(DVector2 r)
 {
     x = r.x;
     y = r.y;
 }
 public static DVector2 TransformPoint(ref DRect r, DVector2 p)
 {
     return(new DVector2((r.width * p.x + r.x), (r.height * p.y + r.y)));
 }
 public static DVector2 Subtract(DVector2 a, DVector2 b)
 {
     return(new DVector2(a.x - b.x, a.y - b.y));
 }