/// <summary>
 /// Creates a rigid transformation from a trafo <paramref name="trafo"/>.
 /// </summary>
 public Euclidean2d(Trafo2d trafo)
 {
     Rot   = Rot2d.FromM22d((M22d)trafo.Forward);
     Trans = (V2d)trafo.Forward.C2.XY;
 }
 /// <summary>
 /// Creates a rigid transformation from a rotation matrix <paramref name="rot"/> and a (subsequent) translation <paramref name="trans"/>.
 /// </summary>
 public Euclidean2d(M22d rot, V2d trans)
 {
     Rot   = Rot2d.FromM22d(rot);
     Trans = trans;
 }