** \todo \a point should be of the type <tt>const Point \&</tt> */
virtual void set_time(Context context, Time time, const Point &point)const;
** \todo \a point should be of the type <tt>const Point \&</tt> */
virtual void set_time(Context context, Time time, const Point &point)const;
/*! \param context Context iterator referring to next Layer.
** \param pos Point which indicates where the Color should come from
** \see Context::get_color()
/*! \param context Context iterator referring to next Layer.
** \param pos Point which indicates where the Color should come from
** \see Context::get_color()