deferred class interface BASIC_PEN

feature(s) from BASIC_PEN
   --  Colour

   set_color (cl: COLOR)
      --  Set pen colour.

      require
         valid_color: cl /= Void
      ensure
         keep_reference: color = cl

feature(s) from BASIC_PEN
   --  Line style

   set_line_solid
      --  Set line style: solid (default).


   set_line_solid_inside_frame
      --  Set line style: solid, kept inside rectangles.


   set_line_invisible
      --  Set line style: no line (invisible).


   set_line_dash
      --  Set line style: - - - -


   set_line_dot
      --  Set line style: .......


   set_line_dash_dot
      --  Set line style: -.-.-.-


   set_line_dash_dot_dot
      --  Set line style: -..-..-


invariant
   valid_color: color /= Void;

end of deferred BASIC_PEN