class interface COSMETIC_PEN
creation
   make
      --  Create 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: -..-..-
feature(s) from COSMETIC_PEN
   --  Line style
   set_line_alternate
      --  Set line style: alternate (every other pixel). 
invariant
   valid_color: color /= Void;
end of COSMETIC_PEN