class interface SIMPLE_PEN creation make -- Create default 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 SIMPLE_PEN -- Width set_width (wi: INTEGER) -- Set pen width in _logical_ units. If width is zero -- the pen is one _pixel_ width. Only line of solid style -- (set_line_solid) support proper widths. Non-solid lines -- width is one pixel. Geometric pens must be used for properly -- scalable pens. require valid_width: wi >= 0 invariant valid_color: color /= Void; valid_width: width >= 0; end of SIMPLE_PEN