+ unsigned get_n_lines() const { return lines.size(); }
+ unsigned get_visible_lines(const Part &, const Geometry &, unsigned *) const;
+ unsigned get_line_length(unsigned) const;
+ unsigned move_offset(unsigned, int) const;
+ void offset_to_coords(unsigned, unsigned &, unsigned &) const;
+ unsigned coords_to_offset(unsigned, unsigned) const;
+ Geometry coords_to_geometry(const Part &, const Geometry &, unsigned, unsigned, unsigned) const;