extern  void init_views ();
extern  void msg ();
extern  void draw_marker ();
extern  void rub_marker ();
extern  void draw_line ();
extern  void rub_line ();
extern  void invert_marker ();
extern  void clear_canvas ();
extern  void drawgraph ();
extern  void draw_update ();
extern  void name_points ();

extern  void read_file();
extern  void write_file();
extern  void do_filter();
extern  void my_canvas_event();