+void frontend_default_colour(frontend *fe, float *output);
+void draw_rect(frontend *fe, int x, int y, int w, int h, int colour);
+void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour);
+void draw_polygon(frontend *fe, int *coords, int npoints,
+ int fill, int colour);
+void start_draw(frontend *fe);
+void draw_update(frontend *fe, int x, int y, int w, int h);
+void end_draw(frontend *fe);
+void deactivate_timer(frontend *fe);
+void activate_timer(frontend *fe);