wn_getscrn(_c)

	status.i4.v = wn_getscrn(plane.i4.r, world_coord.r4.r,
				 screen_coord.i4.r)

	status.i4.v = wn_getscrn_c(plane.i4.v, world_coord.r4.v,
				   screen_coord.i4.r)
 
	This routine returns a screen (pixel) coordinate given a world
	coordinate for the active graphic window.

	plane		(WN_HORZ -> horizontal,
			 WN_VERT -> vertical)
	world_coord	world coordinate
	screen_coord	returned screen coordinate in pixels

	This function returns ACNET status values as follows:

	OK			success
	CBS_INVARG		invalid plane specified or invalid value
				passed for logarithmic scaling
	CBS_NOSETUP		an active window has not been established
	CBS_RANGE		world_coord is not within the limits of
				the active window or it is invalid for
				the scaling of the active window
	CBS_INVALID_DATA	scaling of data resulted in a floating
				point overflow

	This function requires the following include files:

	cbslib_h, acnet_errors_h

	Related functions:

	wn_getworld(_c), wn_view(_c), wn_active(_c), wn_world(_c),
	intro_graphics_windows

	C/C++ usage:

	int	status;
	int	plane = WN_HORZ;
	int	screen_coord;
	float	world_coord = 5.0;

	status = wn_getscrn_c(plane,world_coord,&screen_coord);