11. SHADING


    This option allows you to shade all areas below any given point
in a curve.  The shading will plot a line from each point to the
bottom of the window.  Therefore, curves such as circles may not be
filled in, since the lines plotted from the top points of the circle
will cross through the bottom points and the final shaded image will
appear to be a rectangle with a semicircle on the top.  This option
will not function if the point plot type has been specified (option 3,
'Specify Plot Type').  This particular feature is only available on
GIGI and VT240 Regis (GIGI mode).
