Produces (and possibly draws) a Grid frame grob which is a legend (aka key) that can be placed in other Grid plots.
draw.key(key, draw=FALSE, vp=NULL, …)
A list determining the key. See documentation for
xyplot, in particular the section describing the
argument, for details.
logical, whether the grob is to be drawn.
A Grid frame object (that inherits from ‘grob’).