[R] placing rectangle behind plot

[Sebastian P. Luque]

Hi Gabor,


On Sat, 29 Jul 2006 17:20:29 -0400,
"Gabor Grothendieck" <ggrothendieck at gmail.com> wrote:

> I am trying to create a lattice plot and would like to later, i.e. after
> the plot is drawn, add a grey rectangle behind a portion of it.  The
> following works except that the rectrangle is on top of and obscures a
> portion of the chart.  I also tried adding col = "transparent" to the
> gpar list but that did not help -- I am on windows and perhaps the
> windows device does not support transparency?  At any rate, how can I
> place the rectangle behind the plotted points without drawing the
> rectangle first?

If you only need to draw the rectangle behind the points, why not
'panel.polygon' before 'panel.xyplot'?


xyplot(x ~ x | gl(2, 1), layout=1:2,
       panel=function(x, y, ...) {
           panel.polygon(c(3, 3, 8, 8), c(0, 12, 12, 0), col=2)
           panel.xyplot(x, y, ...)
       })


Cheers,

-- 
Seb