R help - Nov 2004 - Call to trellis.focus(); thenpanel.superpose()

The following works fine with the x11 device, though it
may well be that an initial plot is overwritten.  With a pdf
or postscript device, I get two plots, the first of which
still has the red border from having the focus, while the
second is the plot that I want.

         library(lattice); library(grid)
         plt <- xyplot(uptake ~ conc, groups=Plant, data=CO2)
         print(plt)
         trellis.focus("panel", row=1, column=1)
         arglist=trellis.panelArgs()
         arglist$type <- "l"
         do.call("panel.superpose", args=arglist)
         trellis.unfocus()

Should I be able to use panel.superpose() in this way?

The new abilities provided by trellis.focus() etc add
greatly to the flexibility of what can be done with lattice
plots.  The grid-lattice combination is a great piece of
software.

John Maindonald             email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Centre for Bioinformation Science, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.

On Monday 29 November 2004 04:46, John Maindonald wrote:
> The following works fine with the x11 device, though it
> may well be that an initial plot is overwritten.  With a pdf
> or postscript device, I get two plots, the first of which
> still has the red border from having the focus, while the
> second is the plot that I want.
>
>          library(lattice); library(grid)
>          plt <- xyplot(uptake ~ conc, groups=Plant, data=CO2)
>          print(plt)
>          trellis.focus("panel", row=1, column=1)
>          arglist=trellis.panelArgs()
>          arglist$type <- "l"
>          do.call("panel.superpose", args=arglist)
>          trellis.unfocus()
>
> Should I be able to use panel.superpose() in this way?
Yes. The red border should be 'removed', but that's done by
grid.remove
and maybe it doesn't work on PDF devices.

The solution is to use 

trellis.focus("panel", row=1, column=1, highlight = FALSE)

(which happens automatically for non-interactive sessions).
> The new abilities provided by trellis.focus() etc add
> greatly to the flexibility of what can be done with lattice
> plots.  The grid-lattice combination is a great piece of
> software.
Yes, it can be especially useful for tasks similar to identify(). 
Everything else can probably be done by clever enough use of the panel 
function (though perhaps not as naturally).

Deepayan