[R] Controlling graphics parameters in lattice

[ripley@stats.ox.ac.uk]

On Fri, 6 Dec 2002, Michael Friendly wrote:

> I'm just starting to work with lattice graphics, and am
> having difficulty understanding how to control various graphic
> parameters (font sizes, etc.).  [I'm actually using xyplot
> via plot.effect() in the car package, and would like to be
> able to set some global defaults.]
>
> I read ?xyplot and ?trellis.par.set-- which contains no complete
> list of parameters, just a reference to print(trellis.par.get())
>
> > print(trellis.par.get())
> $fontsize
> $fontsize$default
> [1] 10
>
> I tried
> > trellis.par.set("fontsize", 12)
> >  data(quakes)
> >      Depth <- equal.count(quakes$depth, number=8, overlap=.1)
> >      xyplot(lat ~ long | Depth, data = quakes)
>
> And this crashes the Rgui (Windows, R 1.6.1).  Is this a buglet
> or did I do something wrong?

Both.  Try
trellis.par.set("fontsize", list(default=12))

but it is a bug in the grid package.

> As well, I'm confused about why the following has no effect
> on the background (from a fresh start):
>
> > library(lattice)

You need to open the device whose background you are trying to change:

trellis.device()

> > trellis.par.set("background", "white")
> >  data(quakes)
> >      Depth <- equal.count(quakes$depth, number=8, overlap=.1)
> >      xyplot(lat ~ long | Depth, data = quakes)
>
> Only after I've run xyplot once, I can repeat
>
> > trellis.par.set("background", "white")
> >      xyplot(lat ~ long | Depth, data = quakes)
>
> and the background will change.

That should be detected (no trellis device open) and give an error or open
a device.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595