# [R] panel.rect and log scale in lattice plot

Garbade, Sven Sven@G@rb@de @end|ng |rom med@un|-he|de|berg@de
Wed Mar 23 11:48:44 CET 2022

```thanks, this do the trick!

xyplot(y ~ x,
panel=function(x,y, ...) {
cpl <- current.panel.limits()
yseq <- log(c(100,1000))
panel.rect(xleft=cpl\$xlim[1],
ybottom=yseq[1],
xright=cpl\$xlim[2],
ytop=yseq[2],
fill="lightgray", border="lightgray", alpha=.6)
panel.xyplot(x,y,...)
},
scales=list(y=list(log=2))
)

Best Regards, Sven
________________________________________
Von: Ivan Krylov <krylov.r00t using gmail.com>
Gesendet: Mittwoch, 23. März 2022 11:33
Betreff: Re: [R] panel.rect and log scale in lattice plot

On Wed, 23 Mar 2022 09:38:34 +0000
"Garbade, Sven via R-help" <r-help using r-project.org> wrote:

>            cpl <- current.panel.limits()

If you str() the return value of current.panel.limits() from the panel
function with log-scaling enabled, you can see that it contains the
logarithm of the y-values, as do the y values themselves. This is
consistent with ?xyplot saying:

>> Note that this is in reality a transformation of the data, not the
>> axes. Other than the axis labeling, using this feature is no
>> different than transforming the data in the formula; e.g.,
>> ‘scales=list(x = list(log = 2))’ is equivalent to ‘y ~ log2(x)’.

...although it could be more explicit.

If you take a logarithm of 10 and 500, lrect() should be able to
produce a rectangle in the right place.

--
Best regards,
Ivan

```