R help - Apr 2011 - Define ylim in lattice plot based upon panel function output

Dear R-users,

By default, the xyplot function automatically defines the axis ranges based
upon the content of y and x variables. However, when one includes some calls
to other panel.<something> functions in the panel argument, the results
might be out of range and not show up in the final graphs (see lower ends of
the loess line in the following example). Is there a way one can capture the
results of the functions to update the graph object and set the xlim and
ylim?

Thanks

Sebastien

require(lattice)

df <- data.frame(x=seq(1,30,1),
                 y=c(rep(0,10),rep(10,10),rep(0,10)))

xyplot(y~x,data=df,
       panel=function(x,y,...){
         panel.xyplot(x,y)
         panel.loess(x,y)
       })

	[[alternative HTML version deleted]]

On Tue, Apr 19, 2011 at 7:38 AM, S?bastien Bihorel <pomchip at free.fr>
wrote:
> Dear R-users,
>
> By default, the xyplot function automatically defines the axis ranges based
> upon the content of y and x variables. However, when one includes some
calls
> to other panel.<something> functions in the panel argument, the
results
> might be out of range and not show up in the final graphs (see lower ends
of
> the loess line in the following example). Is there a way one can capture
the
> results of the functions to update the graph object and set the xlim and
> ylim?
Read up on the 'prepanel' argument (in ?xyplot). What you want is
actually already defined -- see ?prepanel.loess.

xyplot(y~x,data=df,
       prepanel = prepanel.loess,
       panel=function(x,y,...){
           panel.xyplot(x,y)
           panel.loess(x,y)
       })

-Deepayan
>
> Thanks
>
> Sebastien
>
> require(lattice)
>
> df <- data.frame(x=seq(1,30,1),
> ? ? ? ? ? ? ? ? y=c(rep(0,10),rep(10,10),rep(0,10)))
>
> xyplot(y~x,data=df,
> ? ? ? panel=function(x,y,...){
> ? ? ? ? panel.xyplot(x,y)
> ? ? ? ? panel.loess(x,y)
> ? ? ? })
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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