[R] Plotmath bug or my misunderstanding?

[Peter Ehlers]

Hi Bert,

I think the 'cex=' argument applies to the outermost 'atop()'.
It then applies that size specification to each of the two
components of the atop(a,b). If one of the components is itself
another atop(a,b), then the individual parts are sized downward
to produce the required cex for the unit.

As for the 'cex=1:2' specification, only the first value is used.

Cheers,
Peter Ehlers

On 2012-05-12 14:05, Bert Gunter wrote:
> This is a followup to a recent post on using atop() to obtain
> multiline expressions.
>
> My reading of the plotmath docs makes it clear that issuing (in base
> graphics) the specification
>
> par(cex = 2)
>
> doubles symbols and regular text in subsequent plotmath expressions.
> However, it is unclear to me what specifying cex _within_ the
> annotation function using plotmath should do, and the following seems
> to want to have it both ways: ignore/obey )or maybe recycle?)
>
> plot(1,type="n", xaxt='n', yaxt='n', ann=FALSE)
>   text(1,1,labels=expression(atop(sigma,"some text")),cex = 2)
> ## obeys the cex specification in symbols and text
>
> HOWEVER
>
> plot(1,type="n", xaxt='n', yaxt='n', ann=FALSE)
>   text(1,1,labels=expression(atop(atop(sigma,"some text"),"another
> level")),cex = 2)
> ## ???
>
> For even more fun, try:
>
> plot(1,type="n", xaxt='n', yaxt='n', ann=FALSE)
>   text(1,1,labels=expression(atop(atop(sigma,"some text"),"another
> level")),cex = 1:2)
> ##????
>
> So I confess to being flummoxed. Enlightenment would be much appreciated.
>
> Cheers,
> Bert
>
>
>
>