[R] Plotmath bug or my misunderstanding?

[Rui Barradas]

Hello,

It seems like a "feature". When trying the example below with more 
atops, the two bottom most lines, and only those two lines, feature 
character expansion relative to the default size and relative to the 
line before last.

plot(1, type="n", xaxt='n', yaxt='n', ann=FALSE, xlim=c(-0.5, 6))
text(1, 1,labels=expression(atop(atop(sigma,"some text"),
     "another level")), cex = 2)
text(3, 1, labels=expression(atop(atop(atop(sigma,"some text"),
     "another level"), "third")), cex = 2)
text(5, 1, labels=expression(atop(atop(atop(atop(sigma,"some text"),
     "another level"), "third"), "4th")), cex = 2)

Anyway, I couldn't find this behavior in the help pages.

Rui Barradas


Em 13-05-2012 11:00,  Bert Gunter escreveu:
> Date: Sat, 12 May 2012 14:05:26 -0700
> From: Bert Gunter<gunter.berton at gene.com>
> To:r-help at r-project.org
> Subject: [R] Plotmath bug or my misunderstanding?
> Message-ID:
> 	<CACk-te0syHj9XjbkfHPYtCMwyWtYdPFYCehxGpxidtBR0_PkdQ at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> 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