[R] Align expression and text in mtext()

David Winsemius dwinsemius at comcast.net
Fri Dec 9 15:12:08 CET 2011

On Dec 8, 2011, at 9:53 PM, Remko Duursma wrote:

> Dear R-helpers,
> I have trouble aligning an expression with a subscript, and text, in  
> margin
> text:
> par(mar=c(6,6,1,1))
> b <- barplot(1:3)
> mtext(c("A","B","C"), at=b, side=1, line=1, cex=1.3)
> mtext(expression(italic(C)[a]~(more~text)), at=0, line=1,  
> side=1,cex=1.3)
> As explained in the help files and elsewhere, I understand that the
> expression is aligned by the bounding box, not the lower end of the  
> 'text'
> in the expression. Playing with adj or padj in mtext() does not  
> really solve
> this?
> Any suggestions or workarounds?
> PS, I tried using a phantom() expression for the text bits; but this  
> messes
> up the horizontal alignment).

I couldn't understand from your statement what you were "having  
trouble" with achieving, and even after running your example I am  
still not clear. If your goal is to get the bottom the the expression  
lined up with the bottom of the axis labels inserted with mtext then  
try padj=.2


David Winsemius, MD
West Hartford, CT

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