lattice: how to "center" a subtitle?

On Apr 4, 2011, at 1:27 PM, Marius Hofert wrote:

Dear David,

do you know how to get plotmath-like symbols in both rows?
I tried s.th. like:

lab <- expression(paste(alpha==1, ", ", beta==2, sep=""))
xlab <- substitute(expression( atop(lab==lab., bold(foo)) ), list(lab.=lab))
xyplot(0 ~ 0, xlab = xlab)

I _did_ have plotmath functions in both rows: But here is your solution:

xyplot(0 ~ 0,  xlab =
   expression( atop(paste(alpha==1, "   ", beta==2), bold(bla) )) )
     )

Note that `paste` in plotmath is different than `paste` in regular R. It has no `sep` argument. I did try both substitute and bquote on you externally expression,  but lattice seems to be doing some non-standard evaluation and I never got it to "work". Using what I thought _should_ work, does work with `plot`:

x=1;y=2
plot(0 ~ 0, xlab = bquote( atop(alpha==.(x)*","~beta==.(y), bold(foo) ) )

+ )

But the same expression throws an error with xyplot:

x=1;y=2
xyplot(0 ~ 0, xlab = bquote( atop(alpha==.(x)*","~beta==.(y), bold(foo) ) )

+ )
Error in trellis.skeleton(formula = 0 ~ 0, cond = list(1L), aspect = "fill",  :
 could not find function "atop"

-- 
David.

Cheers,

Marius

On 2011-04-04, at 18:59 , David Winsemius wrote:

On Apr 4, 2011, at 12:45 PM, Marius Hofert wrote:

Dear David,

I intended to use another x-label. But your suggestion brings me to the idea of just using a two-line xlab, so s.th. like
print(xyplot(0 ~ 0, xlab.top = "This title is now 'centered' for the human's eye", xlab = "but subtitles are _now_ centered\nbla", scales = list(alternating = c(1,1), tck = c(1,0))))

And if you wanted different fontface (underline, italic or bold) then you could use plotmath expressions:

xyplot(0 ~ 0, xlab.top = "This title is now 'centered' for the human's eye", xlab = expression( atop(but~subtitles2~are~underline(now)~centered, bold(bla) )), scales = list(alternating = c(1,1), tck = c(1,0)))

-- 
David.

Thanks!

Cheers,

Marius

On 2011-04-04, at 16:47 , David Winsemius wrote:

On Apr 4, 2011, at 7:39 AM, Marius Hofert wrote:

Dear expeRts,

I recently asked for a real "centered" title (see, e.g., http://tolstoy.newcastle.edu.au/R/e13/help/11/01/0135.html).
A nice solution (from Deepayan Sarkar) is to use "xlab.top" instead of "main":

library(lattice)
trellis.device("pdf")
print(xyplot(0 ~ 0, xlab.top = "This title is now 'centered' for the human's eye", sub = "but subtitles are not centered", scales = list(alternating = c(1,1), tck = c(1,0))))
dev.off()

library(lattice)
trellis.device("pdf")
print(xyplot(0 ~ 0, xlab.top = "This title is now 'centered' for the human's eye", xlab = "but subtitles are _now_ centered", scales = list(alternating = c(1,1), tck = c(1,0))))
dev.off()


(I realize that those are not really subtitles by a 'lab', but that appears acceptable in your current test case.)

My question is whether there is something similar for *sub*titles [so something like "xlab.bottom"]? As you can see from the plot, the subtitle does not seem to be "centered" for the human's eye. I would like to center it according to the x-axis label.

David Winsemius, MD
West Hartford, CT

David Winsemius, MD
West Hartford, CT

David Winsemius, MD
West Hartford, CT