# [R] lattice: how to "center" a subtitle?

Peter Ehlers ehlers at ucalgary.ca
Mon Apr 4 20:01:51 CEST 2011

```On 2011-04-04 10:27, 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)

Marius,

I always find paste a bit tricky with plotmath.
Maybe this will do what you want:

mylab <- expression( atop(lab==list(alpha==1, beta==2), bold(foo)) )
xyplot(0 ~ 0, xlab = mylab)

Peter Ehlers

>
> 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
>>
>
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