[R] CairoPDF and greek letter spacing
dwinsemius at comcast.net
Tue Jan 10 06:36:42 CET 2012
On Jan 10, 2012, at 12:22 AM, Rolf Turner wrote:
> On 10/01/12 15:25, David Winsemius wrote:
>> On Jan 9, 2012, at 8:19 PM, Rolf Turner wrote:
>>> On 10/01/12 11:40, John Walker wrote:
>>>> I have a small problem with R graphics output. When I use the
>>>> package and CairoPDF to generate publication quality graphs I
>>>> often use
>>>> the expression to create an axis title that has microlitres or
>>>> micrometers as a unit. I use something like the following
>>>> 'expression(paste("Length (", mu,"m )"))' as an argument to the
>>>> function. The command works but the mu and 'm' have a space between
>>>> them. It looks like 'u m' rather than 'um'. It only seems to
>>>> happen with
>>>> the CairoPDF output on my linux machine, it's fine on the X11
>>>> I've fixed it in the past by importing the pdf into inkscape and
>>>> manually adjusting the spacing (it's more difficult than it sounds
>>>> because I can't actually adjust the spacing but have to delete
>>>> the mu
>>>> and re-enter it). Is there something I'm doing wrong? Is this a
>>>> bug? How can I fix it?
>>> I can't help, but I can confirm the problem, for what *that* is
>>> It seems be an unfortunate interaction between lattice graphics and
>>> the cairo_pdf() device.
>>> The space between the "mu" and the "m" does not appear with
>>> ``ordinary'' R graphics, irrespective of device, nor does it appear
>>> with lattice graphics and, e.g. the pdf() device. But it does
>>> with lattice graphics *and* the cairo_pdf() device.
>>> That probably means that the problem is subtle and will be difficult
>>> to impossible to fix. :-(
>> Doubtful. Do either of you realize that `paste` is a plotmath
>> function that is misused more often than correctly used (at least
>> as judged by the number o errors submitted to r-help)? I see no
>> workable example, but if I did I would be trying instead :
> You meant expression(Length==mu*m).
I thought what was wanted:
main=expression(Length~group("(",mu*m,")")) # Or
And on a Mac (Leopard, R 2.14.1 Patched) I could not get a different
display on the screen device and either pdf or cairo_pdf so your
experience may have something to do with the as yet unstated OSes.
> And yes that helps a bit, but there's
> still a bit more space between the mu and the m than one would like.
> There's not much in it, but there's just enough to be annoying.
> P. S. And I have never been able to figure out *anything* about how
> paste() and
> expression() interact. It is a complete mystery, and a matter of
> trying things more
> or less at random until something more or less works.
> R. T.
> P^2. S. I just realised that there's more space between the letters
> of "Length" in
> the cairo_pdf version, as well. Which is, I guess, The
> Explanation. Is it a font thing?
> R. T.
David Winsemius, MD
West Hartford, CT
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