[R] Trellis devices and pointize

[Deepayan Sarkar]

On Thu, Jun 12, 2014 at 2:31 PM, Patrick Connolly
<p_connolly at slingshot.co.nz> wrote:
> On Mon, 09-Jun-2014 at 08:33AM +0100, Prof Brian Ripley wrote:
>
> |> The issue here is not trellis.device.
> |>
> |> You are using lattice plots (without mentioning lattice), which are
> |> based on package 'grid' and so using the grid sub-system of a
> |> device. That sub-system does not use the 'pointsize' of the device
> |> as its initial font size.  So you need to use
> |>
> |> grid::gpar(fontsize = 28)
> |>
> |> If I call that after opening the device I get what I guess you expected.
>
> I don't see it making any difference at all.  At one time I supposed that some clever inner
> workings rescaled everything to something more sensible for a plotting
> region that size, but that is not the case.
>
>>   trellis.device(device = pdf, file = "Singers.pdf", height = 160/25.4,
> +                  width = 160/25.4)
>
>> grid::get.gpar()$fontsize
> [1] 12
>> grid::gpar(fontsize = 8)
> $fontsize
> [1] 8
>
>> grid::get.gpar()$fontsize
> [1] 12
>>
>
> Evidently I missed something somewhere.  Grid graphics is sometimes a
> bit too subtle for me.  I know gpar() doesn't work exactly analogously
> to the way par() works.  I can't find any examples in Paul's "R
> Graphics" book or Deepayan's "Lattice" book (but that might just be
> lack of searching skills).
>
> Then I tried putting it in the call to print.trellis:
>
>   print(pik, plot.args = grid::gpar(fontsize = 8))
>
> and in the bwplot() call similar to the way I'd done in panel functions
> with an argument called gp but I get no error message or any
> difference in my resulting plot.
>
> I know I can fiddle with trellis.par.get() and trellis.par.set() but
> that's a bit long-winded when it's so simple to do in base graphics.

Unfortunately that's what you will need to do. The font sizes for text
and points are taken from

> trellis.par.get("fontsize")
$points
[1] 8

$text
[1] 12

and these are the hard-coded defaults for all devices.

There was a discussion last year:

https://stat.ethz.ch/pipermail/r-help/2013-June/354749.html

which almost convinced me to effectively change the default to the
device fontsize, but on further thought I changed my mind (and I see
now that I forgot to follow-up on the list to say so). What did change
was that you can now explicitly set

trellis.par.set(fontsize = list(text = NULL))

to make the default come from grid (which in turn takes the default
from the device).

So,

trellis.device(device = pdf, file = "Singers.pdf", height = 160/25.4,
      width = 160/25.4, pointsize = 28)
trellis.par.set(fontsize = list(text = NULL)) # new line
pik <- bwplot(voice.part ~ height, data = singer)# pointsize ignored
print(pik)
dev.off()

should give you what you want. And if you want this to be the default
behaviour, set

lattice.options(default.theme = list(fontsize = list(text = NULL)))

in your .Rprofile.

-Deepayan


> TA
>
> |>
> |>
> |> On 09/06/2014 07:54, Patrick Connolly wrote:
> |> >How is the pointsize set in trellis.devices?
> |> >
> |> >>From my reading of the trellis.device help file, I understood that the
> |> >pointsize arg would be referenced to the call to the pdf function.
> |> >
> |> >So I set up a trellis pdf device as so:
> |> >
> |> >   trellis.device(device = pdf, file = "Singers.pdf", height = 160/25.4,
> |> >                  width = 160/25.4, pointsize = 28)
> |> >
> |> >A base R graphics plot works as I'd expected.
> |> >
> |> >   plot(1:10, 50:59) # silly plot with huge plotting characters and letters
> |> >
> |> >However, pointsize is ignored in trellis plots;
> |> >
> |> >   pik <- bwplot(voice.part ~ height, data = singer)# pointsize ignored
> |> >   print(pik)
> |> >   dev.off()
> |> >
> |> >There are many trellis cex-type settings, but FWIU they're all
> |> >relative to the default size.  My question is: How do I set that
> |> >default?
> |> >
> |> >
> |> >R version 3.0.2 (2013-09-25)
> |> >Platform: i686-pc-linux-gnu (32-bit)
> |> >
> |> >locale:
> |> >  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
> |> >  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
> |> >  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
> |> >  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
> |> >  [9] LC_ADDRESS=C               LC_TELEPHONE=C
> |> >[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
> |> >
> |> >attached base packages:
> |> >[1] grDevices utils     stats     graphics  methods   base
> |> >
> |> >other attached packages:
> |> >[1] RColorBrewer_1.0-5 lattice_0.20-24
> |> >
> |> >loaded via a namespace (and not attached):
> |> >[1] grid_3.0.2  plyr_1.8    tools_3.0.2
> |> >
> |> >I've tried with R-3.1.0 on another machine so I don't think the
> |> >problem is with an old version.
> |> >
> |> >I doubt it has much to do with pdf specifically.  Attempts to use png,
> |> >bitmap, postscript devices all produce equivalent results.
> |> >
> |> >
> |> >
> |> >(Here's all the example code uninterrupted:)
> |> >
> |> >   trellis.device(device = pdf, file = "Singers.pdf", height = 160/25.4,
> |> >                  width = 160/25.4, pointsize = 28)
> |> >   plot(1:10, 50:59) # silly plot with huge plotting characters and letters
> |> >   pik <- bwplot(voice.part ~ height, data = singer)# pointsize ignored
> |> >   print(pik)
> |> >   dev.off()
> |> >
> |> >
> |> >TIA
> |> >
> |> >
> |>
> |>
> |> --
> |> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> |> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> |> University of Oxford,             Tel:  +44 1865 272861 (self)
> |> 1 South Parks Road,                     +44 1865 272866 (PA)
> |> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>
> --
> ~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.
>    ___    Patrick Connolly
>  {~._.~}                   Great minds discuss ideas
>  _( Y )_                 Average minds discuss events
> (:_~*~_:)                  Small minds discuss people
>  (_)-(_)                              ..... Eleanor Roosevelt
>
> ~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.
>
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