[Rd] How to infer default width and height for a device?

[Henrik Bengtsson]

On Sat, Nov 5, 2011 at 3:08 PM, Henrik Bengtsson <hb at biostat.ucsf.edu> wrote:
> Hi.
>
> GENERAL:
> Is there a general method for inferring default device settings,
> particularly 'width' and 'height', that works for all devices?  AFAIK,
> the answer is no, but there might be functions out there that I don't
> know of.
>
>
> POSTSCRIPT SPECIFIC:
> If not, I'm considering implementing such a method myself.  Is it
> possible for R to infer the default 'width' and 'height' for the
> *postscript* device, or is this defined outside of R?  I've noticed
> that they are not defined by the arguments to postcript():
>
>> args(grDevices::postscript)
> function (file = ifelse(onefile, "Rplots.ps", "Rplot%03d.ps"),
>    onefile, family, title, fonts, encoding, bg, fg, width, height,
>    horizontal, pointsize, paper, pagecentre, print.it, command,
>    colormodel, useKerning, fillOddEven)
>
> and in the list of predefined device options they are zero:
>
>> ps.options()[c("width", "height")]
> $width
> [1] 0
> $height
> [1] 0
>
> and debugging postcript() they are indeed passed as zeros to
> .External(PostScript, ...).

I've already got one reply offline (thanks) pointing me to
help("postcript") and its argument 'paper':

<quote>the size of paper in the printer. The choices are "a4",
"letter" (or "us"), "legal" and "executive" (and these can be
capitalized). Also, "special" can be used, when arguments width and
height specify the paper size. A further choice is "default" (the
default): If this is selected, the papersize is taken from the option
"papersize" if that is set and to "a4" if it is unset or
empty.</quote>

which in code becomes:

  getPSDimensions <- function(options=ps.options(), ...) {
    knownDimensions <- list(
      executive=c(7.25,10.5),
      legal=c(8.5,14),
      letter=c(8.5,11),
      a4=c(8.27, 11.69)
    );

    # See argument 'paper' in help("postcript").
    paper <- tolower(options$paper);

    if (paper == "default") {
      paper <- getOption("papersize", "a4");
    }

    knownDimensions[[paper]];
  } # getPSDimensions()

/Henrik


>
>
>> sessionInfo()
> R version 2.14.0 Patched (2011-11-03 r57560)
> Platform: x86_64-pc-mingw32/x64 (64-bit)
>
> locale:
> [1] LC_COLLATE=English_United States.1252
> [2] LC_CTYPE=English_United States.1252
> [3] LC_MONETARY=English_United States.1252
> [4] LC_NUMERIC=C
> [5] LC_TIME=English_United States.1252
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
> [1] R.utils_1.9.0     R.oo_1.8.3        R.methodsS3_1.2.1
>
> loaded via a namespace (and not attached):
> [1] tools_2.14.0
>
> Thanks
>
> Henrik
>