[R] quartz() and dpi

[JiHO]

Hello all,

I am using quartz (on OS X obviously) to produce PDFs and PNGs from my
plots, for later inclusion in LaTeX.

I am typically using something like:

plot(0)
dev.print(quartz, file="foo.pdf", width=5, height=3)
dev.print(quartz, file="foo.png", width=5, height=3, dpi=72)

I want the sizes of the PDF and PNG to be *equal* in *inches*, which
works with dpi=72. However, when I increase the dpi parameter, instead
of producing an image of the same size with increased resolution, it
creates a larger image of resolution = 72. E.g. try

dev.print(quartz, file="foo-72.png", width=5, height=3, dpi=72)
dev.print(quartz, file="foo-300.png", width=5, height=3, dpi=300)
system("open -a Preview.app foo-*.png")

The inspector in Preview should show 72 dpi for both files. This is with:

> sessionInfo()
R version 2.10.1 (2009-12-14)
x86_64-apple-darwin9.8.0

Is this a know bug/limitation? Is a solution planned? Is there a
workaround for now?

As a final note, I am aware that PDF is superior to PNG, particularly
in a LaTeX workflow; but for particularly complex plots, I sometimes
fall back on high resolution PNGs. Currently it forces me to add a
'scale' argument to includegraphics in latex for those. I would rather
leave the latex document alone, use extension-less file names
includegraphics and decide from R wether to produce a pdf or a png.

Thank you in advance,

JiHO
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