[R] png() and pdf() alignment problems
Jari Oksanen
jari.oksanen at oulu.fi
Sun Feb 3 08:59:26 CET 2008
Dear Roland Kaiser,
I think there may different pixel-to-point scaling in different
devices. This scaling seems not only to vary with the device but even
with your physical screen. This is what happens with my current box
(MacBook):
> quartz()
> par("mar")/par("mai")
[1] 6 6 6 6
> par("cra")
[1] 6 12
> png()
> par("mar")/par("mai")
[1] 4.686347 4.686347 4.686347 4.686347
> par("cra")
[1] 13 16
> dev.off()
> pdf()
> par("mar")/par("mai")
[1] 5 5 5 5
> par("cra")
[1] 10.8 14.4
> x11()
> par("mar")/par("mai")
[1] 4.686347 4.686347 4.686347 4.686347
> par("cra")
[1] 13 16
The quotient gives the par margin line height in inches, par("cra")
the dimensions of the characters in "rasters" (which may be close to
size in points, but may differ a lot in some screens). For your
alignment, I think you want to make margin proportions equal in two
devices, and you must scale so figs so instead of using physically
equal dimensions. The mar/mai ratio or cra does not change with
device width & height, so you must change those so that for fig looks
like it should.
I have no ideas if this works, but I think this still is your problem...
Greetings to the Moderator,
Jari Oksanen
Cheers, Jari Oksanen
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