[R] overlapping a plot with an external image
bitwrit at ozemail.com.au
Thu May 22 12:54:26 CEST 2003
Meinhard Ploner wrote:
> It's possible to overlap an external image (jpg or pdf)
> with a plot generated with R?
> Specifying the image as the background
> of the plot might not be possible...
If the plot is output using postscript(), the default background color is
transparent. For instance, if you have a plot produced
with postscript(...,onefile=FALSE,...) named Rplots.ps, you can insert the
following lines in another Postscript file to get the plot overlaid on
whatever image is in that file.
x y translate
x y scale
the "translate" and "scale" commands allow you to place the plot where you
want it and get the correct size. It's not too hard, but it helps if you
have had some experience with Postscript. Once you have gotten the
translate and scale factors right (Ghostview is a great help) you can just
keep plugging your plots in unless you want to change the image size.
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