[R] Reducing the size of pdf graphics files produced with R

[Joerg van den Hoff]

On Wed, May 23, 2007 at 10:13:22AM -0700, Waichler, Scott R wrote:
> 
> 
> Scott
> 
> Scott Waichler, Senior Research Scientist
> Pacific Northwest National Laboratory
> MSIN K9-36
> P.O. Box 999
> Richland, WA   99352    USA
> 509-372-4423 (voice)
> 509-372-6089 (fax)
> scott.waichler at pnl.gov
> http://hydrology.pnl.gov
> ------------------------------------------------------------------------
> ---------------
>  
> 
> > -----Original Message-----
> > From: Joerg van den Hoff [mailto:j.van_den_hoff at fzd.de] 
> > Sent: Wednesday, May 23, 2007 9:25 AM
> > To: Waichler, Scott R
> > Cc: r-help at stat.math.ethz.ch; j.van_den_hoff at fzd.de
> > Subject: Re: [R] Reducing the size of pdf graphics files 
> > produced with R
> > 
> > On Wed, May 23, 2007 at 07:24:04AM -0700, Waichler, Scott R wrote:
> > > > as you are using MacOS X, you'll have ghostscript 
> > installed anyway. 
> > > > so try in R `dev2bitmap' with `type =pdfwrite'. I believe `gs' 
> > > > _does_ include compression. a quick test showed at least 
> > a reduction 
> > > > by about a factor of 2 relative to `pdf()'. probably one 
> > can fiddle 
> > > > with the ghostscript settings (cf. e.g. `Ps2pdf.htm' in the 
> > > > ghostscipt
> > > > docs: you
> > > > can adjust the resolution for images in the pdf file) to improve 
> > > > this, so as a last resort you could indeed export the graphics as 
> > > > postscript and do the conversion to `pdf' by adjusting 
> > the `ps2pdf'
> > > > switches. but even with the default settings the pdf produced via 
> > > > dev2bitmap/ghostscript is the better solution. apart from 
> > file size 
> > > > I by and then ran into problems when converting `pdf()' output to 
> > > > postscript later on, for instance.
> > > 
> > > Can you give an example of dev2bitmap usage?  I tried using it in 
> > `dev2bitmap(file = "rf.pdf", type = "pdfwrite")' copies the 
> > current device to the pdf-file `rf.pdf', i.e. you should have 
> > plotted something on the screen prior to using this (the 
> > manpage tells you so much...). no `dev.off' is necessary in this case.
> > 
> > in order to "plot directly" into the pdffile, you can use 
> > `bitmap' instead of `dev2bitmap', i.e.
> > 
> > use either:
> > 
> > plot(1:10)
> > dev2bitmap(file = "rf1.pdf", type = "pdfwrite")
> > 
> > or:
> > 
> > bitmap(file = "rf2.pdf", type = "pdfwrite")
> > plot(1:10)
> > dev.off()
> > 
> > both should produce the desired output file (at least after 
> > including the correct `width' and `height' settings).
> 
> I tried the second method, using width=8.5, height=11, but the margins
> in the output were bad, as if it assumed a4 paper or something.  I tried
> inserting paper="special" and paper="letter" in the bitmap call, but
> both caused errors.  Also, the plot was in grayscale instead of color.  
> 
> Scott Waichler

if you look at the source code of `bitmap' you'll see that it essentially
constructs a `gs' command (the string `cmd') which is fed by the output of the
R `postscript' device via a pipe (the manpage of `bitmap' tells the same).
so I presume if you don't get colour or seem to have wrong page size this has
nothing to do with R, but you need to check your ghostscript installation.
only guessing, though. 

joerg