R help - Sep 2006 - embed image (png) in postscript (device)

Hi,

I output multiple "grid-package-based" plots to the postscript device.
Because the graphics are complicated and consists of a lot of datapoints
(~200'000) the files become really big. To avoid this big files and to
shorten the creation, I currently print the plots to the png device and
manually combine them into one multipaged pdf document.

My question is, it is possible to do this in R directly?
Probably I would have to create a png plot first, then reimport it into R
and "put" it on the ps device. Is this a realistic way (in principle)
?

If there is no package to read png files (I didn't find anything), I
probably could solve this. But I still don't know if it would be possible to
"put" this memory representation to a ps device.

Thanks for your time.

-- 
Regards,
Hans-Peter

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On Fri, 1 Sep 2006, Hans-Peter wrote:
> Hi,
> 
> I output multiple "grid-package-based" plots to the postscript
device.
> Because the graphics are complicated and consists of a lot of datapoints
> (~200'000) the files become really big. To avoid this big files and to
> shorten the creation, I currently print the plots to the png device and
> manually combine them into one multipaged pdf document.
> 
> My question is, it is possible to do this in R directly?
> Probably I would have to create a png plot first, then reimport it into R
> and "put" it on the ps device. Is this a realistic way (in
principle) ?
> 
> If there is no package to read png files (I didn't find anything), I
> probably could solve this. 
There are various ways to do so: one is to convert to a format pixmap 
knows, another to convert to TIFF and use rtiff.
> But I still don't know if it would be possible to
> "put" this memory representation to a ps device.
Only crudely.  There is nothing in the R graphics model related to 
bitmaps.  What you could do is draw each pixel as a rectangle (as image() 
does), but then your file size will be even bigger and the chances of it 
being rendered accurately are not high.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

Hi


Hans-Peter wrote:
> Hi,
> 
> I output multiple "grid-package-based" plots to the postscript
device.
> Because the graphics are complicated and consists of a lot of datapoints
> (~200'000) the files become really big. To avoid this big files and to
> shorten the creation, I currently print the plots to the png device and
> manually combine them into one multipaged pdf document.

If you want to automate combining png files into a single pdf, you could
take a look at ImageMagick.

Paul

> My question is, it is possible to do this in R directly?
> Probably I would have to create a png plot first, then reimport it into R
> and "put" it on the ps device. Is this a realistic way (in
principle) ?
> 
> If there is no package to read png files (I didn't find anything), I
> probably could solve this. But I still don't know if it would be
possible to
> "put" this memory representation to a ps device.
> 
> Thanks for your time.
> 
-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/