[Rd] pixmaps and R

From: Thibaut Jombart <jombart_at_biomserv.univ-lyon1.fr>
Date: Mon 03 Apr 2006 - 10:03:32 GMT

Hello list,

here is a question relative to pixmap pictures in R. Manipulating such objects is quite demanding for the RAM, as large matrices are created.

For instance, try to execute the example of rimage library :

### R code ###

library(rimage)
x <- read.jpeg(system.file("data", "cat.jpg", package="rimage")) plot(x)
object.size(x)
save.image()
### end of R code ###

Moreover, the '.RData' will be approximately the size of 'x' (around 4 MB), despite the jpeg size is only 16 KB. Of course it is possible store only the expression reading the pictures instead.
For instance:

### R code ###

y=expression(read.jpeg(system.file("data", "cat.jpg", package="rimage"))) object.size(y)

object.size(eval(y))
plot(eval(y))
### end of R code ###

But... does anybody know if compressed pictures could be stored in R? And if yes, how ?  

Thanks,

Thibaut.

-- 
######################################
Thibaut JOMBART
CNRS UMR 5558 - Laboratoire de Biométrie et Biologie Evolutive
Universite Lyon 1
43 bd du 11 novembre 1918
69622 Villeurbanne Cedex
Tél. : 04.72.43.29.35
Fax : 04.72.43.13.88
jombart@biomserv.univ-lyon1.fr

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Received on Mon Apr 03 20:28:58 2006

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