pixmaps and R

Dear Thibaut,

I am not sure what you want to do and what for you want to have a 
compressed version of an image in R. You can try the EBImage package, 
which is in the devel branch of bioconductor
http://www.bioconductor.org/packages/bioc/1.8/html/EBImage.html
It uses ImageMagick for image I/O and processing (so you need that, 
including header files and Magick++). It is still early in this 
package's life-cycle, so consider it an "alpha" version.

library(EBImage)
y = read.image(system.file("data", "cat.jpg", package="rimage"),
        rgb=TRUE)

object.size(y)
[1] 702888
 > dim(y)
[1] 418 420

and this is 4 Bytes (a 32 bit int of which only the lower 24 bits are 
used) per Pixel, rather than 24 Bytes (3 doubles) in the case below.

object.size(x)  ## your example from rimage
[1] 4214240

And there are some 2D filtering and image processing functions.

Cheers
   Wolfgang

-------------------------------------
Wolfgang Huber
European Bioinformatics Institute
European Molecular Biology Laboratory
Cambridge CB10 1SD
England
Phone: +44 1223 494642
Fax:   +44 1223 494486
Http:  www.ebi.ac.uk/huber
-------------------------------------

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.