R help - Apr 2010 - function which saves an image of a dgtMatrix as png

Hi,

I'm getting crazy:

This does work:

library(Matrix)
a1<-b1<-c(1,2)
c1<-rnorm(2)
aDgt<-spMatrix(ncol=3,nrow=3,i=a1,j=b1,x=c1)
png("myImage.png")
image(aDgt)
dev.off()

But this doesn't !!!

f<-function(x){
png("myImage.png")
image(x)
dev.off()
}
f(aDgt)

My image is saved as a text file and contains nothing at all !!!
Thanks in advance,

Gildas Mazo

image applied to a sparseMatrix object uses lattice functions to
create the image.  As described in R FAQ 7.22 you must use

print(image(x))

or

show(image(x))

or even

plot(image(x))

when a lattice function is called from within another function.
On Wed, Apr 28, 2010 at 1:20 PM, Gildas Mazo <gildas.mazo at curie.fr>
wrote:
> Hi,
>
> I'm getting crazy:
>
> This does work:
>
> library(Matrix)
> a1<-b1<-c(1,2)
> c1<-rnorm(2)
> aDgt<-spMatrix(ncol=3,nrow=3,i=a1,j=b1,x=c1)
> png("myImage.png")
> image(aDgt)
> dev.off()
>
> But this doesn't !!!
>
> f<-function(x){
> png("myImage.png")
> image(x)
> dev.off()
> }
> f(aDgt)
>
> My image is saved as a text file and contains nothing at all !!!
> Thanks in advance,
>
> Gildas Mazo
>
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