Re: [Rd] png() and image()

From: Wolfgang Huber <huber_at_ebi.ac.uk>
Date: Mon 24 Jul 2006 - 11:49:36 GMT

Henrik Bengtsson wrote:
> Hi Wolfgang,
>
> thanks for this - I took a look the EBImage webpage
> [http://www.ebi.ac.uk/~osklyar/projects/EBImage/] and it looks very
> nice. Are there any plans for Windows support too? I am looking for
> a cross-platform solution.
>
> Cheers

Hi Henrik,

there are very strong intentions to also make this available as a Windows precompiled package and/or provide installation instruction for Windows. Until now however, in spite of some effort, we have failed.

As I understand it, a problem seems to be different dll formats of MS Visual C++ (in which ImageMagick is provided) and MinGW.

If anyone is interested in helping with this, they could have a look at the source package on Bioconductor, and contact us for details.

 Best wishes
 Wolfgang

> On 7/21/06, Wolfgang Huber <huber@ebi.ac.uk> wrote:
>>
>> Hi Henrik,
>> this does not directly answer your question, but you might be able to
>> use the function write.image in the package EBImage (Bioconductor) to
>> write matrices into image files (e.g. PNG or JPEG), this might be more
>> flexible and also faster than what you're trying to do.
>> Best wishes
>> Wolfgang
>> ------------------------------------------------------------------
>> Wolfgang Huber EBI/EMBL Cambridge UK http://www.ebi.ac.uk/huber
>>
>> Henrik Bengtsson wrote:

>> > Hi,
>> >
>> > I try to create PNG images of a certain size where each pixel
>> > intensity corresponds to exactly one probe signal in an Affymetrix
>> > array. I try to use png() and image() with zero margins to do this.
>> > Example:
>> >
>> > z <- matrix(1:15, nrow=45, ncol=30)
>> > png("large.png", height=nrow(z), width=ncol(z), bg="red")
>> > par(mar=c(0,0,0,0))
>> > image(z, col=gray.colors(16), axes=FALSE)
>> > dev.off()
>> >
>> > z <- matrix(1:15, nrow=5, ncol=3)
>> > png("tiny.png", height=nrow(z), width=ncol(z), bg="red")
>> > par(mar=c(0,0,0,0))
>> > image(z, col=gray.colors(16), axes=FALSE)
>> > dev.off()
>> >
>> > The problem is that on WinXP the very bottom row and the very right
>> > column of pixels in red. Trying on Linux, it is only the very right
>> > column that is red. See attached images (you might have to zoom in to
>> > see it). I try to do this in R v2.3.1. The same effect is seen if
>> > the jpeg() device is used.
>> >
>> > When rescaling, the same effect is seen (the red border effect is one
>> > pixel wide), e.g.
>> >
>> > z <- matrix(1:15, nrow=45, ncol=30)
>> > png("large5.png", height=5*nrow(z), width=5*ncol(z), bg="red")
>> > par(mar=c(0,0,0,0))
>> > image(z, col=gray.colors(16), axes=FALSE)
>> > dev.off()
>> >
>> > I might be asking for something that is not supported, but is there a
>> > way around this? It is a problem, because I wish to tile the images
>> > in an HTML page.
>> >
>> > Thanks
>> >
>> > Henrik
>> >
>>

-- 
------------------------------------------------------------------
Wolfgang Huber  EBI/EMBL  Cambridge UK  http://www.ebi.ac.uk/huber

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