R devel - Feb 2011 - using rasterImage within image

Has anyone yet tried incorporating rasterImage into the base image()
function?  It seems to make a *huge* difference, with
a very small number of added/changed lines of code.  (Of course I have
barely tested it at all.)
  Is there any reason this *shouldn't* go into the next release?
> source("image.R")
> z <- matrix(runif(1e6),nrow=1000)
> image(z)
> image(z,useRaster=TRUE)
  (Patch against SVN 54284 attached; people can contact me if it doesn't
go through and they want it.)

  Ben Bolker

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Hello,

There's a problem for rasterImage when used in SDI mode in Windows,
which may be worth considering.

https://stat.ethz.ch/pipermail/r-sig-geo/2010-July/008820.html

I had off-list emails with Duncan Murdoch and Paul Murrell about this
and they determined that it was in SDI only, and there's still no
resolution for it as far as I know.  I checked in the latest dev build
of 2.13.0 2011-02-04 r54221 just in case.

This has been in use in the derived function
image.SpatialGridDataFrame in the sp package since rasterImage was
released, the sp function incorporates a warning for users in SDI
mode.

Cheers, Mike.

On Wed, Feb 9, 2011 at 12:49 PM, Ben Bolker <bbolker at gmail.com>
wrote:
>
> ?Has anyone yet tried incorporating rasterImage into the base image()
> function? ?It seems to make a *huge* difference, with
> a very small number of added/changed lines of code. ?(Of course I have
> barely tested it at all.)
> ?Is there any reason this *shouldn't* go into the next release?
>
>> source("image.R")
>> z <- matrix(runif(1e6),nrow=1000)
>> image(z)
>> image(z,useRaster=TRUE)
>
> ?(Patch against SVN 54284 attached; people can contact me if it doesn't
> go through and they want it.)
>
> ?Ben Bolker
>
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>


-- 
Michael Sumner
Institute for Marine and Antarctic Studies, University of Tasmania
Hobart, Australia
e-mail: mdsumner at gmail.com

Ben,

did you actually look at the result of your function with useRaster=TRUE ? ;)
[Hint: don't use an image that is symmetric]

Apart from that nice bug there are more issues as well, try
image(matrix(1:4,2),col=1:3)
The underlying issue is that as.raster() is not quite what you would hope.
Unfortunately I'm not aware of an easy fix (that doesn't involve going
back to RGB decomposition).

In general, I think it's a nice option, but I don't think you'll get
away with only a few lines...

Cheers,
Simon



On Feb 8, 2011, at 8:49 PM, Ben Bolker wrote:
> 
>  Has anyone yet tried incorporating rasterImage into the base image()
> function?  It seems to make a *huge* difference, with
> a very small number of added/changed lines of code.  (Of course I have
> barely tested it at all.)
>  Is there any reason this *shouldn't* go into the next release?
> 
>> source("image.R")
>> z <- matrix(runif(1e6),nrow=1000)
>> image(z)
>> image(z,useRaster=TRUE)
> 
>  (Patch against SVN 54284 attached; people can contact me if it doesn't
> go through and they want it.)
> 
>  Ben Bolker
> 
> <image_diff.txt>______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel