From bbolker at gmail.com  Wed Feb  9 16:06:35 2011
From: bbolker at gmail.com (Ben Bolker)
Date: Wed, 9 Feb 2011 10:06:35 -0500
Subject: [Rd] using rasterImage within image
In-Reply-To: <D8F5413E-025A-4511-BCE1-7ED06CBE99A0@r-project.org>
References: <4D51F2A7.8010505@mcmaster.ca>
	<D8F5413E-025A-4511-BCE1-7ED06CBE99A0@r-project.org>
Message-ID: <4D52AD7B.6070402@gmail.com>

On 11-02-08 10:03 PM, Simon Urbanek wrote:
> 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

  Trying again. Rotated counterclockwise within R (although this *could*
be coded in C if speed were important?)
  Some brute-force testing suggests it is *slightly* slower for small
images (7 vs 8 seconds for 1000 reps) and still much faster (and
produces much smaller images, which don't suffer from antialiasing junk
in my PDF viewer) for large images.
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[Rd] using rasterImage within image
Ben Bolker