[R] General means of matching a color specification to an official R color name

[Romain Francois]

On 10/14/2009 12:05 AM, Barry Rowlingson wrote:
>
> On Tue, Oct 13, 2009 at 10:58 PM, Bryan Hanson<hanson at depauw.edu>  wrote:
>> Works perfectly!  Thanks Barry.  I had actually seen some suggestions on
>> using a distance, but by then I was thinking about hcl spaces and distance
>> isn't so as simple there.  I'm too tired I think.
>>
>> Anyway, you've got me running again!  Thanks, Bryan
>
>   There's a CPAN module for Perl that does hcl colour similarity:
>
>   >http://search.cpan.org/~mbarbon/Color-Similarity-HCL-0.04/lib/Color/Similarity/HCL.pm
>
>   the Perl code is pretty neat, looks easy to R-ify - released under
> the perl license.
>
> Barry

There are a few unexported functions in the xterm256 package to deal 
with this.

 > colors()[ xterm256:::closest.character( "#aabbcc" ) ]
[1] "gold4"

The package pretends it writes the text using the background of 
foreground color as usually represented in R, but it actually first 
grabs the closest color (in the RGB space according to the euclidian 
metric, I have no idea whether a different space or a different metric 
would be better)

This presentation might give a clue : 
http://www.agrocampus-ouest.fr/math/useR-2009//slides/Zeileis+Hornik+Murrell.pdf

Romain

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Romain Francois
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