[R] Colorspace: bug in HLS conversion?

[Achim Zeileis]

On Wed, 12 Mar 2014, Michael Gauland wrote:

> I just started using the colorspace package, and converting between RGB and
> HLS is not working as I expect.  In particular, converting RGB(0,0,0) to HLS
> then back to RGB seems broken:
>
>    #> as(as(RGB(0, 0, 0), "HLS"), "RGB")
> 	 R G B
>    [1,] 1 1 0
>
> That is, converting black to HLS then back again produces yellow!

I can't reproduce this. I get 0,0,0 as expected.

> Other values I've tried work as expected (i.e., I get the same RGB value out
> as I put in).
>
> Is this a bug in the code, or in my understanding of colour conversions?

Maybe you are using an old version of "colorspace"? For version 1.1-1 
(from two years ago, version 1.2-4 is current) the NEWS file says:

o Bug fix in HLS_to_RGB conversion for s == 0.

> Kind Regards,
> Mike
>
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