Re: Colour manipulation

[Ted Zlatanov <tzz@lifelogs.com>]

On Tue, 23 Nov 2010 10:10:51 +0100 Julien Danjou <julien@danjou.info> wrote: 

JD> On Mon, Nov 22 2010, Ted Zlatanov wrote:
>> Have you provided anything for colorblind people?  Or is that not a
>> priority?  (if the latter, I'll give it a try)

JD> Not at all. But I can give it a try, I just know nothing about colour
JD> blindness, what issue I should try to fix, and how. :)

JD> Any hint appreciated, while I read the Wikipedia page.

BTW, the source code for color-lab.el is beautiful.  I like to see
Unicode used properly like this, in code and identifiers.  I am
surprised and glad that Emacs is happy with it all.

I'm not personally colorblind, just interested in helping people with
that disability.  So I can't test things too much without a conversion
tool.  Still, it seems that color-lab.el will quickly become the
standard place for color formulas in Emacs so I think we should
anticipate this common need instead of fixing it later.

I posted a link to the color designer page at
http://colorschemedesigner.com that lets you see any colors as a
colorblind person would.  The source code is JavaScript and probably
easy to obtain.  That kind of conversion tool is valuable.  Here are
some more links:

http://jfly.iam.u-tokyo.ac.jp/color/
http://www.vischeck.com/info/ (LOTS of good links, check out Daltonize too)

Vischeck came from open-source software and they may be willing to
license their algorithm to the FSF.

I would recommend to let users customize a color vision profile as part
of color-lab (see my original long explanation of my work with colors in
GUI design).  Maybe just a list of colors and their contrasting pairs
(with a reasonable set of defaults for each of the various kinds of
colorblindness), from which we can approximate what will look good
anywhere in the colorspace, will be sufficient.  The algorithms are nice
to have but not essential to the original requirement.

Let me know if you need help or ideas going forward.

Ted