W3C home > Mailing lists > Public > www-style@w3.org > September 2013

Re: [css-gcpm][css-color] device-cmyk() interaction with RGB-space colors.

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 24 Sep 2013 14:58:24 -0700
Message-ID: <CAAWBYDAOaVszfRa7Wm5MZFWVJ8shBAhzfc90BccajBuPifZ_Yg@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: Simon Sapin <simon.sapin@exyr.org>, www-style list <www-style@w3.org>
On Tue, Sep 24, 2013 at 2:31 PM, Rik Cabanier <cabanier@gmail.com> wrote:
> The compositing/blending spec doesn't talk about converting colors [1] All
> the formulas (except for 4 special ones) work on individual color channels,
> regardless of what they represent.

Those channels appear to be assumed to be RGB.  If it's compatible
with CMYK, cool, but that needs to be specified (and again, needs to
be defined how you blend/composite between RGB and CMYK).

I doubt that this "just use the channels" approach is compatible with
some other color spaces, like Lab, though.

> I agree we need to define a way how and when individual elements are
> converted to the document's color space.

Sure, something more advanced than just "always convert to RGB
immediately" might be worthwhile.  We talked about this at the f2f,
though, and some of the ideas (like converting individual pixels to
RGB as necessary, or converting entire elements to RGB as soon as you
need to convert some part of it) were all horrible and not worth the
benefit, so I didn't put those ideas into the spec.

~TJ
Received on Tuesday, 24 September 2013 21:59:11 UTC

This archive was generated by hypermail 2.4.0 : Friday, 25 March 2022 10:08:34 UTC