- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Tue, 24 Sep 2013 15:25:28 -0700
- 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 3:14 PM, Rik Cabanier <cabanier@gmail.com> wrote: > On Tue, Sep 24, 2013 at 2:58 PM, Tab Atkins Jr. <jackalmage@gmail.com> > wrote: >> 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. > > Can you point out where that is so I can update the spec? Hmm, I guess it actually doesn't. The few examples that give explicit color numbers are all written with RGB, but there's nothing outside the examples that actually talks about the color value. >> 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. > > It is compatible. You can try it in PhotoShop :-) How does that work, though? I mean, HSL doesn't work in a "just use the channels" approach, which is why the HSL blend modes are non-separable. Why would Lab work? >> > 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. > > It seems we could define something simple. People have a tendency to > overcomplicate color management... Ideas welcome. ~TJ
Received on Tuesday, 24 September 2013 22:26:14 UTC