[csswg-drafts] [css-color-5] Mixing alpha (#5176)

kbabbitt has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-color-5] Mixing alpha ==
In #4915 the working group [resolved](https://github.com/w3c/csswg-drafts/issues/4915#issuecomment-631574709) that in forced colors mode, the color-mix function would be used for background-color, in order to apply the computed color's alpha to the appropriate system color.

At the moment [color-mix](https://drafts.csswg.org/css-color-5/#colormix) does not specify a way to mix the alpha channel. Noting that `a` is currently used for the like-named channel in lab colorspace, and alpha is (at least theoretically) independent of colorspace, my suggestion is to add `alpha` to the production for `color-adjuster`:

<dfn>color-adjuster</dfn> = <<rgb-adjuster>> | <<hsl-adjuster>> | <<hwb-adjuster>>
    | <<xyz-adjuster>> | <<lab-adjuster>> | <<lch-adjuster>> | alpha

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5176 using your GitHub account

Received on Saturday, 6 June 2020 00:30:20 UTC