- From: Chris Lilley via GitHub <sysbot+gh@w3.org>
- Date: Tue, 18 Jul 2017 14:11:44 +0000
- To: public-css-archive@w3.org
Firstly, the color adjustment part of CSS Color 4 is speculative and has not been widely reviewed. it is likely to change. Given that, yes, it was written before CIE-based colors were added to the spec and thus, uses HSL as the computational space. This has obvious problems due to the discontinuity, non-linearity and non-perceptual-uniformity properties of HSL (and also results in clipping for colors outside the sRGB gamut). You are correct that allowing computations to be done in LCH(ab) space would be more perceptually uniform (and also would not suffer from clipping). It is incorrect that Lab does not have a measure of saturation. The formula is simply s = C / L Thus on a CIE Lab diagram, lines of constant chroma are parallel to the central L axis while lines of constant saturation form a cone whose apex is the black point. Luv is much less widely used nowadays compared to Lab. I forget why (and am currently traveling so my color science books are not to hand, so I can't explain why at present). -- GitHub Notification of comment by svgeesus Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/1610#issuecomment-316076150 using your GitHub account
Received on Tuesday, 18 July 2017 14:11:50 UTC