W3C home > Mailing lists > Public > public-css-archive@w3.org > December 2016

Re: [csswg-drafts] [css-color] add `xyy` and/or `xyz` functions

From: Chris Lilley via GitHub <sysbot+gh@w3.org>
Date: Sun, 18 Dec 2016 21:59:07 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-267849913-1482098345-sysbot+gh@w3.org>
If the code can already correctly  convert from whatever source format
 to XYZ and then to sRGB, I see no good reason why the trivial 
conversion from XYZ to Lab would be "error prone".

In addition, Lab uses a known reference white and adaptive state while
 for XYZ, one needs to specify what is the adaptation state. Notice 
that the sample code in the specification uses XYX at two stages, with
 different meaning 9before and after chromatic adaptation).

On the other hand, one good reason to add XYZ would be where absolute,
 rather than relative, luminance needed to be directly specified.

So I am not against adding them, but it needs to be well specified 
exactly what is being referred to by a given XYZ measurement. 
(Absolute vs. relative, unadapted vs. adapted).

Perhaps you could explain the use case a bit more: in particular what 
color space is the input to this script.

As to making rule validity depend on target device gamut, that is a 
fragile solution compared to the usual rendering intent and gamut 
mapping procedure which is standard in the industry.

-- 
GitHub Notification of comment by svgeesus
Please view or discuss this issue at 
https://github.com/w3c/csswg-drafts/issues/815#issuecomment-267849913 
using your GitHub account
Received on Sunday, 18 December 2016 21:59:12 UTC

This archive was generated by hypermail 2.4.0 : Tuesday, 5 July 2022 06:41:06 UTC