W3C home > Mailing lists > Public > www-style@w3.org > February 2018

Re: text-decoration-skip-ink auto should continue past behavior - 30+ years of underline behavior changed by latest CSS draft

From: Gérard Talbot <www-style@gtalbot.org>
Date: Wed, 21 Feb 2018 21:34:02 -0500
To: Tadeus Prastowo <tadeus.prastowo@unitn.it>
Cc: W3C www-style mailing list <www-style@w3.org>
Message-ID: <3f3389d43ab3c466d1b150ea607a52e8@gtalbot.org>
Le 2018-02-21 12:49, Chris Lilley a écrit :

>    Your point appears to be either

>    a) that underlines which cut through descenders are preferable.

Le 2018-02-21 13:38, Tadeus Prastowo a écrit :

> Does CSS originally say that an underline cuts through descenders?

CSS 2.x
Appendix E. Elaborate description of Stacking Contexts, E.2 Painting 
order
https://www.w3.org/TR/CSS21/zindex.html#painting-order
https://www.w3.org/TR/CSS22/zindex.html#painting-order
states that underline text-decoration is painted first and then glyphs 
are painted. Therefore, glyphs with descenders (gjpqy) will paint over 
an underline. Since underline and glyphs often use the same color, this 
will give the visual impression that underline cut through descenders. 
But, in fact, descenders are painted over, are painted above the 
underline. This is what the following test is verifying:

CSS Test: 'underline' decoration painting order and descender
http://test.csswg.org/suites/css2.1/nightly-unstable/html4/painting-order-underline-001.htm
(you need to download
https://www.w3.org/Style/CSS/Test/Fonts/Ahem/
and install Ahem font
AHEM____.TTF  2017-01-31 20:55   22K
to view that test)

Reference file:
http://test.csswg.org/suites/css2.1/nightly-unstable/html4/reference/painting-order-underline-001-ref.htm

Gérard
Received on Thursday, 22 February 2018 02:34:36 UTC

This archive was generated by hypermail 2.3.1 : Thursday, 22 February 2018 02:34:37 UTC