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

From: Allan Sandfeld Jensen <kde@carewolf.com>
Date: Tue, 27 Feb 2018 00:47:35 +0100
To: www-style@w3.org
Cc: Gérard Talbot <www-style@gtalbot.org>, "Myles C. Maxfield" <mmaxfield@apple.com>, OwN-3m-All <own3mall@gmail.com>
Message-ID: <4923892.huNmsl9yZp@twilight>
On Mittwoch, 21. Februar 2018 20:07:43 CET Gérard Talbot wrote:
> Le 2018-02-21 12:27, Myles C. Maxfield a écrit :
> >> On Feb 21, 2018, at 9:22 AM, Myles C. Maxfield <mmaxfield@apple.com>
> >> 
> >> wrote:
> >>> On Feb 21, 2018, at 7:33 AM, OwN-3m-All <own3mall@gmail.com> wrote:
> >>> 
> >>> I initially thought this was a problem with Chrome (since they seem
> >>> to
> >>> be one of the early adopters - bug report here:
> >>> https://bugs.chromium.org/p/chromium/issues/detail?id=813256#c2), but
> >>> now that I've seen the actual spec, I'm shocked that the auto value
> >>> for the text-decoration-skip-ink property is to change the way
> >>> underlined text has worked since the beginning of computers!
> >> 
> >> Yep. This change is intentional.
> >> 
> >>> https://drafts.csswg.org/css-text-decor-4/#text-decoration-skip-ink-prop
> >>> erty
> >>> 
> >>> Underlined text should always have the line over all characters.
> >> 
> >> Nope. This is how computers have historically rendered text.
> 
> Glyphs with descender parts (eg. pqjgy) must overlap an underline
> decoration according to CSS 2.x:
> 
> CSS Test: 'underline' decoration painting order and descender
> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/painting-order-un
> derline-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)
> 
> > However, historically, most high-typographic-quality examples which
> > include underlines make the underlines skip over the descenders.
> > 
> > Or, stated differently, underlines cross descenders in existing
> > software because it was convenient for software authors writing code.
> > However, we’ve done research in underlines through the ages (way
> > before computers were invented) and the best typographical samples
> > always use skipping underlines. This is a situation where changing
> > behavior on the Web doesn’t break content
> 
> If textual links have descenders (or a blank space), then it may look
> like there is 2 links and not 1 link. On 1 hand, it will be easier to
> read  (typographically speaking) the textual link but it may confuse the
> user (or lead him/her to hesitate) in thinking that there are 2 textual
> links.
> 
Those two arguments really should end the discussion right here. It is 
documented CSS 2.x behavior and it is confusing for users given existing 
behavior.

As I see it the only way we can have the underline skip the descender and not 
look like two links is by making the skipped part very short, that is 
underlining a glyph partially, but that would require font support and would 
in that case be a matter of the font dictating how it is to be underlined and 
no longer a CSS matter.

Note also that some fonts have and underline position below the descenders 
which makes the skipping even worse.

Regards
'Allan
Received on Monday, 26 February 2018 23:48:08 UTC

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