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Re: [css3-text] Allow control of text-decoration width

From: Aryeh Gregor <Simetrical+w3c@gmail.com>
Date: Thu, 7 Apr 2011 14:05:53 -0400
Message-ID: <BANLkTimhDdaour-7VxbYK2=FtzysmgTxUA@mail.gmail.com>
To: Koji Ishii <kojiishi@gluesoft.co.jp>
Cc: "www-style@w3.org" <www-style@w3.org>
On Wed, Apr 6, 2011 at 11:34 PM, Koji Ishii <kojiishi@gluesoft.co.jp> wrote:
> It depends on how you define "what users will expect". Try MS Word and you will find it behaves exactly what I said; i.e., the same way CSS behaves. That is one way to define "what users will expect".

Word seems to make the underline on two adjoining characters always
the same height and thickness, but not color (it follows the color of
the letter it's under).  I agree that the way Word works is good.  In
Word, it looks like each letter is either underlined or not, as a
binary per-letter property.  But to determine underline height and
thickness, it looks at an entire run of underlined text at a time, and
draws the same height and thickness for the whole run.

This is kind of how IE9 seems to do things, except for the color.  If
color followed the text where the underline was drawn, and everyone
followed IE's lead in placing underlines consistently for a single run
of text depending on the font and size of the underlined text instead
of the font and size of the element with the text-decoration property,
I'd agree that that would be ideal behavior.

So in particular, changing which element actually has the
text-decoration property should never change the height, thickness, or
color of the underline on any letter, as long as the same set of
letters are underlined.  E.g., these three snippets should all be
visually indistinguishable:

<u><big>A</big><span style=color:red>B</span><small>C</small></u>
<u><big>A</big></u><u><span style=color:red>B</span></u><u><small>C</small></u>
<big><u>A</u></big><span style=color:red><u>B</u></span><small><u>C</u></small>

That's what I think is the most reasonable and correct behavior.
Otherwise you have appearance changing based on the exact positioning
of the <u>s, which is invisible to users of WYSIWYG editors.  Plus,
different-thickness underlines on adjacent letters look ugly, and I
doubt people really want them under normal conditions.  An underline
that's a different color from the text it's under also looks ugly, and
I doubt authors want that either.  Currently IE9 and Chrome 12 dev
display these three snippets all the same (except color), while
Firefox 4.0 and Opera 11 display the third one different from the
first two (including underline thickness and positioning, not just

So actually, I guess I'd be happy if we just a) standardized something
like IE9's behavior for underline thickness and positioning, and b)
had a property (preferably inherited) that said "make all underlines
match the color of the text they're under without regard to what
element generated them".  If authors used the property from (b),
underlines would behave like in Word, which IMO is the expected

Actually, maybe we could even just change the *default* behavior of
underline color to match how it works in Word.  It will change how
existing content is displayed, but I strongly suspect it will improve
more pages than it breaks.  But I'd be happy even if it were opt-in.
I don't think the current CSS text-decoration model is useful or makes
sense.  It would have been much better if there were an inherited
text-underline property from the beginning, with
color/height/thickness determined by where it's drawn.  It's probably
not worth it to do that by this point, but we could still improve
Received on Thursday, 7 April 2011 18:06:41 UTC

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