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Re: [CSS3-text] text-underline-position and superscript

From: Ambrose LI <ambrose.li@gmail.com>
Date: Sun, 26 Dec 2010 08:29:37 -0500
Message-ID: <AANLkTikPhPQ0u3YCNCOHBidQLM5YQSv4yR2a_QdtaeW6@mail.gmail.com>
To: Koji Ishii <kojiishi@gluesoft.co.jp>
Cc: "Belov, Charles" <Charles.Belov@sfmta.com>, "www-style@w3.org" <www-style@w3.org>
2010/12/26 Koji Ishii <kojiishi@gluesoft.co.jp>:
> Are you sure that you two are talking about the same issue?

No, we are not talking about the same things (and I'm pretty sure we
both knew that), but I see that there is a generalized principle that
are common to the two ideas.

The general principle is that:

1. We need some way to specify that, in some situations, no matter
what the glyph-specific underline position is, we want to fix a
constant underline position for some logical grouping of characters.
(For superscript/subscripts: underlines don't move up/down due to the
super/subscripting; For Chinese: underlines don't move up/down when
there are Latin or other non-CJK characters in the sequence)

2. As a corollary of the above, we need some way to specify that
underlines are always visually disjoint if they are semantically
marked up as separate. (This fixes the Chinese problem of two adjacent
underlines running into each other; However, I can't see why we need
to treat it as a Chinese-only problem, as there can be uses in
non-Chinese typography that can require this)

This also means that fixing the underline positions in CJK fonts alone
will not be a complete fix to the Chinese problem, as that would fix
only #2 but not #1, which is also a non-Chinese problem.

> From what I understand, what Charles wants is to fix underlines for superscript and subscript. I agree that what current browsers do today seems odd, but I'm not sure if we need more values to text-underline-position.

What Charles proposed are ways to specify how the constant underline
position in #1 should be determined. Perhaps there can be ways to get
rid of the proposed keywords, but his proposal is a good analysis
(without considering the requirements for the Chinese typography) of
what we will need to deal with when we need the browser to figure out
a constant position for the underlining.

> Does anyone want the current behavior? It looks to me that it's just a bug we should fix without adding new values.
>
> What Ambrose wants is what Kenny brought up before[1] and discussion wasn't followed up by anyone. If you could follow that up, that'd be helpful.

Yes, that would fix #2, but we still need to address #1 even if we are
only talking about Chinese.

> [1] http://lists.w3.org/Archives/Public/www-style/2010Dec/0117.html
>
>
> Regards,
> Koji
>



-- 
cheers,
-ambrose

does anyone know how to fix Snow Leopard? it broke input method
switching and is causing many typing mistakes and is very annoying
Received on Sunday, 26 December 2010 13:30:06 GMT

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