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

From: Belov, Charles <Charles.Belov@sfmta.com>
Date: Mon, 3 Jan 2011 13:57:40 -0800
Message-ID: <E17F75B6E86AE842A57B4534F82D03769C34D5@MTAMAIL.muni.sfgov.org>
To: "Koji Ishii" <kojiishi@gluesoft.co.jp>
Cc: <www-style@w3.org>, "Ambrose LI" <ambrose.li@gmail.com>

Koji Ishii [mailto:kojiishi@gluesoft.co.jp] wrote on Sunday, December
26, 2010 6:23 AM
> Thank you for your summary. Yes, the way you organized issues 
> matches to what I think they should be.
> For issue #1, it's generalized as "underlining to text that 
> contains multiple different properties (fonts, super/sub, 
> etc.)", and I agree that it should be handled better. 
> Actually it does in the current CSS3 text spec[1]. Can you 
> please review it and see if the problem still exists?
> For issue #2, I still see the issue is the same one as Kenny 
> brought up[2]. I'm not against the idea, I actually would 
> like it happen, I'm just saying the issue is different from 
> #1. I was actually hoping to write up something once I've got 
> responses to [2] and we all have got consensus, but it didn't 
> happen unfortunately. If you could go back to the thread and 
> continue the discussions, that'd be helpful to make it happen.
> [1] http://dev.w3.org/csswg/css3-text/#line-decoration
> [2] http://lists.w3.org/Archives/Public/www-style/2010Dec/0117.html

I believe that the information found at 
http://dev.w3.org/csswg/css3-text/#line-decoration addresses my issues
with regard to superscript.  It might be nice to add subscript just so
it is clear what would happen with that.

As a side note, in Firefox at a minimum font size of 18px, the bottom of
several lines of the code in Example X are getting shaved off, the
portion within and including the blockquote tags.

Hope this helps,
Charles Belov
SFMTA Webmaster
> -----Original Message-----
> From: Ambrose LI [mailto:ambrose.li@gmail.com]
> Sent: Sunday, December 26, 2010 11:00 PM
> To: Koji Ishii
> Cc: Belov, Charles; www-style@w3.org
> Subject: Re: [CSS3-text] text-underline-position and superscript
> Sorry for following up on myself again. I'll blame it being 
> early morning, but let me reorganize myself a bit and restate 
> how the two ideas are related:
> ==================================================
> There are two generalized principles common to Charles' and 
> my ideas, and the two general principles are that:
> 1. We need some way to specify that, in some situations, no 
> matter what the glyph-specific underline position is, we want 
> to keep a constant underline position for some logical 
> grouping of characters.
> (1a) For superscript/subscripts: underlines don't move 
> up/down due to the super/subscripting
> (1b) 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.
> (2a) For superscripts/subscripts: The logical markup is 
> provided by SUP or SUB and we make it clear that we want the 
> underlines to move up/down along with the super/subscript
> (2b) For Chinese: The logical markup is provided by U and we 
> make it clear that the two adjacent underlines should never 
> run into each other
> (2c) The Chinese use case could also potentially be useful 
> for non-Chinese situations
> What Charles proposed are ways to specify how the constant 
> underline position in #1 should be determined, and to specify 
> how a non-constant underline position in #2 can be explicitly 
> specified for superscripts and subscripts. 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.
> Charles did not explicitly specify a use case for "pixel 
> positioning", but I suggested it as a possible fix for 
> incorrect underline position in Chinese. The above also shows 
> that the counter-proposal of correcting the underline 
> positions in CJK fonts (which still should be corrected, 
> since this affects also word processors) alone will not be a 
> complete fix to the Chinese problem. Personally, I envision 
> "pixel positioning" to be usable as a workaround for both 
> problem #1, and problem #2 when we are dealing specifically 
> with superscripts and subscripts; it may not be a perfect 
> solution but this could be what Charles had in mind, 
> *especially* if you don't want the proposed additional keywords.
> --
> 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 Monday, 3 January 2011 22:01:36 UTC

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