W3C home > Mailing lists > Public > www-style@w3.org > December 2010

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

From: Belov, Charles <Charles.Belov@sfmta.com>
Date: Tue, 21 Dec 2010 15:02:13 -0800
Message-ID: <E17F75B6E86AE842A57B4534F82D03769C3481@MTAMAIL.muni.sfgov.org>
To: "Ambrose LI" <ambrose.li@gmail.com>
Cc: <www-style@w3.org>
Ambrose LI [mailto:ambrose.li@gmail.com] wrote on Tuesday, December 21, 2010 2:03 PM

> [added] Charles Belov wrote on Tuesday, Dec. 21, 2010 11:50 AM
> > I am running into an issue in English with regard to text that is 
> > mixed regular text and superscript text, where I want an 
> unbroken underline.
> > In actual practice the underline jumps up to be immediately beneath 
> > the superscript text.  I would hope this 
> before-edge/after-edge could 
> > be applied to the anchor tag to produce such an unbroken underline.
> >
> > What I'm looking for is basically alphabetical following the main 
> > alphabetic content, that is, superscripting would be 
> ignored for the 
> > positioning of the underline.  However, the "under" 
> proposal would not 
> > seem to accomplish this, since it would not be immediately 
> beneath the 
> > letters, but rather further beneath.
> >
> > Possibly there is a need for
> >
> > alpha-ignore-super
> > The underline is aligned with the alphabetic baseline 
> without taking 
> > superscript into account. In this case the underline is likely to 
> > cross some descenders in non-superscripted text.
> >
> > I realize I can style the superscripted to not show an underline -- 
> > that's what I'm doing now -- but if there is underlined text both 
> > preceding and following the superscripted text, then that 
> produces an 
> > undesired break in the underline.
> 
> I feel that this case is somewhat similar to what we want to 
> happen for CJK text. That is, there is a need to distinguish 
> between words that are consecutive but must be visually 
> separated when underlined, and a need to keep an underline in 
> one piece no matter what its constituent parts are. The only 
> difference is that in Chinese we want to semantically mark up 
> each part individually and in this case it seems that there 
> is no such intention.

There actually is semantic marking in English in the form of a <sup> tag. 
But that is a good statement of the requirement: we want to keep an 
underline in one piece no matter what its constituent parts are.
 
> > And logically:
> >
> > alpha-conform-sub
> > The underline is aligned with the alphabetic baseline.  The entire 
> > underline is lowered to the position that would be required by 
> > subscripted text, whether or not subscripted text is present in the 
> > current underlined text.
> >
> > alpha-conform-if-sub
> > The underline is aligned with the alphabetic baseline.  If 
> subscript 
> > is present in the underlined portion, the entire underline 
> is lowered 
> > to the position required by the subscripted text.
> >
> > alpha-conform-line-if-sub
> > The underline is aligned with the alphabetic baseline.  If 
> subscript 
> > is present in an underlined portion anywhere on the current 
> text line, 
> > whether or not a subscript is present in the current underlined 
> > portion, the entire underline is lowered to the position 
> that would be 
> > required by the subscripted text were it present in the current 
> > underlined portion.
> >
> > Also, is there a reason that pixel-positioning of the 
> underline is not 
> > part of this proposal?
> 
> "Pixel" (by which I mean finer-grain than above, middle, and 
> below) positioning would be great, since the default 
> underline position for Chinese (for underlines used as proper 
> punctuation marks) often looks wrong.

It would seem that underlines used as proper punctuation marks would
better be an underline character, rather than the underline of a
space character.  Please forgive my ignorance of Chinese but
I thought a character looking like two adjacent sides of a square 
was used to set off quotations in Chinese.  (I do sometimes need to
post Chinese content, although it is rare for it to have a quotation.)

Hope this helps,
Charles Belov
SFMTA Webmaster
 
Received on Tuesday, 21 December 2010 23:07:28 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 17:20:35 GMT