Re: [css3-values] Unit for ideographic advance (ISSUE-195)

2011/11/7 John Daggett <jdaggett@mozilla.com>

>
> Isn't what you're describing something more akin to 'ideo-ch', the
> advance of a full-width character in the inline direction?
>
> Note that 'em', 'ex', 'ch' and 'rem' are all defined relative to the
> font-size so you need to define something in a similar fashion. I think
> what you're trying to define is the ratio of the width/height of the
> ideographic em-box to the width/height of the em-box itself in the
> inline direction, multiplied by the font-size.
>
> What's the use case for this unit?  In other words, what are the cases
> that using em-units won't solve?  Seems like the only situation is
> compressed or expanded fonts.
>
>
If you definition of a normal font is one where all characters are
perfectly square, then yes, we will be talking about “compressed or
expanded fonts”.

That said, there are styles in traditional CJK typography where perfectly
square characters simply don’t make any sense, for example Lishu or
Fangsong. I view the fact that the characters in such fonts are currently
usually padded to perfect squares as an anomaly; they simply should not be
square because the real glyphs in the fonts are not square.

-- 
cheers,
-ambrose

http://gniw.ca/cjk-fullwidth-space-as-unit.php