W3C home > Mailing lists > Public > www-style@w3.org > November 1999

Re: font-size and accents, again

From: L. David Baron <dbaron@fas.harvard.edu>
Date: Mon, 22 Nov 1999 16:51:37 -0500 (EST)
Message-Id: <199911222151.QAA31015@is04.fas.harvard.edu>
To: dbaron@fas.harvard.edu, erik@netscape.com
Cc: fahrner@pobox.com, www-style@w3.org
On Mon, 22 Nov 1999 13:18:31 -0800, erik@netscape.com (Erik van der
Poel) wrote:
> 
> When you say "scaling factor units for line-height", I assume you're
> referring to the normal, number and percentage values:
> 
>   http://www.w3.org/TR/REC-CSS2/visudet.html#propdef-line-height

I'm referring to "normal" and "<number>", but not "<percentage>" (which
I think should work just like 'em' in "<length>").

> Those units are defined in terms of "font size", and since font-size
> corresponds to "em", I think those units should continue to be based on
> the em, rather than the maximum height of the glyphs.

The reason I think this is a bad idea is that it is not backwards
compatible with most current behavior, and the current behavior makes
any line-height above 1.0 "safe" (i.e., it cannot cause overlap).  This
would mean that things that were once reasonable suggestions could now
be unsafe.

Since scaling factors (i.e., 'normal' or a number) are the only safe
way of suggesting line-height because of inheritance, I think they should
be kept safe in all respects.

> If we need a way to refer to the max height of the font, let's introduce
> a new unit called "mx" (or whatever). E.g. the following sets the
> line-height to 1.04 times the max height of the font:
> 
>   P { line-height: 1.04mx }

New units can't be introduced to CSS for at least 4 years or so in any
useful way, since many existing browsers will treat them as pixels.

-David

L. David Baron    Sophomore, Harvard (Physics)    dbaron@fas.harvard.edu
Links, SatPix, CSS, etc.     <URL: http://www.fas.harvard.edu/~dbaron/ >
WSP CSS AC                      <URL: http://www.webstandards.org/css/ >
Received on Monday, 22 November 1999 16:51:40 GMT

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