Re: font-size and accents, again

"L. David Baron" wrote:
> 
> I would propose the following solution for handling fonts that are
> bigger than they claim to be: the 'em' unit should be the actual value
> of the font-size as stated by the font, but scaling factor units for
> line-height and the height used for backgrounds (and padding and
> border) on inline elements should be based on the "true" font-size
> (including all the height of the glyphs).  Note that in this solution
> 'em' units on the line-height property differ from scaling factors in
> more than just how they inherit.  I believe this solution is close to
> current practice (it would correspond to O O C O in the table in [3],
> although my test did not test 'em' units on line-height, which would in
> this solution be treated differently from scaling factors).

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

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.

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 }

(Note that the mx is good enough to specify a length, but in order to
position text accurately, it may be necessary to introduce a way to
refer to the max ascent and max descent.)

Erik