Re: font-size and accents, again

Todd Fahrner wrote:
> 
> In some fonts, letterform
> features will overshoot or fall short of their em (i.e. font-size)
> boundaries at some or all sizes, by design or as a consequence of
> hinting

So, given that style sheet authors can use font-size to specify the
"em", and given that some glyphs overflow their em, how can these
authors ensure that lines of text will not overlap each other? I suppose
the line-height can be set to some value, but what value? If the author
is not sure which font will be selected on the user's system, are they
supposed to take some arbitrary value like 1.2 and just pray that it'll
all work out?

(David Baron, any comments?)

Erik