Re: ascender, descender, cap-height and x-height

At 2:21 PM -0800 2/3/00, Erik van der Poel wrote:
>Thanks for clarifying your position. It certainly seems like a good idea
>to "re-use" the OS/2 table's ascender and descender fields for the
>purposes of "em top" and "em bottom" in those other writing systems that
>don't have ascenders and descenders as we do in Western text.
>
>However, for fonts that *do* contain Western glyphs, is it your hope
>that the OS/2 ascender and descender fields *will* refer to those very
>parts of the glyphs? Or do you think that, realistically, OpenType will
>need to continue to be flexible about this, and allow font designers to
>put their ascenders and descenders wherever they feel like, not
>necessarily equal nor even roughly equal to the positions implied by
>those fields in the OS/2 table?

Although the lowercase ascenders and descenders of Latin text are generally
close to the nominal body height and depth, what we're doing in Adobe's
OpenType fonts is setting the values (not the design) to exactly specify
the body. However, because of the historical vagueness of the OS/2
keywords, I don't think this can become a requirement, and is likely to
remain only a recommendation.

> ...
> I don't know much about the history of Windows's APIs,...

I'm afraid I know less. I'm a typographer, not an engineer, and I've
absorbed only so much by hanging out with them.
- David Lemon

Received on Friday, 4 February 2000 10:50:24 UTC