Re: Tibetan stacks

From: Michael Forgey (
Date: Wed Jan 22 1997 - 23:23:21 EST


Thanks for your response.

> Might I ask why you need to determine the "set of commonly used Tibetan
> stacks"?

"Commonly used Tibetan stacks" is probably poor terminology on my part. But
anyway, the issue I am investigating is what is the best way to produce the
Tibetan stacks given the availability of dual byte fonts?

First of all my font background is primarily True Type in MS Win 3.1/95/NT.

With a single byte font, one must use floating (non-spacing) characters for
dependent vowels, diacritics and so on because there is only room for about
220 characters in the font. Using floating characters can compromise the
typographical quality because the floating characters must be measured to
position well for all possible character combinations. This usually means
including several copies of the same floating character, each positioned a
little differently. This can especially be a problem if one is trying to
support several typefaces with the same logic because different typefaces
can have different positioning requirements for the floating characters. At
least that is the case for Hebrew, and I expect for most any script.

However, with dual byte fonts one can include a much larger number of
glyphs, so one could pre-compose a larger number of Tibetan stacks which
include the dependent vowels and other diacritics, and reduce, maybe
eliminate the use of floating characters. I believe the end result of this
would be a higher quality of typography.

I've probably been about as clear as mud on this, yes?

Microsoft I believe is working on their True Type Open technology which
among other things addresses the issue of positioning diacritics on base
characters. The font will know how to render itself regarding this, and
will not rely upon logic from outside the font. I think this type of
approach will greatly improve things.

Rebuttals, comments, corrections from anyone?


> Michael --
> I don't know the answer to the first question, the number and enumeration
> "common" stacks. The question, like the next one, is too simplified...
> > Then, is there a simple (or not so simple) rule or guideline which
> > determines or states what possible diacritics and diacritic combinations
> > can exist on any given stack?
> For what languages, in what time period? I don't think this has a
simple, pat
> answer for all languages, times, and places.
> Might I ask why you need to determine the "set of commonly used Tibetan
> stacks"?
> Rick

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