[HarfBuzz] HarfBuzz API design

Ed Trager ed.trager at gmail.com
Wed Aug 19 14:38:36 PDT 2009

> Thanks Adam.  So far the focus has been to unify the shaping logic (most
> important for Indic).  Itemization, while pretty well defined, is something
> everyone does slightly differently.  It requires:
>   - Applying Unicode Bidi Algorithm,
>   - Script tagging heuristic for Script=Common characters
>   - Language tagging heuristic
>   - Font assignment
> Except for the first item which is well-defined by Unicode, the other steps
> are less well-defined and different usecases require slightly different
> solutions.  For example, web browsers have very strict font assignment rules
> that follow the CSS spec.  Other applications, less so.  It would be harder to
> justify using a unified itemizer.  At least initially.  But yes, that's one of
> the logical next step
> behdad

I agree that different itemization use cases often require different
solutions, so HarfBuzz should make it easy for users to use whatever
itemization they want. At the same time, is there justification for
providing within HarfBuzz a "default" general itemizer that can be
used by people when they really don't need anything fancier?

So when you mention that "logical next step", does that in fact mean
that HarfBuzz will eventually include an itemizer for general use?

- Ed

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