[HarfBuzz] HarfBuzz shaping of R2L text

[Khaled Hosny]

On Wed, May 29, 2019 at 10:32:12PM +0300, Eli Zaretskii wrote:
> > No idea how Emacs would deal with reordered Indic glyphs which don’t
> > always follow the input order.
> 
> Can you show an example of such a situation and what is expected from
> the correct shaping and display?  I could then see what happens in
> Emacs.

The combining marks in strings like بَّا with the font from
https://github.com/khaledhosny/noname-fixed (don’t recall if I tested
with other fonts, can’t re-test now) would be drawn in the wrong order
without reversing the clusters. Or may be that was a different problem,
not sure anymore. Try removing the reverse_clusters() call and see what
happens.

Regards,
Khaled