bug#33729: 27.0.50; Partial glyphs not rendered for Gujarati with Harfbuzz enabled (renders fine using m17n)

[Eli Zaretskii]

> Date: Sat, 22 Dec 2018 22:59:48 +0200
> From: Khaled Hosny <dr.khaled.hosny@gmail.com>
> Cc: rgm@gnu.org, far.nasiri.m@gmail.com, behdad@behdad.org,
>       33729@debbugs.gnu.org, kaushal.modi@gmail.com
> 
> On Sat, Dec 22, 2018 at 09:38:43PM +0200, Eli Zaretskii wrote:
> > > Date: Sat, 22 Dec 2018 17:49:45 +0200
> > > From: Khaled Hosny <dr.khaled.hosny@gmail.com>
> > > Cc: rgm@gnu.org, far.nasiri.m@gmail.com, behdad@behdad.org,
> > >   33729@debbugs.gnu.org, kaushal.modi@gmail.com
> > > 
> > > Yes, the standard Unicode composition and decomposition. HarfBuzz uses
> > > these during shaping (it prefers composed form for a given sequence if
> > > supported by the font, and falls back to decomposed form otherwise).
> > 
> > Btw, how is this problem solved in the other projects that use
> > Harfuzz?  Does every project need to provide this functionality, or
> > does Harfuzz have it built-in, like with the script tags?  If there's
> > built-in support for this, perhaps Emacs could just use that?
> 
> There is built-in support, and currently we are using that. I can just
> remove the FIXME.

Are there any disadvantages in using the built-in support?  I mean,
why did you envision an Emacs-specific implementation in the first
place?

Thanks.