bug#54914: 28.1.50; Unable to form Brahmi conjuncts in Emacs

["समीर सिंह Sameer Singh" <lumarzeli30@gmail.com>]

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Thank you very much for adding support for Brahmi!

I can notice two problems
1. Vowel signs are not attached properly to conjuncts.
    Correct output=hb-conjuncts-maatra.png   Incorrect
Output=emacs-conjuncts-maatra.png

2. Conjuncts with more than two consonants are not supported.
    Correct output=hb-tri-conjuncts.png   Incorrect
Output=emacs-tri-conjuncts.png

On Sat, Apr 16, 2022 at 3:51 PM Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Robert Pluim <rpluim@gmail.com>
> > Cc: 54914@debbugs.gnu.org,  lumarzeli30@gmail.com
> > Date: Thu, 14 Apr 2022 11:07:23 +0200
> >
> > >>>>> On Wed, 13 Apr 2022 21:26:55 +0300, Eli Zaretskii <eliz@gnu.org>
> said:
> >
> >     >> From: Robert Pluim <rpluim@gmail.com>
> >     >> Cc: Eli Zaretskii <eliz@gnu.org>,  54914@debbugs.gnu.org
> >     >> Date: Wed, 13 Apr 2022 18:56:21 +0200
> >     >>
> >     >> A brute-force example of what Eli's talking about would be:
> >     >>
> >     >> (set-char-table-range composition-function-table
> >     >> '(#x11000 . #x1107F)
> >     >> (list (vector "[\x11000-\x1107F]+" 0 #'font-shape-gstring)))
> >
> >     Eli> Does that really work?  I'm not sure it will catch the
> "consonant,
> >     Eli> virama, consonant" rule (because the virama is a nonspacing
> mark, and
> >     Eli> we have a default rule for those in composite.el).
> >
> > We do indeed. The following handles only Ka through Lla in combination
> > with Virama, and seems to do the right thing here with Segoe UI
> > Historic (which I donʼt think we can set as default for the Brahmi
> > script, since itʼs non-free).
> >
> > ;; <Consonant, Virama, Consonant>, or <Consonant, Virama>, where the
> > ;; latter indicates a vowelless consonant.
> > (set-char-table-range composition-function-table
> >                     '(#x11013 . #x11034)
> >                     (list (vector
> "[\x11013-\x11034]\x11046[\x11013-\x11034]?"
> >                                     0 #'font-shape-gstring)))
>
> I've now added support for the Brahmi script to the master branch;
> please test and report any problems you find.
>
> (We cannot advertise Segoe UI Historic, unfortunately, since it is not
> a free font, AFAICT.)
>

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