On Sat, Oct 2, 2021 at 2:18 PM Eli Zaretskii <
eliz@gnu.org> wrote:
What font displays them individually? You should be able to tell that
if you type "C-u C-x =" on one of these characters.
This is the default font that `emacs -Q` chooses. Using "C-u C-x =" I see,
ftcrhb:-PfEd-DejaVu Sans-normal-normal-normal-*-13-*-*-*-*-0-iso10646-1 (#x56F)
So would it be correct to say that using a proper font solves the
problem?
This is almost correct except that the font (NotoNastaliqUrdu) that causes problems with emacs
works fine in libreoffice and both use harfbuzz.
I don't think the problem is with compositions, because in the 2
examples you described above, there are no character compositions.
Moreover, our pattern for asking HarfBuzz to shape Arabic text is
this:
"[\u0600-\u074F\u200C\u200D]+"
which includes all of the characters, including U+06C1 which you say
causes problems.
You could try setting current-iso639-language to the symbol 'ur'
(without the quotes), that should tell HarfBuzz to shape the text as
appropriate for Urdu. But I think the real problem is with the font,
not with shaping.
Sorry, my lack of understanding of terminology got in the way here. I thought composition referred to
joining characters together.
I did try setting `current-iso639-language` to the symbol `ur`. As you expected it didn't make a difference.