Thanks, but please always show the codepoints themselves that are or
should be involved, because it's impossible to glean that from the
images.

Sorry for not including the codepoints, here they are:

hb-conjuncts-maatra.png & emacs-conjuncts-maatra.png from top to bottom

1. \011013 \011046 \01102C \011038(𑀓𑁆𑀬𑀸)

2. \011013 \011046 \01102E \011043 (𑀓𑁆𑀮𑁃)

3. \011032 \011046 \01102C \01103B(𑀲𑁆𑀬𑀻)

hb-tri-conjuncts.png & emacs-tri-conjuncts.png from top to bottom

1. \011013 \011046 \01102E \011046 \01102F (𑀓𑁆𑀮𑁆𑀯)

2. \01102F \011046 \01102C \011046 \01102F (𑀯𑁆𑀬𑁆𑀯)

3. \01102B \011046 \011027 \011046 \01102D (𑀫𑁆𑀧𑁆𑀭)

Also, where do you see the shaping rules that support those
combinations? I didn't find them in the Unicode Standard or anywhere
else I've read about Brahmi. What are your sources?

Languages like Sanskrit has three or more than three conjuncts. They are supported in scripts like devanagari (https://en.wikipedia.org/wiki/Devanagari_conjuncts#Tri-_and_tetra-consonantal_conjuncts)

So brahmi should be able to support them too.

I could find one example in the "Proposal to include Brahmi in Unicode" document (https://www.unicode.org/L2/L2003/03249r-brahmi-proposal.pdf) (Page 5, 1st image, 3rd character)

On Sat, Apr 16, 2022 at 5:56 PM Eli Zaretskii <eliz@gnu.org> wrote:

> From: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
> Date: Sat, 16 Apr 2022 17:43:49 +0530
> Cc: Robert Pluim <rpluim@gmail.com>, 54914@debbugs.gnu.org
>
> 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

Thanks, but please always show the codepoints themselves that are or
should be involved, because it's impossible to glean that from the
images.

Also, where do you see the shaping rules that support those
combinations? I didn't find them in the Unicode Standard or anywhere
else I've read about Brahmi. What are your sources? That hb-view
does something doesn't yet mean it's correct, since HarfBuzz is just
another piece of software, and can have bugs.