[Bug]: Devanāgarī characters not rendered correctly

[rbnvrw]

Problem description

In termux (and as a result, vim in termux) devanāgarī characters are not rendered correctly: the compound phonemes are rendered separately, which results in weird jumps in the cursor position when going through a word character by character.

It seems something needs to be changed in the terminal, I couldn't find much information, but see e.g. https://askubuntu.com/questions/182642/devnagari-script-in-terminal

Steps to reproduce the behavior.

Type the following characters:

स्वर

It is shown in Termux as:

I.e. the first two characters should be merged but aren't, these are the three separate characters with spaces:
स् व र

Removing the spaces should merge the first two characters. It is the same for other compound characters.

What is the expected behavior?

It should show as:

System information

• Termux application version: googleplay.2025.01.18
• Android OS version: 14
• Device model: Samsung Galaxy S21 5G

Thank you for the great software!

[Grimler91]

Termux application version: googleplay.2025.01.18

Nothing we can do about playstore app here. Is issue reproducible in termux from F-Droid or https://github.com/termux/termux-app/releases? Otherwise please open an issue in playstore repo: https://github.com/termux-play-store/termux-issues

[Biswa96]

I can reproduce the issue in termux-app built from source. I copied the characters from this issue and pasted it in termux app window. copy-paste does not change the word in Firefox Android which shows it correctly.

[rbnvrw]

Maybe an example that more clearly demonstrates the issue, as it has more compound characters:

योगश्चित्तवृत्तिनिरोधः

Should look like

But renders in Termux as:

This also messes up navigation using the cursor keys and text selection.

[Biswa96]

Is this issue related with zero width joiner? https://en.wikipedia.org/wiki/Zero-width_joiner

[rbnvrw]

Is this issue related with zero width joiner? https://en.wikipedia.org/wiki/Zero-width_joiner

I think it's related but not exclusively. For example, the example they give on the wiki without ZWJ:

[ka क] [virāma ्] [ṣa ष] क्ष

Renders in Termux as:

So I think it happens for all conjuncts, see e.g. https://en.m.wikipedia.org/wiki/Conjunct_consonant