Change the highest priority Persian font to Vazirmatn

[MahdiNazemi]

Description

With the introduction of the language setting in version 6.39.0, this may be a good time to update the default font for Persian to Vazirmatn, which can greatly enhance readability and aesthetics. It is worth noting that Vazirmatn font is highly sought after by the Signal community, as can be observed in the following sources:

• Issue Comment on Signal-Desktop repository
• Issue Comment on Signal-Desktop repository
• Signal Users Forum Post
• Signal Users Forum Post

While personal preferences regarding font readability and aesthetics may vary, I believe that Vazirmatn font will cater to the needs of the majority of Signal users who read and write in Persian.

The code has been tested on macOS Sonoma 14.1.1.

First time contributor checklist:

• I have read the README and Contributor Guidelines
• I have signed the Contributor Licence Agreement

Contributor checklist:

• My contribution is not related to translations.
• My commits are in nice logical chunks with good commit messages
• My changes are rebased on the latest main branch
• A yarn ready run passes successfully (more about tests here)
• My changes are ready to be shipped to users

[Xashyar]

Thanks @MahdiNazemi, this already looks a lot better.

[MahdiNazemi]

You're welcome. I'm glad you like how the app looks with Vazirmatin. I know you have been asking for a better font for over five years!
I hope that the maintainers approve the PR.

[Xashyar]

With the introduction of the language setting in version 6.39.0, this may be a good time to update the default font for Persian

@MahdiNazemi Just one last point, would this change the font across the board, or just when using the fa locale?
Most users might not want to switch locales, but want texts in their chat bubbles to look decent.

[MahdiNazemi]

@MahdiNazemi Just one last point, would this change the font across the board, or just when using the fa locale? Most users might not want to switch locales, but want texts in their chat bubbles to look decent.

I concur with your viewpoint, and I also wish for an aesthetically pleasing font irrespective of the locale or language settings. However, I believe that given the availability of the new language setting, switching the language to Persian as a means to obtain such a font is a reasonable compromise until more optimal solutions can be implemented.

There is a way to deal with multilingual text as described here (quote from the MDN Web Docs):

Font selection does not simply stop at the first font in the list that is on the user’s system. Rather, font selection is done one character at a time, so that if an available font does not have a glyph for a needed character, the latter fonts are tried.

My knowledge in this area is very limited, but I imagine for Signal to display Persian texts well, a font like Vazirmatn should be bundled with the app and added to font-family, and more importantly, no higher priority font in the font-family should have a glyph for Persian letters.

This may introduce other issues because Persian and Arabic have some common letters (same unicode representation), but people reading Persian will probably find a font easy on the eyes that those who read in Arabic don't. In this case, I suspect applying the correct font family to a text message necessitates the detection of the language used in the text. This detection process may involve employing a simple n-gram model or a more advanced neural network-based model to distinguish between languages such as Persian and Arabic, ensuring the appropriate font family is applied for each language. Alternatively, the app may be able to get a user's preferred languages or the active keyboard's language from the OS to guide the typeface selection.

These are probably very well-known problems with well-known solutions. Getting an expert's opinion on the issue will probably save us a lot of time.

[scottnonnenberg-signal]

We've done a little research ourselves, and we're feeling good about this change.

I've merged it, and it will be in our next beta release. Thanks for all your effort on this!

[MahdiNazemi]

Thank you for considering the PR and integrating it into the next beta release.