Missing Arabic positional glyphs

microsoft / cascadia-code

This is a fun, new monospaced font that includes programming ligatures and is designed to enhance the modern look and feel of the Windows Terminal.

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Missing Arabic positional glyphs #532

Closed dscorbett closed 2 years ago

dscorbett commented 3 years ago

Cascadia family version

2106.17

Cascadia family variant(s)

Cascadia Code (the version with ligatures), Cascadia Mono (the version without ligatures)

Font file format(s)

.ttf (variable), .ttf (static), .otf (static)

Platform

macOS 10.14.6

Other Software

No response

What happened?

Some Arabic letters are missing some positional glyphs:

U+0649 ARABIC LETTER ALEF MAKSURA: missing 'init' and 'medi'
U+066F ARABIC LETTER DOTLESS QAF: missing 'init' and 'medi'
U+06A2 ARABIC LETTER FEH WITH DOT MOVED BELOW: missing 'init', 'medi', and 'fina'
U+08AA ARABIC LETTER REH WITH LOOP: missing 'fina'
U+08B2 ARABIC LETTER ZAIN WITH INVERTED V ABOVE: missing 'fina'

ىىـ␤ٯٯـ␤ڢڢڢ␤ـࢪ␤ـࢲ

aaronbell commented 3 years ago

Thanks for the feedback! It is my understanding that those positional characters are not used for Arabic. Under what conditions are you encountering the need for these forms?

dscorbett commented 3 years ago

This is a Unicode compliance issue, specifically with ArabicShaping.txt. It shouldn’t matter which languages use which forms.

aaronbell commented 3 years ago

Well, just because Unicode says it does not mean that it is necessary or useful for actual language use. If you want to argue with that I have 9000 Hangul forms to show you.

Can you provide any examples of where these would be necessary?

dscorbett commented 3 years ago

Initial and medial U+0649 ARABIC LETTER ALEF MAKSURA are used in Kazakh and Uyghur.

U+066F ARABIC LETTER DOTLESS QAF is used in ancient Arabic. It does not seem necessary to include this character in a coding font, but as long as it’s included, all its positional forms need support.

U+06A2 ARABIC LETTER FEH WITH DOT MOVED BELOW is the Maghrebi form of U+0641 ARABIC LETTER FEH. It is not useful to include this character in a font but only support its isolated form.

U+08AA ARABIC LETTER REH WITH LOOP is used in Rohingya. See figure 21c of L2/10-288R for isolated and final attestations.

U+08B2 ARABIC LETTER ZAIN WITH INVERTED V ABOVE is used in Berber. See L2/12-181R for isolated and final attestations.

aaronbell commented 3 years ago

Thank you! The additional context is very useful for us to better understand the request.