1506415 - Arabic digits are not enclosed in ARABIC END OF AYAH

Status: UNCONFIRMED

(Core :: Graphics: Text, defect, P3)

Description

[Lateef Shaikh]

Attachment: Tehreer.zip

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Steps to reproduce:

1. Please unzip Tehreer.zip file
2. Open pqm_test.html file. It uses SIL Scheherzade and PakType Tehreer font. The End of Aaya mark encloses numbers properly in Internet Explorer but not in FireFox.

I have attached the font also so that it can help you in debugging the issue may be.


Actual results:

The End of Aaya mark encloses numbers properly in Internet Explorer but not in FireFox


Expected results:

The page should be displayed same as it does in IE. End of Aya should enclose numbers properly

Comment 1

[Jonathan Kew [:jfkthame]]

End of Ayah has always been a tricky character. I think this is somehow related to directionality and how the text gets broken into runs and reordered, though I don't recall all the details offhand.

Interestingly, the Scheherazade example displays as expected if you add unicode-bidi:bidi-override to the style, in both Firefox and Chrome. The PakType Tehreer example doesn't, however, suggesting that the two fonts aren't handling this in the same way.

Also interesting to see that Tehreer displays quite differently in Firefox vs Chrome. Something about the glyph sizing is very odd.

Comment 2

[Behdad Esfahbod]

This is the HarfBuzz issue, and explanation: https://github.com/harfbuzz/harfbuzz/issues/501#issuecomment-334179116

Comment 3

[Lateef Shaikh]

(In reply to Jonathan Kew (:jfkthame) from comment #1)
> End of Ayah has always been a tricky character. I think this is somehow
> related to directionality and how the text gets broken into runs and
> reordered, though I don't recall all the details offhand.
> 
> Interestingly, the Scheherazade example displays as expected if you add
> unicode-bidi:bidi-override to the style, in both Firefox and Chrome. The
> PakType Tehreer example doesn't, however, suggesting that the two fonts
> aren't handling this in the same way.
> 
> Also interesting to see that Tehreer displays quite differently in Firefox
> vs Chrome. Something about the glyph sizing is very odd.

Thank you, I am using unicode-bidi:bidi-override and after some kerning tweaks in my font I am good now. Please close the issue.