Bug 170438 – ಎಕ್ಸ್‌ಪ್ರೆಸ್ wrong rendering of Kannada text: Coretext issue

• Component: Text
• Status: RESOLVED FIXED

[P K]

Created attachment 306154 [details]
Left: Chrome(harfbuzz) correct display: Right: Safari (Coretext webkit) incorrect

Safari in Mac OS and iOS displaying word ಎಕ್ಸ್‌ಪ್ರೆಸ್ incorrectly.

This is happening because of consonant conjugate (u+0c95 u+0ccd u+0cb8) is added with a halant (u+0ccd).

Safari is not constituting the consonant conjugate with a halant (ಕ್ಸ್) instead splitting the two consonant with halants.

This is wrong.

Please fix it.

[Jon Lee]

@P K, which versions on Mac and iOS are you testing against?

[P K]

Created attachment 306172 [details]
issue in iOS 10.3.1

mac os sierra 10.12.4: build 16E195 and iOS 10.3.1: build 14E304.

Please note the plain "ಎಕ್ಸ್‌ಪ್ರೆಸ್" inline text will use Kannadasangam MN font (AAT font), if you are viewing this is either mac or iOS. It will rendered the text correctly.

But the below link uses Google Noto Sans font which is Open Type font renders incorrectly due to bug in Apple CoreText Engine

http://www.prajavani.net/news/article/2017/04/04/481670.html


But the same weblink in Chrome on Mac will render correctly, because it uses harfbuzz, text shaping engine.


Chrome in iOS fails render the text correctly, because all browsers in iOS are required to webkit which uses Apple Coretext engine.


More examples of this issue are

ದಟ್ಸ್, ಎಕ್ಸ್ , ಮಾರ್ಚ್, ಟೆಕ್ಸ್ಟ್, ಬುಕ್ಸ್, ಸಾಫ್ಟ್, ಜಸ್ಟ್, ಪೋಸ್ಟ್‌ಪೇಯ್ಡ್‌  

Please check this below link in Safari and Chrome on mac OS
http://kannadafont.blogspot.com/2017/03/blog-post.html

[Myles C. Maxfield]

I can reproduce this on iOS.

[Radar WebKit Bug Importer]

<rdar://problem/31514818>

[P K]

Please review this webpage. This has loaded webfonts to enable easy testing.

http://kannadafont.blogspot.com/2017/03/blog-post.html

I have tested this issue in mac os Sierra public beta 3 (17A315i)

Kannada words: Passed
ದಟ್ಸ್, ಎಕ್ಸ್ , ಟೆಕ್ಸ್ಟ್, ಬುಕ್ಸ್, ಸಾಫ್ಟ್, ಜಸ್ಟ್, ಪೋಸ್ಟ್‌ಪೇಯ್ಡ್‌, ಎಕ್ಸ್‌ಪ್ರೆಸ್

Kannada word: "FAILED" with Baloo tamma, Nirmala UI, Kannada MN (mac font)
ಮಾರ್ಚ್

Please check.

[P K]

Created attachment 319792 [details]
ಮಾರ್ಚ್ Failed, ಆ್ಯಕ್ಷಿಸ್ Failed

ಮಾರ್ಚ್ Failed in Baloo Thamma and Nirmala UI
ಆ್ಯಕ್ಷಿಸ್ Failed in Baloo Thamma

[Myles C. Maxfield]

Can verify that this is fixed in the latest version of macOS and iOS?

[P K]

Hello Myles,

I am responding to your query.

ಮಾರ್ಚ್ Failed, ಆ್ಯಕ್ಷಿಸ್ Failed

ಮಾರ್ಚ್ Failed in Noto Serif Kannada, Baloo Thamma and Nirmala UI
ಆ್ಯಕ್ಷಿಸ್ Failed in Baloo Thamma

(I was told this was not the right forum for CoreText Issue. I can submit a bugreport in radar directly.)

"ಆ್ಯಕ್ಷಿಸ್": is failing because related to Kannada opentype feature "akhn" for ಕ್ಷ and ಜ್ಞ. When diacritics are added to these composites, Apple CoreText is failing. 

ಮಾರ್ಚ್: I have to compared few Kannada fonts, and determine the difference in opentype features.

If you chose to, you may please close this issue. I will submit a ticket in bugreport directly.

Thanks for your kind support.

[Myles C. Maxfield]

<rdar://problem/35536754>

[P K]

This is resolved in newer OS versions.