NEW255972
[Harfbuzz] Some Arabic fonts are not being shaped correctly 
https://bugs.webkit.org/show_bug.cgi?id=255972
Summary [Harfbuzz] Some Arabic fonts are not being shaped correctly
Saadat Mateen
Reported 2023-04-25 22:58:03 PDT
# Platform details Epiphany version: 44.1 WebKitGTK: 2.40.1 GStreamer: 1.22.2 Distributor: Fedora Linux 38 (Workstation Edition) # Issue Text set in some Arabic fonts is not being shaped correctly. Depending on the font, following issues are occurring: 1. Vertical positioning of glyphs is incorrect. URL: https://fonts.google.com/noto/specimen/Noto+Nastaliq+Urdu 2. All marks (dots/diacritics) are in wrong positions, and separate lines of a paragraph are jumbled. URL: https://fonts.google.com/specimen/Mada 3. Some diacritics are incorrectly positioned. URL: https://fonts.google.com/noto/specimen/Noto+Sans+Arabic Examples of various other Arabic fonts with incorrect shaping may also be seen at https://fonts.google.com/?subset=arabic&noto.script=Arab
Attachments
Incorrect rendering of Noto Nastaliq Urdu in Epiphany 44.1 (314.03 KB, image/png)
2023-04-25 22:59 PDT, Saadat Mateen 		no flags
Details
Correct rendering of Noto Nastaliq Urdu in Firefox 112.0.1 (336.55 KB, image/png)
2023-04-25 23:00 PDT, Saadat Mateen 		no flags
Details
Incorrect rendering of Mada in Epiphany 44.1 (164.19 KB, image/png)
2023-04-25 23:01 PDT, Saadat Mateen 		no flags
Details
Correct rendering of Mada in Firefox 112.0.1 (226.71 KB, image/png)
2023-04-25 23:01 PDT, Saadat Mateen 		no flags
Details
Incorrect rendering of Noto Sans Arabic in Epiphany 44.1 (288.06 KB, image/png)
2023-04-25 23:02 PDT, Saadat Mateen 		no flags
Details
Correct rendering of Noto Sans Arabic in Firefox 112.0.1 (310.02 KB, image/png)
2023-04-25 23:02 PDT, Saadat Mateen 		no flags
Details
Duolingo Arabic course, comparison between Gnome Web 47.2 and Firefox (350.15 KB, image/png)
2024-11-02 08:36 PDT, xipukwjsklhbathblo 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Saadat Mateen
Comment 1 2023-04-25 22:59:14 PDT
Created attachment 466085 [details] Incorrect rendering of Noto Nastaliq Urdu in Epiphany 44.1
Saadat Mateen
Comment 2 2023-04-25 23:00:11 PDT
Created attachment 466086 [details] Correct rendering of Noto Nastaliq Urdu in Firefox 112.0.1
Saadat Mateen
Comment 3 2023-04-25 23:01:09 PDT
Created attachment 466087 [details] Incorrect rendering of Mada in Epiphany 44.1
Saadat Mateen
Comment 4 2023-04-25 23:01:29 PDT
Created attachment 466088 [details] Correct rendering of Mada in Firefox 112.0.1
Saadat Mateen
Comment 5 2023-04-25 23:02:10 PDT
Created attachment 466089 [details] Incorrect rendering of Noto Sans Arabic in Epiphany 44.1 Some incorrect positioning instances marked with a red circle.
Saadat Mateen
Comment 6 2023-04-25 23:02:36 PDT
Created attachment 466090 [details] Correct rendering of Noto Sans Arabic in Firefox 112.0.1
xipukwjsklhbathblo
Comment 7 2024-11-02 08:36:02 PDT
Created attachment 473110 [details] Duolingo Arabic course, comparison between Gnome Web 47.2 and Firefox I'm only learning Arabic, but I can tell that any text with tashkīl in Gnome Web looks very wrong. The diacritics are positioned incorrectly and cause the letters to disconnect from one another.
Michael Catanzaro
Comment 8 2024-11-06 14:43:24 PST
Please mention WebKitGTK versions. The Epiphany versions have no impact on font shaping.
Michael Catanzaro
Comment 9 2024-11-06 14:44:55 PST
Also we have switched from Cairo to Skia, so it's possible that problems prior to WebKitGTK 2.46 are now obsolete. I don't know. I assume that Duolingo screenshot is probably using 2.46, though.
Saadat Mateen
Comment 10 2024-11-06 20:36:21 PST
Just visited Google Fonts using Epiphany Technology Preview, WebKitGTK 2.47.1: * Mark positioning in Noto Sans Arabic[1] is now OK. * Noto Nastaliq Urdu[2] and Mada[3] remain broken. Also found issues in: * Noto Naskh Arabic[4] and Reem Kufi[5] (incorrect mark positioning) * Aref Ruqaa[6] and Gulzar[7] (incorrect positioning of both base and mark glyphs, the output is nearly un-readable) [1] https://fonts.google.com/noto/specimen/Noto+Sans+Arabic [2] https://fonts.google.com/noto/specimen/Noto+Nastaliq+Urdu [3] https://fonts.google.com/specimen/Mada [4] https://fonts.google.com/noto/specimen/Noto+Naskh+Arabic [5] https://fonts.google.com/specimen/Reem+Kufi [6] https://fonts.google.com/specimen/Aref+Ruqaa [7] https://fonts.google.com/noto/specimen/Noto+Nastaliq+Urdu
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