Bug 255972

Summary:

[Harfbuzz] Some Arabic fonts are not being shaped correctly

Product:

WebKit

Reporter:

Saadat Mateen <saadat.mateen>

Component:

WebKitGTK

Assignee:

Nobody <webkit-unassigned>

Status:

NEW

Severity:

Normal

CC:

bugs-noreply, mcatanzaro, philn, webkit-bug-importer, zyx

Priority:

Version:

Other

Hardware:

OS:

Linux

Attachments:

Description	Flags
Incorrect rendering of Noto Nastaliq Urdu in Epiphany 44.1	none
Correct rendering of Noto Nastaliq Urdu in Firefox 112.0.1	none
Incorrect rendering of Mada in Epiphany 44.1	none
Correct rendering of Mada in Firefox 112.0.1	none
Incorrect rendering of Noto Sans Arabic in Epiphany 44.1	none
Correct rendering of Noto Sans Arabic in Firefox 112.0.1	none
Duolingo Arabic course, comparison between Gnome Web 47.2 and Firefox	none

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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