Bug 135510 - Incorrect rendering of Unicode combining half marks on OS X
Summary: Incorrect rendering of Unicode combining half marks on OS X
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: Text (show other bugs)
Version: 528+ (Nightly build)
Hardware: Macintosh OS X 10.9
: P2 Normal
Assignee: Nobody
URL: http://chris.improbable.org/experimen...
Keywords:
Depends on:
Blocks:
 
Reported: 2014-08-01 09:58 PDT by Chris Adams
Modified: 2017-09-19 18:33 PDT (History)
5 users (show)

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Description Chris Adams 2014-08-01 09:58:35 PDT 
One of our users reported a problem with the text displayed on http://www.wdl.org/en/item/10643/. The author name on that page uses the Unicode combining half marks COMBINING LIGATURE LEFT HALF and COMBINING LIGATURE RIGHT HALF (U+FE20, U+FE21)

According to the Unicode 6.0 specification – see page 235-236 of http://www.unicode.org/versions/Unicode6.0.0/ch07.pdf – two adjacent marks should combine into a single curve. 

On OS X, the behaviour depends whether font substitution occurred so e.g. the current WebKit Nightly will display the tests at http://chris.improbable.org/experiments/browser/combining-half-marks/ correctly only for Arial but most other fonts will display incorrectly. 

Recent versions of Internet Explorer on Windows 7 or later display correctly in all cases. Chrome and Firefox are also inconsistent depending on the OS and font combinations.

Previously reported to Apple as rdar://13105608
Comment 1 mitz 2014-08-01 21:08:17 PDT 
Also happens in TextEdit with the same font, so likely not a WebKit issue.
Comment 2 Ebrahim Byagowi 2017-09-16 02:03:11 PDT 
This seem to work now.