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Issue 606173 link

Starred by 0 users
Status: Duplicate
Merged: issue 591346
Owner:
drott@chromium.org
Closed: Apr 2016
Cc:
kojii@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: Linux , Windows , Mac
Pri: 2
Type: Bug



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Combining unicode characters result in rendering of placeholder boxes

Reported by srikuma...@gmail.com, Apr 24 2016 
UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36

Example URL:
http://sriku.org/bugs/combining-char-bug/

Steps to reproduce the problem:
1. Create a UTF8 sequence containing "COMBINING DOT ABOVE" U+0307) or "COMBINING DOT BELOW" (U+0323) characters using "Tamil Sangam" font (default choice of Chrome on MacOSX for Tamil)
2. View sequence in browser

What is the expected behavior?
The appropriate Tamil character along with the dot in the correct relative position must be displayed.

What went wrong?
Boxes are shown instead of the characters.

Please see the referenced URL for snapshots of rendering in Chrome/Safari and data for reproducing the bug. The bug manifests on Windows too. It is also present in current Canary - Version 52.0.2715.0 canary (64-bit).

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? Yes Unclear, but I'd been recommending Chrome for this use since it used to work.

Does this work in other browsers? Yes 

Chrome version: 49.0.2623.112  Channel: n/a
OS Version: OS X 10.11.2
Flash Version: Shockwave Flash 21.0 r0

Works correctly in Safari(Version 9.0.2 (11601.3.9)). Similar rendering problem in Firefox on MacOSX. Quite likely this issue would cut across all combining characters such as "COMBINING

Comment 1 by srikuma...@gmail.com, Apr 24 2016 

(Apologies for incomplete comment. Here is the last bit.)

Works correctly in Safari(Version 9.0.2 (11601.3.9)). Similar rendering problem in Firefox on MacOSX. Quite likely this issue would cut across all combining characters such as "COMBINING DIAERESIS BELOW", "COMBINING MACRON", "COMBINING DIAERESIS", "COMBINING RING BELOW" and "COMBINING TILDE" and in other language scripts too. 

These combining characters work correctly on Roman character sets in Chrome and other browsers.

Example page which uses multiple language scripts where this problem can be further explored is https://stage.patantara.com/carnot/XRfCngTCrn . The script can be switched using the menu at the top near "Show svaras in". Available scripts are Tamil, Telugu, Kannada, Malayalam, Devanagari and the bug occurs with all of them. Again, Safari displays all of them correctly.

Comment 2 by jianli@chromium.org, Apr 25 2016

Components: -Blink Blink>Fonts
Labels: OS-Linux OS-Windows
Could also repro this on Windows and Linux. Firefox on Linux did render this correctly.

Comment 3 by e...@chromium.org, Apr 27 2016

Cc: kojii@chromium.org
Owner: drott@chromium.org
Status: Available (was: Unconfirmed)

Comment 4 by e...@chromium.org, Apr 27 2016 

drott, this seems related to your font fallback changes.

Comment 5 by drott@chromium.org, Apr 27 2016

Mergedinto: 591346
Status: Duplicate (was: Available)
Yes, we have remaining issues finding fallback fonts for combining sequences. Duplicate of issue 591346. Thank you for the helpful test case.

Comment 6 by srikuma...@gmail.com, Dec 24 2016 

Note - the link in "Comment 1"(https://bugs.chromium.org/p/chromium/issues/detail?id=606173#c1) no longer displays this issue due to a work around I added for this bug in that application.

Comment 7 by drott@chromium.org, Dec 28 2016 

Would you be able to put a reproduction of the issue similar to the test case in #1 on jsbin or codepen? Thanks. What was the workaround you are using? Was it specifying a specific font to use?
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