Core Text shaping failure in Indic text due to join-control characters

RESOLVED FIXED in Firefox 45

Status

()

Core
Graphics: Text
RESOLVED FIXED
2 years ago
2 years ago

People

(Reporter: jfkthame, Assigned: jfkthame)

Tracking

unspecified
mozilla45
Unspecified
Mac OS X
Points:
---

Firefox Tracking Flags

(firefox45 fixed)

Details

Attachments

(1 attachment)

(Assignee)

Description

2 years ago
Spun off from bug 1194105 comment 6, as I think this is distinct from the original issue in that bug.

Testcase:

  data:text/html;charset=utf-8,
    <span style="font:36px Telugu MN">&%23xc15;&%23xc4d;&%23x200c;

should render the same as:

  data:text/html;charset=utf-8,
    <span style="font:36px Telugu MN">&%23xc15;&%23xc4d;

i.e. the ZWNJ should not affect it. But it fails, because Telugu MN doesn't include glyphs for ZWNJ/ZWJ, and this causes Core Text to use a fallback (even though it won't be visible). This then makes us think shaping failed, and punt to harfbuzz, which can't actually shape this (AAT-only) font properly.
(Assignee)

Comment 1

2 years ago
Created attachment 8695817 [details] [diff] [review]
Ignore font fallback in Core Text shaping if it's just for a join-control character
Attachment #8695817 - Flags: review?(jdaggett)
(Assignee)

Updated

2 years ago
Assignee: nobody → jfkthame
Status: NEW → ASSIGNED

Updated

2 years ago
Attachment #8695817 - Flags: review?(jdaggett) → review+
(Assignee)

Comment 2

2 years ago
https://hg.mozilla.org/integration/mozilla-inbound/rev/803db6db0f680e066a2e3830cdd22959b07a0459
Bug 1230497 - Ignore font fallback in Core Text shaping if it's just for a join-control character. r=jdaggett

Comment 3

2 years ago
bugherder
https://hg.mozilla.org/mozilla-central/rev/803db6db0f68
Status: ASSIGNED → RESOLVED
Last Resolved: 2 years ago
status-firefox45: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla45
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