Bug 6137 - Disable kerning and some ligatures in the ATSUI code path
Summary: Disable kerning and some ligatures in the ATSUI code path
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: 420+
Hardware: Mac OS X 10.4
: P2 Normal
Assignee: Nobody
Depends on:
Blocks: 5166
  Show dependency treegraph
Reported: 2005-12-18 10:18 PST by mitz
Modified: 2005-12-21 06:38 PST (History)
0 users

See Also:

testcase (191 bytes, text/html)
2005-12-18 10:21 PST, mitz
no flags Details
testcase (747 bytes, text/html)
2005-12-18 10:22 PST, mitz
no flags Details
patch (incl. layout test) (8.19 KB, patch)
2005-12-18 10:53 PST, mitz
no flags Details | Formatted Diff | Diff
revised patch (8.19 KB, patch)
2005-12-18 14:38 PST, mitz
darin: review+
Details | Formatted Diff | Diff

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Description mitz 2005-12-18 10:18:20 PST
[Split off from bug 5166]
The ATSUI code path supports kerning pairs and ligatures. Until the CG code path supports these features, 
they should be disabled in the ATSUI code path, to ensure consistency in rendering and correct text 
metrics (otherwise highlighting can be wrong).

To see the problem, open the testcase.

The fix is to disable kerning and ligatures in the ATSUI code path, until they are supported in the CG code 
path (bug 6135 and bug 6136). A weak heuristic allows ligatures in fonts that are never expected to be 
used in the CG code path. This will hopefully minimize the effect on Arabic.
Comment 1 mitz 2005-12-18 10:21:45 PST
Created attachment 5137 [details]
Comment 2 mitz 2005-12-18 10:22:31 PST
Created attachment 5138 [details]

Comment 3 mitz 2005-12-18 10:53:21 PST
Created attachment 5139 [details]
patch (incl. layout test)

Pixel mode required to detect regressions.
Comment 4 Darin Adler 2005-12-18 14:32:33 PST
Comment on attachment 5139 [details]
patch (incl. layout test)

typo: "to aggressive" where it should say "too aggressive"
Comment 5 mitz 2005-12-18 14:38:04 PST
Created attachment 5142 [details]
revised patch

Corrected typo
Comment 6 Darin Adler 2005-12-18 19:17:12 PST
Comment on attachment 5142 [details]
revised patch

OK, I still don't like the "if it has a, use ligatures" heuristic, but I guess
it will work. r=me