Bug 6137

Summary:

Disable kerning and some ligatures in the ATSUI code path

Product:

WebKit

Reporter:

mitz

Component:

Layout and Rendering

Assignee:

Nobody <webkit-unassigned>

Status:

VERIFIED FIXED

Severity:

Normal

Priority:

Version:

420+

Hardware:

Mac

OS:

OS X 10.4

Bug Depends on:

Bug Blocks:

5166

Attachments:

Description	Flags
testcase	none
testcase	none
patch (incl. layout test)	none
revised patch	darin: review+

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]
testcase

Comment 2 mitz 2005-12-18 10:22:31 PST

Created attachment 5138 [details]
testcase

Oops.

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