Bug 176848

Summary: [HarfBuzz] Wrong offset returned by HarfBuzzShaper::offsetForPosition in some cases
Product: WebKit Reporter: Carlos Garcia Campos <cgarcia>
Component: PlatformAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: bugs-noreply, buildbot, clopez, mcatanzaro, mmaxfield, webkit-bug-importer
Priority: P2 Keywords: Gtk, InRadar, Regression
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch mcatanzaro: review+

Description Carlos Garcia Campos 2017-09-13 09:40:34 PDT
This bug has been revealed after enabling complex text by default in GTK and WPE ports in r221909.
Comment 1 Carlos Garcia Campos 2017-09-13 09:45:52 PDT
Created attachment 320647 [details]
Patch

It doesn't fix all the failures after r221909, but many of them and produces results similar to the mac ones in others. I still need to investigate the weird space issues.
Comment 2 Michael Catanzaro 2017-09-13 09:56:28 PDT
Comment on attachment 320647 [details]
Patch

r=me because this is the path to a better future, but this exacerbates our complex text selection rendering glitch, bug #148220. You can see that some of the expected results are now worse than before. E.g. editing/selection/select-across-readonly-input-4 shows the issue clearly.
Comment 3 Michael Catanzaro 2017-09-13 10:15:02 PDT
(In reply to Michael Catanzaro from comment #2)
> Comment on attachment 320647 [details]
> Patch
> 
> r=me because this is the path to a better future, but this exacerbates our
> complex text selection rendering glitch, bug #148220.

To be clear, I mean r221909 has exacerbated bug #148220. Not this patch. I assume this patch is fine, but I don't know because I don't understand it. I'm just approving it because we have no font reviewers.
Comment 4 Carlos Garcia Campos 2017-09-13 10:15:06 PDT
Committed r221974: <http://trac.webkit.org/changeset/221974>
Comment 5 Myles C. Maxfield 2017-09-13 16:54:54 PDT
At some point we should do https://bugs.webkit.org/show_bug.cgi?id=167566.
Comment 6 Michael Catanzaro 2017-09-13 20:55:20 PDT
(In reply to Myles C. Maxfield from comment #5)
> At some point we should do https://bugs.webkit.org/show_bug.cgi?id=167566.

I'd be excited to share as much code as possible, but I fear we don't have anyone who can help with this. :/
Comment 7 Radar WebKit Bug Importer 2017-09-27 13:00:33 PDT
<rdar://problem/34694467>