Bug 180066 – [WinCairo] Wrongly placed scroll bars in HiDPI

• Status: RESOLVED
• Resolution: FIXED
• Component: WebCore Misc.

[Fujii Hironori]

Created attachment 327728 [details]
screenshot

See the screenshot. I tested with WinCairo port, Release build, trunk@225207, HiDPI display.

[Fujii Hironori]

Seems a relevant bug:
  Bug 169463 – [Win] Scrollbars buttons have incorrect size in HiDPI.

[Fujii Hironori]

Created attachment 327731 [details]
Patch

A screenshot with the fix. https://photos.app.goo.gl/hMKoqN1H2J2CHShD2

[EWS Watchlist]

Attachment 327731 [details] did not pass style-queue:


ERROR: Source/WebCore/platform/win/ScrollbarThemeWin.cpp:290:  Use nullptr instead of NULL.  [readability/null] [5]
Total errors found: 1 in 2 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[EWS Watchlist]

Comment on attachment 327731 [details]
Patch

Attachment 327731 [details] did not pass mac-debug-ews (mac):
Output: http://webkit-queues.webkit.org/results/5385752

New failing tests:
webanimations/animation-opacity-animation-crash.html

[EWS Watchlist]

Created attachment 327733 [details]
Archive of layout-test-results from ews114 for mac-elcapitan

The attached test failures were seen while running run-webkit-tests on the mac-debug-ews.
Bot: ews114  Port: mac-elcapitan  Platform: Mac OS X 10.11.6

[Per Arne Vollan]

Comment on attachment 327731 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=327731&action=review

> Source/WebCore/platform/win/ScrollbarThemeWin.cpp:268
> +    context.save();

You may want to consider using the GraphicsContextStateSaver class here.

> Source/WebCore/platform/win/ScrollbarThemeWin.cpp:410
> +    context.save();

Ditto.

[Fujii Hironori]

Created attachment 327956 [details]
WIP patch

This in not only scroll bars bugs, but also all RenderTheme controls which is using DrawThemeBackground.
I created a WIP patch just applying the same workaround to drawControl.
But, this doesn't solve the issues perfectly. If I scroll web pages, controls are painted at wrong places.

[Fujii Hironori]

Created attachment 328072 [details]
WIP patch

[Fujii Hironori]

Zan,

This WIP patch solves the bug. This code has been removed in Bug 179657.
Could you take a look?

[Fujii Hironori]

Created attachment 328076 [details]
Patch

[Zan Dobersek]

Comment on attachment 328076 [details]
Patch

LGTM. It's breaking the wincairo EWS though, so please commit it yourself.

[WebKit Commit Bot]

Comment on attachment 328076 [details]
Patch

Clearing flags on attachment: 328076

Committed r225397: <https://trac.webkit.org/changeset/225397>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/35799346>