Bug 220197 - WKWebView inside a fullscreen quicklook preview lag while page scrolling
Summary: WKWebView inside a fullscreen quicklook preview lag while page scrolling
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebKit2 (show other bugs)
Version: Safari 14
Hardware: Mac (Intel) macOS 11
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2020-12-30 05:25 PST by sbarex
Modified: 2021-01-11 10:51 PST (History)
3 users (show)

See Also:


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Description sbarex 2020-12-30 05:25:07 PST
I have a Quicklook appex that show the file contents by a WKWebView. 
The preview inside a normal quicklook window works well, but if the window is in fullscreen is not possibile to scroll with the trackpad gesture.

I do not know is is related to bug [219632](https://bugs.webkit.org/show_bug.cgi?id=219632).
Using the deprecated WebView insted of WKWebView the preview can be scrolled on fullscreen mode.

I have created a demo code here:
https://github.com/sbarex/QLTest
Comment 1 sbarex 2021-01-04 08:59:17 PST
Also, non in full screen, if I click on a link to a local anchor, the scroll start after some delay.
Comment 2 Radar WebKit Bug Importer 2021-01-05 10:01:54 PST
<rdar://problem/72817636>
Comment 3 Simon Fraser (smfr) 2021-01-05 10:02:15 PST
The subject says "preview lag" but you also say "is not possibile to scroll". "Lag" implies that it scrolls, but slowly. Could you clarify?
Comment 4 sbarex 2021-01-06 06:30:06 PST
In full screen mode, the two-finger gesture on the trackpad does not scroll the content. But executing the gesuture quickly (which in normal situation would make the content scroll fast) you can scroll about 2 lines at a time, jerky and without the elastic effect.
Comment 5 Simon Fraser (smfr) 2021-01-09 11:49:42 PST
Please give instructions about how to use your test project to get fullscreen QuickLook. Should I run the QLTest target and choose "Open QuickLook for a test file"?

What macOS version are you testing on? Does the bug only occur on some OS versions?
Comment 6 sbarex 2021-01-11 10:51:49 PST
(In reply to Simon Fraser (smfr) from comment #5)
> Please give instructions about how to use your test project to get
> fullscreen QuickLook. Should I run the QLTest target and choose "Open
> QuickLook for a test file"?
> 
> What macOS version are you testing on? Does the bug only occur on some OS
> versions?

You must open the quicklook preview from the finder (open from the app do not show the fullscreen button!). 
Follow these steps:
- download the precompiled test app from https://github.com/sbarex/QLTest/releases
- move the app on the Applications folder (this force the detection of the ql extension)
- launch the app and push on the button "browse for a test file" to select a test file on the finder. 
- From the selected file on Finder open the quicklook preview.
- Maximize the preview to fullscreen.

I'm using Big Sur 11.1 (Intel). On Catalina I do not detect this bug.