Bug 452406

Summary: Poor peformance when opening PDF with lots of forms
Product: [Applications] okular Reporter: Nicolas Fella <nicolas.fella>
Component: generalAssignee: Okular developers <okular-devel>
Status: RESOLVED FIXED    
Severity: normal CC: nate
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: The PDF
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Description Nicolas Fella 2022-04-08 14:49:13 UTC 
STEPS TO REPRODUCE
1. Open the attached PDF 
2. Click "Show Forms"
3. Scroll around in the PDF

OBSERVED RESULT
Scrolling lags a lot


EXPECTED RESULT
Scrolling works normally


SOFTWARE/OS VERSIONS
KDE Frameworks Version: master 
Qt Version: 5.15.3

ADDITIONAL INFORMATION
Poppler from master
Comment 1 Nicolas Fella 2022-04-08 14:49:28 UTC 
Created attachment 148047 [details]
The PDF
Comment 2 Nicolas Fella 2022-04-08 14:51:25 UTC 
Created attachment 148048 [details]
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Comment 3 Nicolas Fella 2022-04-08 15:47:08 UTC 
Commenting https://invent.kde.org/graphics/okular/-/blob/master/gui/pagepainter.cpp#L109 out makes it run smooth
Comment 4 Nicolas Fella 2022-04-08 15:54:11 UTC 
page->_o_nearestPixmap always returns a pixmap with DPR 1, but a dpr of 2 is needed for me, hence the detach in setDevicePixelRatio
Comment 5 Nicolas Fella 2022-04-08 15:59:11 UTC 
That also means the issue is only triggered on high-dpi screens
Comment 6 Bug Janitor Service 2022-05-17 11:54:20 UTC 
A possibly relevant merge request was started @ https://invent.kde.org/graphics/okular/-/merge_requests/612