Bug 507688

Summary: Regression: Broken rendering at high zoom levels of particular pdf document
Product: [Applications] okular Reporter: Jan Rathmann <jan.rathmann>
Component: PDF backendAssignee: Okular developers <okular-devel>
Status: REPORTED ---    
Severity: normal Keywords: regression
Priority: NOR    
Version First Reported In: 25.04.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Screenshot of broken rendering in affected document

Description Jan Rathmann 2025-07-31 10:08:02 UTC 
SUMMARY
The rendering of a particular pdf file is broken when using higher zoom levels (> 150%?).

STEPS TO REPRODUCE
1. Open the following pdf file in Okular:
https://www.nvv.de/fileadmin/nvv/data/2._Fahrtinfo/4._Liniennetz/Liniennetz_KasselPlus_Schematisch.pdf 
2. Set Zoom level to 200%, or zoom in by mouse wheel etc.

OBSERVED RESULT
The rendering looks broken when zoomed in, see attached screenshot.

EXPECTED RESULT
The rendering looks fine at all zoom levels.

ADDITIONAL INFORMATION
This seems to be a regression that happened after Okular 24.12.3 release.

I can reproduce it with:
* Kubuntu 25.04 + Backports-PPA, Okular 25.04.3, Poppler 0.6.5, Frameworks 6.14.0, Qt 6.8.3
* Fedora Rawhide live image 20250725, Okular 25.07.80, Poppler 0.6.5, Frameworks 6.16.0, Qt 6.9.1
* Neon Unstable live image 20250727, Okular 25.11.70, Poppler 0.6.5, Frameworks 6.17.0, Qt 6.9.1
* Neon User live image 20250727, Okular 25.04.3, Popper 0.6.5, Frameworks 6.16.0, Qt 6.9.1

I could _not_ reproduce it with:
* Kubuntu 25.04 live image, Okular 24.12.3, Poppler 0.6.5, Frameworks 6.12.0, Qt 6.8.3
* Fedora 42 live image, Okular 24.12.3, Poppler 0.6.5, Frameworks 6.12.0, Qt 6.8.2
Comment 1 Jan Rathmann 2025-07-31 10:08:48 UTC 
Created attachment 183674 [details]
Screenshot of broken rendering in affected document