Bug 399072

Summary: Horizontal Lines Displayed in Kate with Fractional HiDPI Scaling
Product: [Applications] kate Reporter: bugreporter11
Component: generalAssignee: KWrite Developers <kwrite-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: normal CC: lukebenes
Priority: NOR    
Version: 18.08.1   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description bugreporter11 2018-09-25 19:02:46 UTC 
SUMMARY
This may be related to bug #373232 for Konsole. As in Konsole, Kate displays random horizontal lines when fractional (e.g., 1.3, 1.7) display scaling is used on HiDPI displays. The workaround is to use integer scaling, but this is impractical on many modern devices with 2K or 4K display and laptop-sized displays.

STEPS TO REPRODUCE - on hardware with a high resolution screen such as 2K
1. Open System Settings > Display & Monitor > Scale Display
2. Select a non-integer scale factor and save the setting
3. 

OBSERVED RESULT

Horizontal lines randomly appear which are not part of the document, especially when selecting text or scrolling.

EXPECTED RESULT

A document which is displayed corrected with no extraneous horizontal lines or other visual artifacts.


SOFTWARE VERSIONS
KDE Plasma Version: 5.13.5
KDE Frameworks Version: 5.50.0
Qt Version: Qt 5.11.1 (built against 5.11.1)
QMake version 3.1 

ADDITIONAL INFORMATION

Please see 
https://bugs.kde.org/show_bug.cgi?id=373232
https://bugsfiles.kde.org/attachment.cgi?id=109683
Comment 1 bugreporter11 2018-09-25 19:04:57 UTC 
I see that Kate was fixed upstream in Qt 5.12: https://bugreports.qt.io/browse/QTBUG-66036

I also see that this is a duplicate of 
https://bugreports.qt.io/browse/QTBUG-66036
Comment 2 Dominik Haumann 2018-09-25 19:18:49 UTC 
Yes, Qt 5.12 should finally solve this. Let's close this for now - please reopen, if Qt 5.12 does not fix it for you.

*** This bug has been marked as a duplicate of bug 373232 ***
Comment 3 lukebenes 2019-05-29 14:35:08 UTC 

*** This bug has been marked as a duplicate of bug 390451 ***