Bug 482825

Summary: Falkon displays chunky fonts
Product: [Applications] Falkon Reporter: 0BADC0DE <vincenzo.romano>
Component: generalAssignee: David Rosca <nowrep>
Status: RESOLVED DUPLICATE    
Severity: major CC: demm, tim, zacharieroy
Priority: NOR    
Version: 23.08.4   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Attachments: Screenshot #1
Screenshot #2

Description 0BADC0DE 2024-03-08 07:15:22 UTC
Created attachment 166682 [details]
Screenshot #1

It started with latest update 23.08.5-1 -> 24.02.0-1
It seems to only afftect Falkon: kate, kconsole and kdesettings are unaffected.

STEPS TO REPRODUCE
1.  Open a webpage with text (I used www.kde.org and bugs.kde.org in my screenshots)

OBSERVED RESULT
Text is displayed with chunky fonts.


EXPECTED RESULT
Text is displayed smoothly.

SOFTWARE/OS VERSIONS
Kernel Version : 6.7.8.zen1-1
Plasma Version : 6.0.1-1
KDE Version : 24.02.0-1
Frameworks Version : 5.115.0-1
Qt5 Version : 5.15.12+kde+r10-1
Qt6 Version : 6.6.2-4
Wayland Version : 1.22.0-1
XOrg/Wayland Version : 23.2.4-2
Mesa Version : 1:24.0.2-2
LibVA Version : 2.20.0-1
VDPAU Version : 1.5-2

ADDITIONAL INFORMATION
My setup has 2 screens:
Main: 3840x2160 scaled at 150%
Secondary: 1920x1080 scaled at 100%.
It doesn't change if I move falkon window to the secondary screen.
Falkon has hardware acceleration enabled.
Comment 1 0BADC0DE 2024-03-08 07:15:42 UTC
Created attachment 166683 [details]
Screenshot #2
Comment 2 0BADC0DE 2024-03-08 07:16:22 UTC
I set it as major as the problem is affecting a major feature of the program: displaying text.
Comment 3 zacharieroy 2024-03-08 11:56:29 UTC
I have also ugly fonts in Falkon when i use Wayland with Kde6 but when i start my sessions with X11 i have a nice fonts.
It's only the font in the website the problem. 
i don't have the problem with Firefox. 
The problem could perhaps also be related to qtwebengine6.

I have Mesa IntelĀ® HD Graphics 520
Comment 4 0BADC0DE 2024-03-08 12:36:05 UTC
No other browser I have (chromium, vivaldi, firefox) has this problem.
okular (both text and PDF files) hasn't got this problem.
kate hasn't got this problen.
Falkon shows the problem on all websites I have visited so far.

**It only happens with screen scaling other than 100%.**
Comment 5 0BADC0DE 2024-03-08 12:51:37 UTC
FWIM:

$ vainfo 
Trying display: wayland
vainfo: VA-API version: 1.20 (libva 2.20.1)
vainfo: Driver version: Intel iHD driver for Intel(R) Gen Graphics - 24.1.3 ()

$ vdpauinfo 
display: :1   screen: 0
API version: 1
Information string: OpenGL/VAAPI backend for VDPAU
Comment 6 Tim Carr 2024-03-17 00:16:54 UTC
Duplicate of bug 483192. Seems likely related to upstream: https://bugreports.qt.io/browse/QTBUG-113574

Setting `QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor` seems to be a temporary workaround.

*** This bug has been marked as a duplicate of bug 483192 ***