Bug 497168 - Thumbnails in Browse mode (preview grid) have aliasing artifacts and pixelated appearance when Low resource usage mode is not enabled
Summary: Thumbnails in Browse mode (preview grid) have aliasing artifacts and pixelate...
Status: CONFIRMED
Alias: None
Product: gwenview
Classification: Applications
Component: general (show other bugs)
Version: 24.08.3
Platform: unspecified Linux
: NOR normal
Target Milestone: ---
Assignee: Gwenview Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-12-07 15:31 UTC by 3kc2awgy
Modified: 2025-04-10 00:59 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
example of aliases in gwenview (258.57 KB, image/png)
2024-12-07 15:31 UTC, 3kc2awgy
Details

Note You need to log in before you can comment on or make changes to this bug.
Description 3kc2awgy 2024-12-07 15:31:20 UTC
Created attachment 176417 [details]
example of aliases in gwenview

SUMMARY
Antialiasing in image previews would help a lot with images that have a lot of small elements (e.g. technical drawings)
Please see below how lines on the first image get completely aliased.
https://0x0.st/Xhsv.png 

STEPS TO REPRODUCE
1. gwenview image1.png image2.png 

OBSERVED RESULT
observe aliased lines (if images have them)

EXPECTED RESULT

antialiasing applied to images in browse mode (preview grid)

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: 
KDE Plasma Version: 6.2.4
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.0


ADDITIONAL INFORMATION
Comment 1 3kc2awgy 2024-12-07 15:48:13 UTC
just discovered that some antialiasing can be turned on by checking on this setting:
open menu > configure > configure gwenview > advanced > low resource usage mode
it doesn't seem right though that this, fairly important feature is a side effect of a seemingly unrelated feature.
Comment 2 John Kizer 2024-12-17 04:54:24 UTC
I can reproduce the issue, and the workaround, on Gwenview 24.12.0.

Thumbnails in Dolphin for the same images are clear and smooth (both on the file icons themselves, and in the Information pane), and thumbnails in Gwenview are perfectly smooth when generated in Low resource usage mode, so perhaps there is something in how the pre-existing system thumbnails are displayed that is working differently specifically in Gwenview?
Comment 3 Michael 2025-04-08 05:27:10 UTC
I was just setting up a Kubuntu system for a non-techie friend who comes from the Apple/iPhone world where everything looks smooth and nice. Gwenview's jagged, aliased thumbnails makes it look like KDE is stuck in the late 90's. It's embarrassing that this is the default setting in the default image viewer, and this alone made me want to find another program for her. 

#c1 mentions a workaround. I had actually seen that option before, but didn't connect disabling thumbnail creation to give me anti-aliased thumbnails, especially as the help text under the option says, "...prefer thumbnails of lower quality". I don't think anyone is taking advantage of this setting, except a few rare explorers.

Could the Gwenview developers please flip the bit to enable anti-aliasing for thumbnails? It makes my technical drawings hard to read as well.
Comment 4 John Kizer 2025-04-08 13:08:03 UTC
The version field is intended for the version in which the bug was originally reported and identified - please leave that set as-is so that information can be appropriately tracked by developers. Thanks!
Comment 5 Michael 2025-04-10 00:59:45 UTC
(In reply to 3kc2awgy from comment #1)
> just discovered that some antialiasing can be turned on by checking on this
> setting:
> open menu > configure > configure gwenview > advanced > low resource usage
> mode
> it doesn't seem right though that this, fairly important feature is a side
> effect of a seemingly unrelated feature.

I have been playing with enabling this setting but it makes some photo thumbnails look horrible, so it's not worth it, and I had to turn it back off. 

The true fix is to enable filtering for all thumbnails. This is 2025, we all have the CPU horsepower to do this. Even Dolphin has filtering for all thumbnails now.