Bug 512420 - The wallpaper previews are not displaying correctly when I try to change my wallpaper
Summary: The wallpaper previews are not displaying correctly when I try to change my w...
Status: RESOLVED FIXED
Alias: None
Product: plasmashell
Classification: Plasma
Component: general (other bugs)
Version First Reported In: 6.5.3
Platform: Fedora RPMs Linux
: NOR minor
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2025-11-21 06:49 UTC by romeo.falcou
Modified: 2025-12-10 18:39 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 6.5.5
Sentry Crash Report:


Attachments
Video of the bug (1.73 MB, video/mp4)
2025-11-21 06:53 UTC, romeo.falcou
Details

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Description romeo.falcou 2025-11-21 06:49:35 UTC
SUMMARY
The wallpaper previews are not displaying correctly when I try to change my wallpaper.

STEPS TO REPRODUCE
1. right-click on the desktop
2. click on "Desktop and Wallpaper"
----------------------------------------------------
1. Open system settings
2. Go "Wallpaper" section

OBSERVED RESULT
The wallpaper previews are displayed zoomed in strangely.

EXPECTED RESULT
As in the previous plasma version: the wallpapers are displayed correctly on this screen

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora Linux 43
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.0

ADDITIONAL INFORMATION
I encountered this bug yesterday morning when I performed a package update (dnf upgrade), which updated some KDE packages.
Comment 1 romeo.falcou 2025-11-21 06:53:32 UTC
Created attachment 187016 [details]
Video of the bug
Comment 2 TraceyC 2025-12-09 20:31:05 UTC
Thanks for the bug report, and for the video which does clearly show the improperly scaled & cropped previews.

The video mentions that testing happened on a new VM with a new user.
In the video, it looks like most but not all wallpapers are affected.

You can particularly see the bug with the wallpapers "Fedora Forty-Three", where the top of the rocket is cut off, "Mountain", which only shows the very top of the middle mountain, and Scarlet Tree, which only shows the top of the tree
This can also be seen, at a glance, with: Flow, honeywave, Milky Way

Previews which look the same in the video as on my git-master system:
One Stands Out

In the video, the Desktop Folder Settings are
- Layout: Folder View
- Wallpaper type: Image
- Positioning: Scaled and cropped
- Switch dynamic: Based on whether the Plasma style is light or dark

I'm not able to reproduce this in Plasma built from git-master or Plasma 6.5.3 on Solus

I do see a problem with some wallpapers on Fedora 43 Plasma 6.5.3, seen with Flow, Fedora Forty-Two, Honeywave, Milky Way and others
Comment 3 romeo.falcou 2025-12-10 15:11:25 UTC
(In reply to TraceyC from comment #2)
> Thanks for the bug report, and for the video which does clearly show the
> improperly scaled & cropped previews.
> 
> The video mentions that testing happened on a new VM with a new user.
> In the video, it looks like most but not all wallpapers are affected.
> 
> You can particularly see the bug with the wallpapers "Fedora Forty-Three",
> where the top of the rocket is cut off, "Mountain", which only shows the
> very top of the middle mountain, and Scarlet Tree, which only shows the top
> of the tree
> This can also be seen, at a glance, with: Flow, honeywave, Milky Way
> 
> Previews which look the same in the video as on my git-master system:
> One Stands Out
> 
> In the video, the Desktop Folder Settings are
> - Layout: Folder View
> - Wallpaper type: Image
> - Positioning: Scaled and cropped
> - Switch dynamic: Based on whether the Plasma style is light or dark
> 
> I'm not able to reproduce this in Plasma built from git-master or Plasma
> 6.5.3 on Solus
> 
> I do see a problem with some wallpapers on Fedora 43 Plasma 6.5.3, seen with
> Flow, Fedora Forty-Two, Honeywave, Milky Way and others

Thank you for looking into this and for your detailed analysis. I’ll be happy to provide any additional information or testing if needed.
Comment 4 Nate Graham 2025-12-10 17:25:01 UTC
Thanks for reporting the issue! Looks like it's already fixed by https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/6062 for Plasma 6.6. I'll see if it might be feasible to backport.
Comment 5 Vlad Zahorodnii 2025-12-10 18:38:46 UTC
Git commit 59b1d537e51ff7a49f5ae6b2cc9d6f5a6cf25efc by Vlad Zahorodnii.
Committed on 10/12/2025 at 18:06.
Pushed by vladz into branch 'Plasma/6.5'.

wallpapers/image: Fix wallpaper previews not honoring aspect ratio for sourceSize

If the minimum source size is forced (it happens with my 4K monitor
scaled at 130%), then the sourceSize may have an aspect ratio of 1:1.

This can result in the portait orientation image being loaded instead of
the landscape one.

This change makes sure that the minimum forced source size follows the
aspect ratio of the screen.

(cherry picked from commit df4e7385535822451f532cd7790bd7411164c636)

M  +20   -3    wallpapers/image/imagepackage/contents/ui/ThumbnailsComponent.qml

https://invent.kde.org/plasma/plasma-workspace/-/commit/59b1d537e51ff7a49f5ae6b2cc9d6f5a6cf25efc