Bug 508250

Created attachment 184077 [details]
A Screenshot Of An Aliased PDF Preview In Dolphin

# SUMMARY

(At least PNG and PDF) thumbnails are aliased in Dolphin's preview pane. This is most obvious when they are rotated (presumably, for aesthetic purposes).

# STEPS TO REPRODUCE

1. Create a directory.

2. Add a PDF and/or PNG file. Ideally, solely one of either.

3. Enable the preview pane.

4. Select the directory (using empty space).

# OBSERVED RESULT

In the preview pane, the thumbnail is aliased.

# EXPECTED RESULT

It shouldn't be. Even if the image is low-resolution, its circumference shouldn't be aliased, especially when an analogue photorgraph-esque margin is applied, as Dolphin (or the thumbnailer) does.

# SOFTWARE/OS VERSIONS

> ~~~
> Operating System: Fedora Linux 42
> KDE Plasma Version: 6.4.4
> KDE Frameworks Version: 6.17.0
> Qt Version: 6.9.1
> Kernel Version: 6.15.9-201.fc42.x86_64 (64-bit)
> Graphics Platform: Wayland
> Processors: 16 × AMD Ryzen 7 7840HS w/ Radeon 780M Graphics
> Memory: 32 GiB of RAM (30.6 GiB usable)
> Graphics Processor: AMD Radeon 780M Graphics
> Manufacturer: Framework
> Product Name: Laptop 16 (AMD Ryzen 7040 Series)
> System Version: A7
> ~~~

> ~~~
> sh-5.2$ rpm -qa dolphin kio-extras
> kio-extras-25.04.3-1.fc42.x86_64
> dolphin-25.04.3-1.fc42.x86_64
> ~~~

# ADDITIONAL INFORMATION

Originally discussed at https://discuss.kde.org/t/dolphins-directory-content-thumbnails-are-aliased/38417/4?u=rokejulianlockhart.