Extremely tiny mouse in some apps (Qt?) with fractional scaling enabled

In some apps, even those with support for fractional scaling (like DigiKam), everything looks fine except for the mouse. The mouse within the application turns into a baby ant. Even though the application settings allow you to enable scaling for HiDPI (like digiKam). This only fixes the GUI of the application, not the mouse inside the application.

When I try to resize the application, the “resize mouse” has the correct size. When I move the mouse outside the app, over the desktop background, it also turns in a regular sized mouse.

I believe this might only happen with Qt apps. Is there a way to solve it?

Does something like this work … or maybe it was just for qt4 based apps

I asked via the DigiKam mailing list:
I should enable HiDPI for fractional scaling in Settings > Appearance. Then add QT_SCALE_FACTOR=2 to the .desktop execution command. Did all that but the mouse stays tiny.

This workaround doesn’t seem the right way to solve this:

The link you provided, I tried to create the file in several locations ($HOME, $HOME/.config, $HOME/.local) it has zero effect. Alternatively, tried to find a qt-configor similar named package, doesn’t seem to be available.

$ cat ~/.icons/default/index.theme 
[Icon Theme]

The application scales well, it’s really only the mouse cursor, when it is located inside the window.

I think I know what the fix is but not how to apply it:

In Budgie Desktop Settings, I want to make sure the mouse cursor has a fixed size, resize should not be allowed. I believe this could be a theme dependent setting. I read online several users fixed the issue, by setting a fixed size for mouse cursor. For example in KDE:

Edit: However, changing cursor size from “resolution dependent” to “36” in KDE’s own System Settings keeps it from switching sizes (in the default session too).

Is there a way to do that in Budgie?

hmm - I’m not aware of setting the cursor size via CSS. Possibly it could be done. Not sure.

On your travels around the interweb did you come across this? Make your Mouse Cursor Theme and Size Consistent - Even with Compiz and/or Emerald - Tutorials & Guides - Ubuntu MATE Community … might be useful hints and tips there.