Apply filter effect to windows

[Alessandro Re <ale ale-re net>]

Hello,

I would like to know if it is possible to programmatically apply a filter effect on windows managed by GNOME shell, specifically in a Wayland environment.

For example, say I would like to blur the content of user-selected windows: is it possible (and where) to inject a piece of code in GNOME shell that processes each frame of each window to perform the blur before they are rendered?

The Night Mode in GNOME shell is performing something similar to what I have in mind, although it is apparently working on the entire screen, and not single windows, but this is still Ok for my use cases, as long as it is possible to read and modify the screen.

Thanks and best regards

~Alessandro