I want a window blurring with the background. It’s impossible in GTK because - as you know - it must happen on compositor’s side. But since clutter has BlurEffect for example, I wonder if I could integrate it with my GTK application. Please let me know if it’s possible!
Well, first of all:
Blurring content you can’t control, like a desktop wallpaper which could be anything, over which you want to put content which should be clear and readable, like text or icons, is bad for accessibility, readability, etc…
So, in short, its a bad idea if you ask me.
That being said, even Apple had the same bad idea (and gained much controversy for it), so it is apparently a popular idea. So don’t let me stop you from doing it.
As for accomplish this:
As I understand it the issue is that a application itself doesn’t know of it’s background, which would be necessary to blur it.
An application can tell the compositor that parts of its render image is transparent or partially transparent. The compositor can then also render the windows with the transparency in mind.
Now, this is possible because the application just needs to provide an texture which happens to have transparency.
The issue with blurring would be that it first would need an texture with what’s behind the window. As you need the information of the background in order to blur it. However, for obvious security designs that is not available to an application, which is why this would need to be done by the compositor.
The Blur my Shell extension provides an option to blur windows.
So, best solution would be to leave the application as it and suggest using the extension if blurring is wanted. Maybe provide a preset (not sure if the extension allows that currently though)…