add background blur on macos

[trivial-zero]

This is an attempt to add background blur to macos. I am not familiar to the code base and a little confused about how to properly read config. Any help would be appreciated. Here is a fixed blur radius preview:

[kovidgoyal]

This is a non-public API correct? And dont you have to set a color for the blur? window.backgroundColor IIRC

Not to mention there is no generally applicable solution for this on other platforms that I know of. I am not very keen to add platform specific features that anyway use a private API and so may stop working at any time.

As for your actual implementation, move it into kitty/cocoa_window.m then you can access the config value as simply OPT(whatever).

[page-down]

@BIKA-C

You should use NSVisualEffectView and set the blending mode instead of using the private API.

https://developer.apple.com/documentation/appkit/nsvisualeffectmaterial/nsvisualeffectmaterialunderwindowbackground

[hungvx-dev]

@kovidgoyal @BIKA-C I'm looking forward to this feature.

[hungvx-dev]

@BIKA-C @page-down

You can apply NSVisualEffectView to this PR.

[hungvx-dev]

@kovidgoyal You can update this PR and merge it for the next release. I very need this feature. Please help me.

[FormalSnake]

I need it too!

[hungvx-dev]

@FormalSnake Yes. Because, when using background opacity is below 0.8 then it will be difficult to see, eyestrain. So we need a degree of blur @kovidgoyal

[kovidgoyal]

Kindly stop spamming my inbox. I already stated my concerns with this PR no one has addressed them. Come up with a proper PR and we can discuss further.