Restrict cursor movements?

[matthieucx]

Hello! Thanks you for Niri, it's wondeful🥳

A bit of an odd issue to have, my laptop's screen is faulty and having a column of black pixels on the left edge avoids some graphical glitches. I used to solve this by displaying a 1- pixel-wide black bar rainmeter widget (windows) or by shifting the display by one pixel to the right (linux, using xrandr's transform). I've started playing around with Niri and Wayland, and there's no way (as far as I can tell) to offset the display by one pixel.

But using a 1-pixel-wide waybar on the overlay layer sounds good enough for me! I am just wondering if there is any way to forbid the cursor from entering the waybar area? As it triggers the graphical glitches if it reaches the left edge of the screen. Maybe using the zwp_pointer_constraints_v1 protocol ? (No idea on the how)

Does anyone have any idea on what's possible?

[YaLTeR]

Hello! Hmm, I'm not sure you can restrict the pointer like that. I guess you could patch niri to always draw a solid black column on top of everything though, that will also include fullscreen and lock surfaces, should be relatively straightforward. I can tell where if you're up for it

[matthieucx]

Thanks a lot for the quick reply

Well that sounds even better! It would indeed help a lot to have some pointers

[YaLTeR]

In niri.rs in struct OutputState add a new SolidColorBuffer like background_buffer, but with width = 1 pixel. Initialize it the same way. Then in Niri::render() copy the background SolidColorElement, put it at the very top in front of pointer_element, then change to the 1 pixel buffer that you added. That should make it work.

[matthieucx]

Great, thank you so much! I'll try that over the next week

[matthieucx]

I patched Niri today, thank you so much!! that works perfectly, fullscreen and everything

[YaLTeR]

Nice, glad you got it working!