Support dithering attribute

[tsacha]

Dithering support is already in Future work readme section but I felt it pertinent to create a dedicated issue.

I have a screen flickering issue on my second monitor and disabling Dithering in nvidia-settings seems to be the only way to fix this.
I am not the only one wanting this feature, this Reddit comment led me to discover this project, and the patch worked perfectly to fix my issue on Wayland.

I'd appreciate a feature to control dithering directly within the project.

I made a quick a dirty fork for my personal use https://github.com/tsacha/ndithering/blob/main/ndithering/main.cpp.

Huge thanks for your work! <3

[Tremeschin]

Let me add it real quick via a new ATTRIBUTE=vibrance environment variable or something, I guess the project's name wouldn't really be accurate anymore, but given that a couple people use it for such it might be worth it

[Tremeschin]

Could you build it from source and run like this? Instructions at readme, pure C++ with meson/ninja is fine to test, I personally see no difference locally nor have issues with dithering, could have made a mistake haha 🙂

• ATTRIBUTE=dithering ./build/nvibrant 2 2 2 2

Per nvidia kernel modules, we should use 2 to disable it, minor caveat

enum NvKmsDpyAttributeRequestedDitheringValue {
    NV_KMS_DPY_ATTRIBUTE_REQUESTED_DITHERING_AUTO = 0,
    NV_KMS_DPY_ATTRIBUTE_REQUESTED_DITHERING_ENABLED = 1,
    NV_KMS_DPY_ATTRIBUTE_REQUESTED_DITHERING_DISABLED = 2,
};

I guess the new code could be made a bit more safe, reduce the intermediate vector and parse directly from argv, but we're just reading signed numbers and letting it cast to the data type of the structs, might improve later

[tsacha]

I just ran it on my side and it worked well. 🎉

[Tremeschin]

Awesome, and thanks for the feedback!

I'll revisit the code within the next week™ to simplify, make it safer, add such information on dithering to the readme, and go for a new release. Might ask you to confirm it works again before such, hold on this locally built binary for a bit!

[Tremeschin]

Hey, just released v1.1.0 supporting dithering, and added the readme section. I saw colors slightly changing in my second monitor when disabling/enabling it, hints me it's still working, just wasn't fully confident in my C++ experience 😆

Could you confirm it works and close the issue?

[tsacha]

Hey!

Thanks for the release, it works. ;)