egui-winit: Automatically detect and apply dark or light mode

[emilk]

Closes #1001

Uses the dark-light crate: https://crates.io/crates/dark-light

[emilk]

Oh, dark-light doesn't even compile on Linux yet… I guess we'll wait with this until frewsxcv/rust-dark-light#4 by @edfloreshz is merged and published

[emilk]

Blocked on:

• Linux support? frewsxcv/rust-dark-light#1

[parasyte]

Unfortunately, I think you'll also want frewsxcv/rust-dark-light#3

[emilk]

We want frewsxcv/rust-dark-light#3 but it is not needed in order to merge this

[parasyte]

I suppose polling for changes is acceptable in the meantime.

[Be-ing]

Is there an advantage to egui-winit doing this versus leaving applications to use dark-light if they want?

[emilk]

Is there an advantage to egui-winit doing this versus leaving applications to use dark-light if they want?

One is to have a default: should egui be dark or light by default? Let's ask the system.
Second is convenience.

If the dark-light adds too much compile-time we should make it an optional feature though.

[collin-kemper]

dark-light currently breaks eframe on my machine. dark_light::detect() times out on my machine but takes 25 seconds to do so - meaning that starting an eframe app results in it freezing for the first 25 seconds. I've tried to disable the feature, but it doesn't seem like it is possible to disable it.

Now solved in PR #1437

[emilk]

Have you opened an issue at https://github.com/frewsxcv/rust-dark-light/issues @collin-kemper ?