eframe: add set_minimized and set_maximized

[SunDoge]

This PR adds some window actions to enable the possibility to create client-side decorations in egui applications.

[emilk]

This is really cool, thanks for working on this!

[SunDoge]

The cranky step should pass now.

[emilk]

On my Mac, this PR behaves very badly. The titlebar is back and I cannot move the window 😅

[SunDoge]

Is this problem caused by this PR?

[emilk]

Yeah, I looked a bit closer. Apearently asking window.is_maximized() is what is causing this. 🤦

And there is no winit event for maximize state changing.

[yunfengwangluo]

When learning EGUI, I found that when I click the maximize button, the window in Windows will ignore the position of the task bar and directly enter the full screen state In ubuntu, the taskbar can be explicitly displayed normally

Under normal circumstances, clicking Maximize should only maximize the window, and should not enter the full screen state!

[SunDoge]

Hi @emilk, could you please check if this can be fixed by maintaining the window maximized state in the app?

[SunDoge]

Hi @yunfengwangluo, could you show the command you run? I haven't witnessed this behavior.

[emilk]

It seems winit is quite buggy on Mac. Minimize work, but maximize makes the app hang on the next call to window.fullscreen() (i.e. asking if it is fullscreen).

[emilk]

So the main winit problem was fixed by rust-windowing/winit#2636, but we need to wait for a new winit release, but that's coming pretty soon:

• Winit version 0.28.0 rust-windowing/winit#2634

[emilk]

It now works well on my mac (with the winit 0.28 update).

Update the min_window_size and initial_window_size in examples/custom_window_frame/src/main.rs to avoid this:

[emilk]

Another nice thing to implement would be double-clicking the title-bar to maximize.