Add methods to collapse a window

[emilk]

We should add two methods to egui::Window

• default_collapsed: set whether the initial state of the window is collapsed
• collapsed: set whether the current state of the window is collapsed

[nside]

i'll take it

[nside]

i've got this nside@9285214 but it's overriding the state in the collapsing header. somehow the ctx is needed to retrieve the header state. how would you handle this?

[nside]

why not keep the collapsing header state in the window struct?

[emilk]

struct Window is a builder - it stores no state at all between frames. The position and size of a window is stored in area::State, the scroll offset in scroll_area::State, the collapsing state in collapsing_header::State.

[nside]

I meant adding an Option<collapsing_header::State> field to the struct Window - similar to how area and scroll are handled. Otherwise the collapsed bool would need to be handled similarly to the window open state?

[leo848]

Any updates on this? Is there any way to have a window collapsed by default at this point?

[lordbenedikt]

I also would like this feature. I'm creating an editor app with lots of functionalities that shouldn't be visible right at startup.

[konradmoesch]

I'd also like this feature. Is someone working on this? I see #3517 marked as draft with no progress for four months.
Are you still working on it, @Norlock?
Or would you be open to me taking over the PR or making a whole new attempt at this feature?

[Norlock]

You can also continue, I have been busy with other projects so haven't really looked into it. But let me try if I can make an improvement (today/tomorrow). I will have to look at the code again.