Tab rewrite

[Adanos020]

Tab is no longer a trait which the user has to implement on their own custom widget. A context type is also no longer required.

This makes creating trees easier without limiting customizability.

Example:

// Initial tree setup
let tab1 = TabBuilder::default()
    .title("Tab 1")
    .content(|ui| {
        ui.label("Tab 1");
    })
    .build();
let tab2 = TabBuilder::default()
    .title("Tab 2")
    .inner_margin(Margin::same(4.0))
    .content(|ui| {
        ui.label("Tab 2");
    })
    .build();
let mut tree = Tree::new(vec![tab1, tab2]);

// Then, in your app's `update` function:
egui_dock::show(&mut ui, id, &style, &mut tree)

Part of this PR is closing #1 and #5

[Jerrody]

Would be nice if it will be possible to get data from the tab.
As an example, for the window drag for too be easy to transfer data to the new window.

I don't use egui so many time, so I don't understand how to copy content from the window.

[Adanos020]

Would be nice if it will be possible to get data from the tab. As an example, for the window drag for too be easy to transfer data to the new window.

I don't use egui so many time, so I don't understand how to copy content from the window.

I think moving the add_content function out of Tab and putting it in a wrapper which internally creates an egui::Window could do the trick.

[Jerrody]

Would be nice if it will be possible to get data from the tab. As an example, for the window drag for too be easy to transfer data to the new window.
I don't use egui so many time, so I don't understand how to copy content from the window.

I think moving the add_content function out of Tab and putting it in a wrapper which internally creates an egui::Window could do the trick.

Yes, I made the same. I made a DockWindow that internally also creates an egui::Window, so I think we should just move ownership to the dock_windows and everything works very well.

[Adanos020]

I think the main goals of this PR have just been achieved 👍

[boonkerz]

currently the context is not required anymore but how should i use it?

as example i need to access something from the ui method.

fn ui(&mut self, ui: &mut egui::Ui, _ctx: &mut AppContext) that is what i used before.

[Adanos020]

currently the context is not required anymore but how should i use it?

as example i need to access something from the ui method.

fn ui(&mut self, ui: &mut egui::Ui, _ctx: &mut AppContext) that is what i used before.

Currently you can hold your data in an Rc/Arc, and have the closure of your tab own a copy of it, as demonstrated in this example: https://github.com/Adanos020/egui_dock/blob/main/examples/hello.rs#L57

The reason for this change is that in the previous version you could only have one type and only one instance of the context being passed to all tabs in one Tree, limiting your ability to control what data gets passed where. If you were dealing with many tabs accessing many different pieces of data, you'd have to store all of that data in a single struct.