Makie embedding improvements

[JamesWrigley]

@FaresX, any opinions on 86ddf0a? I'm a little torn about the internal state thing since it doesn't really match ImGui style. On the other hand I want it to be possible for people who don't dynamically create many plots (which I'm guessing is a majority) to show them with minimal hassle.

[FaresX]

If concerned about deviating from ImGui's style, you could avoid explicitly exposing a delete_figure! method. However, whether using the figure itself as a key or an ID as a key, the originally passed figure would persist - though this allows new figures to be passed in, unlike previous implementations. Alternatively, we could maintain the ImGuiID approach: during each frame, compare whether the incoming figure matches the figure associated with its ID. If they differ, refresh the makie_context while purging the original figure. This ensures that even with repeated new figure submissions, the makie_context's memory footprint won't grow indefinitely.

if !haskey(makie_context, id) || f != makie_context[id]
   
    f != makie_context[id] && delete_figure!(makie_context[id])
    

    window = ig.current_window()
    makie_window = ImMakieWindow(window)
    screen = GLMakie.Screen(; window=makie_window, start_renderloop=false)

    makie_context[id] = ImMakieFigure(f, screen)
    scene = Makie.get_scene(f)
    scene.events.window_open[] = true
    display(screen, f)
end

[JamesWrigley]

Alternatively, we could maintain the ImGuiID approach: during each frame, compare whether the incoming figure matches the figure associated with its ID. If they differ, refresh the makie_context while purging the original figure. This ensures that even with repeated new figure submissions, the makie_context's memory footprint won't grow indefinitely.

Hmmm that was my original plan but I decided against it for some reason. But now I can't remember why 🙃 I'll think it over, if it works then yeah let's do that.

EDIT: now I remember, to do this garbage collection automatically we still need to figure out if a user wants to display the same figure again. Which we can't know in general since users may create an arbitrary number of figures with arbitrary IDs.

[FaresX]

I think we can simply remove the figure from makie_context without actively purging its contents. If users require garbage collection, they can handle it within their own context stack, without worrying about lingering internal references preventing proper cleanup - since the detachment ensures no internal retention would block resource release