Call empty! in block deletion

[ffreyer]

Description

See https://discourse.julialang.org/t/removing-row-from-gridlayout/93196

Still shouldn't completely clean up a block, but remove plots and a decent chunk of observables.

Add a description of your PR here.

Type of change

• Bug fix (non-breaking change which fixes an issue)

[jkrumbiegel]

At some point we should add tests that check that a block and the relevant scenes, plots, etc. can be garbage collected once they're deleted. I assume unless the last observable connection is severed, that's not possible.

[ffreyer]

The example from discourse still has a wild amount of listeners in fig.scene.px_area if you remove all blocks with this.

Makie.jl/src/scenes.jl

Lines 177 to 182 in 94b5ec5

	on(events.window_area, priority = typemax(Int)) do w_area
	if !any(x -> x ≈ 0.0, widths(w_area)) && px_area[] != w_area
	px_area[] = w_area
	end
	return Consume(false)
	end

might be partially to blame since on doesn't add to obs.inputs? Though most listeners seem to be maps from

Makie.jl/src/scenes.jl

Lines 240 to 248 in 94b5ec5

	if isnothing(px_area)
	px_area = lift(zero_origin, parent.px_area; ignore_equal_values=true)
	else
	px_area = lift(pixelarea(parent), convert(Observable, px_area); ignore_equal_values=true) do p, a
	# make coordinates relative to parent
	rect = Rect2i(minimum(p) .+ minimum(a), widths(a))
	return rect
	end
	end

which should show up, I think, but don't in any block.blockscene.px_area.inputs?

[jkrumbiegel]

Yes, px_area and scene.camera.projectionview are lifted all over the place.

[ffreyer]

scene.events are also kind of a nightmare to clean up atm, since the events struct is shared between all scenes. So you can't just empty all listeners there and call it a day. You also can't have child.events.x = map(identity, parent.events.x) because it would mess up priority.
Maybe we could add some wrapper that keeps track of where listeners have been added, but still adds them to the scene-global events? I.e.

struct LocalEvents
    global_events::Events
    local_obsfuncs::Vector{Function}
end

that adds to local_obs_funcs on map, on, etc? That could then do off.(local_obsfuncs) when empty!(scene) is called (for each child scene as well).

I think I'll give this a try later today.

[MakieBot]

Compile Times benchmark

Note, that these numbers may fluctuate on the CI servers, so take them with a grain of salt. All benchmark results are based on the mean time and negative percent mean faster than the base branch. Note, that GLMakie + WGLMakie run on an emulated GPU, so the runtime benchmark is much slower. Results are from running:

using_time = @ctime using Backend
# Compile time
create_time = @ctime fig = scatter(1:4; color=1:4, colormap=:turbo, markersize=20, visible=true)
display_time = @ctime Makie.colorbuffer(display(fig))
# Runtime
create_time = @benchmark fig = scatter(1:4; color=1:4, colormap=:turbo, markersize=20, visible=true)
display_time = @benchmark Makie.colorbuffer(display(fig))

	using	create	display	create	display
GLMakie	31.64s (28.91, 32.22) 1.21+-	16.30s (16.10, 16.56) 0.14+-	15.22s (15.13, 15.45) 0.11+-	11.77ms (11.68, 11.83) 0.06+-	133.39ms (130.95, 135.32) 1.38+-
master	32.25s (32.16, 32.37) 0.06+-	16.34s (16.25, 16.50) 0.09+-	15.29s (15.16, 15.44) 0.10+-	11.81ms (11.71, 11.88) 0.06+-	134.20ms (131.33, 135.65) 1.37+-
evaluation	-1.92%, -0.61s invariant (-0.71d, 0.23p, 0.64std)	-0.28%, -0.05s invariant (-0.39d, 0.48p, 0.11std)	-0.43%, -0.06s invariant (-0.61d, 0.27p, 0.11std)	-0.35%, -0.04ms invariant (-0.68d, 0.23p, 0.06std)	-0.61%, -0.82ms invariant (-0.59d, 0.29p, 1.38std)
CairoMakie	26.06s (25.86, 26.27) 0.15+-	16.41s (16.26, 16.72) 0.18+-	2.53s (2.50, 2.58) 0.03+-	10.59ms (10.44, 10.95) 0.18+-	4.17ms (4.07, 4.35) 0.11+-
master	26.12s (25.80, 26.48) 0.22+-	16.46s (16.16, 16.82) 0.24+-	2.53s (2.48, 2.59) 0.04+-	10.62ms (10.38, 10.82) 0.13+-	4.18ms (4.03, 4.34) 0.11+-
evaluation	-0.23%, -0.06s invariant (-0.31d, 0.57p, 0.19std)	-0.32%, -0.05s invariant (-0.25d, 0.65p, 0.21std)	-0.14%, -0.0s invariant (-0.10d, 0.86p, 0.03std)	-0.22%, -0.02ms invariant (-0.15d, 0.78p, 0.15std)	-0.24%, -0.01ms invariant (-0.09d, 0.87p, 0.11std)
WGLMakie	39.32s (38.73, 39.94) 0.43+-	20.40s (20.15, 20.99) 0.29+-	24.67s (24.40, 25.14) 0.26+-	16.50ms (15.81, 17.21) 0.49+-	2.38s (2.22, 2.52) 0.11+-
master	39.35s (39.12, 39.63) 0.19+-	20.52s (20.32, 20.80) 0.15+-	24.49s (24.37, 24.61) 0.07+-	16.84ms (16.58, 17.19) 0.21+-	2.39s (2.09, 2.52) 0.15+-
evaluation	-0.08%, -0.03s invariant (-0.10d, 0.86p, 0.31std)	-0.58%, -0.12s invariant (-0.52d, 0.35p, 0.22std)	+0.73%, 0.18s invariant (0.93d, 0.13p, 0.17std)	-2.01%, -0.33ms invariant (-0.87d, 0.14p, 0.35std)	-0.38%, -0.01s invariant (-0.07d, 0.90p, 0.13std)