Improve EditorTable performance

[EVAST9919]

The issue occurs while we are hovering the mouse over the table, generating input sub-tree with thousands of items that will be never used for input handling (with all the overhead that comes with it).

Map for testing: https://osu.ppy.sh/beatmapsets/1238185#mania/2574372

master	pr

[smoogipoo]

minor nit:

Suggested change

	protected override bool ShouldBeConsideredForInput(Drawable child) => base.ShouldBeConsideredForInput(child) && child == BackgroundFlow;
	protected override bool ShouldBeConsideredForInput(Drawable child) => child == BackgroundFlow && base.ShouldBeConsideredForInput(child);

.

[smoogipoo]

That map is nowhere near as bad for me as your screenshots indicate. ~20ms -> ~8ms. It's a worthwhile improvement though I worry about the locality of these optimisations preventing similar issues from being tackled directly in o!f in the future. This is exactly the sort of situation which I'd expect IsMaskedAway to handle.

I'm curious why your screenshots are showing 3000ms per frame?

[EVAST9919]

This is exactly the sort of situation which I'd expect IsMaskedAway to handle.

IsMaskedAway isn't doing much since the content is a grid container, which doesn't have at least a parent container per row, so no optimisations can be performed. By that I mean we are trying to iterate the whole structure and checking whether a cell is masked away and that's per mouse move.

I'm curious why your screenshots are showing 3000ms per frame?

https://streamable.com/75hi6b
Because this is what literally happens on mouse move

[smoogipoo]

which doesn't have at least a parent container per row

It's one container per cell, right? And 95+% of those cells are off-screen. But more so than that IsMaskedAway doesn't care about that because it's at a Drawable level.

Because this is what literally happens on mouse move

Are you using a 1000Hz poll rate mouse?

---

I'm going to tentatively merge this, but be aware that this is one of the simplest cases I would hope o!f can easily optimise for. If not, it would affect things like comments container, beatmap listing overlay, markdown/wiki, etc.

[EVAST9919]

Are you using a 1000Hz poll rate mouse?

I'm not sure, but seems like it, because when window isn't focused and input thread is limited to 60fps - things are much better.