[Task] Low hanging UI performance fruits

[kvakvs]

Describe your idea

For tools which edit nodes and segments, add code to cache the visible nodes and segments and not recalculate them until the camera moves.

For speed limit tool apply similar improvement
[17:32] aubergine18: when the main speed limit tool is active, it iterates all segments, and for each one does a big bunch of checks to see if it's visible, if it can handle speed limits, etc
[17:32] aubergine18: well, if cached, yes, it would be one time only
[17:32] aubergine18: but it's not currently cached from what I can see

[originalfoo]

Actually, looking at code again, there is some degree of caching I think - currentlyVisibleSegmentIds

https://github.com/krzychu124/Cities-Skylines-Traffic-Manager-President-Edition/blob/master/TLM/TLM/UI/SubTools/SpeedLimits/SpeedLimitsTool.cs#L146-L152

EDIT; I don't know if other tools do the same

[Strdate]

I was copying some TMPE code for my own mod and yes, the signs were cached (in particular parking signs)

[kvakvs]

First experiment:
Caching node ids while the camera is not moving, for Lane Connectors tool.
Master build (unchanged) filters all visible nodes every frame and lose 12-17ms per frame.
With cache changes nodes only re-filter when camera is moved, and that just takes 1-2 ms per frame.

[originalfoo]

Here's another low fruit: https://github.com/krzychu124/Cities-Skylines-Traffic-Manager-President-Edition/blob/master/TLM/TLM/UI/MainMenu/StatsLabel.cs

When the path find stats display is not active, it should not do anything. Even when it is active, it should avoid using Update() on a UI component. Ideally the UI should be disabled and not visible when not in use.

For compatibility with the FPS Booster mod, we should avoid any Update() on UI components (except panels which still retain the base method).