Type Alias: UIShowEffect

type UIShowEffect = 
  | "none"
  | "fade"
  | "pop"
  | "zoom"
  | "slide-up"
  | "slide-down"
  | "slide-left"
  | "slide-right"
  | "drop";

UI transition maths (UITransitionComponent): eases, the pose of an entity at a point of a show / hide effect, and the idle "attention" loops. Pure functions over scratch objects — no allocation, so the system can call them per entity per frame.