Motion.Tween
luastra/motionMotion.Tween is part of the declarative motion model consumed by supported UI motion properties. It describes deterministic values and timing; the host scheduler applies frames without rerunning app.render for every animation frame.
Before you use it
Add luastra/motion to this module's dependencies in luastra.json, then import it with require("luastra/motion"). Motion itself needs no capability; a visible result requires ui.render and a component that accepts the returned descriptor through its motion field.
How it fits
Motion types describe immutable timing data and are erased after analysis.
When to use it
Use Motion.Tween when declaring motion separately from UI layout and assigning it to a component's motion property. Keep the value deterministic and within the documented channels so every host can reproduce the same transition.
Fields or definition
| Parameter | Type / values | Description |
|---|---|---|
| kind | "tween" | Literal discriminator identifying the exact alternative in this union. |
| from | number | Numeric channel value at the beginning of the transition. |
| to | number | Numeric channel value at the end of the transition. |
| durationMs | number | Duration of this motion or delay in milliseconds. |
| easing | Easing | Named interpolation curve used between the start and end values. |
What happens next
A checked descriptor, sequence, channel map, or easing value.
Failures and fixes
Unknown options, invalid bounds, or unsupported channels fail validation. Motion must not drive application logic; use Timer for state changes, and rely on the host to present the final state when reduced motion is enabled.
Availability
Public-source alpha API in 0.5.0-alpha; presentation follows host and reduced-motion policy.
Exact declaration
export type Tween = {
kind: "tween",
from: number,
to: number,
durationMs: number,
easing: Easing,
}