TimeCurveKind

type TimeCurveKind = 'linear' | 'hold' | 'ramp' | 'stutter' | 'reverse'

import type { TimeCurveKind } from '@driftengine/core';

In depth

A curve is a reparameterisation, not an animation. It answers exactly one question — "given localSec into this segment, how far has the source advanced?" — which is what lets a caller drive a fixed-timestep simulation, a recorded stream or a video from the same maths.

Every curve is speed-neutral over its own segment: whatever it steals it pays back, so curveSpanSec equals durationSec for every kind. That is the property that keeps a re-timed clip the length it was asked for. A curve that slowed time without catching up would quietly shorten the footage a fixed clip length can cover, and the clip would stop before the thing it was cut for.

Pure, closed-form and allocation-free: evaluated once per rendered frame.