Function toward 

pub fn toward(
    id: impl Into<TransitionId>,
    target: f32,
    window: &mut Window,
    cx: &mut App,
) -> f32

Drives a decoration from a value the application already has.

Where animated loops on its own, this eases towards target whenever the application moves it — a ripple started by a press, a tilt that follows a pointer, a shake that grows as a value approaches its limit. Returns target immediately when the reader has asked for less motion.