ExpressiveMotion class

Centralised transition motion tokens (easing curves + durations) for Material 3 motion.

M3 runs two motion systems and this class is the transitions half (curves + durations, for screen/element entrances and exits). The motion-physics half — springs for component/state interaction — lives in ExpressiveSpringScheme (spring_scheme.dart).

Expressive but disciplined: motion settles, it does not oscillate. Animation signals state and rewards the key action, it never bounces for show. Widgets read these tokens instead of inlining their own durations/curves so an app shares one motion language and a single tuning point.

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

durationOf(BuildContext context, Duration duration) → Duration

Returns duration, or Duration.zero when the platform/user has asked for reduced motion — call sites then snap straight to the end state. Always gate animated widgets through this.

Constants

emphasized → const Curve

The genuine M3 emphasized curve — a two-segment ThreePointCubic (accelerate → decelerate), for the boldest single begin-and-end-on-screen moment (in-place state morphs: selection, expand). NOT a single Cubic; that trap maps to standard.

emphasizedAccelerate → const Curve

M3 emphasized-accelerate (alias of exit).

emphasizedDecelerate → const Curve

M3 emphasized-decelerate (alias of enter) — explicit name for transitions that bring something onto the screen.

enter → const Curve

Entrances rise-and-fade in on this. M3 emphasized-decelerate — the curve for an element entering the screen.

entrance → const Duration

One-shot entrances (list items, screen sections, a hero card). ≈ M3 Durations.medium3 (350ms).

exit → const Curve

Exits. M3 emphasized-accelerate — the curve for an element leaving.

press → const Duration

Press / tap feedback. ≈ M3 Durations.short3 (150ms).

routeEnter → const Duration

Route enter (a screen arriving). M3 pair: Emphasized-decelerate @ 400ms.

routeExit → const Duration

Route exit (a screen leaving). M3 pair: Emphasized-accelerate @ 200ms.

settle → const Duration

In-place state changes (chip selection, card status, expand/collapse). ≈ M3 Durations.medium1 (250ms).

standard → const Curve

M3 standard easing — utilitarian, begins-and-ends-on-screen.