Struct Tween 

pub struct Tween { /* private fields */ }

Smooth scalar tween between 0.0 and 1.0 (or any pair of values the caller interprets). Drives animations such as the scroll-bar hover expansion and toggle-switch on/off slide.

Implementations

impl Tween

pub const fn new(initial: f64, duration_secs: f64) -> Self

New tween that starts at initial with the same value as its target (no animation in flight).

pub fn set_target(&mut self, new_target: f64)

Update the target. If it differs from the current target, re-anchors the animation at the current interpolated value so reversals are smooth.

Widgets that own a Tween must also report tween.is_animating() from Widget::needs_draw() so retained parents repaint every frame until the tween settles. Tween::tick is the draw-request point; set_target intentionally does not invalidate because many widgets retarget from paint while synchronizing with external state.

pub fn tick(&mut self) -> f64

Advance the animation based on elapsed wall time and return the new interpolated value. Ease-out cubic. While in flight this also calls request_draw so the host keeps drawing frames until completion.

pub fn value(&self) -> f64

Current interpolated value without advancing.

pub fn is_animating(&self) -> bool

Whether the tween still needs frames to reach its target.

Trait Implementations

impl Clone for Tween

fn clone(&self) -> Tween

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for Tween

fn default() -> Self

Returns the “default value” for a type.

impl Copy for Tween