Struct Tween 

pub struct Tween<T: Interpolable + Copy> { /* private fields */ }

A generic tween interpolating a value of type T from a start to an end value over a fixed duration, driven by an Easing curve.

Works with any type implementing Interpolable — the engine provides implementations for f64, Vector2D, Vector3D, and Color.

Why hand-written accessors

Lombok’s Data derive is intentionally not applied here for the same reason as EngineCell: the derive does not propagate generic bounds, so deriving on Tween<T> would force T: Default-style bounds that Interpolable types do not carry. The accessor pairs below follow the same naming contract as the Lombok-generated ones (get_* / set_*).

Implementations

impl<T: Interpolable + Copy> Tween<T>

Implements creation, playback control, and value sampling for Tween.

pub fn create(from: T, to: T, duration: f64) -> Tween<T>

Creates a new linear tween from from to to over duration seconds.

The tween starts in the Delayed state only when a delay is later attached via Tween::with_delay; by default it starts Running.

Arguments

• T - The start value.
• T - The end value.
• f64 - The interpolation duration in seconds.

Returns

• Tween<T> - The new tween.

pub fn with_easing(self, easing: Easing) -> Tween<T>

Sets the easing curve, replacing the default Easing::Linear.

Arguments

• Easing - The easing curve to apply.

Returns

• Tween<T> - The tween, for chaining.

pub fn with_delay(self, delay: f64) -> Tween<T>

Sets a start delay in seconds. While the delay elapses the tween reports its from value and stays in the Delayed state.

Arguments

• f64 - The delay in seconds.

Returns

• Tween<T> - The tween, for chaining.

pub fn with_mode(self, mode: AnimationMode) -> Tween<T>

Sets the completion mode (Once, Loop, or PingPong), replacing the default AnimationMode::Once.

Arguments

• AnimationMode - The completion mode.

Returns

• Tween<T> - The tween, for chaining.

pub fn with_on_complete(self, on_complete: Rc<dyn Fn()>) -> Tween<T>

Attaches a callback fired every time the tween completes a cycle (once for Once mode, every wrap for Loop and PingPong).

Arguments

• Rc<dyn Fn()> - The completion callback.

Returns

• Tween<T> - The tween, for chaining.

pub fn update(&mut self, delta_time: f64) -> T

Advances the tween by the given delta time and returns the current eased value.

Has no effect while the tween is Paused or Finished.

Arguments

• f64 - The time elapsed since the last update, in seconds.

Returns

• T - The current interpolated value.

pub fn value(&self) -> T

Returns the current interpolated value without advancing time.

Returns

• T - The current eased value.

pub fn eased_progress(&self) -> f64

Returns the eased progress of the current cycle in the range 0.0 to 1.0.

Returns

• f64 - The eased progress.

pub fn raw_progress(&self) -> f64

Returns the raw (uneased) progress of the current cycle.

Returns

• f64 - The raw progress in the range 0.0 to 1.0.

pub fn pause(&mut self)

Pauses the tween.

pub fn resume(&mut self)

Resumes a paused tween.

pub fn reset(&mut self)

Resets the tween to its initial state so it can be replayed.

pub fn is_finished(&self) -> bool

Returns whether the tween has finished (AnimationMode::Once only).

Returns

• bool - True if the tween is finished.

pub fn get_state(&self) -> TweenState

Returns the current playback state.

Returns

• TweenState - The playback state.

pub fn get_duration(&self) -> f64

Returns the configured duration in seconds.

Returns

• f64 - The duration.

Trait Implementations

impl<T: Interpolable + Copy> Clone for Tween<T>

fn clone(&self) -> Tween<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Interpolable + Copy + Debug> Debug for Tween<T>

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Interpolable + Copy> Updatable for Tween<T>

Forwards Tween::update through the Updatable trait so tweens can participate in the same generic update loop as entities, animators, scenes, and physics worlds.

fn update(&mut self, delta_time: f64)

Advance the object’s internal state by the given delta time.