plushie/animation

Animation helpers for frame-based interpolation.

Use with subscription.on_animation_frame to drive updates. Create an animation with new, start it, then advance each frame.

Types

Animation

</>

An animation interpolating between two values over time.

pub type Animation {
  Animation(
    from: Float,
    to: Float,
    duration_ms: Int,
    started_at: option.Option(Int),
    easing: Easing,
    value: Float,
    finished: Bool,
  )
}

Constructors

Animation(
  from: Float,
  to: Float,
  duration_ms: Int,
  started_at: option.Option(Int),
  easing: Easing,
  value: Float,
  finished: Bool,
)

Easing

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Easing function type.

pub type Easing {
  Linear
  EaseIn
  EaseOut
  EaseInOut
  EaseInQuad
  EaseOutQuad
  EaseInOutQuad
  Spring
}

Constructors

```
Linear
```
```
EaseIn
```
```
EaseOut
```
```
EaseInOut
```
```
EaseInQuad
```
```
EaseOutQuad
```
```
EaseInOutQuad
```
```
Spring
```

Values

advance

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pub fn advance(anim: Animation, now: Int) -> Animation

Advance the animation to the given timestamp. Returns updated animation. Check finished field to know when it’s done.

apply_easing

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pub fn apply_easing(easing: Easing, t: Float) -> Float

Apply an easing function to a progress value (0.0 to 1.0).

is_finished

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pub fn is_finished(anim: Animation) -> Bool

Check if the animation has finished.

lerp

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pub fn lerp(from: Float, to: Float, t: Float) -> Float

Linear interpolation between two values.

new

</>

pub fn new(
  from: Float,
  to: Float,
  duration_ms: Int,
  easing: Easing,
) -> Animation

Create a new animation (not yet started).

start

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pub fn start(anim: Animation, now: Int) -> Animation

Start the animation at the given timestamp (monotonic ms).

value

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pub fn value(anim: Animation) -> Float

Get the current value.