---
title: "VectorizedDecayAnimationSpec"
description: "[VectorizedDecayAnimationSpec]s are stateless vector based decay animation specifications. They
do not assume any starting/ending conditions. Nor do they manage a lifecycle. All it stores is
the configuration that is particular to the type of the decay animation: friction multiplier for
[exponentialDecay]. Its stateless nature allows the same [VectorizedDecayAnimationSpec] to be
reused by a few different running animations with different starting and ending values.

Since [VectorizedDecayAnimationSpec]s are stateless, it requires starting value/velocity and
ending value to be passed in, along with playtime, to calculate the value or velocity at that
time. Play time here is the progress of the animation in terms of milliseconds, where 0 means the
start of the animation and [getDurationNanos] returns the play time for the end of the animation.

__Note__: For use cases where the starting values/velocity and ending values aren't expected to
change, it is recommended to use [DecayAnimation] that caches these static values and hence does
not require them to be supplied in the value/velocity calculation."
type: "interface"
---

<div class='type'>Interface</div>


<a id='references'></a>

<div class='sourceset sourceset-common'>Common</div>



```kotlin
public interface VectorizedDecayAnimationSpec<V : AnimationVector>
```


`VectorizedDecayAnimationSpec`s are stateless vector based decay animation specifications. They
do not assume any starting/ending conditions. Nor do they manage a lifecycle. All it stores is
the configuration that is particular to the type of the decay animation: friction multiplier for
`exponentialDecay`. Its stateless nature allows the same `VectorizedDecayAnimationSpec` to be
reused by a few different running animations with different starting and ending values.

Since `VectorizedDecayAnimationSpec`s are stateless, it requires starting value/velocity and
ending value to be passed in, along with playtime, to calculate the value or velocity at that
time. Play time here is the progress of the animation in terms of milliseconds, where 0 means the
start of the animation and `getDurationNanos` returns the play time for the end of the animation.

__Note__: For use cases where the starting values/velocity and ending values aren't expected to
change, it is recommended to use `DecayAnimation` that caches these static values and hence does
not require them to be supplied in the value/velocity calculation.


## Functions

```kotlin
public fun getValueFromNanos(playTimeNanos: Long, initialValue: V, initialVelocity: V): V
```


Returns the value of the animation at the given time.

#### Parameters

| | |
| --- | --- |
| playTimeNanos | The time elapsed in milliseconds since the initialValue of the animation |
| initialValue | The initialValue value of the animation |
| initialVelocity | The initialValue velocity of the animation |



```kotlin
public fun getDurationNanos(initialValue: V, initialVelocity: V): Long
```


Returns the duration of the decay animation, in nanoseconds.

#### Parameters

| | |
| --- | --- |
| initialValue | initialValue value of the animation |
| initialVelocity | initialValue velocity of the animation |



```kotlin
public fun getVelocityFromNanos(playTimeNanos: Long, initialValue: V, initialVelocity: V): V
```


Returns the velocity of the animation at the given time.

#### Parameters

| | |
| --- | --- |
| playTimeNanos | The time elapsed in milliseconds since the initialValue of the animation |
| initialValue | The initialValue value of the animation |
| initialVelocity | The initialValue velocity of the animation |



```kotlin
public fun getTargetValue(initialValue: V, initialVelocity: V): V
```


Returns the target value of the animation based on the initial condition of the animation (
i.e. initial value and initial velocity).

#### Parameters

| | |
| --- | --- |
| initialValue | The initial value of the animation |
| initialVelocity | The initial velocity of the animation |