ts-explicit-animation.md

# Explicit Animation

You can create explicit animation with your custom settings.

>  **NOTE**
>
>  The APIs of this module are supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.
>
> The functionality of this module depends on UI context. This means that the APIs of this module cannot be used where the UI context is unclear. For details, see [UIContext](../apis/js-apis-arkui-UIContext.md#uicontext).
>
> Since API version 10, you can use the [animateTo](../apis/js-apis-arkui-UIContext.md#animateto) API in [UIContext](../apis/js-apis-arkui-UIContext.md#uicontext) to obtain the UI context.

animateTo(value: AnimateParam, event: () => void): void

Since API version 9, this API is supported in ArkTS widgets.

| Name            | Type       |       Mandatory    |        Description       |
| ---------------- | ------------ | -------------------- | -------------------- |
| value | [AnimateParam](#animateparam)| Yes| Animation settings.|
| event | () => void | Yes| Closure function that displays the dynamic effect. The system automatically inserts the transition animation if the status changes in the closure function.|

## AnimateParam

| Name| Type| Description|
| -------- | -------- | -------- |
| duration | number | Animation duration, in ms.<br>Default value: **1000**<br>Since API version 9, this API is supported in ArkTS widgets.<br>**NOTE**<br>- The maximum animation duration on an ArkTS widget is 1000 ms. If the set value exceeds the limit, the value **1000** will be used.<br>- A value less than 0 evaluates to the value **0**.<br>- Floating-point values will be rounded down to integers. For example, if the value set is 1.2, **1** will be used.|
| tempo | number | Animation playback speed. A larger value indicates faster animation playback, and a smaller value indicates slower animation playback. The value **0** means that there is no animation.<br>Default value: **1.0**<br>**NOTE**<br>A value less than 0 evaluates to the value **1**.|
| curve | [Curve](ts-appendix-enums.md#curve) \| [ICurve](../apis/js-apis-curve.md#icurve) \| string | Animation curve.<br>Default value: **Curve.EaseInOut**<br>Since API version 9, this API is supported in ArkTS widgets.|
| delay | number | Delay of animation playback, in ms. By default, the playback is not delayed.<br>Default value: **0**<br>**NOTE**<br>- A value less than 0 evaluates to the value **0**.<br>- Floating-point values will be rounded down to integers. For example, if the value set is 1.2, **1** will be used.|
| iterations | number | Number of times that the animation is played. By default, the animation is played once. The value **-1** indicates that the animation is played for an unlimited number of times.<br>Default value: **1**|
| playMode | [PlayMode](ts-appendix-enums.md#playmode) | Animation playback mode. By default, the animation is played from the beginning after the playback is complete.<br>Default value: **PlayMode.Normal**<br>Since API version 9, this API is supported in ArkTS widgets.<br>For details about the restrictions, see **Notes about PlayMode**.|
| onFinish   | () =&gt; void   | Callback invoked when the animation playback is complete.<br>Since API version 9, this API is supported in ArkTS widgets.|

> **Notes about PlayMode**:
> - **PlayMode.Normal** and **PlayMode.Alternate** are recommended. Under these settings, the first round of the animation is played forwards. If **PlayMode.Reverse** or **PlayMode.AlternateReverse** is used, the first round of the animation is played backwards. In this case, the animation jumps to the end state and then starts from there.
> - When using **PlayMode.Alternate** or **PlayMode.AlternateReverse**, make sure the final state of the animation is the same as the value of the state variable. In other words, make sure the last round of the animation is played forwards. When **PlayMode.Alternate** is used, **iterations** must be set to an odd number. When **PlayMode.AlternateReverse** is used, **iterations** must be set to an even number.
> - **PlayMode.Reverse** is not recommended. Under this setting, the animation jumps to the end state at the beginning, and its final state will be different from the value of the state variable.

## Example

```ts
// xxx.ets
@Entry
@Component
struct AnimateToExample {
  @State widthSize: number = 250
  @State heightSize: number = 100
  @State rotateAngle: number = 0
  private flag: boolean = true

  build() {
    Column() {
      Button('change size')
        .width(this.widthSize)
        .height(this.heightSize)
        .margin(30)
        .onClick(() => {
          if (this.flag) {
            animateTo({
              duration: 2000,
              curve: Curve.EaseOut,
              iterations: 3,
              playMode: PlayMode.Normal,
              onFinish: () => {
                console.info('play end')
              }
            }, () => {
              this.widthSize = 150
              this.heightSize = 60
            })
          } else {
            animateTo({}, () => {
              this.widthSize = 250
              this.heightSize = 100
            })
          }
          this.flag = !this.flag
        })
      Button('change rotate angle')
        .margin(50)
        .rotate({ x: 0, y: 0, z: 1, angle: this.rotateAngle })
        .onClick(() => {
          animateTo({
            duration: 1200,
            curve: Curve.Friction,
            delay: 500,
            iterations: -1, // The value -1 indicates that the animation is played for an unlimited number of times.
            playMode: PlayMode.Alternate,
            onFinish: () => {
              console.info('play end')
            }
          }, () => {
            this.rotateAngle = 90
          })
        })
    }.width('100%').margin({ top: 5 })
  }
}
```

![animation1](figures/animation1.gif)