harmony 鸿蒙Special Effect Drawing Combination

2025-06-12
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Special Effect Drawing Combination

The useEffect attribute is used to combine the drawing of special effects, such as background blur.

NOTE

This attribute is supported since API version 12. Updates will be marked with a superscript to indicate their earliest API version.

useEffect

useEffect(value: boolean)

Specifies whether to combine the drawing of special effects, such as background blur.

Atomic service API: This API can be used in atomic services since API version 12.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
value	boolean	Yes	Whether the component inherits the special effect settings of the EffectComponent component. The value true means the component inherits the special effect settings of the EffectComponent component, and false means the opposite. Default value: false

useEffect¹⁴⁺

useEffect(useEffect: boolean, effectType: EffectType)

Specifies whether to apply the effect defined by the parent EffectComponent or the window.

Atomic service API: This API can be used in atomic services since API version 14.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
useEffect	boolean	Yes	Whether to apply the effect defined by the parent EffectComponent or the window. The value true means to apply the effect defined by the parent EffectComponent or the window. Default value: false
effectType	EffectType	Yes	Type of effect to apply to the component, which is defined by the parent EffectComponent or the window. Default value: EffectType.DEFAULT

useEffect¹⁸⁺

useEffect(useEffect: Optional<boolean>, effectType?: EffectType)

Specifies whether to apply the effect defined by the parent EffectComponent or the window. Compared to useEffect¹⁴⁺, this API supports the undefined type for the useEffect parameter.

Atomic service API: This API can be used in atomic services since API version 18.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Name	Type	Mandatory	Description
useEffect	Optional<boolean>	Yes	Whether to apply the effect defined by the parent EffectComponent or the window. The value true means to apply the effect defined by the parent EffectComponent or the window. Default value: false If useEffect is set to undefined, the previous value is retained.
effectType	EffectType	No	Type of effect to apply to the component, which is defined by the parent EffectComponent or the window. Default value: EffectType.DEFAULT

EffectType¹⁴⁺

Enumerates the types of effect templates.

Atomic service API: This API can be used in atomic services since API version 14.

System capability: SystemCapability.ArkUI.ArkUI.Full

Name	Value	Description
DEFAULT	0	Uses the effect template defined by the parent EffectComponent or .
WINDOW_EFFECT	1	Uses the effect template defined by the window.

Effect Template

Device Type	Fuzzy Radius (Unit: px)	Saturation	Brightness	Color
Mobile device	0	0	0	’#ffffffff’
2-in-1 device: dark mode	80	1.5	1.0	’#e52e3033’
2-in-1 device: light mode	80	1.9	1.0	’#e5ffffff’
Tablet	0	0	0	’#ffffffff’

Example

This example shows how to combine the drawing of special effects, including background blur.

//Index.ets
@Entry
@Component
struct Index {
  @State isUse: boolean = true;

  build() {
    Stack() {
      Image($r("app.media.mountain"))
        .autoResize(true)
      EffectComponent() {
        Column({ space: 20 }) {
           Column() {
           }
           .position({ x: 0, y: 0 })
           .width(150)
           .height(800)
           .useEffect(this.isUse, EffectType.WINDOW_EFFECT)
         
           Column() {
           }
           .position({ x: 200, y: 20 })
           .width(150)
           .height(300)
           .useEffect(this.isUse, EffectType.DEFAULT)

           Column() {
           }
           .position({ x: 400, y: 20 })
           .width(150)
           .height(300)
           .useEffect(this.isUse)
        }
        .width('100%')
        .height('100%')
      }
      .backgroundBlurStyle(BlurStyle.Thin)

       Column() {
       }
        .position({ x: 600, y: 0 })
        .width(150)
        .height(800)
        .useEffect(this.isUse, EffectType.WINDOW_EFFECT)

      Row() {
        Button('useEffect')
        .margin(30)
        .onClick(() => {
          this.isUse = !this.isUse;
        })
      }
      .position({ x: 300, y: 450 })
    }
    .backgroundColor(Color.Black)
    .width('100%')
  }
}

en-us_image_useeffect_effecttype