PinchGesture
PinchGesture is used to trigger a pinch gesture, which requires two to five fingers with a minimum 5 vp distance between the fingers.
NOTE
This gesture is supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.
APIs
PinchGesture(value?: { fingers?: number, distance?: number })
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| fingers | number | No | Minimum number of fingers to trigger a pinch. The value ranges from 2 to 5. Default value: 2 |
| distance | number | No | Minimum recognition distance, in vp. Default value: 5 NOTE If the value is less than or equal to 0, it will be converted to the default value. |
Events
| Name | Description |
|---|---|
| onActionStart(event:(event?: GestureEvent) => void) | Triggered when a pinch gesture is recognized. |
| onActionUpdate(event:(event?: GestureEvent) => void) | Triggered when the user moves the finger in the pinch gesture on the screen. |
| onActionEnd(event:(event?: GestureEvent) => void) | Triggered when the finger used for the pinch gesture is lift. |
| onActionCancel(event: () => void) | Triggered when a tap cancellation event is received after the pinch gesture is recognized. NOTE This event is triggered when the window loses focus. |
Example
// xxx.ets
@Entry
@Component
struct PinchGestureExample {
@State scaleValue: number = 1
@State pinchValue: number = 1
@State pinchX: number = 0
@State pinchY: number = 0
build() {
Column() {
Column() {
Text('PinchGesture scale:\n' + this.scaleValue)
Text('PinchGesture center:\n(' + this.pinchX + ',' + this.pinchY + ')')
}
.height(200)
.width(300)
.padding(20)
.border({ width: 3 })
.margin({ top: 100 })
.scale({ x: this.scaleValue, y: this.scaleValue, z: 1 })
// The gesture event is triggered by pinching three fingers together.
.gesture(
PinchGesture({ fingers: 3 })
.onActionStart((event?: GestureEvent) => {
console.info('Pinch start')
})
.onActionUpdate((event?: GestureEvent) => {
if (event) {
this.scaleValue = this.pinchValue * event.scale
this.pinchX = event.pinchCenterX
this.pinchY = event.pinchCenterY
}
})
.onActionEnd(() => {
this.pinchValue = this.scaleValue
console.info('Pinch end')
})
)
}.width('100%')
}
}
