Canvas
The <Canvas> component can be used to customize drawings.
NOTE
This component is supported since API version 8. Updates will be marked with a superscript to indicate their earliest API version.
Child Components
Not supported
APIs
Canvas(context?: CanvasRenderingContext2D)
Since API version 9, this API is supported in ArkTS widgets.
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| context | CanvasRenderingContext2D | No | For details, see CanvasRenderingContext2D. A CanvasRenderingContext2D object cannot be shared by multiple Canvas objects. |
Attributes
The universal attributes are supported.
Events
In addition to the universal events, the following events are supported.
| Name | Description |
|---|---|
| onReady(event: () => void) | Triggered when a canvas is ready or its size changes. When this event is triggered, the canvas is cleared. The width and height of the canvas can then be obtained, and you can use the canvas APIs to draw images. If the canvas is merely relocated, the onAreaChange event is triggered, but the onReady event is not. Since API version 9, this API is supported in ArkTS widgets. |
Example
// xxx.ets
@Entry
@Component
struct CanvasExample {
private settings: RenderingContextSettings = new RenderingContextSettings(true)
private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
build() {
Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
Canvas(this.context)
.width('100%')
.height('100%')
.backgroundColor('#ffff00')
.onReady(() => {
this.context.fillRect(0, 30, 100, 100)
})
}
.width('100%')
.height('100%')
}
}
