CanvasRenderingContext2D

Use RenderingContext to draw rectangles, text, images, and other objects on a canvas.

NOTE

The APIs of this module are supported since API version 8. Updates will be marked with a superscript to indicate their earliest API version.

APIs

CanvasRenderingContext2D(setting: RenderingContextSetting)

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

Parameters

RenderingContextSettings

RenderingContextSettings(antialias?: boolean)

Configures the settings of a CanvasRenderingContext2D object, including whether to enable antialiasing.

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

Parameters

Attributes

NOTE

The string-type value of fillStyle, shadowColor, and strokeStyle can be in 'rgb(255, 255, 255)', 'rgba(255, 255, 255, 1.0)', or '#FFFFFF' format.

fillStyle

// xxx.ets
@Entry
@Component
struct FillStyleExample {
  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.fillStyle = '#0000ff'
          this.context.fillRect(20, 20, 150, 100)
        })
    }
    .width('100%')
    .height('100%')
  }
}

lineWidth

// xxx.ets
@Entry
@Component
struct LineWidthExample {
  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.lineWidth = 5
        this.context.strokeRect(25, 25, 85, 105)
      })
    }
    .width('100%')
    .height('100%')
  }
}

strokeStyle

// xxx.ets
@Entry
@Component
struct StrokeStyleExample {
  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.lineWidth = 10
          this.context.strokeStyle = '#0000ff'
          this.context.strokeRect(25, 25, 155, 105)
        })
    }
    .width('100%')
    .height('100%')
  }
}

lineCap

// xxx.ets
@Entry
@Component
struct LineCapExample {
  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.lineWidth = 8
          this.context.beginPath()
          this.context.lineCap = 'round'
          this.context.moveTo(30, 50)
          this.context.lineTo(220, 50)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

lineJoin

// xxx.ets
@Entry
@Component
struct LineJoinExample {
  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.beginPath()
        this.context.lineWidth = 8
        this.context.lineJoin = 'miter'
        this.context.moveTo(30, 30)
        this.context.lineTo(120, 60)
        this.context.lineTo(30, 110)
        this.context.stroke()
      })
    }
    .width('100%')
    .height('100%')
  }
}

miterLimit

// xxx.ets
@Entry
@Component
struct MiterLimit {
  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.lineWidth = 8
          this.context.lineJoin = 'miter'
          this.context.miterLimit = 3
          this.context.moveTo(30, 30)
          this.context.lineTo(60, 35)
          this.context.lineTo(30, 37)
          this.context.stroke()
      })
    }
    .width('100%')
    .height('100%')
  }
}

font

// xxx.ets
@Entry
@Component
struct Fonts {
  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.font = '30px sans-serif'
          this.context.fillText("Hello World", 20, 60)
      })
    }
    .width('100%')
    .height('100%')
  }
}

textAlign

// 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.strokeStyle = '#0000ff'
        this.context.moveTo(140, 10)
        this.context.lineTo(140, 160)
        this.context.stroke()
        this.context.font = '18px sans-serif'
        this.context.textAlign = 'start'
        this.context.fillText('textAlign=start', 140, 60)
        this.context.textAlign = 'end'
        this.context.fillText('textAlign=end', 140, 80)
        this.context.textAlign = 'left'
        this.context.fillText('textAlign=left', 140, 100)
        this.context.textAlign = 'center'
        this.context.fillText('textAlign=center',140, 120)
        this.context.textAlign = 'right'
        this.context.fillText('textAlign=right',140, 140)
      })
    }
    .width('100%')
    .height('100%')
  }
}

textBaseline

// xxx.ets
@Entry
@Component
struct TextBaseline {
  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.strokeStyle = '#0000ff'
          this.context.moveTo(0, 120)
          this.context.lineTo(400, 120)
          this.context.stroke()
          this.context.font = '20px sans-serif'
          this.context.textBaseline = 'top'
          this.context.fillText('Top', 10, 120)
          this.context.textBaseline = 'bottom'
          this.context.fillText('Bottom', 55, 120)
          this.context.textBaseline = 'middle'
          this.context.fillText('Middle', 125, 120)
          this.context.textBaseline = 'alphabetic'
          this.context.fillText('Alphabetic', 195, 120)
          this.context.textBaseline = 'hanging'
          this.context.fillText('Hanging', 295, 120)
      })
    }
    .width('100%')
    .height('100%')
  }
}

globalAlpha

// xxx.ets
@Entry
@Component
struct GlobalAlpha {
  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.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(0, 0, 50, 50)
          this.context.globalAlpha = 0.4
          this.context.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(50, 50, 50, 50)
      })
    }
    .width('100%')
    .height('100%')
  }
}

lineDashOffset

// xxx.ets
@Entry
@Component
struct LineDashOffset {
  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.arc(100, 75, 50, 0, 6.28)
          this.context.setLineDash([10,20])
          this.context.lineDashOffset = 10.0
          this.context.stroke()
      })
    }
    .width('100%')
    .height('100%')
  }
}

globalCompositeOperation

// xxx.ets
@Entry
@Component
struct GlobalCompositeOperation {
  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.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(20, 20, 50, 50)
          this.context.globalCompositeOperation = 'source-over'
          this.context.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(50, 50, 50, 50)
          this.context.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(120, 20, 50, 50)
          this.context.globalCompositeOperation = 'destination-over'
          this.context.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(150, 50, 50, 50)
      })
    }
    .width('100%')
    .height('100%')
  }
}

shadowBlur

// xxx.ets
@Entry
@Component
struct ShadowBlur {
  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.shadowBlur = 30
          this.context.shadowColor = 'rgb(0,0,0)'
          this.context.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(20, 20, 100, 80)
      })
    }
    .width('100%')
    .height('100%')
  }
}

shadowColor

// xxx.ets
@Entry
@Component
struct ShadowColor {
  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.shadowBlur = 30
          this.context.shadowColor = 'rgb(0,0,255)'
          this.context.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(30, 30, 100, 100)
      })
    }
    .width('100%')
    .height('100%')
  }
}

shadowOffsetX

// xxx.ets
@Entry
@Component
struct ShadowOffsetX {
  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.shadowBlur = 10
          this.context.shadowOffsetX = 20
          this.context.shadowColor = 'rgb(0,0,0)'
          this.context.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(20, 20, 100, 80)
      })
    }
    .width('100%')
    .height('100%')
  }
}

shadowOffsetY

// xxx.ets
@Entry
@Component
struct ShadowOffsetY {
  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.shadowBlur = 10
          this.context.shadowOffsetY = 20
          this.context.shadowColor = 'rgb(0,0,0)'
          this.context.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(30, 30, 100, 100)
      })
    }
    .width('100%')
    .height('100%')
  }
}

imageSmoothingEnabled

// xxx.ets
@Entry
@Component
struct ImageSmoothingEnabled {
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  private img:ImageBitmap = new ImageBitmap("common/images/icon.jpg")
  
  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Canvas(this.context)
        .width('100%')
        .height('100%')
        .backgroundColor('#ffff00')
        .onReady(() =>{
          this.context.imageSmoothingEnabled = false
          this.context.drawImage( this.img,0,0,400,200)
      })
    }
    .width('100%')
    .height('100%')
  }
}

Methods

fillRect

fillRect(x: number, y: number, w: number, h: number): void

Fills a rectangle on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct FillRect {
  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(30,30,100,100)
       })
      }
    .width('100%')
    .height('100%')
  }
}

strokeRect

strokeRect(x: number, y: number, w: number, h: number): void

Draws an outlined rectangle on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct StrokeRect {
  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.strokeRect(30, 30, 200, 150)
      })
    }
    .width('100%')
    .height('100%')
  }
}

clearRect

clearRect(x: number, y: number, w: number, h: number): void

Clears the content in a rectangle on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct ClearRect {
  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.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(20,20,200,200)
          this.context.clearRect(30,30,150,100)
      })
    }
    .width('100%')
    .height('100%')
  }
}

fillText

fillText(text: string, x: number, y: number, maxWidth?: number): void

Draws filled text on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct FillText {
  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.font = '30px sans-serif'
          this.context.fillText("Hello World!", 20, 100)
      })
    }
    .width('100%')
    .height('100%')
  }
}

strokeText

strokeText(text: string, x: number, y: number, maxWidth?:number): void

Draws a text stroke on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct StrokeText {
  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.font = '55px sans-serif'
          this.context.strokeText("Hello World!", 20, 60)
      })
    }
    .width('100%')
    .height('100%')
  }
}

measureText

measureText(text: string): TextMetrics

Measures the specified text to obtain its width. This API returns a TextMetrics object.

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

Parameters

Return value

TextMetrics

Example

// xxx.ets
@Entry
@Component
struct MeasureText {
  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.font = '50px sans-serif'
          this.context.fillText("Hello World!", 20, 100)
          this.context.fillText("width:" + this.context.measureText("Hello World!").width, 20, 200)
      })
    }
    .width('100%')
    .height('100%')
  }
}

stroke

stroke(path?: Path2D): void

Strokes a path.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Stroke {
  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.moveTo(25, 25)
          this.context.lineTo(25, 105)
          this.context.lineTo(75, 105)
          this.context.lineTo(75, 25)
          this.context.strokeStyle = 'rgb(0,0,255)'
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

beginPath

beginPath(): void

Creates a drawing path.

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

Example

// xxx.ets
@Entry
@Component
struct BeginPath {
  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.beginPath()
          this.context.lineWidth = 6
          this.context.strokeStyle = '#0000ff'
          this.context.moveTo(15, 80)
          this.context.lineTo(280, 160)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

moveTo

moveTo(x: number, y: number): void

Moves a drawing path to a target position on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct MoveTo {
  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.beginPath()
          this.context.moveTo(10, 10)
          this.context.lineTo(280, 160)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

lineTo

lineTo(x: number, y: number): void

Connects the current point to a target position using a straight line.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct LineTo {
  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.beginPath()
          this.context.moveTo(10, 10)
          this.context.lineTo(280, 160)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

closePath

closePath(): void

Draws a closed path.

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

Example

// xxx.ets
@Entry
@Component
struct ClosePath {
  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.beginPath()
            this.context.moveTo(30, 30)
            this.context.lineTo(110, 30)
            this.context.lineTo(70, 90)
            this.context.closePath()
            this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

createPattern

createPattern(image: ImageBitmap, repetition: string | null): CanvasPattern | null

Creates a pattern for image filling based on a specified source image and repetition mode.

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

Parameters

Return value

Example

// xxx.ets
@Entry
@Component
struct CreatePattern {
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  private img:ImageBitmap = new ImageBitmap("common/images/icon.jpg")

  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Canvas(this.context)
        .width('100%')
        .height('100%')
        .backgroundColor('#ffff00')
        .onReady(() =>{
          var pattern = this.context.createPattern(this.img, 'repeat')
          this.context.fillStyle = pattern
          this.context.fillRect(0, 0, 200, 200)
        })
    }
    .width('100%')
    .height('100%')
  }
}

bezierCurveTo

bezierCurveTo(cp1x: number, cp1y: number, cp2x: number, cp2y: number, x: number, y: number): void

Draws a cubic bezier curve on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct BezierCurveTo {
  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.beginPath()
          this.context.moveTo(10, 10)
          this.context.bezierCurveTo(20, 100, 200, 100, 200, 20)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

quadraticCurveTo

quadraticCurveTo(cpx: number, cpy: number, x: number, y: number): void

Draws a quadratic curve on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct QuadraticCurveTo {
  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.beginPath()
          this.context.moveTo(20, 20)
          this.context.quadraticCurveTo(100, 100, 200, 20)
          this.context.stroke()
      })
    }
    .width('100%')
    .height('100%')
  }
}

arc

arc(x: number, y: number, radius: number, startAngle: number, endAngle: number, counterclockwise?: boolean): void

Draws an arc on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Arc {
  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.beginPath()
          this.context.arc(100, 75, 50, 0, 6.28)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

arcTo

arcTo(x1: number, y1: number, x2: number, y2: number, radius: number): void

Draws an arc based on the radius and points on the arc.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct ArcTo {
  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.moveTo(100, 20)
          this.context.arcTo(150, 20, 150, 70, 50)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

ellipse

ellipse(x: number, y: number, radiusX: number, radiusY: number, rotation: number, startAngle: number, endAngle: number, counterclockwise?: boolean): void

Draws an ellipse in the specified rectangular region on the canvas.

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

Parameters

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.beginPath()
          this.context.ellipse(200, 200, 50, 100, Math.PI * 0.25, Math.PI * 0.5, Math.PI * 2)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

rect

rect(x: number, y: number, w: number, h: number): void

Creates a rectangle on the canvas.

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

Parameters

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.rect(20, 20, 100, 100) // Create a 100*100 rectangle at (20, 20)
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

fill

fill(fillRule?: CanvasFillRule): void

Fills the area inside a closed path on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Fill {
  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.rect(20, 20, 100, 100) // Create a 100*100 rectangle at (20, 20)
          this.context.fill()
        })
    }
    .width('100%')
    .height('100%')
  }
}

fill(path: Path2D, fillRule?: CanvasFillRule): void

Fills the area inside a closed path on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Fill {
  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(() =>{
          let region = new Path2D()
          region.moveTo(30, 90)
          region.lineTo(110, 20)
          region.lineTo(240, 130)
          region.lineTo(60, 130)
          region.lineTo(190, 20)
          region.lineTo(270, 90)
          region.closePath()
          // Fill path
          this.context.fillStyle = '#00ff00'
          this.context.fill(region, "evenodd")
        })
    }
    .width('100%')
    .height('100%')
  }
}

clip

clip(fillRule?: CanvasFillRule): void

Sets the current path to a clipping area.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Clip {
  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.rect(0, 0, 100, 200)
          this.context.stroke()
          this.context.clip()
          this.context.fillStyle = "rgb(255,0,0)"
          this.context.fillRect(0, 0, 200, 200)
        })
    }
    .width('100%')
    .height('100%')
  }
}

clip(path: Path2D, fillRule?: CanvasFillRule): void

Sets the current path to a clipping path.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Clip {
  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(() =>{
          let region = new Path2D()
          region.moveTo(30, 90)
          region.lineTo(110, 20)
          region.lineTo(240, 130)
          region.lineTo(60, 130)
          region.lineTo(190, 20)
          region.lineTo(270, 90)
          region.closePath()
          this.context.clip(region,"evenodd")
          this.context.fillStyle = "rgb(0,255,0)"
          this.context.fillRect(0, 0, this.context.width, this.context.height)
        })
    }
    .width('100%')
    .height('100%')
  }
}

filter

filter(filter: string): void

Provides filter effects. This API is a void API.

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

Parameters

getTransform

getTransform(): Matrix2D

Obtains the current transformation matrix being applied to the context. This API is a void API.

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

resetTransform

resetTransform(): void

Resets the current transform to the identity matrix. This API is a void API.

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

direction

direction(direction: CanvasDirection): void

Sets the current text direction used to draw text. This API is a void API.

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

rotate

rotate(angle: number): void

Rotates a canvas clockwise around its coordinate axes.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Rotate {
  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.rotate(45 * Math.PI / 180)
          this.context.fillRect(70, 20, 50, 50)
        })
    }
    .width('100%')
    .height('100%')
  }
}

scale

scale(x: number, y: number): void

Scales the canvas based on the given scale factors.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Scale {
  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.lineWidth = 3
          this.context.strokeRect(30, 30, 50, 50)
          this.context.scale(2, 2) // Scale to 200%
          this.context.strokeRect(30, 30, 50, 50)
        })
    }
    .width('100%')
    .height('100%')
  }
}

transform

transform(a: number, b: number, c: number, d: number, e: number, f: number): void

Defines a transformation matrix. To transform a graph, you only need to set parameters of the matrix. The coordinates of the graph are multiplied by the matrix values to obtain new coordinates of the transformed graph. You can use the matrix to implement multiple transform effects.

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

NOTE

The following formulas calculate coordinates of the transformed graph. x and y represent coordinates before transformation, and x' and y' represent coordinates after transformation.

• x' = scaleX * x + skewY * y + translateX

• y' = skewX * x + scaleY * y + translateY

Parameters

Example

// xxx.ets
@Entry
@Component
struct Transform {
  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.fillStyle = 'rgb(0,0,0)'
          this.context.fillRect(0, 0, 100, 100)
          this.context.transform(1, 0.5, -0.5, 1, 10, 10)
          this.context.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(0, 0, 100, 100)
          this.context.transform(1, 0.5, -0.5, 1, 10, 10)
          this.context.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(0, 0, 100, 100)
        })
    }
    .width('100%')
    .height('100%')
  }
}

setTransform

setTransform(a: number, b: number, c: number, d: number, e: number, f: number): void

Resets the existing transformation matrix and creates a new transformation matrix by using the same parameters as the transform() API.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct SetTransform {
  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.fillStyle = 'rgb(255,0,0)'
          this.context.fillRect(0, 0, 100, 100)
          this.context.setTransform(1,0.5, -0.5, 1, 10, 10)
          this.context.fillStyle = 'rgb(0,0,255)'
          this.context.fillRect(0, 0, 100, 100)
        })
    }
    .width('100%')
    .height('100%')
  }
}

setTransform(transform?: Matrix2D): void

Resets the current transformation to the identity matrix, and then creates a new transformation matrix based on the specified Matrix2D object. This API is a void API.

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

translate

translate(x: number, y: number): void

Moves the origin of the coordinate system.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct Translate {
  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(10, 10, 50, 50)
          this.context.translate(70, 70)
          this.context.fillRect(10, 10, 50, 50)
        })
    }
    .width('100%')
    .height('100%')
  }
}

drawImage

drawImage(image: ImageBitmap | PixelMap, dx: number, dy: number): void

drawImage(image: ImageBitmap | PixelMap, dx: number, dy: number, dw: number, dh: number): void

drawImage(image: ImageBitmap | PixelMap, sx: number, sy: number, sw: number, sh: number, dx: number, dy: number, dw: number, dh: number):void

Draws an image on the canvas.

Since API version 9, this API is supported in ArkTS widgets, except that PixelMap objects are not supported.

Parameters

Example

// xxx.ets
@Entry
@Component
struct ImageExample {
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  private img:ImageBitmap = new ImageBitmap("common/images/example.jpg")

  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Canvas(this.context)
        .width('100%')
        .height('100%')
        .backgroundColor('#ffff00')
        .onReady(() =>{
          this.context.drawImage( this.img,0,0,500,500,0,0,400,200)
      })
    }
    .width('100%')
    .height('100%')
  }
}

createImageData

createImageData(sw: number, sh: number): ImageData

Creates an ImageData object with the specified dimensions.

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

Parameters

createImageData(imageData: ImageData): ImageData

Creates an ImageData object.

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

Parameters

Return value

getPixelMap

getPixelMap(sx: number, sy: number, sw: number, sh: number): PixelMap

Obtains the PixelMap object created with the pixels within the specified area on the canvas.

Parameters

Return value

getImageData

getImageData(sx: number, sy: number, sw: number, sh: number): ImageData

Obtains the ImageData object created with the pixels within the specified area on the canvas.

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

Parameters

Return value

Example

// xxx.ets
@Entry
@Component
struct GetImageData {
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  private img:ImageBitmap = new ImageBitmap("/common/images/1234.png")

  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Canvas(this.context)
        .width('100%')
        .height('100%')
        .backgroundColor('#ffff00')
        .onReady(() =>{
          this.context.drawImage(this.img,0,0,130,130)
          var imagedata = this.context.getImageData(50,50,130,130)
          this.context.putImageData(imagedata,150,150)
        })
    }
    .width('100%')
    .height('100%')
  }
}

putImageData

putImageData(imageData: ImageData, dx: number, dy: number): void

putImageData(imageData: ImageData, dx: number, dy: number, dirtyX: number, dirtyY: number, dirtyWidth: number, dirtyHeight: number): void

Puts an ImageData object onto a rectangular area on the canvas.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct PutImageData {
  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(() =>{
          var imageData = this.context.createImageData(100, 100)
          for (var i = 0; i < imageData.data.length; i += 4) {
            imageData.data[i + 0] = 255
            imageData.data[i + 1] = 0
            imageData.data[i + 2] = 255
            imageData.data[i + 3] = 255
          }
          this.context.putImageData(imageData, 10, 10)
        })
    }
    .width('100%')
    .height('100%')
  }
}

setLineDash

setLineDash(segments: number[]): void

Sets the dash line style.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct SetLineDash {
  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.arc(100, 75, 50, 0, 6.28)
          this.context.setLineDash([10,20])
          this.context.stroke()
        })
    }
    .width('100%')
    .height('100%')
  }
}

getLineDash

getLineDash(): number[]

Obtains the dash line style.

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

Return value

Example

// xxx.ets
@Entry
@Component
struct CanvasGetLineDash {
  @State message: string = 'Hello World'
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()=>{
            console.error('before getlinedash clicked')
            let res = this.context.getLineDash()
            console.error(JSON.stringify(res))
          })
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() => {
            this.context.arc(100, 75, 50, 0, 6.28)
            this.context.setLineDash([10,20])
            this.context.stroke()
            let res = this.context.getLineDash()
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

imageSmoothingQuality

imageSmoothingQuality(quality: imageSmoothingQuality)

Sets the quality of image smoothing. This API is a void API.

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

Parameters

transferFromImageBitmap

transferFromImageBitmap(bitmap: ImageBitmap): void

Displays the specified ImageBitmap object.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct TransferFromImageBitmap {
  private settings: RenderingContextSettings = new RenderingContextSettings(true)
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  private offContext: OffscreenCanvasRenderingContext2D = new OffscreenCanvasRenderingContext2D(600, 600, this.settings)

  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Canvas(this.context)
        .width('100%')
        .height('100%')
        .backgroundColor('#ffff00')
        .onReady(() =>{
          var imageData = this.offContext.createImageData(100, 100)
          for (var i = 0; i < imageData.data.length; i += 4) {
            imageData.data[i + 0] = 255
            imageData.data[i + 1] = 0
            imageData.data[i + 2] = 255
            imageData.data[i + 3] = 255
          }
          this.offContext.putImageData(imageData, 10, 10)
          var image = this.offContext.transferToImageBitmap()
          this.context.transferFromImageBitmap(image)
        })
    }
    .width('100%')
    .height('100%')
  }
}

toDataURL

toDataURL(type?: string, quality?: number): string

Generates a URL containing image display information.

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

Parameters

Return value

Example

// xxx.ets
@Entry
@Component
struct ToDataURL {
  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(() =>{
          var dataURL = this.context.toDataURL()
        })
    }
    .width('100%')
    .height('100%')
  }
}

restore

restore(): void

Restores the saved drawing context.

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.save() // save the default state
          this.context.fillStyle = "#00ff00"
          this.context.fillRect(20, 20, 100, 100)
          this.context.restore() // restore to the default state
          this.context.fillRect(150, 75, 100, 100)
        })
    }
    .width('100%')
    .height('100%')
  }
}

save

save(): void

Saves all states of the canvas in the stack. This API is usually called when the drawing state needs to be saved.

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.save() // save the default state
          this.context.fillStyle = "#00ff00"
          this.context.fillRect(20, 20, 100, 100)
          this.context.restore() // restore to the default state
          this.context.fillRect(150, 75, 100, 100)
        })
    }
    .width('100%')
    .height('100%')
  }
}

createLinearGradient

createLinearGradient(x0: number, y0: number, x1: number, y1: number): void

Creates a linear gradient.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct CreateLinearGradient {
  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(() =>{
          var grad = this.context.createLinearGradient(50,0, 300,100)
          grad.addColorStop(0.0, '#ff0000')
          grad.addColorStop(0.5, '#ffffff')
          grad.addColorStop(1.0, '#00ff00')
          this.context.fillStyle = grad
          this.context.fillRect(0, 0, 400, 400)
        })
    }
    .width('100%')
    .height('100%')
  }
}

createRadialGradient

createRadialGradient(x0: number, y0: number, r0: number, x1: number, y1: number, r1: number): void

Creates a linear gradient.

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

Parameters

Example

// xxx.ets
@Entry
@Component
struct CreateRadialGradient {
  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(() =>{
          var grad = this.context.createRadialGradient(200,200,50, 200,200,200)
          grad.addColorStop(0.0, '#ff0000')
          grad.addColorStop(0.5, '#ffffff')
          grad.addColorStop(1.0, '#00ff00')
          this.context.fillStyle = grad
          this.context.fillRect(0, 0, 440, 440)
        })
    }
    .width('100%')
    .height('100%')
  }
}

CanvasPattern

Defines an object created using the createPattern API.

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