harmony 鸿蒙Path2D

  • 2022-08-09
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Path2D

Path2D allows you to describe a path through an existing path. This path can be drawn through the stroke or fill API of 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.

addPath

addPath(path: path2D, transform?:Matrix2D): void

Adds a path to this path.

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

Parameters

Name Type Mandatory Default Value Description
path path2D Yes - Path to be added to this path.
transform Matrix2D No null Transformation matrix of the new path.

Example

  // xxx.ets
  @Entry
  @Component
  struct AddPath {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
  
    private path2Da: Path2D = new Path2D("M250 150 L150 350 L350 350 Z")
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.addPath(this.path2Da)
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001211898520

closePath

closePath(): void

Moves the current point of the path back to the start point of the path, and draws a straight line between the current point and the start point. If the shape has already been closed or has only one point, this method does nothing.

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)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.moveTo(200, 100)
            this.path2Db.lineTo(300, 100)
            this.path2Db.lineTo(200, 200)
            this.path2Db.closePath()
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001212218482

moveTo

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

Moves the current coordinate point of the path to the target point, without drawing a line during the movement.

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

Parameters

Name Type Mandatory Default Value Description
x number Yes 0 X-coordinate of the target point.
y number Yes 0 Y-coordinate of the target point.

Example

  // xxx.ets
  @Entry
  @Component
  struct MoveTo {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.moveTo(50, 100)
            this.path2Db.lineTo(250, 100)
            this.path2Db.lineTo(150, 200)
            this.path2Db.closePath()
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001257138389

lineTo

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

Draws a straight line from the current point to the target point.

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

Parameters

Name Type Mandatory Default Value Description
x number Yes 0 X-coordinate of the target point.
y number Yes 0 Y-coordinate of the target point.

Example

  // xxx.ets
  @Entry
  @Component
  struct LineTo {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.moveTo(100, 100)
            this.path2Db.lineTo(100, 200)
            this.path2Db.lineTo(200, 200)
            this.path2Db.lineTo(200, 100)
            this.path2Db.closePath()
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001256858435

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

Name Type Mandatory Default Value Description
cp1x number Yes 0 X-coordinate of the first parameter of the bezier curve.
cp1y number Yes 0 Y-coordinate of the first parameter of the bezier curve.
cp2x number Yes 0 X-coordinate of the second parameter of the bezier curve.
cp2y number Yes 0 Y-coordinate of the second parameter of the bezier curve.
x number Yes 0 X-coordinate of the end point on the bezier curve.
y number Yes 0 Y-coordinate of the end point on the bezier curve.

Example

  // xxx.ets
  @Entry
  @Component
  struct BezierCurveTo {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.moveTo(10, 10)
            this.path2Db.bezierCurveTo(20, 100, 200, 100, 200, 20)
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001257058445

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

Name Type Mandatory Default Value Description
cpx number Yes 0 X-coordinate of the bezier curve parameter.
cpy number Yes 0 Y-coordinate of the bezier curve parameter.
x number Yes 0 X-coordinate of the end point on the bezier curve.
y number Yes 0 Y-coordinate of the end point on the bezier curve.

Example

  // xxx.ets
  @Entry
  @Component
  struct QuadraticCurveTo {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.moveTo(10, 10)
            this.path2Db.quadraticCurveTo(100, 100, 200, 20)
            this.context.stroke(this.path2Db)
        })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001212058512

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

Name Type Mandatory Default Value Description
x number Yes 0 X-coordinate of the center point of the arc.
y number Yes 0 Y-coordinate of the center point of the arc.
radius number Yes 0 Radius of the arc.
startAngle number Yes 0 Start radian of the arc.
endAngle number Yes 0 End radian of the arc.
counterclockwise boolean No false Whether to draw the arc counterclockwise.

Example

  // xxx.ets
  @Entry
  @Component
  struct Arc {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.arc(100, 75, 50, 0, 6.28)
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001212378446

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

Name Type Mandatory Default Value Description
x1 number Yes 0 X-coordinate of the first point on the arc.
y1 number Yes 0 Y-coordinate of the first point on the arc.
x2 number Yes 0 X-coordinate of the second point on the arc.
y2 number Yes 0 Y-coordinate of the second point on the arc.
radius number Yes 0 Radius of the arc.

Example

  // xxx.ets
  @Entry
  @Component
  struct ArcTo {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.arcTo(150, 20, 150, 70, 50)
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001212058510

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

Name Type Mandatory Default Value Description
x number Yes 0 X-coordinate of the ellipse center.
y number Yes 0 Y-coordinate of the ellipse center.
radiusX number Yes 0 Ellipse radius on the x-axis.
radiusY number Yes 0 Ellipse radius on the y-axis.
rotation number Yes 0 Rotation angle of the ellipse. The unit is radian.
startAngle number Yes 0 Angle of the start point for drawing the ellipse. The unit is radian.
endAngle number Yes 0 Angle of the end point for drawing the ellipse. The unit is radian.
counterclockwise boolean No false Whether to draw the ellipse counterclockwise.
true: Draw the ellipse counterclockwise.
false: Draw the ellipse clockwise.

Example

  // xxx.ets
  @Entry
  @Component
  struct CanvasExample {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()

    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.ellipse(200, 200, 50, 100, 0, Math.PI * 1, Math.PI*2)
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001257138391

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

Name Type Mandatory Default Value Description
x number Yes 0 X-coordinate of the upper left corner of the rectangle.
y number Yes 0 Y-coordinate of the upper left corner of the rectangle.
w number Yes 0 Width of the rectangle.
h number Yes 0 Height of the rectangle.

Example

  // xxx.ets
  @Entry
  @Component
  struct CanvasExample {
    private settings: RenderingContextSettings = new RenderingContextSettings(true)
    private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings)
    private path2Db: Path2D = new Path2D()
  
    build() {
      Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .backgroundColor('#ffff00')
          .onReady(() =>{
            this.path2Db.rect(20, 20, 100, 100);
            this.context.stroke(this.path2Db)
          })
      }
      .width('100%')
      .height('100%')
    }
  }

en-us_image_0000001256978385

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