Canvas

• Properties
  • number width: Canvas width.
  • number height : Canvas height.

Method set

cancelAnimationFrame

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The API usage is as follows: Canvas.cancelAnimationFrame(number requestID)

• Functional description: Cancels the animation frame request added to the schedule by requestAnimationFrame. Supports use in 2D Canvas and WebGL Canvas, but does not support mixed 2D and WebGL methods.
• Parameters and descriptions: number requestID。

createImageData

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The API usage is as follows: Image Canvas.createImage()

• Functional description: Creates an ImageData object. Supports use in 2D Canvas only.
• Parameters and descriptions: ImageData

createImage

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The API usage is as follows: ImageData Canvas.createImageData()

• Functional description: Creates an image object. Supports use in 2D Canvas and WebGL Canvas, but does not support mixed 2D and WebGL methods.
• Parameters and descriptions: Image

createPath2D

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The API usage is as follows: Path2D Canvas.createPath2D(Path2D path)

• Functional description: Creates a Path2D object.
• Parameters and descriptions: Path2D path。
• Return value: Path2D。

getContext

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The API usage is as follows: RenderingContext Canvas.getContext(string contextType)

• Functional description: This method returns the drawing context of the Canvas.

• Parameters and descriptions: string contextType， Context type.

  Legal value	Description
  2d	2d drawing context
  webgl	webgl drawing context
  webgl2	webgl2 drawing context

• Return value: RenderingContext, , supports getting 2D and WebGL drawing contexts.

requestAnimationFrame

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The API usage is as follows: number Canvas.requestAnimationFrame(function callback)

• Functional description: Executed at the next redraw. Supports use in 2D Canvas and WebGL Canvas, but does not support mixed 2D and WebGL methods.
• Parameters and descriptions: function callback， Executed callback.
• Return value: number, Request ID.

toDataURL

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The API usage is as follows: string Canvas.toDataURL(string type, number encoderOptions)

• Functional description: Returns a data URI containing the image display. You can use the type parameter to specify its type, which defaults to PNG format.
• Parameters and descriptions:
  • string type： Image format, defaults to image/png.
  • number encoderOptions： When the image format is specified as image/jpeg or image/webp, the image quality can be selected from the range of 0 to 1. If the value is out of range, the default value of 0.92 will be used. Other parameters will be ignored.
• Return value: string。