HTMLCanvasElement

The HTMLCanvasElement interface provides properties and methods for manipulating the layout and presentation of canvas elements. The HTMLCanvasElement interface also inherits the properties and methods of the HTMLElement interface.

Properties

Inherits properties from its parent, HTMLElement.

HTMLCanvasElement.height

Is a positive integer reflecting the height HTML attribute of the <canvas> element interpreted in CSS pixels. When the attribute is not specified, or if it is set to an invalid value, like a negative, the default value of 150 is used.

HTMLCanvasElement.mozOpaque (en-US) Non-standard

Is a Boolean reflecting the moz-opaque HTML attribute of the <canvas> element. It lets the canvas know whether or not translucency will be a factor. If the canvas knows there's no translucency, painting performance can be optimized.

HTMLCanvasElement.width (en-US)

Is a positive integer reflecting the width HTML attribute of the <canvas> element interpreted in CSS pixels. When the attribute is not specified, or if it is set to an invalid value, like a negative, the default value of 300 is used.

HTMLCanvasElement.mozPrintCallback Non-standard

Is a function that is Initially null, Web content can set this to a JavaScript function that will be called if the page is printed. This function can then redraw the canvas at a higher resolution that is suitable for the printer being used. See this blog post.

Methods

Inherits methods from its parent, HTMLElement.

HTMLCanvasElement.captureStream() (en-US) Experimental

Returns a CanvasCaptureMediaStream (en-US) that is a real-time video capture of the surface of the canvas.

HTMLCanvasElement.getContext()

Returns a drawing context on the canvas, or null if the context ID is not supported. A drawing context lets you draw on the canvas. Calling getContext with "2d" returns a CanvasRenderingContext2D object, whereas calling it with "experimental-webgl" (or "webgl") returns a WebGLRenderingContext (en-US) object. This context is only available on browsers that implement WebGL.

HTMLCanvasElement.toDataURL()

Returns a data-URL containing a representation of the image in the format specified by the type parameter (defaults to png). The returned image is in a resolution of 96dpi.

HTMLCanvasElement.toBlob() (en-US)

Creates a Blob object representing the image contained in the canvas; this file may be cached on the disk or stored in memory at the discretion of the user agent.

HTMLCanvasElement.transferControlToOffscreen() (en-US) Experimental

Transfers control to an OffscreenCanvas (en-US) object, either on the main thread or on a worker.

HTMLCanvasElement.mozGetAsFile() (en-US) Non-standard Deprecated

Returns a File object representing the image contained in the canvas; this file is a memory-based file, with the specified name. If type is not specified, the image type is image/png.

Specifications

Specification Status Comment
Media Capture from DOM Elements
The definition of 'HTMLCanvasElement' in that specification.
Rascunho atual Adds the method captureStream().
HTML Living Standard
The definition of 'HTMLCanvasElement' in that specification.
Padrão em tempo real The method getContext() now returns a RenderingContext rather than an opaque object. The methods probablySupportsContext(), setContext() and transferControlToProxy()have been added.
HTML 5.1
The definition of 'HTMLCanvasElement' in that specification.
Recomendação
HTML5
The definition of 'HTMLCanvasElement' in that specification.
Recomendação Initial definition.

Compatibilidade com navegadores

BCD tables only load in the browser

See also

  • HTML element implementing this interface: <canvas>.