HTMLCanvasElement

HTMLCanvasElement 介面提供控制 canvas 元素的屬性和方法. HTMLCanvasElement 介面也繼承了 HTMLElement 介面的屬性和方法.

EventTarget Node Element HTMLElement HTMLCanvasElement

屬性

從父代繼承的屬性,HTMLElement.

HTMLCanvasElement.height (en-US)
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.

方法

從父代繼承的方法, 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() (en-US)
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.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.

規範

Specification
HTML Standard
# htmlcanvaselement

瀏覽器相容性

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See also

  • HTML element implementing this interface: <canvas>.