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.
屬性
從父代繼承的屬性,HTMLElement
.
HTMLCanvasElement.height
(en-US)-
Is a positive
integer
reflecting theheight
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 of150
is used. HTMLCanvasElement.mozOpaque
(en-US) 非標準-
Is a
Boolean
reflecting themoz-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 thewidth
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 of300
is used. HTMLCanvasElement.mozPrintCallback
非標準-
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) 實驗性質-
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 aCanvasRenderingContext2D
object, whereas calling it with"experimental-webgl"
(or"webgl"
) returns aWebGLRenderingContext
(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 topng
). 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) 非標準 已棄用-
Returns a
File
object representing the image contained in the canvas; this file is a memory-based file, with the specifiedname
. Iftype
is not specified, the image type isimage/png
.
規範
Specification |
---|
HTML Standard # htmlcanvaselement |
瀏覽器相容性
BCD tables only load in the browser
See also
- HTML element implementing this interface:
<canvas>
.