From 218934fa2ed1c702a6d3923d2aa2cc6b43c48684 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:43:23 -0500 Subject: initial commit --- files/uk/web/api/htmlcanvaselement/index.html | 264 ++++++++++++++++++++++++++ 1 file changed, 264 insertions(+) create mode 100644 files/uk/web/api/htmlcanvaselement/index.html (limited to 'files/uk/web/api/htmlcanvaselement') diff --git a/files/uk/web/api/htmlcanvaselement/index.html b/files/uk/web/api/htmlcanvaselement/index.html new file mode 100644 index 0000000000..9f1a6452ed --- /dev/null +++ b/files/uk/web/api/htmlcanvaselement/index.html @@ -0,0 +1,264 @@ +--- +title: HTMLCanvasElement +slug: Web/API/HTMLCanvasElement +tags: + - API + - Canvas + - HTML DOM + - Interface + - NeedsTranslation + - Reference + - TopicStub +translation_of: Web/API/HTMLCanvasElement +--- +
+
{{APIRef("Canvas API")}}
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+ +

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 {{domxref("HTMLElement")}} interface.

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{{InheritanceDiagram}}

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Properties

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Inherits properties from its parent, {{domxref("HTMLElement")}}.

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{{domxref("HTMLCanvasElement.height")}}
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Is a positive integer reflecting the {{htmlattrxref("height", "canvas")}} HTML attribute of the {{HTMLElement("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.
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{{domxref("HTMLCanvasElement.mozOpaque")}} {{non-standard_inline}}
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Is a {{jsxref("Boolean")}} reflecting the {{htmlattrxref("moz-opaque", "canvas")}} HTML attribute of the {{HTMLElement("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.
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{{domxref("HTMLCanvasElement.width")}}
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Is a positive integer reflecting the {{htmlattrxref("width", "canvas")}} HTML attribute of the {{HTMLElement("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.
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{{domxref("HTMLCanvasElement.mozPrintCallback")}}{{non-standard_inline}}
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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.
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Methods

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Inherits methods from its parent, {{domxref("HTMLElement")}}.

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{{domxref("HTMLCanvasElement.captureStream()")}} {{experimental_inline}}
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Returns a {{domxref("CanvasCaptureMediaStream")}} that is a real-time video capture of the surface of the canvas.
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{{domxref("HTMLCanvasElement.getContext()")}}
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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 {{domxref("CanvasRenderingContext2D")}} object, whereas calling it with "experimental-webgl" (or "webgl") returns a {{domxref("WebGLRenderingContext")}} object. This context is only available on browsers that implement WebGL.
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{{domxref("HTMLCanvasElement.toDataURL()")}}
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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.
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{{domxref("HTMLCanvasElement.toBlob()")}}
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Creates a {{domxref("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.
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{{domxref("HTMLCanvasElement.transferControlToOffscreen()")}} {{experimental_inline}}
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Transfers control to an {{domxref("OffscreenCanvas")}} object, either on the main thread or on a worker.
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{{domxref("HTMLCanvasElement.mozGetAsFile()")}} {{non-standard_inline}} {{deprecated_inline}}
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Returns a {{domxref("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.
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Specifications

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SpecificationStatusComment
{{SpecName('Media Capture DOM Elements', '#html-media-element-media-capture-extensions', 'HTMLCanvasElement')}}{{Spec2('Media Capture DOM Elements')}}Adds the method captureStream().
{{SpecName('HTML WHATWG', "#the-canvas-element", "HTMLCanvasElement")}}{{Spec2('HTML WHATWG')}}The method getContext() now returns a {{domxref("RenderingContext")}} rather than an opaque object.
+ The methods probablySupportsContext(), setContext() and transferControlToProxy()have been added.
{{SpecName('HTML5.1', "scripting-1.html#the-canvas-element", "HTMLCanvasElement")}}{{Spec2('HTML5.1')}} 
{{SpecName('HTML5 W3C', "scripting-1.html#the-canvas-element", "HTMLCanvasElement")}}{{Spec2('HTML5 W3C')}}Initial definition.
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Browser compatibility

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{{CompatibilityTable}}
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FeatureChromeEdgeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support (2D context)4.0{{CompatVersionUnknown}}{{CompatGeckoDesktop('1.9.2')}}9.09.0 [1]3.1
toBlob()50{{CompatNo}}{{CompatGeckoDesktop('19')}} [2]{{CompatUnknown}}{{CompatUnknown}}{{CompatNo}} (bug 71270)
probablySupportsContext(),
+ setContext(),
+ transferControlToProxy() {{experimental_inline}}		{{CompatNo}}{{CompatUnknown}}{{CompatNo}}{{CompatNo}}{{CompatNo}}{{CompatNo}}
mozGetAsFile() {{non-standard_inline}} {{deprecated_inline}}{{CompatNo}}{{CompatNo}}{{CompatGeckoDesktop('2')}}{{CompatNo}}{{CompatNo}}{{CompatNo}}
captureStream() {{experimental_inline}}{{CompatNo}}{{CompatNo}}{{CompatGeckoDesktop('41')}}{{CompatNo}}{{CompatNo}}{{CompatNo}}
transferControlToOffscreen() {{experimental_inline}}{{CompatNo}}{{CompatNo}}{{CompatGeckoDesktop(44)}} [3]{{CompatNo}}{{CompatNo}}{{CompatNo}}
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+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidEdgeFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support (2D context)2.1{{CompatVersionUnknown}}{{CompatVersionUnknown}}{{CompatVersionUnknown}}{{CompatUnknown}}10.0 [1]3.2
webgl context{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}{{CompatVersionUnknown}} as experimental-webgl{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
toBlob(){{CompatNo}} (bug 67587)50{{CompatNo}}{{CompatGeckoMobile('18')}} [2]{{CompatUnknown}}{{CompatUnknown}}{{CompatNo}} (bug 71270)
probablySupportsContext(),
+ setContext(),
+ transferControlToProxy() {{experimental_inline}}		{{CompatNo}}{{CompatNo}}{{CompatUnknown}}{{CompatNo}}{{CompatNo}}{{CompatNo}}{{CompatNo}}
mozGetAsFile() {{non-standard_inline}} {{deprecated_inline}}{{CompatNo}}{{CompatNo}}{{CompatNo}}{{CompatGeckoMobile('2')}}{{CompatNo}}{{CompatNo}}{{CompatNo}}
captureStream() {{experimental_inline}}{{CompatNo}}{{CompatNo}}{{CompatNo}}{{CompatGeckoMobile('41')}}{{CompatNo}}{{CompatNo}}{{CompatNo}}
transferControlToOffscreen() {{experimental_inline}}{{CompatNo}}{{CompatNo}}{{CompatNo}}{{CompatGeckoMobile(44)}} [3]{{CompatNo}}{{CompatNo}}{{CompatNo}}
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[1] Opera Mini 5.0 and later has partial support.

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[2] Support for the third parameter, has been added in Gecko 25 only: when used with the "image/jpeg" type, this argument specifies the image quality.

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[3] This feature is behind a feature preference setting. In about:config, set gfx.offscreencanvas.enabled to true.

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See also

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