CanvasRenderingContext2D.getContextAttributes()
The CanvasRenderingContext2D.getContextAttributes()
method
returns an object that contains the actual context parameters. Context attributes can be
requested with
HTMLCanvasElement.getContext()
on context creation.
Syntax
ctx.getContextAttributes();
Return value
A CanvasRenderingContext2DSettings
object that contains the actual context
parameters.
It has the following members:
alpha
-
A Boolean indicating if the canvas contains an alpha channel. If
false
, the backdrop is always opaque, which can speed up drawing of transparent content and images. desynchronized
-
A Boolean indicating the user agent reduced the latency by desynchronizing the canvas paint cycle from the event loop.
Examples
Given context attributes were provided on context creation using
HTMLCanvasElement.getContext()
let canvas = document.createElement('canvas');
let ctx = canvas.getContext('2d', {alpha: false});
the getContextAttributes()
method lets you read back actual attributes
used by
the user agent:
ctx.getContextAttributes();
// returns {alpha: false, desynchronized: false}
Specifications
Specification |
---|
HTML Standard # 2dcontext:dom-context-2d-canvas-getcontextattributes-2 |
Browser compatibility
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