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Is there any way to obtain the canvas that a context is used for?
Why I'm asking is because I'm creating a prototype function for CanvasRenderingContext2D in which I need the width/height of the canvas element.
E.g.:
var cv = document.getElementById('canvas'); var ctx = cv.getContext('2d'); // Using only 'ctx', how to get 'cv'? 
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getContext() The HTMLCanvasElement. getContext() method returns a drawing context on the canvas, or null if the context identifier is not supported, or the canvas has already been set to a different context mode.
The CanvasRenderingContext2D interface, part of the Canvas API, provides the 2D rendering context for the drawing surface of a <canvas> element. It is used for drawing shapes, text, images, and other objects.
The getImageData() method returns an ImageData object that copies the pixel data for the specified rectangle on a canvas. Note: The ImageData object is not a picture, it specifies a part (rectangle) on the canvas, and holds information of every pixel inside that rectangle.
You cannot use multiple contexts for one canvas element. In WebKit, this is explicitly mentioned in the source: // A Canvas can either be "2D" or "webgl" but never both.
ctx.canvas should return the canvas DOM node, from which you can get height and width.
I tried it with https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API/Tutorial/Basic_usage
Firefox was able to return ctx.canvas, as well as ctx.canvas.width and ctx.canvas.height. Also confirmed in Chrome.
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