Uint8ClampedArray shim

uint8clampedarray.js

if (!window.Uint8ClampedArray && window.Uint8Array && window.ImageData) {
window.Uint8ClampedArray = function(input,arg1,arg2) {
	var len = 0;
	if (typeof input == "undefined") { }
	else if (!isNaN(parseInt(input.length))) { //an array, yay
		len = input.length;
	}
	else if (input instanceof ArrayBuffer) {
		return new Uint8ClampedArray(new Uint8Array(input,arg1,arg2));
	}
	else {
		len = parseInt(input);
		if (isNaN(len) || len < 0) {
			throw new RangeError();
		}
		input = undefined;
	}
	len = Math.ceil(len / 4);
	
	if (len == 0) len = 1;
	
	var array = document.createElement("canvas")
	              .getContext("2d")
	              .createImageData(len, 1)
	              .data;
	
	if (typeof input != "undefined") {
		for (var i=0;i<input.length;i++) {
			array[i] = input[i];
		}
	}
	try {
		Object.defineProperty(array,"buffer",{
			get: function() {
				return new Uint8Array(this).buffer;
			}
		});
	} catch(e) { try {
		array.__defineGetter__("buffer",function() {
			return new Uint8Array(this).buffer;
		});
	} catch(e) {} }
	return array;
}
}

Sadly, this is only any good for the native clamping support. The buffer property is pretty much useless because CanvasPixelArray doesn't implement the ArrayBufferView interface.