canvasContextBinding.js

ko.bindingHandlers.canvasContext = {
	init: function(element, valueAccessor, allBindingsAccessor, viewModel) {
		if ("undefined" === typeof viewModel.__canvasContexts__) {
			viewModel.__canvasContexts__ = [];
		}

		// works now :)
		if ("function" !== typeof element.getContext && FlashCanvas) {
			FlashCanvas.initElement(element);
		}

		// sharing canvas context with VM – useful when debugging
		viewModel.__canvasContexts__.push(element.getContext("2d"));
	},
	update: function(element, valueAccessor, allBindingsAccessor, viewModel) {
		var callback = ko.utils.unwrapObservable(valueAccessor());
		callback.call(viewModel, element.getContext("2d"));
	}
};