Pony.fm/resources/assets/scripts/app/directives/src-loader.coffee

angular.module('ponyfm').directive 'pfmSrcLoader', () ->
	(scope, element, attrs) ->
		size = attrs.pfmSrcSize || 'normal'
		element.css {opacity: .5}

		update = (val) ->
			element.attr 'src', '/images/icons/loading_' + size + '.png'

			image = element.clone()
			image.removeAttr 'pfm-src-loader'
			image.removeAttr 'pfm-src-size'

			# If the given value is null, don't bother trying to
			# load something - it will result in an HTTP error.
			if val
				image[0].onload = ->
					element.attr 'src', val
					element.css {opacity: 0}
					element.animate {opacity: 1}, 250

				image[0].src = val

		update scope.$eval attrs.pfmSrcLoader

		scope.$watch attrs.pfmSrcLoader, update