) {
          var canvas = document.getElementById('canvas');

          var _getContext = canvas.getContext;
          canvas.getContext = function(contextType, contextAttributes) {
            if (contextAttributes) {
              contextAttributes.antialias = false;
              contextAttributes.imageSmoothingEnabled = false;
              contextAttributes.preserveDrawingBuffer = true;
            }

            return _getContext.call(this, contextType, contextAttributes);
          };

          //