code: function(args) {
  
                  var tpl = '<filter><feFlood flood-color="${color}" flood-opacity="${opacity}" result="colored"/><feMorphology result="morphed" in="SourceGraphic" operator="dilate" radius="${width}"/><feComposite result="composed" in="colored" in2="morphed" operator="in"/><feGaussianBlur result="blured" in="composed" stdDeviation="${blur}"/><feBlend in="SourceGraphic" in2="blured" mode="normal"/></filter>';
  
                  return joint.util.template(tpl)({
                      color: args.color || 'red',
                      width: Number.isFinite(args.width) ? args.width : 1,
                      blur: Number.isFinite(args.blur) ? args.blur : 0,
                      opacity: Number.isFinite(args.opacity) ? args.opacity : 1
                  });
              }
docs: `color` ... color ('red') `width`... width (1) `blur` ... blur (0) `opacity` ... opacity (1)