example/leaflet/src/geo/LatLngBounds.js
function (bufferRatio) { // (Number) -> LatLngBounds
		var sw = this._southWest,
		    ne = this._northEast,
		    heightBuffer = Math.abs(sw.lat - ne.lat) * bufferRatio,
		    widthBuffer = Math.abs(sw.lng - ne.lng) * bufferRatio;

		return new L.LatLngBounds(
		        new L.LatLng(sw.lat - heightBuffer, sw.lng - widthBuffer),
		        new L.LatLng(ne.lat + heightBuffer, ne.lng + widthBuffer));
	}
function (bufferRatio) { // (Number) -> LatLngBounds
		var sw = this._southWest,
		    ne = this._northEast,
		    heightBuffer = Math.abs(sw.lat - ne.lat) * bufferRatio,
		    widthBuffer = Math.abs(sw.lng - ne.lng) * bufferRatio;

		return new L.LatLngBounds(
		        new L.LatLng(sw.lat - heightBuffer, sw.lng - widthBuffer),
		        new L.LatLng(ne.lat + heightBuffer, ne.lng + widthBuffer));
	}
function ( bufferRatio ) { // (Number) -> LatLngBounds
 var sw = this . _southWest , ne = this . _northEast , heightBuffer = Math . abs ( sw . lat - ne . lat ) * bufferRatio , widthBuffer = Math . abs ( sw . lng - ne . lng ) * bufferRatio ; return new L . LatLngBounds ( new L . LatLng ( sw . lat - heightBuffer , sw . lng - widthBuffer ) , new L . LatLng ( ne . lat + heightBuffer , ne . lng + widthBuffer ) ) ; }
extend the bounds by a percentage
extend the bounds by a percentage