code: function (pxBounds, maxBounds, zoom) {
  		var nwOffset = this.project(maxBounds.getNorthWest(), zoom).subtract(pxBounds.min),
  		    seOffset = this.project(maxBounds.getSouthEast(), zoom).subtract(pxBounds.max),
  
  		    dx = this._rebound(nwOffset.x, -seOffset.x),
  		    dy = this._rebound(nwOffset.y, -seOffset.y);
  
  		return new L.Point(dx, dy);
  	}
docs: returns offset needed for pxBounds to get inside maxBounds at a specified zoom