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