code: function(map) {
          /**
           * If nothing to do with resolutions has been set, assume a single
           * resolution determined by ratio*extent/size - if an image has a
           * pixel aspect ratio different than one (as calculated above), the
           * image will be stretched in one dimension only.
           */
          if( this.options.maxResolution == null ) {
              this.options.maxResolution = this.aspectRatio *
                                           this.extent.getWidth() /
                                           this.size.w;
          }
          OpenLayers.Layer.prototype.setMap.apply(this, arguments);
      }
docs: APIMethod: setMap
  
  Parameters:
  map - {<OpenLayers.Map>}