docs: function (bounds) {
          bounds = this.adjustBounds(bounds);
          // Make a list, so that getFullRequestString uses literal "," 
          var extent = [bounds.left, bounds. bottom, bounds.right, bounds.top];
  
          var imageSize = this.getImageSize(); 
          
          // make lists, so that literal ','s are used 
          var url = this.getFullRequestString(
                       {mapext:   extent,
                        imgext:   extent,
                        map_size: [imageSize.w, imageSize.h],
                        imgx:     imageSize.w / 2,
                        imgy:     imageSize.h / 2,
                        imgxy:    [imageSize.w, imageSize.h]
                        });
          
          return url;
      }