code: function() {
          var win = $(window),
              options = this.options,
              element = this.element,
              parent = options.context ? element.parents(options.context) : element.parent();
  
          this.viewport = {
              width: win.width(),
              height: win.height()
          };
  
          this.elementHeight = element.outerHeight(true); // Include margin
          this.parentHeight = parent.height(); // Exclude padding
          this.parentTop = parent.offset().top;
  
          // Disable pin if element is larger than the viewport
          if (options.lock && this.elementHeight >= this.viewport.height) {
              this.active = false;
  
          // Enable pin if the parent is larger than the child
          } else {
              this.active = (element.is(':visible') && this.parentHeight > this.elementHeight);
          }
      }
docs: Calculate the dimensions and offsets of the interacting elements.