# Source: src/ol/interaction/doubleclickzoominteraction.js

    // FIXME works for View2D only

    goog.provide('ol.interaction.DoubleClickZoom');

    goog.require('goog.asserts');
    goog.require('ol.MapBrowserEvent');
    goog.require('ol.MapBrowserEvent.EventType');
    goog.require('ol.interaction.Interaction');

    /**
     * @classdesc
     * Allows the user to zoom by double-clicking on the map.
     *
     * @constructor
     * @extends {ol.interaction.Interaction}
     * @param {olx.interaction.DoubleClickZoomOptions=} opt_options Options.
     * @todo api
     */
    ol.interaction.DoubleClickZoom = function(opt_options) {

      var options = goog.isDef(opt_options) ? opt_options : {};

      /**
       * @private
       * @type {number}
       */
      this.delta_ = goog.isDef(options.delta) ? options.delta : 1;

      goog.base(this);

      /**
       * @private
       * @type {number}
       */
      this.duration_ = goog.isDef(options.duration) ? options.duration : 250;

    };
    goog.inherits(ol.interaction.DoubleClickZoom, ol.interaction.Interaction);

    /**
     * @inheritDoc
     */
    ol.interaction.DoubleClickZoom.prototype.handleMapBrowserEvent =
        function(mapBrowserEvent) {
      var stopEvent = false;
      var browserEvent = mapBrowserEvent.browserEvent;
      if (mapBrowserEvent.type == ol.MapBrowserEvent.EventType.DBLCLICK) {
        var map = mapBrowserEvent.map;
        var anchor = mapBrowserEvent.coordinate;
        var delta = browserEvent.shiftKey ? -this.delta_ : this.delta_;
        // FIXME works for View2D only
        var view = map.getView().getView2D();
        ol.interaction.Interaction.zoomByDelta(
            map, view, delta, anchor, this.duration_);
        mapBrowserEvent.preventDefault();
        stopEvent = true;
      }
      return !stopEvent;
    };