code: function(contentSize) {
          $.console.assert(contentSize, "[Viewport.resetContentSize] contentSize is required");
          $.console.assert(contentSize instanceof $.Point, "[Viewport.resetContentSize] contentSize must be an OpenSeadragon.Point");
          $.console.assert(contentSize.x > 0, "[Viewport.resetContentSize] contentSize.x must be greater than 0");
          $.console.assert(contentSize.y > 0, "[Viewport.resetContentSize] contentSize.y must be greater than 0");
  
          this._setContentBounds(new $.Rect(0, 0, 1, contentSize.y / contentSize.x), contentSize.x);
          return this;
      }
docs: Updates the viewport's home bounds and constraints for the given content size.
  @function
  @param {OpenSeadragon.Point} contentSize - size of the content in content units
  @return {OpenSeadragon.Viewport} Chainable.
  @fires OpenSeadragon.Viewer.event:reset-size