function drawWorld( viewer ) {
    viewer.imageLoader.clear();
    viewer.world.draw();

    /**
     * <em>- Needs documentation -</em>
     *
     * @event update-viewport
     * @memberof OpenSeadragon.Viewer
     * @type {object}
     * @property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised the event.
     * @property {?Object} userData - Arbitrary subscriber-defined object.
     */
    viewer.raiseEvent( 'update-viewport', {} );
}
Raised when any spring animation ends (zoom, pan, etc.).

@event animation-finish
@memberof OpenSeadragon.Viewer
@type {object}
@property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised this event.
@property {?Object} userData - Arbitrary subscriber-defined object.