declare namespace viewer {
    /**
     * Auxiliary class for blocking and unblocking events on a HTML element. Example for blocking the contextmenu:
     * ```
     * blocker = new gloperate.EventBlocker(element);
     * blocker.block('contextmenu');
     * ```
     */
    class EventBlocker {
        /**
         * Lookup table for blocked events and their listener.
         */
        private _blockListenerByEvent;
        /**
         * Element associated to this blocker.
         */
        protected _element: HTMLElement;
        /**
         * Creates an event blocker instance associated to a specific HTML element.
         * @param element - Element that is to be associated with this blocker for block und unblock.
         * @param events - Optional events that are blocked immediately.
         */
        constructor(element: HTMLElement, events?: Array<string>);
        /**
         * Blocks a specific event by adding a listener the prevents the default and stops propagation.
         * @param eventIdentifier - Event identifier that is to be blocked, e.g., 'contextmenu'.
         */
        block(eventIdentifier: string): void;
        /**
         * Unblocks a previously blocked event by removing the blocker/listener.
         * @param eventIdentifier - Event identifier that is to be unblocked, e.g., 'contextmenu'.
         */
        unblock(eventIdentifier: string): void;
    }
}
export = viewer;