import { RendererFactory2 } from '@angular/core';
import { DokuBackdropRef } from './backdrop-ref';
import * as i0 from "@angular/core";
export declare class DokuBackdropService {
    private rendererFactory;
    private document;
    private backdrops;
    private renderer;
    constructor(rendererFactory: RendererFactory2, document: Document);
    /**
     * Open backdrop element.
     */
    open(): DokuBackdropRef;
    /**
     * Close backdrop element by ref.
     */
    close(backdropRef: DokuBackdropRef): void;
    /**
     * Close all backdrops.
     */
    closeAll(): void;
    private createBackdropElement;
    static ɵfac: i0.ɵɵFactoryDeclaration<DokuBackdropService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<DokuBackdropService>;
}