/**
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/LICENSE
 */
import { Direction, Directionality } from '@angular/cdk/bidi';
import { Platform } from '@angular/cdk/platform';
import { ChangeDetectorRef, EventEmitter, NgZone, OnChanges, OnDestroy, OnInit, SimpleChanges, TemplateRef } from '@angular/core';
import { VtsConfigKey, VtsConfigService } from '@ui-vts-kit/ng-vts/core/config';
import { VtsScrollService } from '@ui-vts-kit/ng-vts/core/services';
import { NumberInput, VtsSafeAny } from '@ui-vts-kit/ng-vts/core/types';
import * as i0 from "@angular/core";
export declare class VtsBackTopComponent implements OnInit, OnDestroy, OnChanges {
    private doc;
    vtsConfigService: VtsConfigService;
    private scrollSrv;
    private platform;
    private cd;
    private zone;
    private cdr;
    private directionality;
    readonly _vtsModuleName: VtsConfigKey;
    static ngAcceptInputType_vtsVisibilityHeight: NumberInput;
    static ngAcceptInputType_vtsDuration: NumberInput;
    private scrollListenerDestroy$;
    private destroy$;
    private target;
    visible: boolean;
    dir: Direction;
    vtsTemplate?: TemplateRef<void>;
    vtsVisibilityHeight: number;
    vtsTarget?: string | HTMLElement;
    vtsDuration: number;
    readonly vtsClick: EventEmitter<boolean>;
    constructor(doc: VtsSafeAny, vtsConfigService: VtsConfigService, scrollSrv: VtsScrollService, platform: Platform, cd: ChangeDetectorRef, zone: NgZone, cdr: ChangeDetectorRef, directionality: Directionality);
    ngOnInit(): void;
    clickBackTop(): void;
    private getTarget;
    private handleScroll;
    private registerScrollEvent;
    ngOnDestroy(): void;
    ngOnChanges(changes: SimpleChanges): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<VtsBackTopComponent, [null, null, null, null, null, null, null, { optional: true; }]>;
    static ɵcmp: i0.ɵɵComponentDeclaration<VtsBackTopComponent, "vts-back-top", ["vtsBackTop"], { "vtsTemplate": { "alias": "vtsTemplate"; "required": false; }; "vtsVisibilityHeight": { "alias": "vtsVisibilityHeight"; "required": false; }; "vtsTarget": { "alias": "vtsTarget"; "required": false; }; "vtsDuration": { "alias": "vtsDuration"; "required": false; }; }, { "vtsClick": "vtsClick"; }, never, never, false, never>;
}