import { AfterContentInit, AfterViewInit, ElementRef, OnDestroy, OnInit } from '@angular/core';
import { Observable } from 'rxjs';
import { RxVirtualScrollElement, RxVirtualScrollStrategy, RxVirtualScrollViewport, RxVirtualViewRepeater } from './model';
import * as i0 from "@angular/core";
import * as i1 from "@angular/common";
/**
 * @Component RxVirtualScrollViewport
 *
 * @description
 * Container component comparable to CdkVirtualScrollViewport acting as viewport
 * for `*rxVirtualFor` to operate on.
 *
 * Its main purpose is to implement the `RxVirtualScrollViewport` interface
 * as well as maintaining the scroll runways' height in order to give
 * the provided `RxVirtualScrollStrategy` room to position items.
 *
 * Furthermore, it will gather and forward all events to the consumer of `rxVirtualFor`.
 *
 * @docsCategory RxVirtualFor
 * @docsPage RxVirtualFor
 * @publicApi
 */
export declare class RxVirtualScrollViewportComponent implements RxVirtualScrollViewport, OnInit, AfterViewInit, AfterContentInit, OnDestroy {
    private elementRef;
    scrollElement: RxVirtualScrollElement;
    initialScrollIndex: number;
    /** @internal */
    private scrollSentinel;
    /** @internal */
    private runway;
    private _scrollStrategy$;
    private scrollStrategy$;
    private _scrollStrategy;
    set scrollStrategy(scrollStrategy: RxVirtualScrollStrategy<unknown> | Observable<RxVirtualScrollStrategy<unknown>>);
    reserveSpaceAtEnd?: number;
    /** @internal */
    viewRepeater: RxVirtualViewRepeater<unknown>;
    readonly elementScrolled$: Observable<void>;
    private hasScrolledYet;
    /** @internal */
    private _containerRect$;
    readonly containerRect$: Observable<{
        width: number;
        height: number;
    }>;
    /**
     * @description
     *
     * The range to be rendered by `*rxVirtualFor`. This value is determined by the
     * provided `RxVirtualScrollStrategy`. It gives the user information about the
     * range of items being actually rendered to the DOM.
     * Note this value updates before the `renderCallback` kicks in, thus it is only
     * in sync with the DOM when the next `renderCallback` emitted an event.
     */
    readonly viewRange: Observable<import("./model").ListRange>;
    /**
     * @description
     *
     * The index of the currently scrolled item. The scrolled item is the topmost
     * item actually being visible to the user.
     */
    readonly scrolledIndexChange: Observable<number>;
    /** @internal */
    private readonly destroy$;
    /** @internal */
    constructor(elementRef: ElementRef<HTMLElement>, scrollElement: RxVirtualScrollElement, scrollStrategy?: RxVirtualScrollStrategy<unknown>);
    ngOnInit(): void;
    ngAfterViewInit(): void;
    /** @internal */
    ngAfterContentInit(): void;
    /** @internal */
    ngOnDestroy(): void;
    getScrollElement(): HTMLElement;
    getScrollTop(): number;
    scrollTo(position: number, behavior?: ScrollBehavior): void;
    scrollToIndex(index: number, behavior?: ScrollBehavior): void;
    measureOffset(): number;
    protected updateContentSize(size: number): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<RxVirtualScrollViewportComponent, [null, { optional: true; }, { optional: true; host: true; }]>;
    static ɵcmp: i0.ɵɵComponentDeclaration<RxVirtualScrollViewportComponent, "rx-virtual-scroll-viewport", never, { "initialScrollIndex": "initialScrollIndex"; "scrollStrategy": "scrollStrategy"; "reserveSpaceAtEnd": "reserveSpaceAtEnd"; }, { "viewRange": "viewRange"; "scrolledIndexChange": "scrolledIndexChange"; }, ["viewRepeater"], ["*"]>;
}
export declare class RxVirtualScrollViewportModule {
    static ɵfac: i0.ɵɵFactoryDeclaration<RxVirtualScrollViewportModule, never>;
    static ɵmod: i0.ɵɵNgModuleDeclaration<RxVirtualScrollViewportModule, [typeof RxVirtualScrollViewportComponent], [typeof i1.CommonModule], [typeof RxVirtualScrollViewportComponent]>;
    static ɵinj: i0.ɵɵInjectorDeclaration<RxVirtualScrollViewportModule>;
}