import { CdkVirtualScrollViewport, VirtualScrollStrategy } from '@angular/cdk/scrolling';
import { Observable } from 'rxjs';
export declare class VirtualScrollWindowStrategy implements VirtualScrollStrategy {
    scrolledIndexChange: Observable<number>;
    private destroy$;
    private _viewport;
    private _itemSizePx;
    private _offsetSizePx;
    private _minBufferPx;
    private _maxBufferPx;
    private readonly _scrolledIndexChange;
    private readonly destroy;
    constructor(itemSizePx: number, offsetSizePx: number, minBufferPx: number, maxBufferPx: number);
    /**
     * Attaches this scroll strategy to a viewport.
     * @param viewport The viewport to attach this strategy to.
     */
    attach(viewport: CdkVirtualScrollViewport): void;
    /** Detaches this scroll strategy from the currently attached viewport. */
    detach(): void;
    /**
     * Update the item size and buffer size.
     * @param itemSize The size of the items in the virtually scrolling list.
     * @param offsetSizePx The size of the offset (in pixels)..
     * @param minBufferPx The minimum amount of buffer (in pixels) before needing to render more
     * @param maxBufferPx The amount of buffer (in pixels) to render when rendering more.
     */
    updateItemAndBufferSize(itemSize: number, offsetSizePx: number, minBufferPx: number, maxBufferPx: number): void;
    /** @docs-private Implemented as part of VirtualScrollStrategy. */
    onContentScrolled(): void;
    /** @docs-private Implemented as part of VirtualScrollStrategy. */
    onDataLengthChanged(): void;
    /** @docs-private Implemented as part of VirtualScrollStrategy. */
    onContentRendered(): void;
    /** @docs-private Implemented as part of VirtualScrollStrategy. */
    onRenderedOffsetChanged(): void;
    /**
     * Scroll to the offset for the given index.
     * @param index The index of the element to scroll to.
     * @param behavior The ScrollBehavior to use when scrolling.
     */
    scrollToIndex(index: number, behavior: ScrollBehavior): void;
    /** Update the viewport's total content size. */
    private _updateTotalContentSize;
    /** Update the viewport's rendered range. */
    private _updateRenderedRange;
}
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