interface ScaleParameters {
    clientHeight: number;
    headerHeight: number;
    maxElementHeight: number;
    numRows: number;
    rowHeight: number;
}
export interface Scale {
    toVirtual: (scrollTop: number) => number;
    fromVirtual: (virtualScrollTop: number) => number;
    factor: number;
    canvasHeight: number;
    virtualCanvasHeight: number;
    parameters: ScaleParameters;
}
/**
 * The state to handle virtual scrolling
 *
 * - scrollTop: the current scrollTop of HTML <div> container
 * - scrollTopAnchor: the scrollTop position that anchors the virtual scroll calculations. It differs from scrollTop when local scrolling is applied.
 * - localOffset: the local offset added to the virtual scrollTop to scroll locally (for small scroll deltas)
 * - scale: the scale mapping scrollTop to virtual scrollTop
 */
export interface ScrollState {
    scale: Scale | undefined;
    scrollTop: number | undefined;
    scrollTopAnchor: number | undefined;
    localOffset: number;
}
type ScrollAction = {
    type: 'SET_SCALE';
    scale: Scale;
} | {
    type: 'ON_SCROLL';
    scrollTop: number;
} | {
    type: 'SCROLL_TO';
    scrollTop: number;
} | {
    type: 'LOCAL_SCROLL';
    delta: number;
} | {
    type: 'GLOBAL_SCROLL';
    scrollTop: number;
};
export declare function initializeScrollState(): ScrollState;
export declare function scrollReducer(state: ScrollState, action: ScrollAction): ScrollState;
export declare function computeDerivedValues({ scale, scrollTop, scrollTopAnchor, localOffset, padding }: ScrollState & {
    padding: number;
}): {
    sliceTop?: number | undefined;
    visibleRowsStart?: number | undefined;
    visibleRowsEnd?: number | undefined;
    renderedRowsStart?: number | undefined;
    renderedRowsEnd?: number | undefined;
};
export declare function createScale(parameters: {
    clientHeight: number;
    headerHeight: number;
    maxElementHeight: number;
    numRows: number;
    rowHeight: number;
}): Scale;
interface LocalScrollAction {
    type: 'LOCAL_SCROLL';
    delta: number;
}
interface ScrollToAction {
    type: 'SCROLL_TO';
    scrollTop: number;
}
export declare function getScrollActionForRow({ rowIndex, scale, scrollTopAnchor, localOffset, }: {
    rowIndex: number;
    scale: Scale;
    scrollTopAnchor: number;
    localOffset: number;
}): ScrollToAction | LocalScrollAction | undefined;
export {};