export interface StreamLayer {
    path: string;
    index: number;
}
/** Centered streamgraph stack — layers sum to a smooth filled band per series. */
export declare function layoutStreamgraph(series: number[][], width: number, height: number, pad?: {
    left: number;
    right: number;
    top: number;
    bottom: number;
}): StreamLayer[];
/** Multi-line tooltip label for streamgraph at index i. */
export declare function streamTooltipLabel(series: number[][], index: number, names?: string[]): string;