export interface SankeyInputNode {
    id: string;
}
export interface SankeyInputLink {
    source: string;
    target: string;
    value: number;
}
export interface SankeyLaidOutNode<TNodeMeta = unknown> {
    id: string;
    meta?: TNodeMeta;
    /** Layer index (0 = leftmost). */
    layer: number;
    /** Left pixel coordinate (X0). */
    x0: number;
    /** Right pixel coordinate (X1 = X0 + nodeWidth). */
    x1: number;
    /** Top pixel coordinate. */
    y0: number;
    /** Bottom pixel coordinate. */
    y1: number;
    /** Effective node value (max(Σ incoming, Σ outgoing)). */
    value: number;
    sourceLinks: SankeyLaidOutLink[];
    targetLinks: SankeyLaidOutLink[];
}
export interface SankeyLaidOutLink<TLinkMeta = unknown> {
    source: SankeyLaidOutNode;
    target: SankeyLaidOutNode;
    value: number;
    meta?: TLinkMeta;
    /** Y coordinate at the source node (midpoint of the link height). */
    y0: number;
    /** Y coordinate at the target node. */
    y1: number;
    /** Pixel width of the link (proportional to value). */
    width: number;
    /** Index (for stable ordering / iteration). */
    index: number;
}
export interface SankeyLayoutOptions {
    /** Total width of the layout area in pixels. */
    width: number;
    /** Total height of the layout area in pixels. */
    height: number;
    /** Width of a node. @default 24 */
    nodeWidth?: number;
    /** Vertical spacing between nodes within a layer. @default 8 */
    nodePadding?: number;
    /** Number of relaxation iterations. @default 6 */
    iterations?: number;
    /** Layer alignment. @default 'justify' */
    nodeAlign?: 'left' | 'right' | 'center' | 'justify';
}
export interface SankeyLayoutResult {
    nodes: SankeyLaidOutNode[];
    links: SankeyLaidOutLink[];
}
export declare function computeSankeyLayout(inputNodes: ReadonlyArray<SankeyInputNode & {
    meta?: unknown;
}>, inputLinks: ReadonlyArray<SankeyInputLink & {
    meta?: unknown;
}>, options: SankeyLayoutOptions): SankeyLayoutResult;
/**
 * Generate a cubic Bézier path between the source and target endpoints of a
 * Sankey link. The control points sit at half the X distance, producing the
 * characteristic S-curve.
 */
export declare function sankeyLinkPath(link: SankeyLaidOutLink): string;