/** Linear interpolation scale: maps a value in [d0,d1] to [r0,r1]. */
export declare function scaleLinear(domain: readonly [number, number], range: readonly [number, number]): (value: number) => number;
/** Produce ~count human-friendly ticks spanning [min,max] (rounded step). */
export declare function niceTicks(min: number, max: number, count?: number): number[];
export type Curve = "linear" | "smooth";
export type Point = readonly [number, number];
export declare function buildLinePath(points: readonly Point[], curve?: Curve): string;
export declare function buildAreaPath(points: readonly Point[], baselineY: number, curve?: Curve): string;
/** SVG path for a pie slice (innerR omitted) or donut slice (innerR set). */
export declare function arcPath(cx: number, cy: number, r: number, startAngle: number, endAngle: number, innerR?: number): string;