export type Vector2 = [number, number];
export declare function sub([x1, y1]: Vector2, [x2, y2]: Vector2): Vector2;
export declare function add([x1, y1]: Vector2, [x2, y2]: Vector2): Vector2;
export declare function dist([x0, y0]: Vector2, [x1, y1]: Vector2): number;
/**
 * Calculate angle of vector [x, y].
 */
export declare function angle([x, y]: Vector2): number;
/**
 * Calculate angle of [x, y], then + Math.PI / 2.
 * Because of the difference between `Geometric coordinate system` and `Visualization coordinate system`.
 * @returns
 */
export declare function angleWithQuadrant([x, y]: Vector2): number;
export declare function angleBetween(v0: Vector2, v1: Vector2): number;
export declare function calcBBox(points: Vector2[]): number[];
/**
 * Get the center of two points.
 */
export declare function mid([x1, y1]: Vector2, [x2, y2]: Vector2): Vector2;