import type { RGBColour } from "./types";
/**
 * Calculate the distance between two RGB colours using the CIEDE2000 colour-difference formula.
 *
 * The CIEDE2000 colour-difference formula is a standard method for calculating the perceptual difference
 * between two colours in the CIELAB colour space. It takes into account human visual perception and the
 * non-linearities in how we perceive colour differences.
 *
 * @param colour1 - The first colour to compare.
 * @param colour2 - The second colour to compare.
 * @returns The distance between the two colours. Smaller numbers (minimum 0) mean the colours are more similar,
 * larger numbers (typically not exceeding 100 for visible colours) indicate more dissimilar colours.
 */
export declare const RGBdistance: (colour1: RGBColour, colour2: RGBColour) => number;