import type { number_percent } from '../../../types/number_percent';
import type { number_integer, number_positive } from '../../../types/number_positive';
/**
 * Converts RGB values to HSL values
 *
 * @param red [0-255]
 * @param green [0-255]
 * @param blue [0-255]
 * @returns [hue, saturation, lightness] [0-1]
 *
 * @private util of `@promptbook/color`
 */
export declare function rgbToHsl(red: number_positive & number_integer, green: number_positive & number_integer, blue: number_positive & number_integer): readonly [number_percent, number_percent, number_percent];