import { HexString } from "./hexToRGB";
/**
 * Gets the contrast ratio between a background color and a foreground color.
 *
 * @see https://www.w3.org/TR/WCAG20-TECHS/G17.html#G17-tests
 *
 * @param background The background color
 * @param foreground The foreground color. This is normally the `color` css
 * value.
 * @return the contrast ratio between the background and foreground colors.
 */
export default function getContrastRatio(background: HexString, foreground: HexString): number;