import { HexString } from "./hexToRGB";
/**
 * The type of contrast ratio compliance to confirm to. The ratios in order are:
 * - 3:1 for large text (18pt normal or 14pt bold)
 * - 4.5:1 for normal text
 * - 7:1 for Level AAA requirements.
 *
 * @see https://www.w3.org/TR/WCAG20/#visual-audio-contrast
 * @see https://www.w3.org/TR/WCAG20/#larger-scaledef
 */
export declare type ContrastRatioCompliance = "large" | "normal" | "AAA";
/**
 * The contrast ratio that can be used for large text where large text is
 * considered 18pt or 14pt bold.
 */
export declare const LARGE_TEXT_CONTRAST_RATIO = 3;
/**
 * The contrast ratio that can be used for normal text.
 */
export declare const NORMAL_TEXT_CONTRAST_RATIO = 4.5;
/**
 * The AAA contrast ratio for passing WGAC 2.0 color contrast ratios.
 */
export declare const AAA_CONTRAST_RATIO = 7;
/**
 * Checks if there is an acceptable contrast ratio between the background and
 * foreground colors based on the provided compliance level.
 *
 * @param background The background color to check against
 * @param foreground The foreground color to check against
 * @param compliance The compliance level to use or a custom number as a ratio.
 * @return true if there is enough contrast between the foreground and
 * background colors for the provided compliance level.
 */
export default function isContrastCompliant(background: HexString, foreground: HexString, compliance?: ContrastRatioCompliance | number): boolean;