import type { PageData } from '../format/document.js';
export interface ColorContrastOptions {
    /** Source colors are unchanged by default; adaptive mode improves screen contrast. */
    contrastMode?: 'preserve' | 'adaptive';
    minColorContrast?: number;
    background?: string;
}
/** Adjusts only colors too close to the background, retaining alpha and hue. */
export declare function adaptiveContrastColor(source: string, options: ColorContrastOptions): string;
export declare function contrastPolicyKey(options: ColorContrastOptions): string;
export declare function createContrastPage(page: PageData, options: ColorContrastOptions): PageData;
export declare function applyXpsContrastXml(xml: string, options: ColorContrastOptions): string;