/**
 * Convert RGBA color to CMYK color model
 * @param rgba Object containing r, g, b values (0-255) and optional a (0-1)
 * @returns {Object} CMYK values (c, m, y, k as percentages 0-100) and alpha channel
 * @example rgbaToCmyk({ r: 0, g: 0, b: 0, a: 1 }); // { c: 0, m: 0, y: 0, k: 100, a: 1 }
 */
export declare const rgbaToCmyk: ({ r, g, b, a, }: {
    r: number;
    g: number;
    b: number;
    a?: number;
}) => {
    c: number;
    m: number;
    y: number;
    k: number;
    a: number;
};