/**
 * Convert RGBA color to hexadecimal color code
 * @param rgba Object containing r, g, b values (0-255) and optional a (0-1)
 * @returns {string} Hexadecimal color code including alpha channel
 * @example rgbaToHexA({ r: 0, g: 0, b: 0, a: 1 }); // "#000000ff"
 */
export declare const rgbaToHexA: ({ r, g, b, a, }: {
    r: number;
    g: number;
    b: number;
    a?: number;
}) => string;