export type CwebpOptions = {
    input: string;
    output: string;
    /** quality: 0..100, default 75 */
    quality?: number;
    /** size: max bytes */
    size?: number;
    preset?: 'default' | 'photo' | 'picture' | 'drawing' | 'icon' | 'text';
    hint?: 'photo' | 'picture' | 'graph';
    low_memory?: boolean;
    lossless?: boolean;
    /** near_lossless: 0..100, typically 60 */
    near_lossless?: number;
    /** method: 0..6, default 4 */
    method?: number;
    auto_filter?: boolean;
    /** deblocking_filter: 0..100, typically 20..50 */
    deblocking_filter?: number;
    /** spatial_noise_shaping: 0..100, default 50 */
    spatial_noise_shaping?: number;
    /** metadata: default 'none' */
    metadata?: 'all' | 'none' | 'exif' | 'icc' | 'xmp';
    /** crop is applied before resize */
    crop?: {
        top: number;
        left: number;
        width: number;
        height: number;
    };
    resize?: {
        width: number;
        height: number;
    };
};
export declare function cwebp(options: CwebpOptions, cb: (code: number | null) => void): void;
export declare function cwebp(options: CwebpOptions): Promise<number | null>;