import { fabric } from 'fabric';
/**
 * Extend an exiting method.
 *
 * @param shape
 * @param methodName
 * @param callback
 */
export declare function extendMethod<U extends T, T extends typeof fabric.StaticCanvas | typeof fabric.Object | typeof fabric.Text | typeof fabric.Group | typeof fabric.Image | typeof fabric.Polyline, M extends MethodsName<T['prototype']>>(shape: T, methodName: M, callback: (this: InstanceType<U>, ...args: any) => any): (this: InstanceType<T>) => any;
/**
 * Create an extension.
 * @param callback
 */
export declare function extension(name: string, callback: (instance: typeof fabric) => void): (instance?: typeof fabric) => void;
/**
 * Normalize the key combinations of shortcuts.
 *
 * @param keyCombination
 */
export declare const normalizeShortcutKey: (keyCombination: string) => string;
/**
 * Normalize the key combinations of keyboard events.
 *
 * @param keyCombination
 */
export declare const normalizeEventKey: (event: {
    ctrlKey: boolean;
    metaKey: boolean;
    shiftKey: boolean;
    altKey: boolean;
    key?: string;
}) => string;
declare module 'fabric' {
    namespace fabric {
        interface IUtil {
            installedExtensions: {
                [key: string]: boolean;
            };
        }
    }
}