import { RenderManager } from '../render/RenderManager';
/**
 * Base class for any extension for render manager.
 */
export declare abstract class ExtensionBase extends EventTarget {
    get [Symbol.toStringTag](): string;
    /**Owner viewer name. */
    readonly viewerName: string;
    /**Any extension data which can be stored in browser local storage and restored after (any extension settings, buttons state and so one).
     *State will be saved in local storage with 'tangl-ext-extensionName' key.
     */
    state: any;
    /**Extension type (ext, mode, control).*/
    readonly type: string;
    /**Is extension need to hide toolbar or not.*/
    hideToolbar: boolean;
    /**Get unique extension name. */
    static getName: () => string;
    /**Get unique extension name. */
    getName: () => string;
    /** Optional icon for placing on HelpToolbar. */
    readonly helpIcon: string | undefined;
    /** Optional description for placing on HelpToolbar. */
    readonly helpDesc: string | undefined;
    private restoreStateHandler;
    private saveStateHandler;
    /**
     * Render function for rendering dedicated toolbar content.
     * @param container - Parent DOM container.
     * @group Hooks
     */
    dedicatedToolbarRender(container: HTMLElement): void;
    /**
     * Render function for rendering shared toolbar content.
     * @param container - Parent DOM container.
     * @group Hooks
     */
    sharedToolbarRender(container: HTMLElement): void;
    /**
     * Render function for rendering additional UI above viewer canvas.
     * @param container - Parent DOM container.
     * @group Hooks
     */
    uiRender(container: HTMLElement): void;
    ui: string;
    static getHelpDialogName(): string;
    isShowHelpButton(): boolean;
    /**
     * @param viewerName - Owner viewer name.
     * @param helpDesc - Optional description for help button.
     * @param helpIcon - Optional icon for help button.
     * @protected
     */
    protected constructor(viewerName: string, helpDesc?: string, helpIcon?: string);
    /**
     * Get current {@link RenderManager} instance.
     */
    getRenderManager(): RenderManager;
    /**
     * Sets external hook handler for restoring extension state in the local storage.
     * @param handler - handler hook function.
     */
    setRestoreStateHandler(handler: (stateName: string, state: any) => Promise<any>): this;
    /**
     * Sets external hook handler for storing extension state in the local storage.
     * @param handler - handler hook function.
     */
    setSaveStateHandler(handler: (stateName: string, state: any) => void): this;
    /**
     * Save extension state in the local storage.
     */
    saveState(): Promise<void>;
    /**
     * Restore extension state from the local storage.
     */
    restoreState(): Promise<void>;
    /**
     * Hook when current extension command is changed or finished.
     * Called by ExtensionManager.setCurrentCommandExtension().
     * @group Hooks
     */
    commandChanged(newCommand: ExtensionBase | undefined): void;
    /**
     * Hook when extension is added to ExtensionManager.
     * Called by ExtensionManager.addExtension().
     * @group Hooks
     */
    abstract added(): void;
    /**
     * Hook when extension is deleted from ExtensionManager.
     * Called by ExtensionManager.clear().
     * @group Hooks
     */
    abstract deleted(): void;
}