import { BaseLabel } from './BaseLabel.js';
import type { LabelProperties } from './BaseLabel.js';
import type { WidgetAutoXML } from '../xml/WidgetAutoXML.js';
import type { Root } from '../core/Root.js';
import type { Viewport } from '../core/Viewport.js';
import type { Widget } from './Widget.js';
import type { ObservableCallback } from '../state/ObservableCallback.js';
import type { Observable } from '../state/Observable.js';
/**
 * A widget which displays a line of text.
 *
 * Similar to {@link Label}, except the observable attached to this label is
 * watched; when its value changes, the displayed text is updated. The
 * observable can also be swapped via the {@link LiveLabel#textSource}
 * accessor.
 *
 * @category Widget
 */
export declare class LiveLabel extends BaseLabel {
    static autoXML: WidgetAutoXML;
    /**
     * The current observable in this label. For internal use only, check
     * {@link LiveLabel#textSource} for the public accessor.
     */
    protected _textSource: Observable<string>;
    /**
     * The watch callback for the observable. For internal use only, used for
     * cleaning up the watcher.
     */
    protected _textWatcher: ObservableCallback<string> | null;
    /**
     * Does the displayed value need to be updated?
     */
    private textDirty;
    /**
     * @param textSource - The observable to get the text for the label.
     */
    constructor(textSource: Observable<string>, properties?: Readonly<LabelProperties>);
    protected handlePreLayoutUpdate(): void;
    /** The current text value. */
    get currentText(): string;
    /** The observable that is displayed in this label */
    set textSource(textSource: Observable<string>);
    get textSource(): Observable<string>;
    attach(root: Root, viewport: Viewport, parent: Widget | null): void;
    detach(): void;
}