import { Viewer } from '../viewers/Viewer';
export type WorkerViewerCommand = (payload: unknown) => unknown | Promise<unknown>;
export type WorkerViewerDispose = () => void | Promise<void>;
export interface WorkerViewerRuntime {
    readonly viewer: Viewer;
    readonly canvas: OffscreenCanvas;
    status(message: string): void;
    emit(type: string, detail?: unknown): void;
    registerCommand(name: string, command: WorkerViewerCommand): () => void;
    onDispose(dispose: WorkerViewerDispose): () => void;
    ready(detail?: unknown): void;
}
/**
 * Creates a u-space Viewer after the main thread transfers an OffscreenCanvas.
 * Call this at module top level; the message listener is installed synchronously
 * before the returned promise waits for the host initialization message.
 */
export declare function createWorkerViewer(): Promise<WorkerViewerRuntime>;