import type { CanvasDocument } from './canvasDocument.js';
export declare function serializeCanvasDoc(doc: CanvasDocument): string;
export declare function parseCanvasDoc(raw: string): CanvasDocument;
export type CanvasHistoryState = {
    past: string[];
    future: string[];
    last: string;
};
export declare function createCanvasHistory(doc: CanvasDocument): CanvasHistoryState;
/** Push current `last` to past when document changes (skips no-ops). */
export declare function pushCanvasHistory(state: CanvasHistoryState, nextDoc: CanvasDocument): CanvasHistoryState;
export declare function undoCanvasHistory(state: CanvasHistoryState): {
    state: CanvasHistoryState;
    doc: CanvasDocument;
} | null;
export declare function redoCanvasHistory(state: CanvasHistoryState): {
    state: CanvasHistoryState;
    doc: CanvasDocument;
} | null;