/**
 * Export a semiotic chart to PNG (default) or SVG from the browser.
 *
 * PNG export composites the canvas data layer underneath the SVG overlay,
 * producing a complete image. SVG export captures only the SVG overlay
 * (axes, labels, annotations) since canvas content cannot be represented
 * as SVG.
 *
 * @example
 * ```tsx
 * const ref = useRef<HTMLDivElement>(null)
 * // ... render chart inside ref ...
 * <button onClick={() => exportChart(ref.current!)}>Download</button>
 * ```
 */
export declare function exportChart(container: HTMLElement, options?: {
    format?: "svg" | "png";
    filename?: string;
    scale?: number;
    background?: string;
}): Promise<void>;
