import type { Source } from './types';
export interface CompositionOptions {
    /** Image URL prepended as a lone front cover (adds a page). */
    frontCover?: string | null;
    /** Image URL appended as a lone back cover (adds a page). */
    backCover?: string | null;
    /** Replace source pages with image URLs, keyed by 0-based source index (negative = from the end). */
    pages?: Record<number, string> | null;
}
/**
 * Wrap `base` so image covers/replacements sit alongside it, or return `base`
 * unchanged when nothing is requested. Covers ADD pages (front prepended, back
 * appended); `pages` REPLACE existing source pages. `pages` indexes the base's own
 * pages, so it is unaffected by an added cover.
 */
export declare function composeSource(base: Source, options: CompositionOptions): Source;