import type { PageContent } from '../renderer/types';
import type { Source } from './types';
export type ImageFit = 'contain' | 'cover';
export interface ImageSourceOptions {
    /** How many adjacent pages to prefetch around a requested page. Default 1. */
    preload?: number;
    /** How each image fits its page; a hint consumed by the render layer. Default 'contain'. */
    fit?: ImageFit;
}
/**
 * Default content source for image books: decodes a list of image URLs to
 * ImageBitmaps, memoizes them, and prefetches neighbors on access.
 */
export declare class ImageSource implements Source {
    #private;
    readonly pageCount: number;
    readonly fit: ImageFit;
    constructor(urls: string[], options?: ImageSourceOptions);
    get(index: number): Promise<PageContent>;
    prefetch(indices: number[]): void;
    destroy(): void;
}