export declare const isKittyImageLine: (line: string) => boolean;
export interface KittyViewportFrame {
    lines: string[];
    /** Reserved rows must stay empty so Pi pre-clears them before placing pixels. */
    imageRows: ReadonlySet<number>;
}
/** Index immutable retained frames once. Scrolling then touches only the viewport
 * and its intersecting images, never a long run of offscreen blank reservations.
 * The two-entry, byte-bounded crop cache avoids rebuilding megabyte transmissions
 * on unchanged frames. No image data is decoded, uploaded or deleted here. */
export declare class KittyViewport {
    private source;
    private images;
    private readonly crops;
    private cropBytes;
    clear(): void;
    slice(source: readonly string[], start: number, end: number): KittyViewportFrame;
    private crop;
}
/** Hide only background placements that can reach the visible terminal. Leave
 * offscreen scrollback intact; removing it would force unnecessary reuploads on
 * close. Return text-only frames unchanged instead of copying retained history. */
export declare function hideKittyImages(lines: string[], viewportHeight?: number): string[];
//# sourceMappingURL=kitty-viewport.d.ts.map