export declare const SCROLL_OVERLAY_BLOCK_SIZE = "--ds-scroll-overlay-block-size";
export declare const SCROLL_OVERLAY_CONTENT_BLOCK_SIZE = "--ds-scroll-overlay-content-block-size";
export declare const SCROLL_OVERLAY_FADE_BLOCK_SIZE = "--ds-scroll-overlay-fade-block-size";
interface ScrollOverlayControllerOptions {
    host: HTMLElement;
    viewport: HTMLElement;
    content: HTMLElement;
    overlay: HTMLElement;
    overlayContentSelector?: string;
    onGeometryChange?: () => void;
}
/**
 * Keeps a content-owned alpha mask pinned behind a fixed overlay.
 *
 * The mask lives on the long content element so native scrollbars stay outside
 * the fade and the actual parent surface shows through. Its stop positions are
 * therefore expressed in content coordinates and must follow scrollTop.
 */
export declare class ScrollOverlayController {
    private readonly options;
    private resizeObserver?;
    private overlayBlockSize;
    private overlayContentBlockSize;
    private fadeBlockSize;
    constructor(options: ScrollOverlayControllerOptions);
    connect(): void;
    disconnect(): void;
    sync(): void;
    getOverlayBlockSize(): number;
    getOverlayContentBlockSize(): number;
    private syncOverlayGeometry;
    private syncFadeWindow;
}
export {};
//# sourceMappingURL=scroll-overlay-controller.d.ts.map