export declare const STACK_LAYER_OFFSET_Y = -18;
export declare const STACK_LAYER_SCALE_STEP = 0.05;
export declare const STACK_LAYER_MAX_DEPTH = 3;
export declare const STACK_OPACITY_BY_DEPTH: readonly [1, 0.92, 0.78, 0.62, 0.38, 0.16, 0];
export declare const STACK_STATE_EPSILON = 0.001;
export interface FlipOverlayStackEntry {
    id: string;
    zIndex: number;
    openSequence: number;
    width: number;
    height: number;
    visible: boolean;
    globalMask: boolean;
    maskClass: string;
}
export declare function subscribeOverlayStackChanged(listener: () => void): () => void;
export declare function getOverlayStackVersion(): number;
export declare function getVisibleOverlayStackEntries(): FlipOverlayStackEntry[];
export declare function upsertOverlayStackEntry(entry: FlipOverlayStackEntry): void;
export declare function removeOverlayStackEntry(id: string): void;
export declare function isOverlaySizeMatched(current: FlipOverlayStackEntry, above: FlipOverlayStackEntry): boolean;
export declare function resolveStackOpacity(depth: number): number;
export declare function nextOverlayInstanceId(): string;
export declare function nextOverlayOpenSequence(): number;