import { FusionSurfaceBud, FusionSurfaceTransition } from './types';
export interface FusionSurfaceDriverHooks {
    path: () => SVGPathElement | null;
    layer: (id: string) => HTMLElement | null;
    onBreak: (id: string) => void;
    onSettle: () => void;
    /** A bud removed from `buds` has finished closing and is gone. */
    onLeave: (id: string) => void;
}
export interface FusionSurfaceDriverOptions {
    radius: number;
    fillet: number;
    breakAt: number;
    transition: FusionSurfaceTransition;
    contentBlur: number;
    reducedMotion: boolean;
}
export declare function fusionSurfaceOpenTarget(open: FusionSurfaceBud['open']): number;
/** The layer's CSS box: `width` runs along the edge, `height` out of it. */
export declare function fusionSurfaceLayerSize(decl: FusionSurfaceBud): [number, number];
export declare class FusionSurfaceDriver {
    private readonly buds;
    private readonly hooks;
    private options;
    private size;
    private raf;
    private lastNow;
    private lastD;
    private destroyed;
    constructor(hooks: FusionSurfaceDriverHooks, options: FusionSurfaceDriverOptions);
    configure(options: Partial<FusionSurfaceDriverOptions>): void;
    setSize(width: number, height: number): void;
    /** Declarations in, targets out. A new bud starts closed and opens; a bud
     *  that disappears from the list closes before it is dropped. */
    setBuds(decls: readonly FusionSurfaceBud[]): void;
    /** Buds that were removed from the list and are still closing. */
    leavingBuds(): FusionSurfaceBud[];
    destroy(): void;
    private create;
    private edgeLength;
    private retarget;
    private wake;
    /** Whether a frame would change anything. Waking only then is what keeps
     *  `settle` meaning "a motion finished" rather than "something re-rendered". */
    private needsFrame;
    /** The neck has narrowed past the break point this frame. */
    private breaks;
    private breakCache;
    /** The detach at which the default pinch reaches the break point (about
     *  96% of `breakAt`), by bisection; cached per `breakAt`. */
    private breakDistance;
    /** A closed bud whose remnant has sunk is a fresh bud again: opening it
     *  grows a new one instead of re-inflating the old drop. */
    private reopens;
    /** A removed bud that has finished closing. */
    private gone;
    private readonly tick;
    /** One frame of every spring, then the break, reopen and removal rules. */
    private step;
    private shapeOf;
    draw(): void;
    private writeLayer;
}