import { type ReactNode } from "react";
export interface SizeBuckets {
    /** For most mobile phones — or any box that narrow. */
    small: boolean;
    /** iPad Mini through a 16" MacBook Pro — or any box that wide. */
    medium: boolean;
    /** Most external monitors — or any box that wide. */
    large: boolean;
}
export declare function deriveSizeBuckets(width: number): SizeBuckets;
/** A width that lands in the same bucket the window is in, for the first frame. */
export declare function screenSeedWidth(screen: SizeBuckets): number;
/** Null means no enclosing boundary — the window is the container. */
export declare const ContainerSizeContext: import("react").Context<SizeBuckets | null>;
/**
 * Publishes a measured width to descendants as buckets.
 *
 * The value is memoized on the buckets, not the width, so a resize that does not
 * cross a threshold produces no new value and re-renders no consumer. That
 * matters because a subtree under one boundary can hold dozens of readers, and a
 * drag on a resizable panel emits a measurement per frame.
 *
 * It renders nothing itself, so it is unit-testable; the measuring wrapper that
 * feeds it a width lives in `size_boundary`.
 */
export declare function ContainerSizeProvider(props: {
    width: number;
    children: ReactNode;
}): import("react").JSX.Element;
/** The nearest boundary's buckets, or null when nothing encloses this component. */
export declare function useEnclosingContainerSize(): SizeBuckets | null;
/**
 * ONE BOX'S OWN WIDTH, measured — put `measure` on the element as its `ref`.
 *
 * `null` until the first observation, which is the frame a browser paints before
 * it has laid anything out and the whole answer where there is no layout engine
 * at all: a server render, a jsdom test. A surface that FORKS on the width
 * renders its unmeasured frame invisible rather than guessing, so the first
 * paint anybody sees is already in the right mode.
 *
 * The `ref` callback returns the disconnect, which React 19 runs as its cleanup —
 * so the observer's life is the element's, with no effect to keep in step.
 */
export declare function useMeasuredWidth(): {
    measure: (node: HTMLElement | null) => (() => void) | undefined;
    width: number | null;
};
/** A measured box. `null` on both axes until the first observation. */
export interface MeasuredSize {
    width: number;
    height: number;
}
/**
 * BOTH axes of one box, for the rare thing that needs the height too — a canvas,
 * a virtualized grid.
 *
 * Separate from `useMeasuredWidth` because the RE-RENDER contract differs, which
 * is the whole reason either exists: a width reader must not wake for a height
 * change (a mobile keyboard, a growing sibling), and a box reader has to.
 */
export declare function useMeasuredSize(): {
    measure: (node: HTMLElement | null) => (() => void) | undefined;
    size: MeasuredSize | null;
};