export interface ThumbHashEncodeInput {
    readonly width: number;
    readonly height: number;
    /** RGBA pixels, 4 bytes per pixel, row-major. */
    readonly rgba: Uint8Array;
}
/** Maximum side length thumbhash will accept (per its README). */
export declare const THUMBHASH_MAX_SIDE = 100;
/** Encode RGBA pixel data to a compact ThumbHash. Throws if dims
 *  invalid or exceed THUMBHASH_MAX_SIDE. */
export declare function encodeThumbHash(input: ThumbHashEncodeInput): Uint8Array;
/** Decode a ThumbHash back to RGBA pixels. */
export declare function decodeThumbHash(hash: Uint8Array): {
    readonly width: number;
    readonly height: number;
    readonly rgba: Uint8Array;
};
/** Decode ThumbHash directly to a PNG data URL — convenient for
 *  <img src="…"> placeholders in the browser. */
export declare function thumbHashToImageUrl(hash: Uint8Array): string;
/** Coerce a wire-form thumbHash to Uint8Array. Schema accepts both
 *  Uint8Array (CBOR-native, Phase 2.B) and base64-string (JSON
 *  fallback). Returns null if input is empty or undecodable. */
export declare function coerceThumbHash(input: Uint8Array | string | undefined): Uint8Array | null;
/** One-shot helper: take a wire-form thumbHash (Uint8Array | base64
 *  string | undefined) and return a renderable PNG data URL, or null
 *  if it cannot be decoded. */
export declare function thumbHashWireToImageUrl(input: Uint8Array | string | undefined): string | null;
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