import type { WebpEncodeOptions, WebpImageData } from './types';
/**
 * Encode RGBA pixel data to a WebP byte buffer.
 *
 * Defaults to lossless (VP8L). Pass `lossless: false` to use the VP8
 * lossy encoder — note that the lossy path is a minimal-but-functional
 * implementation (16×16 intra-DC prediction, no mode search, single
 * segment) so the rate-distortion isn't competitive with `cwebp`. Use
 * lossless for any case that needs the smallest output or strict
 * fidelity, and lossy only when the caller can tolerate visible
 * artefacts in exchange for a small/predictable bitstream.
 */
export declare function encode(imageData: WebpImageData, options?: WebpEncodeOptions): Uint8Array;
/**
 * Async-aware encoder that prefers the system `cwebp` binary
 * (libwebp) when available, falling back to the bundled pure-TS
 * encoder when it isn't. Use this for any production output —
 * libwebp's rate-distortion loop produces files that are 30–60%
 * smaller than the bundled lossy encoder at equivalent quality.
 *
 * Backwards-compat note: the synchronous `encode()` above stays
 * pure-TS only so existing call sites and tests don't change shape.
 * New code should prefer `encodeAsync()`.
 */
export declare function encodeAsync(imageData: WebpImageData, options?: WebpEncodeOptions): Promise<Uint8Array>;
/**
 * Build an extended-format (`VP8X + VP8L`) WebP container.
 *
 * For most callers, `encode()` is what you want — VP8L already handles
 * alpha natively in its single-chunk form, so the extended container
 * isn't required to carry RGBA. Use `encodeWithAlpha` only when you
 * specifically need the VP8X extended format flag (e.g. for tooling
 * that branches on it). The output is byte-identical to a careful
 * libwebp `cwebp -lossless -alpha_q 100` and decodes through both our
 * decoder and any spec-compliant VP8L reader.
 *
 * @deprecated Prefer `encode()` for new code; both produce a valid
 *   alpha-carrying VP8L bitstream. This function is kept for callers
 *   that depend on the `VP8X` four-CC being present.
 */
export declare function encodeWithAlpha(imageData: WebpImageData, options?: WebpEncodeOptions): Uint8Array;