/** A PNG colour type: `gray` = 1ch, `rgb` = 3ch, `gray-alpha` = 2ch, `rgba` = 4ch. */
export type PngColor = 'gray' | 'rgb' | 'gray-alpha' | 'rgba';
/**
 * Wrap raw 8-bit samples into a minimal PNG file (RFC 2083): a single `IDAT`
 * with filter-none scanlines, no interlacing, colour types 0/2/4/6. Produces a
 * format every writer already embeds — `detectImageFormat` recognises this
 * output (the HTML data-URI and docx media paths both rely on it).
 *
 * @param samples Row-major, 8-bit, `CHANNELS[color]` interleaved values per pixel.
 */
export declare function encodePng(width: number, height: number, color: PngColor, samples: Uint8Array): Uint8Array;