/**
 * Just enough PNG to cut a rectangle out of a simulator screenshot.
 *
 * The simulator encodes with stb_image_write — 8-bit, non-interlaced, no
 * palette — so this handles that shape (RGB and RGBA in, RGB out) and refuses
 * anything else loudly rather than returning a scrambled image. A real image
 * library would be a dependency for one 320x240 crop.
 */
/** Decoded pixels, three bytes per pixel, row-major. */
export interface RgbImage {
    width: number;
    height: number;
    data: Buffer;
}
/** Decode an 8-bit non-interlaced RGB/RGBA PNG into packed RGB bytes. */
export declare function decodePng(png: Buffer): RgbImage;
/** Encode packed RGB bytes as an 8-bit RGB PNG (filter type 0 on every row). */
export declare function encodePng(img: RgbImage): Buffer;
/** Cut `w`x`h` at (`x`,`y`) out of a PNG and re-encode it. */
export declare function cropPng(png: Buffer, x: number, y: number, w: number, h: number): Buffer;