/// <reference types="node" />
import stream from 'stream';
/**
 * Base image encoder class. An ImageEncoder receives a 8-bit grayscale
 * image from Buffer and writes common image file data (e.g., PNG)
 * into a given stream.
 */
export default abstract class ImageEncoder {
    protected config: any;
    constructor(config?: any);
    mimeType(): string;
    abstract write(image: Buffer, width: number, height: number): Promise<stream.Readable>;
}