/// <reference types="node" />
/// <reference types="node" />
import { Readable } from "stream";
/**
 * The input types that can be converted to a ReadableStream.
 * @alias ReadStreamInput
 */
export type ReadStreamInput = Buffer | string;
/**
 * Utility class for working with images.
 * @class
 * @category Utils
 * @hideconstructor
 */
export declare const ReadStreamUtils: {
    /**
     * Creates a ReadableStream from a Buffer.
     * @param buffer - The Buffer to be streamed.
     * @returns A ReadableStream.
     */
    bufferToStream(buffer: Buffer): Readable;
    /**
     * Creates a ReadableStream from a file path.
     * @param filePath - The path to the image file.
     * @returns A ReadableStream of the file contents.
     */
    fileToStream(filePath: string): Readable;
    /**
     * Downloads an image from a URL and returns it as a ReadableStream.
     * @param url - The URL of the image.
     * @returns A ReadableStream containing the image data.
     */
    urlToStream(url: string): Promise<Readable>;
    /**
     * Converts a Base64 string to a ReadableStream.
     * @param base64 - The Base64 string to be converted.
     * @returns A ReadableStream of the image data.
     * @throws {Error} If the Base64 string is invalid.
     */
    base64ToStream(base64: string): Readable;
    /**
     * Returns a ReadableStream from an object.
     * The object can be a Buffer, a file path, or a URL.
     * @param input
     * @returns A ReadableStream of the image data.
     * @throws {Error} If the input type is invalid.
     */
    getReadStream(input: ReadStreamInput): Promise<Readable>;
};