/**
 * Helper functions for getting images printed.
 *
 * @experimental
 * @module
 */
import type { ImageData, ImageDataArray } from './dom.js';
/** A minimal form of the DOM's {@link ImageData}. */
export type EposImageData = ImageData | {
    readonly width: number;
    readonly height: number;
    readonly data: ImageDataArray | Uint8Array;
} | {
    width: number;
    height: number;
    data: ImageDataArray | Uint8Array;
};
/** How the image encoder should handle halftone stuff. */
export declare enum EposImageHalftone {
    Dither = 0,
    ErrorDiffusion = 1,
    Threshold = 2
}
/** Converts the image to a monochrome printer imagedata. */
export declare const toMonoImage: (img: EposImageData, halftone: EposImageHalftone, brightness: number) => Uint8Array;
/** Converts the image to a grayscale printer imagedata. Only for supported models */
export declare const toGrayImage: (img: EposImageData, brightness: number) => Uint8Array;
/**
 * A pure JS Uint8Array Base64 encoder. You should probably use {@link utoa} instead.
 *
 * Based on {@link https://stackoverflow.com/a/62362724 Stackoverflow: How to convert uint8 Array to base64 Encoded String?}
 *
 * Dependencies:
 * - {@link number}
 * - {@link Number.prototype.length}
 * - {@link Number.prototype.toString}
 * - {@link string}
 * - {@link String.prototype.startsWith}
 * - {@link String.prototype.match}
 * - {@link String.prototype.map}
 * - {@link RegExp}
 * - {@link undefined}
 * - {@link Error} (optional)
 * - {@link JSON.stringify} (optional, for error message)
 *
 * @param alphabet The base64 alphabet to use
 * @param padding The character to use for padding
 */
export declare const rawUtoa: (u8: Uint8Array, alphabet?: string, padding?: string) => string;
/**
 * Uint8Array to Ascii. Similar to {@link btoa}, but safer.
 *
 * Internally, this first attempts to call {@link Uint8Array.prototype.toBase64},
 * if it is available in the runtime ({@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/toBase64#browser_compatibility caniuse}).
 *
 * Due to our minimum deno version being 2.3.1 (Alpine 3.23.3 Stable),
 * which doesn't implement it (was added in 2.5), we need to fallback if needed.
 * If it isn't installed, we fallback to, if {@link btoa} and {@link TextDecoder}
 * are both available, trying to use {@link btoa} on the result of
 * {@link TextDecoder.prototype.decode}.
 *
 * Should {@link TextDecoder} be unavailable or error (likely for some binary
 * data), we attempt to call {@link btoa} with our own text decoder based on
 * {@link String.fromCharCode}. This too can fail on some binary outputs.
 *
 * Should this too fail, or should {@link btoa} not be available, we use
 * {@link https://stackoverflow.com/a/62362724 this implementation from stackoverflow},
 * exposed as {@link rawUtoa}.
 */
export declare const utoa: (u8: Uint8Array) => string;
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