/// <reference lib="dom" preserve="true" />
/**
 * Error correction level, ordered by recovery capacity (and overhead):
 * L ~7%, M ~15%, Q ~25%, H ~30%.
 */
export type QrErrorCorrectionLevel = 'L' | 'M' | 'Q' | 'H';
/**
 * Encoding mode for the payload.
 * - `numeric`: digits only (most compact)
 * - `alphanumeric`: 0-9 A-Z and ` $%*+-./:` (uppercase only)
 * - `byte`: any string, encoded as UTF-8
 *
 * When omitted, the smallest applicable mode is auto-detected.
 */
export type QrMode = 'numeric' | 'alphanumeric' | 'byte';
export interface QrCodeOptions {
    /**
     * Error correction level. Default: `M`.
     */
    ecl?: QrErrorCorrectionLevel;
    /**
     * QR version 1..40 (matrix grows by 4 modules per step: v1=21x21, v40=177x177).
     * Default: `0` = auto-select the smallest version that fits the payload.
     */
    typeNumber?: number;
    /**
     * Force an encoding mode. Default: auto-detect (`numeric` < `alphanumeric` < `byte`).
     * Ignored when the content is a `Uint8Array` (always `byte`).
     */
    mode?: QrMode;
}
export interface QrSvgOptions {
    /** Pixels per module (the rendered `width`/`height` = `(size + border*2) * scale`). Default `4`. */
    scale?: number;
    /** Quiet-zone width in modules. The spec recommends `4`. Default `4`. */
    border?: number;
    /** Color of dark modules. Default `#000000`. */
    dark?: string;
    /** Color of light modules / background. Default `#ffffff`. */
    light?: string;
}
export interface QrAsciiOptions {
    /** Quiet-zone width in modules. Default `2`. */
    border?: number;
    /** Swap dark/light glyphs (useful on dark terminal backgrounds). Default `false`. */
    invert?: boolean;
}
export interface QrCanvasOptions {
    /** Pixels per module. Default `4`. */
    scale?: number;
    /** Quiet-zone width in modules. Default `4`. */
    border?: number;
    /** Color of dark modules. Default `#000000`. */
    dark?: string;
    /** Color of light modules. Default `#ffffff`. */
    light?: string;
}
/**
 * Create a QR code from a string or raw bytes.
 *
 * @example
 * createQrCode('https://example.com').toDataUrl()
 * createQrCode('HELLO', { ecl: 'H' }).toSvg({ scale: 8 })
 */
export declare function createQrCode(content: string | Uint8Array, opt?: QrCodeOptions): QrCode;
/**
 * An immutable QR code: a square matrix of dark/light modules, plus renderers.
 */
export declare class QrCode {
    /** Width/height of the matrix in modules (`typeNumber * 4 + 17`). */
    readonly size: number;
    /** `modules[row][col]` - `true` = dark. */
    readonly modules: readonly boolean[][];
    /** Error correction level used. */
    readonly ecl: QrErrorCorrectionLevel;
    constructor(
    /** Width/height of the matrix in modules (`typeNumber * 4 + 17`). */
    size: number, 
    /** `modules[row][col]` - `true` = dark. */
    modules: readonly boolean[][], 
    /** Error correction level used. */
    ecl: QrErrorCorrectionLevel);
    /** Whether the module at `[row, col]` is dark. */
    isDark(row: number, col: number): boolean;
    /**
     * Render as a standalone SVG document string.
     */
    toSvg(opt?: QrSvgOptions): string;
    /**
     * Render as an `data:image/svg+xml` URL, ready for `<img src>` or CSS `background`.
     */
    toDataUrl(opt?: QrSvgOptions): string;
    /**
     * Render as ASCII art using block characters - handy for terminals and logs.
     * Each module is 2 chars wide so the output keeps a square aspect ratio.
     */
    toAscii(opt?: QrAsciiOptions): string;
    /** Same as {@link toAscii} with defaults. */
    toString(): string;
    /**
     * Paint the QR code onto a 2d canvas context (browser).
     */
    renderToCanvas(ctx: CanvasRenderingContext2D, opt?: QrCanvasOptions): void;
}