/**
 * Copyright Aquera Inc 2023
 *
 * This source code is licensed under the BSD-3-Clause license found in the
 * LICENSE file in the root directory of this source tree.
 */
import { CSSResultArray, TemplateResult, PropertyValues } from 'lit';
import { ErrorCorrectionLevel } from './nile-qr-code-utils.js';
import NileElement from '../internal/nile-element.js';
/**
 * Nile QR Code component.
 *
 
 * @tag nile-qr-code
 *
 * @csspart base - The canvas element used to draw the QR code.
 *
 * @fires nile-qr-image-error - Emitted when the center image fails to load.
 *
 * @example
 
 *
 
 */
export declare class NileQrCode extends NileElement {
    /**
     * The styles for QR Code.
     * @remarks If you are extending this class you can extend the base styles with super. Eg `return [super(), myCustomStyles]`
     */
    static get styles(): CSSResultArray;
    /**
     * The QR code's value — the text or URL to encode.
     */
    value: string;
    /**
     * The size of the QR code, in pixels.
     */
    size: number;
    /**
     * The fill color. This can be any valid CSS color, but not a CSS custom property.
     */
    fill: string;
    /**
     * The background color. This can be any valid CSS color or `'transparent'`.
     * It cannot be a CSS custom property.
     */
    background: string;
    /**
     * The edge radius of each module. Must be between 0 and 0.5.
     * Use this to create a rounded effect.
     */
    radius: number;
    /**
     * The level of error correction to use.
     * - `'L'` — Low (~7%)
     * - `'M'` — Medium (~15%)
     * - `'Q'` — Quartile (~25%)
     * - `'H'` — High (~30%)
     *
     * When using an image overlay, `'H'` is recommended so the QR remains scannable.
     */
    errorCorrection: ErrorCorrectionLevel;
    /**
     * The label for assistive devices to announce.
     * If unspecified, the `value` will be used instead.
     */
    label: string;
    /**
     * URL of an image to overlay in the center of the QR code (e.g. a logo).
     * The image is drawn on top of the QR modules, so use `error-correction="H"`
     * to ensure the code remains scannable.
     */
    image: string;
    /**
     * Size of the center image as a fraction of the overall QR code size
     * (0.1 – 0.4). Defaults to 0.25 (25% of the QR code).
     */
    imageSize: number;
    /**
     * Padding around the center image in pixels. Creates a clear area
     * between the image and the surrounding QR modules.
     */
    imagePadding: number;
    /**
     * Optional border radius for the center image in pixels.
     * Set to a high value for a circular mask.
     */
    imageRadius: number;
    /**
     * Apply a linear gradient to the QR modules instead of a flat color.
     * Format: `"direction, color1, color2[, ...]"` where direction is an
     * angle in degrees (e.g. `"135, #6366f1, #ec4899"`).
     * When set, this overrides the `fill` property for module rendering.
     */
    fillGradient: string;
    private _loadedImage;
    private _imageLoadPromise;
    private canvas;
    protected updated(changedProperties: PropertyValues): void;
    render(): TemplateResult;
    /**
     * Downloads the QR code as a PNG image.
     * @param filename - The name of the downloaded file (defaults to `'qr-code.png'`).
     */
    download(filename?: string): void;
    /**
     * Returns the QR code canvas content as a data URL.
     * @param type - MIME type (defaults to `'image/png'`).
     */
    toDataURL(type?: string): string;
    private loadImage;
    private drawQrCode;
    /**
     * Returns the fill style for QR modules — either a gradient or the flat fill color.
     */
    private resolveModuleFill;
    private drawCenterImage;
    private drawRoundedModule;
    private drawRoundedRect;
    private clipRoundedRect;
}
export default NileQrCode;
declare global {
    interface HTMLElementTagNameMap {
        'nile-qr-code': NileQrCode;
    }
}