import { LitElement } from 'lit';
export type SkyIconSizeValue = string | number;
export type SkyIconRotateValue = string | number;
export type SkyIconFlip = '' | 'horizontal' | 'vertical' | 'horizontal,vertical';
interface IconifyCollection {
    left?: number;
    top?: number;
    width?: number;
    height?: number;
}
interface IconifySetData extends IconifyCollection {
    icons?: Record<string, IconifyIcon>;
}
interface IconifyIcon {
    body?: string;
    left?: number;
    top?: number;
    width?: number;
    height?: number;
    viewBox?: string;
}
/**
 * @element sky-icon
 *
 * @summary Icon renderer with Iconify fetch/caching, lazy loading, and optional slotted SVG fallback.
 *
 * @status stable
 * @since 1.0.0
 *
 * @documentation https://sky-ui.com/components/icon
 *
 * @slot - Optional fallback `<svg>` content when remote icon data is unavailable.
 * @property {string} icon - Icon name in `prefix:icon-name` format.
 * @property {SkyIconSizeValue} width - Icon width value.
 * @property {SkyIconSizeValue} height - Icon height value.
 * @property {string} color - Icon color value.
 * @property {boolean} inline - Applies inline alignment behavior for text contexts.
 * @property {SkyIconFlip} flip - Flip transform descriptor.
 * @property {boolean} hFlip - Horizontal flip shortcut.
 * @property {boolean} vFlip - Vertical flip shortcut.
 * @property {SkyIconRotateValue} rotate - Rotation descriptor.
 * @property {boolean} lazy - Defers loading until the icon is visible.
 *
 * @method registerLocalSet Registers a local Iconify set for offline/custom usage.
 * @method registerLocalIcon Registers a single local icon override.
 *
 * @csspart icon - The icon container element.
 * @csspart svg - The rendered SVG element.
 *
 * @Behavior
 * - Resolves icons from local registrations first, then Iconify API.
 * - Uses bounded in-memory caching for fetched SVG payloads.
 * - Supports custom slotted SVG fallback when external fetch fails or is blocked.
 *
 * @example
 * ```html
 * <sky-icon icon="ion:home" width="24" height="24" color="#3b82f6"></sky-icon>
 * ```
 * ```vue
 * <template>
 *   <sky-icon icon="ion:home" width="24" height="24" color="#3b82f6"></sky-icon>
 * </template>
 * ```
 * ```jsx
 * export default function Demo() {
 *   return <sky-icon icon="ion:home" width="24" height="24" color="#3b82f6"></sky-icon>;
 * }
 * ```
 */
export declare class SkyIcon extends LitElement {
    /** Cache: icon name -> final SVG string (bounded by MAX_ICON_CACHE_SIZE, LRU eviction). */
    private static _iconCache;
    /** Cache for in-flight fetches: icon name -> Promise<svg> */
    private static _iconPromiseCache;
    /** Local icon sets (prefix -> Iconify set data) for offline/custom icons */
    private static _localSets;
    /** Single local icons (full name -> icon data) */
    private static _localIcons;
    /**
     * Register a local icon set (Iconify-compatible JSON) for offline or custom icons.
     * @param prefix - Set prefix (e.g. "ion", "custom"); use as icon="prefix:iconName".
     * @param data - Set data with `icons` and optional defaults (width, height, left, top).
     */
    static registerLocalSet(prefix: string, data: IconifySetData): void;
    /**
     * Register a single local icon (one-off custom icon without a full set).
     * @param fullName - Full icon name, e.g. "ion:heart".
     * @param icon - Icon data (body, width, height, viewBox, etc.).
     */
    static registerLocalIcon(fullName: string, icon: IconifyIcon): void;
    /** Named prop preset from nearest `sky-config-provider`. */
    preset: string;
    private _presets;
    static styles: import("lit").CSSResult;
    icon: string;
    width: SkyIconSizeValue;
    height: SkyIconSizeValue;
    color: string;
    inline: boolean;
    flip: SkyIconFlip;
    hFlip: boolean;
    vFlip: boolean;
    rotate: SkyIconRotateValue;
    lazy: boolean;
    private _svgContent;
    private _hasSlottedSvg;
    private _observer;
    private _visible;
    connectedCallback(): void;
    disconnectedCallback(): void;
    updated(changed: Map<string, unknown>): void;
    private _onSlotChange;
    private _startObserver;
    private _stopObserver;
    private _setSvgContent;
    private _loadIcon;
    private _fetchAndBuild;
    private _buildSvg;
    private _normalize;
    private _rotationDeg;
    private _flipHas;
    private _transform;
    private _baseStyle;
    render(): import("lit-html").TemplateResult<1>;
}
export {};