import { Instance, SharedRenderer } from './renderer';
/**
 * Load (and cache) an image. Resolves once the bitmap is decoded and ready.
 *
 * Note: we do NOT set `img.crossOrigin` — for same-origin assets that would
 * trigger an unnecessary CORS preflight that most static dev servers don't
 * satisfy. Drawing images into a 2D canvas does not taint the canvas if the
 * image is same-origin. Consumers serving cross-origin images should set
 * proper CORS headers on their CDN.
 */
export declare function loadImage(src: string): Promise<HTMLImageElement>;
export interface RevealStartOptions {
    /** Image to reveal. */
    image: HTMLImageElement;
    /** Output canvas size (CSS px). Reveal canvas matches the shader canvas. */
    cssWidth: number;
    cssHeight: number;
    /** Phase scheduler hooks. */
    onRevealComplete?: () => void;
}
export interface RevealState {
    /** The DOM canvas painted on top of the shader canvas. */
    canvas: HTMLCanvasElement;
    ctx: CanvasRenderingContext2D;
    /** Per-frame hook invoked after the shader has rendered. Decides what to do
     *  with the overlay this frame (paint mask, hold, fade out, idle). */
    afterShaderFrame: (s: SharedRenderer, inst: Instance, nowMs: number) => void;
    /** Begin a new reveal animation. */
    startReveal: (opts: RevealStartOptions) => void;
    /** Begin the fade-out (hide) phase. */
    startHide: (durationMs?: number) => void;
    /**
     * Dissolve the currently held image into a sustained "generating" state:
     * the image is broken into the effect's pixel-cell grid and the cells churn
     * (pop in/out with the preset's flicker clock) indefinitely while the
     * shader effect plays through the gaps. No-op unless an image is currently
     * revealed/held. Ends when `startReveal` (next image) or `startHide` runs.
     */
    startBoil: () => void;
    /** Force-clear the overlay back to idle. */
    clear: () => void;
    /** True while a reveal/hold/hide is in progress. */
    isActive: () => boolean;
    dispose: () => void;
}
export interface CreateRevealOptions {
    /** The DOM canvas overlay (sibling of the shader canvas). */
    canvas: HTMLCanvasElement;
    cssWidth: number;
    cssHeight: number;
    /** Shader canvas — its opacity is driven by the reveal so the image
     *  cross-fades over it. */
    shaderCanvas: HTMLCanvasElement;
}
export declare function createReveal(opts: CreateRevealOptions): RevealState;
/** Pull a random image from `pool`, never repeating the previous index. */
export declare function pickRandomImage(pool: string[], lastIdx: number): {
    src: string;
    idx: number;
} | null;