export interface SampledPalette {
    /** One CSS hex color per shader palette slot (7 entries). */
    colors: string[];
    /** Average image color — used as the card surface behind the effect. */
    cardBg: string;
}
/**
 * Sample an image-derived recolor for the running effect from `src` (any
 * drawable canvas — typically the reveal overlay showing the current image).
 *
 * `presetColors` is the active preset mode's 7-slot palette; the returned
 * `colors` array maps image colors onto those slots by luminance rank.
 * Returns null when sampling isn't possible (SSR, empty canvas).
 */
export declare function samplePaletteFromCanvas(src: HTMLCanvasElement, presetColors: readonly string[]): SampledPalette | null;