import type { FikaExportWatermark, FikaWatermarkSurface } from '../configs/exportWatermark';
export declare const EXPORT_WATERMARK_MARKER = "fika:export-watermark";
export interface WatermarkImage {
    bytes: Uint8Array;
    mime: 'image/png' | 'image/jpeg';
    width: number;
    height: number;
}
export interface ApplyPptxExportWatermarkImages {
    onLight: WatermarkImage;
    onDark?: WatermarkImage;
    /** Per-slide polarity from `preferredInk`. Gaps are inferred from the slide XML. */
    slideSurfaces?: Array<FikaWatermarkSurface | undefined>;
    masterSurface?: FikaWatermarkSurface;
}
/** Reads dimensions from the PNG/JPEG header — no decoder or DOM needed. */
export declare function readWatermarkImage(bytes: Uint8Array): WatermarkImage;
/** Resolves `image` (data: URL or fetchable URL) to raw bytes plus dimensions. */
export declare function loadWatermarkImage(image: string): Promise<WatermarkImage>;
/**
 * Same cliff as `perceivedDark` in textContrast: AERT brightness 140 or WCAG
 * luminance 0.25. Dark surface → light mark.
 */
export declare function watermarkSurfaceFromRgb(r: number, g: number, b: number): FikaWatermarkSurface;
export declare function watermarkSurfaceFromHex(hex: string): FikaWatermarkSurface;
/** Photo fills use the invert mark; solids/gradients follow the sampled color. */
export declare function inferWatermarkSurfaceFromSlideXml(xml: string): FikaWatermarkSurface;
/** True when the package already carries the export watermark on any slide. */
export declare function hasPptxExportWatermark(bytes: ArrayBuffer | Uint8Array): Promise<boolean>;
/**
 * Returns a new package with the watermark on every slide and slide master.
 * Throws when the input is not a presentation package.
 */
export declare function applyPptxExportWatermark(bytes: ArrayBuffer | Uint8Array, watermark: FikaExportWatermark, images: WatermarkImage | ApplyPptxExportWatermarkImages): Promise<Uint8Array>;
/**
 * Browser download through a real `HTMLAnchorElement.click()` — the same seam
 * pptxgenjs uses, which embedding hosts rely on to capture export bytes.
 */
export declare function downloadPptxBytes(bytes: Uint8Array, fileName: string): void;