/**
 * @copyright
 * Copyright 2026 Steven Roussey
 * All Rights Reserved
 */
import type { ImageValue } from "./imageValue";
export type PreviewResizeFn = (image: ImageValue, width: number, height: number) => Promise<ImageValue>;
export declare function registerPreviewResizeFn(fn: PreviewResizeFn | undefined): void;
export declare function getPreviewBudget(): number;
export declare function setPreviewBudget(px: number): void;
/**
 * Engine-applied chain-head downscale for `runPreview`. Idempotent: when
 * the input is already within budget, returns the input unchanged
 * (referential equality is the no-op signal). When over budget, calls the
 * registered resize fn (typically routed through Sharp on node and an
 * OffscreenCanvas/WebGPU resize on browser) and composes `previewScale`:
 * `out.previewScale = in.previewScale × downscaleRatio`.
 */
export declare function previewSource(image: ImageValue): Promise<ImageValue>;
//# sourceMappingURL=previewBudget.d.ts.map