import type { MatchOptions, RawImage } from './types.js';
import { AsciiFrame } from './frame.js';
export declare const CHROMATIC_VERSION = "chromatic-v1";
/**
 * chromatic-v1 reference matcher (ALGORITHM.md §C). Deterministic and
 * all-integer; like structural-v1 this implementation defines correctness for
 * every backend.
 *
 * It is a different algorithm rather than an approximation of structural-v1.
 * structural-v1 matches a 1-bit mask and *fits* colour to it, which is why a
 * free foreground and background make its rerank exact. A colour glyph's colour
 * is baked, so there is nothing to fit: the objective is direct squared error
 * between the cell's 64 reduced samples and the glyph's own, composited over
 * the backdrop it will be drawn on. That removes the flat path (§6), polarity
 * (§8), and the candidate prefilter (§9) — measurements showed a shortlist over
 * a curated palette costs more quality than it saves time.
 */
export declare function matchFrameChromatic(source: RawImage, options: MatchOptions): AsciiFrame;