/**
 * Colour transforms between the document's sRGB colours and a CMYK output
 * profile: the separation postext-pdf writes, and the soft proof the
 * canvas viewers paint (CMYK → Lab → screen sRGB).
 */
import type { IccProfile, XYZ } from './icc.js';
export type RenderingIntent = 'perceptual' | 'relative' | 'saturation' | 'absolute';
export interface Lab {
    L: number;
    a: number;
    b: number;
}
export interface Cmyk {
    /** 0..1 each. */
    c: number;
    m: number;
    y: number;
    k: number;
}
export declare const D50: XYZ;
export declare function xyzToLab(v: XYZ, white?: XYZ): Lab;
export declare function labToXyz(lab: Lab, white?: XYZ): XYZ;
/** CIE76 colour difference. */
export declare function deltaE(p: Lab, q: Lab): number;
export declare function srgbToLinear(v: number): number;
export declare function linearToSrgb(v: number): number;
export declare function srgbToXyz(r: number, g: number, b: number): XYZ;
export declare function xyzToSrgb(v: XYZ): [number, number, number];
export declare function srgbToLab(r: number, g: number, b: number): Lab;
export declare function labToSrgb(lab: Lab): [number, number, number];
/** Device CMYK (0..1) → Lab through the profile's A2B table. `absolute`
 *  maps paper white to the paper's own colour (soft proof with paper
 *  simulation); the other intents give media-relative Lab. */
export declare function cmykToLab(profile: IccProfile, cmyk: Cmyk, intent?: RenderingIntent): Lab;
/** Lab → device CMYK through the profile's B2A table. */
export declare function labToCmyk(profile: IccProfile, lab: Lab, intent?: RenderingIntent): Cmyk;
/** Total area coverage of a CMYK value, in percent (0..400). */
export declare function totalAreaCoverage(cmyk: Cmyk): number;
export interface OutputTransformOptions {
    intent?: RenderingIntent;
    /** Scale the source so sRGB black lands on the profile's darkest
     *  printable black instead of being clipped (relative intent only). */
    blackPointCompensation?: boolean;
    /** Neutral colours (r = g = b) become K only, with K picked so L* matches. */
    preserveNeutrals?: boolean;
}
export interface OutputTransform {
    profile: IccProfile;
    /** sRGB 0..1 → CMYK 0..1. */
    fromRgb(r: number, g: number, b: number): Cmyk;
    /** CMYK → media-relative Lab (relative) or paper-simulating Lab. */
    toLab(cmyk: Cmyk, paper?: boolean): Lab;
    /** CMYK → screen sRGB 0..1, the soft proof of one colour. */
    proof(cmyk: Cmyk, paper?: boolean): [number, number, number];
    /** The profile's darkest black (relative Lab of its B2A for L* 0). */
    blackPoint: Lab;
    /** L* of paper with K only at `k` (relative): the K-only neutral ramp. */
    kOnlyFor(L: number): number;
}
/** Build (and memoize per profile + options) a transform from the
 *  document's sRGB colours to an output CMYK profile. */
export declare function outputTransform(profile: IccProfile, options?: OutputTransformOptions): OutputTransform;
/** A dense RGB → RGBA-ish lookup (`size³` entries × `channels`), filled by
 *  `fn` and applied per pixel with trilinear interpolation. */
export interface RgbLut {
    size: number;
    channels: number;
    data: Float32Array;
}
export declare function buildRgbLut(size: number, channels: number, fn: (r: number, g: number, b: number) => number[]): RgbLut;
/** Evaluate an `RgbLut` at 0..255 integer RGB into `out` (tetrahedral). */
export declare function sampleRgbLut(lut: RgbLut, r8: number, g8: number, b8: number, out: Float32Array | number[]): void;
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