/**
* Color utilities - RGB/LAB conversion, color naming
*/
import chroma from "chroma-js";
// Cache for color.pizza API lookups
const colorNameCache = new Map<string, string>();
/**
* Convert RGB to LAB color space (perceptually uniform)
*/
export function rgbToLab(r: number, g: number, b: number): [number, number, number] {
const color = chroma(r, g, b);
return color.lab() as [number, number, number];
}
/**
* Convert LAB to RGB
*/
export function labToRgb(l: number, a: number, b: number): [number, number, number] {
const color = chroma.lab(l, a, b);
const [r, g, b_] = color.rgb();
// Clamp to valid range
return [
Math.max(0, Math.min(255, Math.round(r))),
Math.max(0, Math.min(255, Math.round(g))),
Math.max(0, Math.min(255, Math.round(b_))),
];
}
/**
* Convert RGB to HSL
*/
export function rgbToHsl(r: number, g: number, b: number): { h: number; s: number; l: number } {
const color = chroma(r, g, b);
const [h, s, l] = color.hsl();
return {
h: Math.round(isNaN(h) ? 0 : h),
s: Math.round(s * 100),
l: Math.round(l * 100),
};
}
/**
* Convert RGB to hex string
*/
export function rgbToHex(r: number, g: number, b: number): string {
return chroma(r, g, b).hex();
}
/**
* Get color name from color.pizza API
*/
async function fetchColorName(hex: string): Promise<string | null> {
try {
const hexCode = hex.replace("#", "");
const response = await fetch(`https://api.color.pizza/v1/${hexCode}`, {
signal: AbortSignal.timeout(5000),
});
if (!response.ok) return null;
const data = await response.json();
if (data.colors?.[0]?.name) {
return data.colors[0].name;
}
} catch {
// API unavailable, fall through to basic names
}
return null;
}
/**
* Basic color name lookup (fallback)
*/
function getBasicColorName(r: number, g: number, b: number): string {
const colors: Record<string, [number, number, number]> = {
black: [0, 0, 0],
white: [255, 255, 255],
red: [255, 0, 0],
green: [0, 128, 0],
blue: [0, 0, 255],
yellow: [255, 255, 0],
cyan: [0, 255, 255],
magenta: [255, 0, 255],
orange: [255, 165, 0],
purple: [128, 0, 128],
pink: [255, 192, 203],
brown: [139, 69, 19],
gray: [128, 128, 128],
navy: [0, 0, 128],
teal: [0, 128, 128],
lime: [0, 255, 0],
};
let nearest = "unknown";
let minDist = Infinity;
for (const [name, [cr, cg, cb]] of Object.entries(colors)) {
const dist = (r - cr) ** 2 + (g - cg) ** 2 + (b - cb) ** 2;
if (dist < minDist) {
minDist = dist;
nearest = name;
}
}
return nearest;
}
/**
* Get human-readable color name
* Uses color.pizza API with fallback to basic names
*/
export async function getColorName(
r: number,
g: number,
b: number,
useApi = true
): Promise<string> {
const hex = rgbToHex(r, g, b);
// Check cache
if (colorNameCache.has(hex)) {
return colorNameCache.get(hex)!;
}
// Try color.pizza API
if (useApi) {
const apiName = await fetchColorName(hex);
if (apiName) {
colorNameCache.set(hex, apiName);
return apiName;
}
}
// Fallback to basic color name
const basicName = getBasicColorName(r, g, b);
colorNameCache.set(hex, basicName);
return basicName;
}
/**
* Euclidean distance in LAB space
*/
export function labDistance(
lab1: [number, number, number],
lab2: [number, number, number]
): number {
return Math.sqrt(
(lab1[0] - lab2[0]) ** 2 +
(lab1[1] - lab2[1]) ** 2 +
(lab1[2] - lab2[2]) ** 2
);
}
