#Color Convert

High‑quality color space conversion utilities for the MoonBit language. This library provides a focused, dependency‑free set of functions to convert between many common (and some modern) color spaces used in graphics, imaging, CSS, and perceptual color work.

#Highlights

sRGB inter‑conversion with: HSV, HSL, HCG, HWB, CMYK, Gray, XYZ (D65), CIE Lab, CIE LCH, OKLab, OKLCH, Apple 16‑bit RGB
Hex string parsing & formatting (#RGB, #RRGGBB, plain forms)
Named CSS colors → RGB (case‑insensitive) and reverse keyword lookup
Modern perceptual color support (OKLab / OKLCH) with XYZ bridge
Pure functions, no global mutation, no external deps
Comprehensive tests for numerical correctness

#Installation

Add the module to your MoonBit project (assuming standard MoonBit tooling):

moon add CAIMEOX/color

write simple code like:

let (h, s, v) = rgb2hsv(255.0F, 0.0F, 0.0F)
let (r, g, b) = hsl2rgb(240.0F, 100.0F, 50.0F)
let hex = rgb2hex(r, g, b) // "0000FF"

#Usage Examples

// Name lookup
let rgb = name2rgb("rebeccapurple")

// Round‑trip through OKLab
let (l, a, b) = rgb2oklab(92.0F, 191.0F, 84.0F)
let (rr, gg, bb) = oklab2rgb(L, A, B)

// Hex to RGB
let (r2, g2, b2) = hex2rgb("#ABCDEF") // (171,205,239)

// XYZ ↔ Lab ↔ LCH
let (x, y, z) = rgb2xyz(255.0F, 255.0F, 255.0F)
let (l, a, b3) = xyz2lab(x, y, z)
let (_, c, h) = lab2lch(l, a, b3)

#API Overview

All numeric channel inputs & outputs follow common conventions:

sRGB channels: Float 0–255 (matches test expectations)
Percentage style outputs: Many functions return saturation / value / lightness / chroma / gray as 0–100 floats (mirroring common JS libs like color‑convert)
Hex: uppercase string without leading # (add it yourself if needed)
XYZ: D65 white, scaled 0–100

From	To	Function
RGB	HSV	rgb2hsv
RGB	HSL	rgb2hsl
RGB	CMYK	rgb2cmyk
RGB	Hex	rgb2hex
RGB	HWB	rgb2hwb
RGB	HCG	rgb2hcg
RGB	XYZ	rgb2xyz
RGB	Lab	rgb2lab
RGB	Gray%	rgb2gray
RGB	OKLab	rgb2oklab
RGB	Apple 16‑bit	rgb2apple
HSV	RGB	hsv2rgb
HSV	HSL	hsv2hsl
HSL	RGB	hsl2rgb
HSL	HSV	hsl2hsv
HWB	RGB	hwb2rgb
HCG	RGB	hcg2rgb
CMYK	RGB	cmyk2rgb
XYZ	RGB	xyz2rgb
XYZ	Lab	xyz2lab
Lab	XYZ	lab2xyz
Lab	LCH	lab2lch
LCH	Lab	lch2lab
OKLab	XYZ	oklab2xyz
OKLab	RGB	oklab2rgb
OKLab	OKLCH	oklab2oklch
OKLCH	OKLab	oklch2oklab
Gray%	RGB	gray2rgb
Hex	RGB	hex2rgb
Name	RGB	name2rgb (raises NameNotFound)
RGB	Name	rgb2keyword (optional)
Apple 16‑bit	RGB	apple2rgb

#Error Handling

name2rgb raises NameNotFound if the color keyword does not exist.
hex2rgb raise error for malformed inputs (guard pattern); you can pre‑validate if stricter behavior is desired.

#Precision Notes

Floating point operations introduce minor rounding differences. Tests assert stringified tuple outputs produced on the reference platform. When writing new tests allow for small epsilon (≈1e‑3–1e‑2) if comparing numerically.

#Running Tests

moon test

Update expected outputs after intentional algorithm changes with:

moon test -u

#License

Apache 2.0 — see LICENSE file.

#Acknowledgments

Thanks to color-convert and color-name for reference data and inspiration

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