1 files changed, 110 insertions, 0 deletions
diff --git a/tools/colors.js b/tools/colors.js
new file mode 100644
index 0000000..f8f7ace
--- /dev/null
+++ b/tools/colors.js
@@ -0,0 +1,110 @@
+"use strict"
+
+function rgb_from_any(color) {
+	switch (color.mode) {
+	case "rgb": return color
+	case "lrgb": return rgb_from_lrgb(color)
+	case "oklab": return rgb_from_oklab(color)
+	}
+}
+
+function lrgb_from_any(color) {
+	switch (color.mode) {
+	case "rgb": return lrgb_from_rgb(color)
+	case "lrgb": return color
+	case "oklab": return lrgb_from_oklab(color)
+	}
+}
+
+function oklab_from_any(color) {
+	switch (color.mode) {
+	case "rgb": return oklab_from_rgb(color)
+	case "lrgb": return oklab_from_lrgb(color)
+	case "oklab": return color
+	}
+}
+
+function format_hex(color) {
+	let {r, g, b} = rgb_from_any(color)
+	let adj = 1
+	r = Math.round(Math.max(0, Math.min(1, r)) * 255)
+	g = Math.round(Math.max(0, Math.min(1, g)) * 255)
+	b = Math.round(Math.max(0, Math.min(1, b)) * 255)
+	let x = (r << 16) | (g << 8) | b
+	return "#" + x.toString(16).padStart(6, "0")
+}
+
+function parse_hex(str) {
+	let x = parseInt(str.substring(1), 16)
+	return {
+		mode: "rgb",
+		r: ((x >> 16) & 255) / 255.0,
+		g: ((x >> 8) & 255) / 255.0,
+		b: ((x) & 255) / 255.0
+	}
+}
+
+function lrgb_from_rgb({ r, g, b }) {
+	function to_linear(c) {
+		let ac = Math.abs(c)
+		if (ac < 0.04045)
+			return c / 12.92
+		return (Math.sign(c) || 1) * Math.pow((ac + 0.055) / 1.055, 2.4)
+	}
+	return {
+		mode: "lrgb",
+                r: to_linear(r),
+                g: to_linear(g),
+                b: to_linear(b)
+        }
+}
+
+function rgb_from_lrgb({ r, g, b }) {
+	function from_linear(c) {
+		let ac = Math.abs(c)
+		if (ac > 0.0031308)
+			return (Math.sign(c) || 1) * (1.055 * Math.pow(ac, 1 / 2.4) - 0.055)
+		return c * 12.92
+	}
+        return {
+                mode: "rgb",
+                r: from_linear(r),
+                g: from_linear(g),
+                b: from_linear(b)
+	}
+}
+
+function oklab_from_lrgb({ r, g, b }) {
+	let L = Math.cbrt(0.4122214708 * r + 0.5363325363 * g + 0.0514459929 * b)
+        let M = Math.cbrt(0.2119034982 * r + 0.6806995451 * g + 0.1073969566 * b)
+        let S = Math.cbrt(0.0883024619 * r + 0.2817188376 * g + 0.6299787005 * b)
+        return {
+                mode: "oklab",
+                l: 0.2104542553 * L + 0.793617785 * M - 0.0040720468 * S,
+                a: 1.9779984951 * L - 2.428592205 * M + 0.4505937099 * S,
+                b: 0.0259040371 * L + 0.7827717662 * M - 0.808675766 * S
+        }
+}
+
+function lrgb_from_oklab({ l, a, b }) {
+        let L = Math.pow(l + 0.3963377774 * a + 0.2158037573 * b, 3)
+        let M = Math.pow(l - 0.1055613458 * a - 0.0638541728 * b, 3)
+        let S = Math.pow(l - 0.0894841775 * a - 1.291485548 * b, 3)
+        return {
+                mode: "lrgb",
+                r: +4.0767416621 * L - 3.3077115913 * M + 0.2309699292 * S,
+                g: -1.2684380046 * L + 2.6097574011 * M - 0.3413193965 * S,
+                b: -0.0041960863 * L - 0.7034186147 * M + 1.707614701 * S
+	}
+}
+
+function oklab_from_rgb(rgb) {
+        return oklab_from_lrgb(lrgb_from_rgb(rgb))
+}
+
+function rgb_from_oklab(oklab) {
+	return rgb_from_lrgb(lrgb_from_oklab(oklab))
+}
+
+if (typeof module === "object")
+	module.exports = { format_hex, parse_hex, rgb_from_any, lrgb_from_any, oklab_from_any }