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javascript/snippets/rgb-to-hsl.md

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+---
+title: RGB to HSL
+type: snippet
+tags: [math]
+cover: planning
+dateModified: 2020-10-04T11:25:12+03:00
+---
+
+Converts a RGB color tuple to HSL format.
+
+- Use the [RGB to HSL conversion formula](https://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl/) to convert to the appropriate format.
+- The range of all input parameters is [0, 255].
+- The range of the resulting values is H: [0, 360], S: [0, 100], L: [0, 100].
+
+```js
+const RGBToHSL = (r, g, b) => {
+  r /= 255;
+  g /= 255;
+  b /= 255;
+  const l = Math.max(r, g, b);
+  const s = l - Math.min(r, g, b);
+  const h = s
+    ? l === r
+      ? (g - b) / s
+      : l === g
+      ? 2 + (b - r) / s
+      : 4 + (r - g) / s
+    : 0;
+  return [
+    60 * h < 0 ? 60 * h + 360 : 60 * h,
+    100 * (s ? (l <= 0.5 ? s / (2 * l - s) : s / (2 - (2 * l - s))) : 0),
+    (100 * (2 * l - s)) / 2,
+  ];
+};
+```
+
+```js
+RGBToHSL(45, 23, 11); // [21.17647, 60.71428, 10.98039]
+```