Create RGBToHSL.md

snippets/RGBToHSL.md

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+---
+title: RGBToHSL
+tags: math,intermediate
+---
+
+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); // [21.17647058823529, 60.71428571428573, 10.980392156862745]
+```