mon-entreprise/site/source/hexToHSL.ts

36 lines
809 B
TypeScript

export function hexToHSL(hex: string): [number, number, number] {
const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex)
if (result === null) {
throw new Error('Accept only hex strings')
}
let r = parseInt(result[1], 16)
let g = parseInt(result[2], 16)
let b = parseInt(result[3], 16)
r /= 255
g /= 255
b /= 255
const max = Math.max(r, g, b)
const min = Math.min(r, g, b)
let h = 0
let s = 0
const l = (max + min) / 2
if (max !== min) {
const d = max - min
s = l > 0.5 ? d / (2 - max - min) : d / (max + min)
switch (max) {
case r:
h = (g - b) / d + (g < b ? 6 : 0)
break
case g:
h = (b - r) / d + 2
break
case b:
h = (r - g) / d + 4
break
}
h /= 6
}
return [h * 360, s * 100, l * 100].map(Math.round) as [number, number, number]
}