react-best-gradient-color-picker/src/utils/converters.ts

An easy to use color/gradient picker for React.js

export function rgb2cmyk(r: number, g: number, b: number) {
  let computedC = 0
  let computedM = 0
  let computedY = 0
  let computedK = 0

  if (
    r === null ||
    g === null ||
    b === null ||
    isNaN(r) ||
    isNaN(g) ||
    isNaN(b)
  ) {
    console.log('Please enter numeric RGB values!')
    return { c: 0, m: 0, k: 0, y: 1 }
  }
  if (r < 0 || g < 0 || b < 0 || r > 255 || g > 255 || b > 255) {
    console.log('RGB values must be in the range 0 to 255.')
    return { c: 0, m: 0, k: 0, y: 1 }
  }

  if (r === 0 && g === 0 && b === 0) {
    computedK = 1
    return { c: 0, m: 0, k: 0, y: 1 }
  }

  computedC = 1 - r / 255
  computedM = 1 - g / 255
  computedY = 1 - b / 255

  const minCMY = Math.min(computedC, Math.min(computedM, computedY))
  computedC = (computedC - minCMY) / (1 - minCMY)
  computedM = (computedM - minCMY) / (1 - minCMY)
  computedY = (computedY - minCMY) / (1 - minCMY)
  computedK = minCMY

  return { c: computedC, m: computedM, y: computedY, k: computedK }
}

export const cmykToRgb = ({
  c,
  m,
  y,
  k,
}: {
  c: number
  m: number
  y: number
  k: number
}) => {
  const r = 255 * (1 - c) * (1 - k)
  const g = 255 * (1 - m) * (1 - k)
  const b = 255 * (1 - y) * (1 - k)

  return { r: r, g: g, b: b }
}

export const getHexAlpha = (opacityPercent: number): string => {
  if (typeof opacityPercent !== 'number') {
    return 'FF'
  }

  if (opacityPercent < 0) {
    return '00'
  }

  if (opacityPercent > 1) {
    return 'FF'
  }

  return Math.round(opacityPercent * 255)
    .toString(16)
    .padStart(2, '0')
    .toUpperCase()
}