Function rgbToHsv

Conversions/RgbHsvConversion.js:48–82

(red, green, blue)

 * @return The tuple of HSV-components.
 */
export function rgbToHsv(red, green, blue) {
  if (red < 0 || red > 255) {
    throw new Error('red should be between 0 and 255')
  }

  if (green < 0 || green > 255) {
    throw new Error('green should be between 0 and 255')
  }

  if (blue < 0 || blue > 255) {
    throw new Error('blue should be between 0 and 255')
  }

  const dRed = red / 255
  const dGreen = green / 255
  const dBlue = blue / 255
  const value = Math.max(Math.max(dRed, dGreen), dBlue)
  const chroma = value - Math.min(Math.min(dRed, dGreen), dBlue)
  const saturation = value === 0 ? 0 : chroma / value
  let hue

  if (chroma === 0) {
    hue = 0
  } else if (value === dRed) {
    hue = 60 * ((dGreen - dBlue) / chroma)
  } else if (value === dGreen) {
    hue = 60 * (2 + (dBlue - dRed) / chroma)
  } else {
    hue = 60 * (4 + (dRed - dGreen) / chroma)
  }

  hue = (hue + 360) % 360

  return [hue, saturation, value]
}

export function approximatelyEqualHsv(hsv1, hsv2) {
  const bHue = Math.abs(hsv1[0] - hsv2[0]) < 0.2