a.rs

  pub fn from_hex(hex: impl AsRef<str>) -> Option<Color> {
    let hex = hex.as_ref();
    let bytes = hex.as_bytes();
    let (mut r, mut g, mut b);

    if hex.len() == 4 && bytes[0] == b'#' {
      // triplet form (#rgb)
      let mut h = u16::from_str_radix(&hex[1..], 16).ok()?;

      b = (h & 0xf) as _;
      b += b << 4;

      h >>= 4;
      g = (h & 0xf) as _;
      g += g << 4;

      h >>= 4;
      r = (h & 0xf) as _;
      r += r << 4;
    } else if hex.len() == 7 && bytes[0] == b'#' {
      // #rrggbb form
      let mut h = u32::from_str_radix(&hex[1..], 16).ok()?;

      b = (h & 0xff) as _;

      h >>= 8;
      g = (h & 0xff) as _;

      h >>= 8;
      r = (h & 0xff) as _;
    } else {
      return None;
    }

    Some(Color(Col::TrueColor { r, g, b }))
  }