比较UIColor相似度与百分比

Question

我有以下颜色，

let userskin = hexStringToUIColor(hex: "#EFC1A2")

skinColor1.backgroundColor = hexStringToUIColor(hex: "#F0C6A9")
skinColor2.backgroundColor = hexStringToUIColor(hex: "#EACBBD")
skinColor3.backgroundColor = hexStringToUIColor(hex: "#EFC1A2")
skinColor4.backgroundColor = hexStringToUIColor(hex: "#F6D6C2")
skinColor5.backgroundColor = hexStringToUIColor(hex: "#F7D7BD")

我想比较userskin是与skinColor列表相同的百分比。我想在皮肤上选择项目。