该轮子涉及的语法知识

LLToolFunc类包含的语法

一: 怎么设置数值类型参数大小范围 0=< x =<1？

public func interpolationFrom(from:CGFloat,to:CGFloat,percent:CGFloat) -> CGFloat{
    let ratio = max(0, min(1, percent))
    return from + (to - from)*ratio
}
/// let ratio = max(0, min(1, percent))
通过min, max来判断设置

二: 如何获取UIColor对象的RGBA各个的数值

    let fromColor  = UIColor.white
    var fromR:CGFloat = 0
    var fromG:CGFloat = 0
    var fromB:CGFloat = 0
    var fromA:CGFloat = 0
    fromColor.getRed(&fromR, green: &fromG, blue: &fromB, alpha: &fromA)
通过UIColor的对象方法getRed获取