获取给定UIColor的较浅和较深的颜色变化 [英] Get lighter and darker color variations for a given UIColor

问题描述

如何在Swift中获得给定UIColor的明暗变化？

How to get different lighter and darker variations of a given UIColor in Swift?

推荐答案

已更新

在以下 UIColor扩展名下使用：

extension UIColor {

    func lighter(by percentage: CGFloat = 30.0) -> UIColor? {
        return self.adjust(by: abs(percentage) )
    }

    func darker(by percentage: CGFloat = 30.0) -> UIColor? {
        return self.adjust(by: -1 * abs(percentage) )
    }

    func adjust(by percentage: CGFloat = 30.0) -> UIColor? {
        var red: CGFloat = 0, green: CGFloat = 0, blue: CGFloat = 0, alpha: CGFloat = 0
        if self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) {
            return UIColor(red: min(red + percentage/100, 1.0),
                           green: min(green + percentage/100, 1.0),
                           blue: min(blue + percentage/100, 1.0),
                           alpha: alpha)
        } else {
            return nil
        }
    }
}

用法：

let color = UIColor(red:0.96, green:0.54, blue:0.10, alpha:1.0)
color.lighter(30) // returns lighter color by 30%
color.darker(30) // returns darker color by 30%

.lighter（）和 .darker（）的形式，则可以使用 .adjust（） ，正值表示变亮，负值表示变暗

instead of .lighter() and .darker(), you can use .adjust() with positive values for lightening and negative values for darkening

color.adjust(-30) // 30% darker color
color.adjust(30) // 30% lighter color

输出：

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