为给定的UIColor获得更浅和更暗的颜色变化

Question

如何在Swift中获得给定UIColor的不同更亮和更暗的变化？

Answer 1

更新

使用以下UIColor扩展：

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%

而不是.lighter()和.darker()，你可以使用.adjust()正值闪电和负值变暗

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

输出：

Answer 2

我想提供另一个使用亮度和饱和度而不是RGB的版本

extension UIColor {
  /**
   Create a ligher color
   */
  func lighter(by percentage: CGFloat = 30.0) -> UIColor {
    return self.adjustBrightness(by: abs(percentage))
  }

  /**
   Create a darker color
   */
  func darker(by percentage: CGFloat = 30.0) -> UIColor {
    return self.adjustBrightness(by: -abs(percentage))
  }

  /**
   Try to increase brightness or decrease saturation
   */
  func adjustBrightness(by percentage: CGFloat = 30.0) -> UIColor {
    var h: CGFloat = 0, s: CGFloat = 0, b: CGFloat = 0, a: CGFloat = 0
    if self.getHue(&h, saturation: &s, brightness: &b, alpha: &a) {
      if b < 1.0 {
        let newB: CGFloat = max(min(b + (percentage/100.0)*b, 1.0), 0.0)
        return UIColor(hue: h, saturation: s, brightness: newB, alpha: a)
      } else {
        let newS: CGFloat = min(max(s - (percentage/100.0)*s, 0.0), 1.0)
        return UIColor(hue: h, saturation: newS, brightness: b, alpha: a)
      }
    }
    return self
  }
}

Answer 3

修改RGB值的版本

在这里，我把简单的UIColor扩展，这是基于以前的答案。它对我来说非常合适。

下面演示：

颜色操作代码

public extension UIColor {

    /**
     Create a lighter color
     */
    public func lighter(by percentage: CGFloat = 30.0) -> UIColor {
        return self.adjustBrightness(by: abs(percentage))
    }

    /**
     Create a darker color
     */
    public func darker(by percentage: CGFloat = 30.0) -> UIColor {
        return self.adjustBrightness(by: -abs(percentage))
    }

    /**
     Changing R, G, B values
     */

    func adjustBrightness(by percentage: CGFloat = 30.0) -> UIColor {

        var red: CGFloat = 0.0
        var green: CGFloat = 0.0
        var blue: CGFloat = 0.0
        var alpha: CGFloat = 0.0

        if self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) {

            let pFactor = (100.0 + percentage) / 100.0

            let newRed = (red*pFactor).clamped(to: 0.0 ... 1.0)
            let newGreen = (green*pFactor).clamped(to: 0.0 ... 1.0)
            let newBlue = (blue*pFactor).clamped(to: 0.0 ... 1.0)

            return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: alpha)
        }

        return self
    }
}

夹紧功能扩展可轻松保持最小值和最大值之间的值。

extension Comparable {

    func clamped(to range: ClosedRange<Self>) -> Self {

        if self > range.upperBound {
            return range.upperBound
        } else if self < range.lowerBound {
            return range.lowerBound
        } else {
            return self
        }
    }
}

Answer 4

Kenji-Tran的答案很好，只要您的起始颜色不是黑色（亮度值0）。通过添加几行额外代码，您还可以使黑色“更亮”（即将其变亮为灰度或颜色值）。

注意：我无法使用编辑添加此更改，由于我的“新男孩”代表，我不允许评论Kenji-Tran的答案，因此我找不到其他方式来分享我的知识然后通过发布新答案。我希望没关系。

extension UIColor {
  /**
   Create a ligher color
   */
  func lighter(by percentage: CGFloat = 30.0) -> UIColor {
    return self.adjustBrightness(by: abs(percentage))
  }

  /**
   Create a darker color
   */
  func darker(by percentage: CGFloat = 30.0) -> UIColor {
    return self.adjustBrightness(by: -abs(percentage))
  }

  /**
   Try to increase brightness or decrease saturation
   */
  func adjustBrightness(by percentage: CGFloat = 30.0) -> UIColor {
    var h: CGFloat = 0, s: CGFloat = 0, b: CGFloat = 0, a: CGFloat = 0
    if self.getHue(&h, saturation: &s, brightness: &b, alpha: &a) {
      if b < 1.0 {
        /**
         Below is the new part, which makes the code work with black as well as colors
        */
        let newB: CGFloat
        if b == 0.0 {
            newB = max(min(b + percentage/100, 1.0), 0.0)
        } else {
            newB = max(min(b + (percentage/100.0)*b, 1.0), 0,0)
        }
        return UIColor(hue: h, saturation: s, brightness: newB, alpha: a)
      } else {
        let newS: CGFloat = min(max(s - (percentage/100.0)*s, 0.0), 1.0)
        return UIColor(hue: h, saturation: newS, brightness: b, alpha: a)
      }
    }
    return self
  }
}

Answer 5

对于Swift 5.0：

extension UIColor {

func lighter(by percentage: CGFloat = 10.0) -> UIColor {
    return self.adjust(by: abs(percentage))
}

func darker(by percentage: CGFloat = 10.0) -> UIColor {
    return self.adjust(by: -abs(percentage))
}

func adjust(by percentage: CGFloat) -> UIColor {
    var alpha, hue, saturation, brightness, red, green, blue, white : CGFloat
    (alpha, hue, saturation, brightness, red, green, blue, white) = (0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0)

    let multiplier = percentage / 100.0

    if self.getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: &alpha) {
        let newBrightness: CGFloat = max(min(brightness + multiplier*brightness, 1.0), 0.0)
        return UIColor(hue: hue, saturation: saturation, brightness: newBrightness, alpha: alpha)
    }
    else if self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) {
        let newRed: CGFloat = min(max(red + multiplier*red, 0.0), 1.0)
        let newGreen: CGFloat = min(max(green + multiplier*green, 0.0), 1.0)
        let newBlue: CGFloat = min(max(blue + multiplier*blue, 0.0), 1.0)
        return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: alpha)
    }
    else if self.getWhite(&white, alpha: &alpha) {
        let newWhite: CGFloat = (white + multiplier*white)
        return UIColor(white: newWhite, alpha: alpha)
    }

    return self
    }
}

Answer 6

适用于iOS 12的Swift 4.x在Xcode 10中测试过

从你的颜色开始作为UIColor并选择一个变暗因子（作为CGFloat）

let baseColor = UIColor.red
let darkenFactor: CGFloat = 2

CGColor类型有一个可选值components，它将颜色分解为RGBA（作为CGFloat数组，其值介于0和1之间）。然后，您可以使用从CGColor中获取的RGBA值重建UIColor并对其进行操作。

let darkenedBase = UIColor(displayP3Red: startColor.cgColor.components![0] / darkenFactor, green: startColor.cgColor.components![1] / darkenFactor, blue: startColor.cgColor.components![2] / darkenFactor, alpha: 1)

在这个例子中，每个RGB值被除以2，使得颜色一半变暗。 alpha值保持不变，但您可以选择将暗因子应用于alpha值而不是RGB。

Answer 7

使用lukszar clampled函数，我使用实际比例的RGB值为UIColor扩展编写了这个函数。我希望它有所帮助

public extension UIColor {

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

  public func darker(by percentage: CGFloat = 30.0) -> UIColor {
    return self.adjustBrightness(by: -abs(percentage))
  }

  func adjustBrightness(by percentage: CGFloat = 30.0) -> UIColor {

    let ratio = percentage/100

    var red:   CGFloat = 0.0
    var green: CGFloat = 0.0
    var blue:  CGFloat = 0.0
    var alpha: CGFloat = 0.0

    if self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) {
      let newRed =   (red   + ((ratio < 0) ? red   * ratio : (1 - red)   * ratio)).clamped(to: 0.0 ... 1.0)
      let newGreen = (green + ((ratio < 0) ? green * ratio : (1 - green) * ratio)).clamped(to: 0.0 ... 1.0)
      let newBlue =  (blue  + ((ratio < 0) ? blue  * ratio : (1 - blue)  * ratio)).clamped(to: 0.0 ... 1.0)
      return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: alpha)
    }
    return self
  }
}

Answer 8

支持RGB，HSBA和WB（灰度）的Swift 4版本

这是TranQuan的answer的变体，它也支持像.white和.black这样的灰度颜色。 （注意：我删除了饱和度调整，因为我不属于这样的简单函数。）

extension UIColor {
    /**
     Create a ligher color
     */
    func lighter(by percentage: CGFloat = 10.0) -> UIColor {
        return self.adjustBrightness(by: abs(percentage))
    }

    /**
     Create a darker color
     */
    func darker(by percentage: CGFloat = 10.0) -> UIColor {
        return self.adjustBrightness(by: -abs(percentage))
    }

    /**
     Try to adjust brightness and falls back to adjusting colors if necessary
     */
    func adjustBrightness(by percentage: CGFloat) -> UIColor {
        var alpha, hue, saturation, brightness, red, green, blue, white : CGFloat
        (alpha, hue, saturation, brightness, red, green, blue, white) = (0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0)

        let multiplier = percentage / 100.0

        if self.getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: &alpha) {
            let newBrightness: CGFloat = max(min(brightness + multiplier*brightness, 1.0), 0.0)
            return UIColor(hue: hue, saturation: saturation, brightness: newBrightness, alpha: alpha)
        }
        else if self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) {
            let newRed: CGFloat = min(max(red + multiplier*red, 0.0), 1.0)
            let newGreen: CGFloat = min(max(green + multiplier*green, 0.0), 1.0)
            let newBlue: CGFloat = min(max(blue + multiplier*blue, 0.0), 1.0)
            return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: alpha)
        }
        else if self.getWhite(&white, alpha: &alpha) {
            let newWhite: CGFloat = (white + multiplier*white)
            return UIColor(white: newWhite, alpha: alpha)
        }

        return self
    }
}