Question

假设我有一个十六进制，例如：5fc9f8

是否有接受“黑暗等级”（-10到10）的函数并返回反映该值的十六进制？

在黑暗中，我的意思是在颜色上添加黑色/去除黑色。

Answer 1

import UIKit

extension String {
    subscript (range: Range<Int>) -> String {
        return range.startIndex < 0 || range.endIndex > count(self) ? "Out of Range" : substringWithRange(Range(start:advance(startIndex,range.startIndex),end:advance(startIndex,range.endIndex)))
    }
    var hexaCGFloat: CGFloat {
        return CGFloat(strtoul(self, nil, 16))
    }
}
extension UIColor {
    var rgbComponents:(red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) {
        var r:CGFloat = 0, g:CGFloat = 0, b:CGFloat = 0, a:CGFloat = 0
        if getRed(&r, green: &g, blue: &b, alpha: &a) {
            return (r,g,b,a)
        }
        return (0,0,0,0)
    }
    var hsbComponents:(hue: CGFloat, saturation: CGFloat, brightness: CGFloat, alpha: CGFloat) {
        var h:CGFloat = 0, s:CGFloat = 0, b:CGFloat = 0, a:CGFloat = 0
        if getHue(&h, saturation: &s, brightness: &b, alpha: &a){
            return (h,s,b,a)
        }
        return (0,0,0,0)
    }
    var hslComponents:(hue: CGFloat, saturation: CGFloat, lightness: CGFloat, alpha: CGFloat) {
        let rgb = rgbComponents, hsb = hsbComponents
        let maximum = max(rgb.red, rgb.green, rgb.blue)
        let minimum = min(rgb.red, rgb.green, rgb.blue)
        let range = maximum - minimum
        let lightness = (maximum + minimum) / 2.0
        let saturation = range == 0 ? 0 : range / { return lightness < 0.5 ? lightness * 2 : 2 - (lightness * 2) }()
        return (hsb.hue, saturation, lightness, hsb.alpha)
    }
    convenience init(hue: CGFloat, var saturation:CGFloat , var lightness:CGFloat , alpha: CGFloat) {
        lightness *= 2
        saturation *= lightness <= 1 ? lightness : 2 - lightness
        self.init(hue: hue, saturation: lightness == 0 ? 0 : (2*saturation)/(lightness+saturation), brightness: (lightness+saturation)/2, alpha: 1)
    }

    convenience init(htmlColor:String, alpha: Double) {
        self.init(red: htmlColor[0...1].hexaCGFloat / 255.0, green: htmlColor[2...3].hexaCGFloat / 255.0, blue: htmlColor[4...5].hexaCGFloat / 255.0, alpha: CGFloat(alpha)  )
    }
}

<强>测试

let color = UIColor(htmlColor: "5fc9f8", alpha: 1)

let colorHSL = color.hslComponents

let lighterColor = UIColor(hue:colorHSL.hue, saturation: colorHSL.saturation, lightness: min(colorHSL.lightness * 1.3,1.0), alpha: 1)
let darkerColor = UIColor(hue:colorHSL.hue, saturation: colorHSL.saturation, lightness: max(colorHSL.lightness * 0.5,0.0), alpha: 1)

Answer 2

RGB（红绿蓝色，十六进制代码表示的颜色）与亮度等颜色变换不一致。最简单的方法是将RGB颜色转换为HSB（色调饱和度亮度）或HSL（色调饱和度亮度），将亮度或亮度调整到所需亮度，然后将其转换回RGB。

有关如何将RGB转换为HSL的信息，请参阅here或here。

Answer 3

假设您通过以下方式设置背景颜色：

self.view.backgroundColor = UIColor.redColor()

我不打算告诉你如何将亮度改变一定量，这取决于你，但我会准确地告诉你改变backgroundColor亮度所需要的东西。（在这种情况下）：

//if you want the full brightness... brightness: 1.0
self.view.backgroundColor = UIColor(hue: 1.0, saturation: 1.0, brightness: 0.5, alpha: 1.0)

这会使亮度降低 50％，因为brightness: 0.5不是brightness: 1.0

但正如您所看到的，很容易将此功能绑定到增加或减少 backgroundColor的亮度（在此情况）。

Answer 4

This function will split RGB input value into each component color then add '1' to each (decreasing black, as you put it). Then it will recombine it to an RGB string and return the value. Changing the += to -= in a Darken function will "add black". function Lighten(RGB) { var R = parseInt(RGB.substring(0, 2)); var G = parseInt(RGB.substring(2, 4)); var B = parseInt(RGB.substring(4, 6)); R += 1; G += 1; B += 1; RGB = R.toString() + G.toString() + B.toString(); return RGB; } You could also add a second parameter to take a fixed amount to increase by.

给定一个颜色的十六进制，我怎样才能使颜色变浅和变暗？

4 个答案: