我提出了以下解决方案,但想知道是否有人采用更清晰的方法(在
Xcode-Playground中测试)：
let colors = CGColorGetComponents( UIColor.greenColor().CGColor ) let hexCol:String = Nsstring(format: "#%02x%02x%02x",Int(colors[0] * 255.0),Int(colors[1] * 255.0),Int(colors[2] * 255.0))
结果是#00ff00
其中UIColor.greenColor()是任何UIColor的示例.
编辑：
取自莱昂纳多的答案,我觉得有点重构(他的所有测试仍然适用).
extension UIColor {
typealias RGBComponents = (red: CGFloat,green: CGFloat,blue: CGFloat,alpha: CGFloat)
typealias HSBComponents = (hue: CGFloat,saturation: CGFloat,brightness: CGFloat,alpha: CGFloat)
var rgbComponents:RGBComponents {
var c:RGBComponents = (0,0)
if getRed(&c.red,green: &c.green,blue: &c.blue,alpha: &c.alpha) {
return c
}
return (0,0)
}
var cssRGBA:String {
return String(format: "rgba(%d,%d,%.02f)",Int(rgbComponents.red * 255),Int(rgbComponents.green * 255),Int(rgbComponents.blue * 255),Float(rgbComponents.alpha))
}
var hexRGB:String {
return String(format: "#%02x%02x%02x",Int(rgbComponents.blue * 255))
}
var hexRGBA:String {
return String(format: "#%02x%02x%02x%02x",Int(rgbComponents.alpha * 255) )
}
var hsbComponents:HSBComponents {
var c:HSBComponents = (0,0)
if getHue(&c.hue,saturation: &c.saturation,brightness: &c.brightness,0)
}
}
let v1 = UIColor.redColor().rgbComponents.red
let v2 = UIColor.redColor().cssRGBA
let v3 = UIColor.redColor().hexRGBA
let v4test = UIColor.RGBComponents(red: 0.0,green: 0.0,blue: 0.0,alpha: 0.0)
解决方法
Xcode 8.2•Swift 3.0.2
从UIColor获取红色,绿色,蓝色和Alpha组件：
extension UIColor {
var rgba: (red: 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)
}
// hue,saturation,brightness and alpha components from UIColor**
var hsba: (hue: CGFloat,alpha: CGFloat) {
var hue: CGFloat = 0,saturation: CGFloat = 0,brightness: CGFloat = 0,alpha: CGFloat = 0
if getHue(&hue,saturation: &saturation,brightness: &brightness,alpha: &alpha) {
return (hue,brightness,alpha)
}
return (0,0)
}
var htmlRGB: String {
return String(format: "#%02x%02x%02x",Int(rgba.red * 255),Int(rgba.green * 255),Int(rgba.blue * 255))
}
var htmlRGBA: String {
return String(format: "#%02x%02x%02x%02x",Int(rgba.blue * 255),Int(rgba.alpha * 255) )
}
}
测试它：
HTML颜色
let myWhiteWebColor = UIColor(red: 1,green: 1,blue: 1,alpha: 1).htmlRGBA // #ffffffff let myGreyWebColor = UIColor(red: 0.5,green: 0.5,blue: 0.5,alpha: 1).htmlRGBA // #7f7f7fff let myBlackWebColor = UIColor(red: 0,green: 0,blue: 0,alpha: 1).htmlRGBA // #000000ff let myRedWebColor = UIColor(red: 1,alpha: 1).htmlRGBA // #ff0000ff let myGreenWebColor = UIColor(red: 0,alpha: 1).htmlRGBA // #00ff00ff let myBlueWebColor = UIColor(red: 0,alpha: 1).htmlRGBA // #0000ffff let myColorBlack = UIColor.black.htmlRGBA // #000000ff let myLghtGrayColor = UIColor.lightGray.htmlRGBA // #aaaaaaff let myDarkGrayColor = UIColor.darkGray.htmlRGBA // #555555ff let myRedHueWebColor = UIColor(hue: 1,saturation: 1,brightness: 1,alpha: 1).htmlRGBA //ff0000ff
RGB组件
UIColor.red.rgba // (1.0,0.0,1.0) UIColor.red.rgba.red // 1 UIColor.red.rgba.green // 0 UIColor.red.rgba.blue // 0 UIColor.red.rgba.alpha // 1 UIColor.green.rgba // (0.0,1.0,1.0) UIColor.green.rgba.red // 0 UIColor.green.rgba.green // 1 UIColor.green.rgba.blue // 0 UIColor.green.rgba.alpha // 1 UIColor.blue.rgba // (0.0,1.0) UIColor.blue.rgba.red // 0 UIColor.blue.rgba.green // 0 UIColor.blue.rgba.blue // 1 UIColor.blue.rgba.alpha // 1
Hue组件
UIColor.red.hsba // (0.0,1.0) UIColor.red.hsba.hue // 1 UIColor.red.hsba.saturation // 1 UIColor.red.hsba.brightness // 1 UIColor.red.hsba.alpha // 1 UIColor.green.hsba // (0.333333333333333,1.0) UIColor.green.hsba.hue // 0.3333333333333333 UIColor.green.hsba.saturation // 1 UIColor.green.hsba.brightness // 1 UIColor.green.hsba.alpha // 1 UIColor.blue.hsba // (0.666666666666667,1.0) UIColor.blue.hsba.hue // 0.666666666666667 UIColor.blue.hsba.saturation // 1.0 UIColor.blue.hsba.brightness // 1.0 UIColor.blue.hsba.alpha // 1.0 UIColor.clear.hsba // (.0 0,.1 0,.2 0,.3 0) UIColor.blue.htmlRGB //"#0000ff" UIColor.blue.htmlRGBA //"#0000ffff"