iOS 14 / macOS 10.16

There is a new initializer that takes a Color and returns a UIColor for iOS or NSColor for macOS now. With the help of those you can implement the following extensions:

iOS / macOS

import SwiftUI#if canImport(UIKit)import UIKit#elseif canImport(AppKit)import AppKit#endifextension Color {    var components: (red: CGFloat, green: CGFloat, blue: CGFloat, opacity: CGFloat) {        #if canImport(UIKit)        typealias NativeColor = UIColor        #elseif canImport(AppKit)        typealias NativeColor = NSColor        #endif        var r: CGFloat = 0        var g: CGFloat = 0        var b: CGFloat = 0        var o: CGFloat = 0        guard NativeColor(self).getRed(&r, green: &g, blue: &b, alpha: &o) else {            // You can handle the failure here as you want            return (0, 0, 0, 0)        }        return (r, g, b, o)    }}

Usage

Color.red.components.red // 0.9999999403953552 // <- SwiftUI Colors are not pure!

Waiting for an API I've abused CustomStringConvertible protocol for the simple rgba case where the color description format is #rrggbbaa

debugPrint(Color.red)debugPrint(Color(red: 1.0, green: 0.0, blue: 0.0))debugPrint(Color(red: 1.0, green: 0.3, blue: 0.0))debugPrint(Color(.sRGB, red: 1.0, green: 0.0, blue: 0.5, opacity: 0.3))debugPrint(Color(hue: 1.0, saturation: 0.0, brightness: 1.0))debugPrint(Color(.displayP3, red: 1.0, green: 0.0, blue: 0.0, opacity: 1.0).description)red#FF0000FF#FF4C00FF#FF00804D#FFFFFFFF"DisplayP3(red: 1.0, green: 0.0, blue: 0.0, opacity: 1.0)"

as you can see, things like Color.red just dump "red" but if you are working with simple RGB colors generated by code (ie from a color picker) then this is not too bad

extension SwiftUI.Color {    var redComponent: Double? {        let val = description        guard val.hasPrefix("#") else { return nil }        let r1 = val.index(val.startIndex, offsetBy: 1)        let r2 = val.index(val.startIndex, offsetBy: 2)        return Double(Int(val[r1...r2], radix: 16)!) / 255.0    }    var greenComponent: Double? {        let val = description        guard val.hasPrefix("#") else { return nil }        let g1 = val.index(val.startIndex, offsetBy: 3)        let g2 = val.index(val.startIndex, offsetBy: 4)        return Double(Int(val[g1...g2], radix: 16)!) / 255.0    }    var blueComponent: Double? {        let val = description        guard val.hasPrefix("#") else { return nil }        let b1 = val.index(val.startIndex, offsetBy: 5)        let b2 = val.index(val.startIndex, offsetBy: 6)        return Double(Int(val[b1...b2], radix: 16)!) / 255.0    }    var opacityComponent: Double? {        let val = description        guard val.hasPrefix("#") else { return nil }        let b1 = val.index(val.startIndex, offsetBy: 7)        let b2 = val.index(val.startIndex, offsetBy: 8)        return Double(Int(val[b1...b2], radix: 16)!) / 255.0    }}

You can use UIColor and transform the UIColor to Color after.Code:

extension UIColor {    func hexValue() -> String {        let values = self.cgColor.components        var outputR: Int = 0        var outputG: Int = 0        var outputB: Int = 0        var outputA: Int = 1        switch values!.count {            case 1:                outputR = Int(values![0] * 255)                outputG = Int(values![0] * 255)                outputB = Int(values![0] * 255)                outputA = 1            case 2:                outputR = Int(values![0] * 255)                outputG = Int(values![0] * 255)                outputB = Int(values![0] * 255)                outputA = Int(values![1] * 255)            case 3:                outputR = Int(values![0] * 255)                outputG = Int(values![1] * 255)                outputB = Int(values![2] * 255)                outputA = 1            case 4:                outputR = Int(values![0] * 255)                outputG = Int(values![1] * 255)                outputB = Int(values![2] * 255)                outputA = Int(values![3] * 255)            default:                break        }        return "#" + String(format:"%02X", outputR) + String(format:"%02X", outputG) + String(format:"%02X", outputB) + String(format:"%02X", outputA)    }}