Match OpenSwiftUI.Color to SwiftUI.Color

Author: Cosmo

Sources/OpenSwiftUI/Views/Color.swift

@@ -1,13 +1,91 @@
+import Foundation
+
+public class AnyColorBox {
+}
+
+extension AnyColorBox: Hashable {
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(ObjectIdentifier(self).hashValue)
+    }
+}
+
+extension AnyColorBox: Equatable {
+    public static func == (lhs: AnyColorBox, rhs: AnyColorBox) -> Bool {
+        return ObjectIdentifier(lhs) == ObjectIdentifier(rhs)
+    }
+}
+
+public class SystemColorType: AnyColorBox {
+    public enum SystemColor: String {
+        case clear
+        case black
+        case white
+        case gray
+        case red
+        case green
+        case blue
+        case orange
+        case yellow
+        case pink
+        case purple
+        case primary
+        case secondary
+        case accentColor
+    }
+    
+    public let value: SystemColor
+    
+    internal init(value: SystemColorType.SystemColor) {
+        self.value = value
+    }
+    
+    public var description: String {
+        return value.rawValue
+    }
+}
+
+public class DisplayP3: AnyColorBox {
+    public let red: Double
+    public let green: Double
+    public let blue: Double
+    public let opacity: Double
+    
+    internal init(red: Double, green: Double, blue: Double, opacity: Double) {
+        self.red = red
+        self.green = green
+        self.blue = blue
+        self.opacity = opacity
+    }
+}
+
+extension Double {
+    fileprivate var hexString: String {
+        return String(format: "%02X", Int((self * 255).rounded()))
+    }
+}
+
+public class _Resolved: AnyColorBox {
+    public let linearRed: Double
+    public let linearGreen: Double
+    public let linearBlue: Double
+    public let opacity: Double
+    
+    internal init(linearRed: Double, linearGreen: Double, linearBlue: Double, opacity: Double) {
+        self.linearRed = linearRed
+        self.linearGreen = linearGreen
+        self.linearBlue = linearBlue
+        self.opacity = opacity
+    }
+    
+    public var description: String {
+        return "#\(linearRed.hexString)\(linearGreen.hexString)\(linearBlue.hexString)\(opacity.hexString)"
+    }
+}
+
 public struct Color: View, Hashable, CustomStringConvertible {
     public typealias Body = Never
 
-    // These values should be private,
-    // but then they are not accessible
-    // in implementations of OpenSwiftUI
-    public let _red: Double
-    public let _green: Double
-    public let _blue: Double
-    public let _opacity: Double
+    public let provider: AnyColorBox
 
     public enum RGBColorSpace: Equatable {
         case sRGB
@@ -16,47 +94,60 @@ public struct Color: View, Hashable, CustomStringConvertible {
     }
 
     public init(_ colorSpace: Color.RGBColorSpace = .sRGB, red: Double, green: Double, blue: Double, opacity: Double = 1) {
-        self._red = red
-        self._green = green
-        self._blue = blue
-        self._opacity = opacity
+        switch colorSpace {
+        case .sRGB:
+            self.provider = _Resolved(linearRed: red, linearGreen: green, linearBlue: blue, opacity: opacity)
+        case .sRGBLinear:
+            self.provider = _Resolved(linearRed: red, linearGreen: green, linearBlue: blue, opacity: opacity)
+        case .displayP3:
+            self.provider = DisplayP3(red: red, green: green, blue: blue, opacity: opacity)
+        }
     }
 
     public init(_ colorSpace: Color.RGBColorSpace = .sRGB, white: Double, opacity: Double = 1) {
-        self._red = white
-        self._green = white
-        self._blue = white
-        self._opacity = opacity
+        switch colorSpace {
+        case .sRGB:
+            self.provider = _Resolved(linearRed: white, linearGreen: white, linearBlue: white, opacity: opacity)
+        case .sRGBLinear:
+            self.provider = _Resolved(linearRed: white, linearGreen: white, linearBlue: white, opacity: opacity)
+        case .displayP3:
+            self.provider = DisplayP3(red: white, green: white, blue: white, opacity: opacity)
+        }
     }
 
     public init(hue: Double, saturation: Double, brightness: Double, opacity: Double = 1) {
-        // TODO: Implement HSBA to RGBA conversion.
-        fatalError("Not implemented")
+        let rgb = Color.hsbToRGB(hue: hue, saturation: saturation, brightness: brightness)
+        self.provider = _Resolved(linearRed: rgb.red, linearGreen: rgb.green, linearBlue: rgb.blue, opacity: opacity)
+    }
+    
+    internal init(_ systemColor: SystemColorType.SystemColor) {
+        self.provider = SystemColorType(value: systemColor)
     }
 
     public var body: Never {
         fatalError()
     }
 
     public var description: String {
-        return "Red: \(_red), Green: \(_green), Blue: \(_blue)"
+        return "\(provider)"
     }
 }
 
 extension Color {
-    public static let clear: Color = Color(hue: 0, saturation: 0, brightness: 0, opacity: 0)
-    public static let black: Color = Color(red: 0, green: 0, blue: 0)
-    public static let white: Color = Color(red: 1, green: 1, blue: 1)
-    public static let gray: Color = Color(red: 0.5, green: 0.5, blue: 0.5)
-    public static let red: Color = Color(red: 1, green: 0, blue: 0)
-    public static let green: Color = Color(red: 0, green: 1, blue: 0)
-    public static let blue: Color = Color(red: 0, green: 0, blue: 1)
-    public static let orange: Color = Color(red: 1, green: 0.5, blue: 0)
-    public static let yellow: Color = Color(red: 1, green: 1, blue: 0)
-    public static let pink: Color = Color(red: 1, green: 0, blue: 1)
-    public static let purple: Color = Color(red: 0.5, green: 0, blue: 1)
-    public static let primary: Color = Color(red: 1, green: 1, blue: 1)
-    public static let secondary: Color = Color(red: 0.8, green: 0.8, blue: 0.8)
+    public static let clear: Color = Color(.clear)
+    public static let black: Color = Color(.black)
+    public static let white: Color = Color(.white)
+    public static let gray: Color = Color(.gray)
+    public static let red: Color = Color(.red)
+    public static let green: Color = Color(.green)
+    public static let blue: Color = Color(.blue)
+    public static let orange: Color = Color(.orange)
+    public static let yellow: Color = Color(.yellow)
+    public static let pink: Color = Color(.pink)
+    public static let purple: Color = Color(.purple)
+    public static let primary: Color = Color(.primary)
+    public static let secondary: Color = Color(.secondary)
+    public static let accentColor: Color = Color(.accentColor)
 }
 
 extension View {
@@ -77,7 +168,53 @@ extension EnvironmentValues {
 }
 
 
-
+extension Color {
+    internal static func hsbToRGB(hue: Double, saturation: Double, brightness: Double) -> (red: Double, green: Double, blue: Double) {
+        // Based on:
+        // http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
+        
+        var red: Double = 0
+        var green: Double = 0
+        var blue: Double = 0
+        
+        let i = floor(hue * 6)
+        let f = hue * 6 - i
+        let p = brightness * (1 - saturation)
+        let q = brightness * (1 - f * saturation)
+        let t = brightness * (1 - (1 - f) * saturation)
+        
+        switch(i.truncatingRemainder(dividingBy: 6)) {
+        case 0:
+            red = brightness
+            green = t
+            blue = p
+        case 1:
+            red = q
+            green = brightness
+            blue = p
+        case 2:
+            red = p
+            green = brightness
+            blue = t
+        case 3:
+            red = p
+            green = q
+            blue = brightness
+        case 4:
+            red = t
+            green = p
+            blue = brightness
+        case 5:
+            red = brightness
+            green = p
+            blue = q
+        default:
+            break
+        }
+        
+        return (red, green, blue)
+    }
+}
 
 public enum ColorScheme: CaseIterable {
     case light