closed #89 make custom widgets codable

Shared/Color+Codable.swift

@@ -0,0 +1,100 @@
+//
+//  Color+Codable.swift
+//  FirestoreCodableSamples
+//
+//  Created by Peter Friese on 18.03.21.
+//
+
+import SwiftUI
+
+// Inspired by https://cocoacasts.com/from-hex-to-uicolor-and-back-in-swift
+// Make Color codable. This includes support for transparency.
+// See https://www.digitalocean.com/community/tutorials/css-hex-code-colors-alpha-values
+extension Color: Codable {
+    init(hex: String) {
+        let rgba = hex.toRGBA()
+        
+        self.init(.sRGB,
+                  red: Double(rgba.r),
+                  green: Double(rgba.g),
+                  blue: Double(rgba.b),
+                  opacity: Double(rgba.alpha))
+    }
+    
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let hex = try container.decode(String.self)
+        
+        self.init(hex: hex)
+    }
+    
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(toHex)
+    }
+    
+    var toHex: String? {
+        return toHex()
+    }
+    
+    func toHex(alpha: Bool = false) -> String? {
+        guard let components = cgColor?.components, components.count >= 3 else {
+            return nil
+        }
+        
+        let r = Float(components[0])
+        let g = Float(components[1])
+        let b = Float(components[2])
+        var a = Float(1.0)
+        
+        if components.count >= 4 {
+            a = Float(components[3])
+        }
+        
+        if alpha {
+            return String(format: "%02lX%02lX%02lX%02lX",
+                          lroundf(r * 255),
+                          lroundf(g * 255),
+                          lroundf(b * 255),
+                          lroundf(a * 255))
+        }
+        else {
+            return String(format: "%02lX%02lX%02lX",
+                          lroundf(r * 255),
+                          lroundf(g * 255),
+                          lroundf(b * 255))
+        }
+    }
+}
+
+extension String {
+    func toRGBA() -> (r: CGFloat, g: CGFloat, b: CGFloat, alpha: CGFloat) {
+        var hexSanitized = self.trimmingCharacters(in: .whitespacesAndNewlines)
+        hexSanitized = hexSanitized.replacingOccurrences(of: "#", with: "")
+        
+        var rgb: UInt64 = 0
+        
+        var r: CGFloat = 0.0
+        var g: CGFloat = 0.0
+        var b: CGFloat = 0.0
+        var a: CGFloat = 1.0
+        
+        let length = hexSanitized.count
+        
+        Scanner(string: hexSanitized).scanHexInt64(&rgb)
+        
+        if length == 6 {
+            r = CGFloat((rgb & 0xFF0000) >> 16) / 255.0
+            g = CGFloat((rgb & 0x00FF00) >> 8) / 255.0
+            b = CGFloat(rgb & 0x0000FF) / 255.0
+        }
+        else if length == 8 {
+            r = CGFloat((rgb & 0xFF000000) >> 24) / 255.0
+            g = CGFloat((rgb & 0x00FF0000) >> 16) / 255.0
+            b = CGFloat((rgb & 0x0000FF00) >> 8) / 255.0
+            a = CGFloat(rgb & 0x000000FF) / 255.0
+        }
+        
+        return (r, g, b, a)
+    }
+}