Merge branch 'dev'

.gitignore

@@ -3,3 +3,4 @@
 /Packages
 /*.xcodeproj
 xcuserdata/
+.swiftpm/xcode

Package.swift

@@ -5,6 +5,9 @@ import PackageDescription
 
 let package = Package(
   name: "UIPreview",
+  platforms: [
+    .iOS(.v13)
+  ],
   products: [
     // Products define the executables and libraries a package produces, and make them visible to other packages.
     .library(

Sources/UIPreview/Binding+Mock.swift

@@ -1,4 +1,7 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
+import UIKit
 
 @available(iOS 13, *)
 extension Binding {

Sources/UIPreview/CatalogPage.swift

@@ -0,0 +1,47 @@
+#if canImport(SwiftUI)
+import SwiftUI
+#endif
+import UIKit
+
+@available(iOS 13, *)
+struct CatalogPage<Content: UIViewCatalogPresentable>: View {
+
+  let schemes: [ColorScheme]
+
+  var body: some View {
+    NavigationView {
+      ScrollView(.vertical, showsIndicators: true) {
+        ForEach(values: Content.previewModels) { model in
+          ForEach(values: schemes) { scheme in
+            item(title: "\(scheme):  \(model)") {
+              ColorSchemePreview(scheme: scheme) {
+                Content.preview(with: model)
+              }
+            }
+          }
+        }
+      }.navigationBarTitle(String(describing: Content.self))
+    }
+  }
+
+  func item<Content: View>(title: String,
+                           @ViewBuilder content: @escaping () -> Content
+  ) -> some View {
+    VStack(alignment: .center, spacing: 12.0) {
+      Text(title)
+        .font(.subheadline)
+        .fontWeight(.bold)
+      content()
+    }
+    .frame(maxWidth: .infinity, alignment: .center)
+    .padding()
+  }
+}
+
+@available(iOS 13, *)
+struct CatalogPage_Previews: PreviewProvider {
+  static var previews: some View {
+    CatalogPage<UISwitch>(schemes: [.light, .dark, ])
+    CatalogPage<UILabel>(schemes: [.light, .dark, ])
+  }
+}

Sources/UIPreview/Demo.swift

@@ -1,34 +1,30 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
+import UIKit
 
-@available(iOS 13, *)
+extension UISwitch: UICatalogPresentable {
-struct ContentView: View {
+  public static var previewModels = [true, false]
-  var body: some View {
+
-    Text("Hello, world!")
+  public func apply(previewModel: Bool) {
-      .background(Color(.red)).padding()
+    isOn = previewModel
   }
 }
 
-@available(iOS 13, *)
+extension UILabel: UICatalogPresentable {
-struct ContentView_Previews: PreviewProvider {
+  public static var previewModels: [String] {
-  static var previews: some View {
+    ["123", "345", "Hello world", "How do you do"]
-    ContentView()
+  }
-      .previewDarkTheme()
+
+  public func apply(previewModel: String) {
+    text = previewModel
+  }
+
+  public static func makePreviewInstance() -> Self {
+    let label = UILabel()
+    label.adjustsFontForContentSizeCategory = true
+    label.font = UIFont.preferredFont(forTextStyle: .caption1)
+    return label as! Self
   }
 }
 
-@available(iOS 13, *)
-struct Demo_Previews: PreviewProvider {
-  static var previews: some View {
-    Group {
-      UIViewPreview(UIView())
-        .frame(width: 100, height: 30)
-        .background(Color(.red))
-        .previewLayout(.sizeThatFits)
-      UIViewPreview(UILabel(), update: {
-        $0.text = "Hello"
-        $0.font = UIFont.preferredFont(forTextStyle: .caption1)
-        $0.adjustsFontForContentSizeCategory = true
-      }).previewAsComponent()
-    }
-  }
-}

Sources/UIPreview/ForEach+Raw.swift

@@ -1,4 +1,6 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
 
 @available(iOS 13, *)
 extension ForEach where Data.Element: Hashable, ID == Data.Element, Content: View {

Sources/UIPreview/PreviewColorScheme.swift

@@ -1,4 +1,6 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
 
 @available(iOS 13, *)
 extension View {

Sources/UIPreview/PreviewComponent.swift

@@ -1,4 +1,6 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
 
 @available(iOS 13, *)
 extension View {
@@ -24,7 +26,7 @@ struct ComponentPreview<Component: View>: View {
     ForEach(values: ColorScheme.allCases) { scheme in
       ForEach(values: ContentSizeCategory.smallestAndLargest) { category in
         self.component
-          .previewLayout(.sizeThatFits)
+          .previewLayout(.sizeThatFits).padding()
           .background(Color(.systemBackground))
           .colorScheme(scheme)
           .environment(\.sizeCategory, category)

Sources/UIPreview/PreviewScreen.swift

@@ -1,4 +1,6 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
 
 //xcrun simctl list devicetypes
 public let defaultDeviceNames: [String] =

Sources/UIPreview/UICatalog.swift

@@ -0,0 +1,29 @@
+#if canImport(SwiftUI)
+import SwiftUI
+#endif
+import UIKit
+
+public enum UICatalog {
+  public enum Theme {
+    case light, dark
+  }
+
+  public static func makePreviewPage<Content>(_ content: Content.Type,
+                                              themes: [Theme] = [.light, .dark]
+  ) -> UIViewController where Content: UIViewCatalogPresentable {
+    guard #available(iOS 13, *) else {
+      return UIViewController()
+    }
+    return CatalogPage<Content>(schemes: themes.map(\.scheme)).asViewController()
+  }
+}
+
+@available(iOS 13, *)
+extension UICatalog.Theme {
+  var scheme: ColorScheme {
+    switch self {
+    case .light: return .light
+    case .dark: return .dark
+    }
+  }
+}

Sources/UIPreview/UICatalogPresentable.swift

@@ -0,0 +1,31 @@
+#if canImport(SwiftUI)
+import SwiftUI
+#endif
+import UIKit
+
+public protocol UICatalogPresentable {
+  associatedtype PreviewModel: Hashable
+
+  func apply(previewModel: PreviewModel)
+
+  static var previewModels: [PreviewModel] { get }
+
+  static func makePreviewInstance() -> Self
+}
+
+public typealias UIViewCatalogPresentable = UIView & UICatalogPresentable
+
+
+@available(iOS 13, *)
+extension UICatalogPresentable where Self: UIView {
+  public func preview(with model: PreviewModel) -> some View {
+    UIViewPreview(self) { $0.apply(previewModel: model) }
+  }
+
+  public static func preview(with model: PreviewModel) -> some View {
+    makePreviewInstance().preview(with: model)
+  }
+
+  public static func makePreviewInstance() -> Self { self.init() }
+}
+

Sources/UIPreview/UIViewControllerPreview.swift

@@ -1,6 +1,9 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
 import UIKit
 
+@available(iOS 13, *)
 public struct UIViewControllerPreview<ContentView: UIViewController>: UIViewControllerRepresentable {
   let contextBuilder: () -> ViewCoordinator<ContentView>
 

Sources/UIPreview/UIViewPreview.swift

@@ -1,6 +1,9 @@
+#if canImport(SwiftUI)
 import SwiftUI
+#endif
 import UIKit
 
+@available(iOS 13, *)
 public struct UIViewPreview<ContentView: UIView>: UIViewRepresentable {
   let contextBuilder: () -> ViewCoordinator<ContentView>
 

Sources/UIPreview/View+UIViewController.swift

@@ -0,0 +1,11 @@
+#if canImport(SwiftUI)
+import SwiftUI
+#endif
+import UIKit
+
+@available(iOS 13, *)
+extension View {
+  public func asViewController() -> UIViewController {
+    UIHostingController(rootView: self)
+  }
+}