Fix/progess spinner resizing

Examples/Sources/ControlsExample/ControlsApp.swift

@@ -16,71 +16,83 @@ struct ControlsApp: App {
     @State var text = ""
     @State var flavor: String? = nil
     @State var enabled = true
+    @State var progressViewSize: Int = 10
+    @State var isProgressViewResizable = true
 
     var body: some Scene {
         WindowGroup("ControlsApp") {
             #hotReloadable {
-                VStack(spacing: 30) {
-                    VStack {
-                        Text("Button")
-                        Button("Click me!") {
-                            count += 1
+                ScrollView {
+                    VStack(spacing: 30) {
+                        VStack {
+                            Text("Button")
+                            Button("Click me!") {
+                                count += 1
+                            }
+                            Text("Count: \(count)")
                         }
-                        Text("Count: \(count)")
-                    }
-                    .padding(.bottom, 20)
+                        .padding(.bottom, 20)
+
+                        #if !canImport(UIKitBackend)
+                            VStack {
+                                Text("Toggle button")
+                                Toggle("Toggle me!", active: $exampleButtonState)
+                                    .toggleStyle(.button)
+                                Text("Currently enabled: \(exampleButtonState)")
+                            }
+                            .padding(.bottom, 20)
+                        #endif
 
-                    #if !canImport(UIKitBackend)
                         VStack {
-                            Text("Toggle button")
-                            Toggle("Toggle me!", active: $exampleButtonState)
-                                .toggleStyle(.button)
-                            Text("Currently enabled: \(exampleButtonState)")
+                            Text("Toggle switch")
+                            Toggle("Toggle me:", active: $exampleSwitchState)
+                                .toggleStyle(.switch)
+                            Text("Currently enabled: \(exampleSwitchState)")
                         }
-                        .padding(.bottom, 20)
-                    #endif
 
-                    VStack {
-                        Text("Toggle switch")
-                        Toggle("Toggle me:", active: $exampleSwitchState)
-                            .toggleStyle(.switch)
-                        Text("Currently enabled: \(exampleSwitchState)")
-                    }
+                        #if !canImport(UIKitBackend)
+                            VStack {
+                                Text("Checkbox")
+                                Toggle("Toggle me:", active: $exampleCheckboxState)
+                                    .toggleStyle(.checkbox)
+                                Text("Currently enabled: \(exampleCheckboxState)")
+                            }
+                        #endif
 
-                    #if !canImport(UIKitBackend)
                         VStack {
-                            Text("Checkbox")
-                            Toggle("Toggle me:", active: $exampleCheckboxState)
-                                .toggleStyle(.checkbox)
-                            Text("Currently enabled: \(exampleCheckboxState)")
+                            Text("Slider")
+                            Slider($sliderValue, minimum: 0, maximum: 10)
+                                .frame(maxWidth: 200)
+                            Text("Value: \(String(format: "%.02f", sliderValue))")
                         }
-                    #endif
 
-                    VStack {
-                        Text("Slider")
-                        Slider($sliderValue, minimum: 0, maximum: 10)
-                            .frame(maxWidth: 200)
-                        Text("Value: \(String(format: "%.02f", sliderValue))")
-                    }
+                        VStack {
+                            Text("Text field")
+                            TextField("Text field", text: $text)
+                            Text("Value: \(text)")
+                        }
 
-                    VStack {
-                        Text("Text field")
-                        TextField("Text field", text: $text)
-                        Text("Value: \(text)")
-                    }
+                        Toggle("Enable ProgressView resizability", active: $isProgressViewResizable)
+                        Slider($progressViewSize, minimum: 10, maximum: 100)
+                        ProgressView()
+                            .resizable(isProgressViewResizable)
+                            .frame(width: progressViewSize, height: progressViewSize)
 
-                    VStack {
-                        Text("Drop down")
-                        HStack {
-                            Text("Flavor: ")
-                            Picker(of: ["Vanilla", "Chocolate", "Strawberry"], selection: $flavor)
+                        VStack {
+                            Text("Drop down")
+                            HStack {
+                                Text("Flavor: ")
+                                Picker(
+                                    of: ["Vanilla", "Chocolate", "Strawberry"], selection: $flavor)
+                            }
+                            Text("You chose: \(flavor ?? "Nothing yet!")")
                         }
-                        Text("You chose: \(flavor ?? "Nothing yet!")")
-                    }
-                }.padding().disabled(!enabled)
+                    }.padding().disabled(!enabled)
 
-                Toggle(enabled ? "Disable all" : "Enable all", active: $enabled)
-                    .padding()
+                    Toggle(enabled ? "Disable all" : "Enable all", active: $enabled)
+                        .padding()
+                }
+                .frame(minHeight: 600)
             }
         }.defaultSize(width: 400, height: 600)
     }

Sources/AppKitBackend/AppKitBackend.swift

@@ -485,6 +485,15 @@ public final class AppKitBackend: AppBackend {
     }
 
     public func naturalSize(of widget: Widget) -> SIMD2<Int> {
+        if let spinner = widget.subviews.first as? NSProgressIndicator,
+            spinner.style == .spinning
+        {
+            let size = spinner.intrinsicContentSize
+            return SIMD2(
+                Int(size.width),
+                Int(size.height)
+            )
+        }
         let size = widget.intrinsicContentSize
         return SIMD2(
             Int(size.width),
@@ -1168,11 +1177,32 @@ public final class AppKitBackend: AppBackend {
     }
 
     public func createProgressSpinner() -> Widget {
+        let container = NSView()
+        let spinner = NSProgressIndicator()
+        spinner.translatesAutoresizingMaskIntoConstraints = false
+        spinner.isIndeterminate = true
+        spinner.style = .spinning
+        spinner.startAnimation(nil)
+        container.addSubview(spinner)
+        return container
+    }
+
+    public func setSize(
+        ofProgressSpinner widget: Widget,
+        to size: SIMD2<Int>
+    ) {
+        guard Int(widget.frame.size.height) != size.y else { return }
+        setSize(of: widget, to: size)
         let spinner = NSProgressIndicator()
+        spinner.translatesAutoresizingMaskIntoConstraints = false
         spinner.isIndeterminate = true
         spinner.style = .spinning
         spinner.startAnimation(nil)
-        return spinner
+        spinner.widthAnchor.constraint(equalToConstant: CGFloat(size.x)).isActive = true
+        spinner.heightAnchor.constraint(equalToConstant: CGFloat(size.y)).isActive = true
+
+        widget.subviews = []
+        widget.addSubview(spinner)
     }
 
     public func createProgressBar() -> Widget {

Sources/SwiftCrossUI/Backend/AppBackend.swift

@@ -550,6 +550,16 @@ public protocol AppBackend: Sendable {
     /// Creates an indeterminate progress spinner.
     func createProgressSpinner() -> Widget
 
+    /// Sets the size of a progress spinner.
+    ///
+    /// This method exists because AppKitBackend requires special handling to resize progress spinners.
+    ///
+    /// The default implementation forwards to ``AppBackend/setSize(of:to:)``.
+    func setSize(
+        ofProgressSpinner widget: Widget,
+        to size: SIMD2<Int>
+    )
+
     /// Creates a progress bar.
     func createProgressBar() -> Widget
     /// Updates a progress bar to reflect the given progress (between 0 and 1), and the
@@ -1123,6 +1133,13 @@ extension AppBackend {
         todo()
     }
 
+    public func setSize(
+        ofProgressSpinner widget: Widget,
+        to size: SIMD2<Int>
+    ) {
+        setSize(of: widget, to: size)
+    }
+
     public func createProgressBar() -> Widget {
         todo()
     }

Sources/SwiftCrossUI/Builders/MenuItemsBuilder.swift

@@ -4,7 +4,7 @@ public struct MenuItemsBuilder {
     public static func buildBlock() -> [MenuItem] {
         []
     }
-    
+
     public static func buildPartialBlock(first: Button) -> [MenuItem] {
         [.button(first)]
     }

Sources/SwiftCrossUI/Layout/LayoutSystem.swift

@@ -59,7 +59,8 @@ public enum LayoutSystem {
         var tag: String?
 
         public init(
-            computeLayout: @escaping @MainActor (ProposedViewSize, EnvironmentValues) ->
+            computeLayout:
+                @escaping @MainActor (ProposedViewSize, EnvironmentValues) ->
                 ViewLayoutResult,
             commit: @escaping @MainActor () -> ViewLayoutResult,
             tag: String? = nil

Sources/SwiftCrossUI/Views/EitherView.swift

@@ -59,7 +59,7 @@ extension EitherView: TypeSafeView {
         switch storage {
             case .a(let a):
                 switch children.node {
-                    case let .a(nodeA):
+                    case .a(let nodeA):
                         result = nodeA.computeLayout(
                             with: a,
                             proposedSize: proposedSize,
@@ -82,7 +82,7 @@ extension EitherView: TypeSafeView {
                 }
             case .b(let b):
                 switch children.node {
-                    case let .b(nodeB):
+                    case .b(let nodeB):
                         result = nodeB.computeLayout(
                             with: b,
                             proposedSize: proposedSize,

Sources/SwiftCrossUI/Views/ProgressView.swift

@@ -4,6 +4,7 @@ public struct ProgressView<Label: View>: View {
     private var label: Label
     private var progress: Double?
     private var kind: Kind
+    private var isSpinnerResizable: Bool = false
 
     private enum Kind {
         case spinner
@@ -23,7 +24,7 @@ public struct ProgressView<Label: View>: View {
     private var progressIndicator: some View {
         switch kind {
             case .spinner:
-                ProgressSpinnerView()
+                ProgressSpinnerView(isResizable: isSpinnerResizable)
             case .bar:
                 ProgressBarView(value: progress)
         }
@@ -50,6 +51,14 @@ public struct ProgressView<Label: View>: View {
         self.kind = .bar
         self.progress = value.map(Double.init)
     }
+
+    /// Makes the ProgressView resize to fit the available space.
+    /// Only affects ``Kind/spinner``.
+    public func resizable(_ isResizable: Bool = true) -> Self {
+        var progressView = self
+        progressView.isSpinnerResizable = isResizable
+        return progressView
+    }
 }
 
 extension ProgressView where Label == EmptyView {
@@ -101,7 +110,11 @@ extension ProgressView where Label == Text {
 }
 
 struct ProgressSpinnerView: ElementaryView {
-    init() {}
+    let isResizable: Bool
+
+    init(isResizable: Bool = false) {
+        self.isResizable = isResizable
+    }
 
     func asWidget<Backend: AppBackend>(backend: Backend) -> Backend.Widget {
         backend.createProgressSpinner()
@@ -113,16 +126,40 @@ struct ProgressSpinnerView: ElementaryView {
         environment: EnvironmentValues,
         backend: Backend
     ) -> ViewLayoutResult {
-        let size = ViewSize(backend.naturalSize(of: widget))
-        return ViewLayoutResult.leafView(size: size)
+        let naturalSize = backend.naturalSize(of: widget)
+
+        guard isResizable else {
+            // Required to reset its size when resizability
+            // gets changed at runtime
+            return ViewLayoutResult.leafView(size: ViewSize(naturalSize))
+        }
+
+        let minimumDimension: Double
+
+        if let proposedWidth = proposedSize.width,
+            let proposedHeight = proposedSize.height
+        {
+            minimumDimension = max(min(proposedWidth, proposedHeight), 0)
+        } else {
+            minimumDimension = Double(min(naturalSize.x, naturalSize.y))
+        }
+
+        return ViewLayoutResult.leafView(
+            size: .init(minimumDimension, minimumDimension)
+        )
     }
 
     func commit<Backend: AppBackend>(
         _ widget: Backend.Widget,
         layout: ViewLayoutResult,
         environment: EnvironmentValues,
         backend: Backend
-    ) {}
+    ) {
+        // Doesn't change the rendered size of ProgressSpinner
+        // on UIKitBackend, but still sets container size to
+        // (width: n, height: n) n = min(proposedSize.x, proposedSize.y)
+        backend.setSize(ofProgressSpinner: widget, to: layout.size.vector)
+    }
 }
 
 struct ProgressBarView: ElementaryView {

Sources/SwiftCrossUI/Views/ScrollView.swift

@@ -122,14 +122,16 @@ public struct ScrollView<Content: View>: TypeSafeView, View {
         // Compute the outer size.
         var outerSize = finalChildResult.size
         if axes.contains(.horizontal) {
-            outerSize.width = proposedSize.width
+            outerSize.width =
+                proposedSize.width
                 ?? (finalChildResult.size.width + verticalScrollBarWidth)
         } else {
             outerSize.width += verticalScrollBarWidth
         }
 
         if axes.contains(.vertical) {
-            outerSize.height = proposedSize.height
+            outerSize.height =
+                proposedSize.height
                 ?? (finalChildResult.size.height + horizontalScrollBarHeight)
         } else {
             outerSize.height += horizontalScrollBarHeight