PickerView: add an initial implementation of PickerView

This adds a constrained implementation of PickerView.  It sketches out
the various pieces that are needed to get a working picker view.
Ideally, we would use the `CBS_OWNERDRAWVARIABLE` to render the views
individually sized, but that seems to cause an issue with the draw
operation, where the draw is never invoked for each item.  This
currently restricts us to equal sized views rather than variable sized
views.

The other important missing piece here is the lack of support for
multi-component pickers.  This should be possible to do in practice
since the backing widget tree is a ListBox and an Edit container.  We
should be able to render more complicated views accordingly.

Resolves: #425

Author: compnerd

Examples/UICatalog/UICatalog.swift

@@ -60,6 +60,9 @@ final class UICatalog: ApplicationDelegate, SceneDelegate {
       TableView(frame: Rect(x: 4.0, y: 310.0, width: 254.0, height: 48.0),
                 style: .plain)
 
+  lazy var pickerview: PickerView =
+      PickerView(frame: Rect(x: 4.0, y: 362.0, width: 256.0, height: 24.0))
+
   lazy var imageview: ImageView = {
 #if SWIFT_PACKAGE
     let bundle: Bundle = Bundle.module
@@ -72,7 +75,7 @@ final class UICatalog: ApplicationDelegate, SceneDelegate {
     }
     let image: Image? = Image(contentsOfFile: resource.path)
     let view = ImageView(image: image)
-    view.frame = Rect(x: 64.0, y: 362.0, width: 128.0, height: 128.0)
+    view.frame = Rect(x: 64.0, y: 394.0, width: 128.0, height: 128.0)
     return view
   }()
 
@@ -82,7 +85,7 @@ final class UICatalog: ApplicationDelegate, SceneDelegate {
 
     // Set the preferred window size and restrict resizing by setting the
     // minimum and maximum to the same value.
-    let size: Size = Size(width: 265, height: 494)
+    let size: Size = Size(width: 265, height: 530)
     windowScene.sizeRestrictions?.minimumSize = size
     windowScene.sizeRestrictions?.maximumSize = size
 
@@ -103,6 +106,7 @@ final class UICatalog: ApplicationDelegate, SceneDelegate {
     window.addSubview(self.stepperLabel)
     window.addSubview(self.stepper)
     window.addSubview(self.tableview)
+    window.addSubview(self.pickerview)
     window.addSubview(self.imageview)
 
     self.label.font = Font(name: "Consolas", size: 10)!
@@ -137,6 +141,10 @@ Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deseru
 
     self.tableview.dataSource = self
 
+    self.pickerview.dataSource = self
+    self.pickerview.delegate = self
+    self.pickerview.reloadAllComponents()
+
     window.makeKeyAndVisible()
   }
 
@@ -175,3 +183,29 @@ extension UICatalog: TableViewDataSource {
     return cell
   }
 }
+
+extension UICatalog: PickerViewDataSource {
+  public func numberOfComponents(in pickerView: PickerView) -> Int {
+    return 1
+  }
+
+  public func pickerView(_ pickerView: PickerView,
+                         numberOfRowsInComponent component: Int) -> Int {
+    return 7
+  }
+}
+
+extension UICatalog: PickerViewDelegate {
+  public func pickerView(_ pickerView: PickerView, titleForRow row: Int,
+                         forComponent component: Int) -> String? {
+    return [
+      "Sunday",
+      "Monday",
+      "Tuesday",
+      "Wednesday",
+      "Thursday",
+      "Friday",
+      "Saturday",
+    ][row]
+  }
+}

Sources/SwiftWin32/CMakeLists.txt

@@ -107,6 +107,7 @@ target_sources(SwiftWin32 PRIVATE
   "Views and Controls/EdgeInsets.swift"
   "Views and Controls/ImageView.swift"
   "Views and Controls/Label.swift"
+  "Views and Controls/PickerView.swift"
   "Views and Controls/ProgressView.swift"
   "Views and Controls/Slider.swift"
   "Views and Controls/Stepper.swift"