Initial commit: Snipping Tool menu bar screenshot app

Sources/KeyCaptureRepresentable.swift

@@ -0,0 +1,54 @@
+import AppKit
+import Carbon.HIToolbox
+import SwiftUI
+
+/// Invisible NSView overlay that becomes first responder while recording
+/// and reports the next key combo (key code + modifiers) it sees.
+final class KeyCaptureView: NSView {
+    var onCapture: ((UInt32, UInt32) -> Void)?
+    var onCancel: (() -> Void)?
+
+    override var acceptsFirstResponder: Bool { true }
+
+    override func keyDown(with event: NSEvent) {
+        if Int(event.keyCode) == kVK_Escape {
+            onCancel?()
+            return
+        }
+
+        var modifiers: UInt32 = 0
+        if event.modifierFlags.contains(.control) { modifiers |= UInt32(controlKey) }
+        if event.modifierFlags.contains(.option) { modifiers |= UInt32(optionKey) }
+        if event.modifierFlags.contains(.shift) { modifiers |= UInt32(shiftKey) }
+        if event.modifierFlags.contains(.command) { modifiers |= UInt32(cmdKey) }
+
+        // Require at least one modifier so plain letters still work normally elsewhere.
+        guard modifiers != 0 else { return }
+        onCapture?(UInt32(event.keyCode), modifiers)
+    }
+}
+
+struct KeyCaptureRepresentable: NSViewRepresentable {
+    @Binding var isRecording: Bool
+    let onCapture: (UInt32, UInt32) -> Void
+
+    func makeNSView(context: Context) -> KeyCaptureView {
+        let view = KeyCaptureView()
+        view.onCapture = { keyCode, modifiers in
+            onCapture(keyCode, modifiers)
+            isRecording = false
+        }
+        view.onCancel = {
+            isRecording = false
+        }
+        return view
+    }
+
+    func updateNSView(_ nsView: KeyCaptureView, context: Context) {
+        if isRecording {
+            DispatchQueue.main.async {
+                nsView.window?.makeFirstResponder(nsView)
+            }
+        }
+    }
+}