example work

veilid-flutter/example/lib/virtual_keyboard.dart

@@ -0,0 +1,80 @@
+import 'package:flutter/material.dart';
+import 'package:xterm/xterm.dart';
+
+class VirtualKeyboardView extends StatelessWidget {
+  const VirtualKeyboardView(this.keyboard, {super.key});
+
+  final VirtualKeyboard keyboard;
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: keyboard,
+      builder: (context, child) => ToggleButtons(
+        children: [Text('Ctrl'), Text('Alt'), Text('Shift')],
+        isSelected: [keyboard.ctrl, keyboard.alt, keyboard.shift],
+        onPressed: (index) {
+          switch (index) {
+            case 0:
+              keyboard.ctrl = !keyboard.ctrl;
+              break;
+            case 1:
+              keyboard.alt = !keyboard.alt;
+              break;
+            case 2:
+              keyboard.shift = !keyboard.shift;
+              break;
+          }
+        },
+      ),
+    );
+  }
+}
+
+class VirtualKeyboard extends TerminalInputHandler with ChangeNotifier {
+  final TerminalInputHandler _inputHandler;
+
+  VirtualKeyboard(this._inputHandler);
+
+  bool _ctrl = false;
+
+  bool get ctrl => _ctrl;
+
+  set ctrl(bool value) {
+    if (_ctrl != value) {
+      _ctrl = value;
+      notifyListeners();
+    }
+  }
+
+  bool _shift = false;
+
+  bool get shift => _shift;
+
+  set shift(bool value) {
+    if (_shift != value) {
+      _shift = value;
+      notifyListeners();
+    }
+  }
+
+  bool _alt = false;
+
+  bool get alt => _alt;
+
+  set alt(bool value) {
+    if (_alt != value) {
+      _alt = value;
+      notifyListeners();
+    }
+  }
+
+  @override
+  String? call(TerminalKeyboardEvent event) {
+    return _inputHandler.call(event.copyWith(
+      ctrl: event.ctrl || _ctrl,
+      shift: event.shift || _shift,
+      alt: event.alt || _alt,
+    ));
+  }
+}