flutter_server_box/lib/data/provider/virtual_keyboard.dart

import 'package:flutter/widgets.dart';
import 'package:xterm/core.dart';

class VirtualKeyboard extends TerminalInputHandler with ChangeNotifier {
  VirtualKeyboard();

  bool ctrl = false;
  bool alt = false;

  void reset(TerminalKeyboardEvent e) {
    if (e.ctrl) {
      ctrl = false;
    }
    if (e.alt) {
      alt = false;
    }
    notifyListeners();
  }

  @override
  String? call(TerminalKeyboardEvent event) {
    final e = event.copyWith(
      ctrl: event.ctrl || ctrl,
      alt: event.alt || alt,
    );
    reset(e);
    return defaultInputHandler.call(e);
  }
}