sclass JOnScreenKeyboard extends JPanel {

  JPanel[] panel;

  JButton[][] button;

  event keyPressed(S key);

  static final S[][] key = {

    {"Esc", "F1", "F2", "F3", "F4", "F5", "F6", "F7", "F8", "F9",

        "F10", "F11", "F12", "PrtSc", "Insert", "Delete", "Home",

        "End", "PgUp", "PgDn"}, {"3\n2", "&", "é", "\"", "'", "(",

        "§", "è", "!", "ç", "à", ")", "-", "BkSpc", "NumLock", "/",

        "*", "-"}, {"Tab", "A", "Z", "E", "R", "T", "Y", "U", "I",

        "O", "P", "^", "$", "Enter", "7", "8", "9", "+"},

    {"ShiftLock",

        "Q", "S", "D", "F", "G", "H", "J", "K", "L", "M", "ù", "µ",

        "4", "5", "6"}, {"Shift", "<", "W", "X", "C", "V", "B",

        "N", ",", ";", ":", "=", "Shift", "Up", "1", "2", "3", "Enter"},

    {"Ctrl", "Fn", "Win", "Alt", "Space", "AltGr", "Context",

        "Ctrl", "Left", "Down", "Right", "0", "."}

  };

  *() {

    init();

  }

  void init {

    setLayout(new GridLayout(0, 1));

    panel = new JPanel[6];

    for (int row = 0; row < key.length; row++) {

        panel[row] = new JPanel();

        button = new JButton[20][20];

        for (int column = 0; column < key[row].length; column++) {

            button[row][column] = new JButton(key[row][column]);

            //button[row][column].putClientProperty("column", column);

            //button[row][column].putClientProperty("row", row);

            button[row][column].putClientProperty("key", key[row][column]);

            button[row][column].addActionListener(e -> {

              JButton btn = cast e.getSource();

              S key = cast btn.getClientProperty("key");

              _print("JOnScreenKeyboard key pressed: " + key);

              keyPressed(key);

            });

            panel[row].add(button[row][column]);

        }

        add(panel[row]);

    }

  }

  JScrollPane withScrollPane() {

    var sp = jscroll_borderless_center(this);

    onFirstResize(sp, -> scrollToCenter(sp));

    ret sp;

  }

}