Add Onboard support, fullscreen, text with buttons

- Add dbus-python dependency in 'osk' extra
- If dbus is present, attempt to connect to Onboard
- If Onboard is present, show it before asking for a new person's name,
    and hide after entering it.
- Go fullscreen when the client starts
- Show text under the toolbar buttons, make icons smaller.

piket_client/gui.py

     QWidget,
 )
 from PySide2.QtGui import QIcon
-from PySide2.QtCore import QSize
+from PySide2.QtCore import QSize, Qt
 
 # pylint: enable=E0611
 import requests
 
+try:
+    import dbus
+except ImportError:
+    dbus = None
+
 from piket_client.sound import PLOP_WAVE
 
 
 
         self.main_widget = None
         self.toolbar = None
+        self.osk = None
         self.init_ui()
 
     def init_ui(self) -> None:
         """ Initialize the UI: construct main widget and toolbar. """
+
+        # Connect to dbus, get handle to virtual keyboard
+        if dbus:
+            try:
+                session_bus = dbus.SessionBus()
+                self.osk = session_bus.get_object('org.onboard.Onboard',
+                        '/org/onboard/Onboard/Keyboard')
+            except dbus.exceptions.DBusException:
+                # Onboard not present or dbus broken
+                self.osk = None
+
+        # Go full screen
+        self.setWindowState(Qt.WindowActive | Qt.WindowFullScreen)
+
+        # Initialize main widget
         self.main_widget = NameButtons()
         self.setCentralWidget(self.main_widget)
 
         font_metrics = self.fontMetrics()
-        icon_size = font_metrics.height() * 2.5
+        icon_size = font_metrics.height() * 2
 
         # Initialize toolbar
         self.toolbar = QToolBar()
+        self.toolbar.setToolButtonStyle(Qt.ToolButtonTextUnderIcon)
         self.toolbar.setIconSize(QSize(icon_size, icon_size))
 
         # Left
         self.toolbar.addAction(
             self.load_icon("add_person.svg"), "Nieuw persoon", self.add_person
         )
-        self.toolbar.addAction(self.load_icon("undo.svg"), "Heydrich")
+        self.toolbar.addAction(self.load_icon("undo.svg"), "Oeps")
 
         self.toolbar.addWidget(self.create_spacer())
 
         self.toolbar.addAction(self.load_icon("beer_bottle.svg"), "Bierrr")
         self.addToolBar(self.toolbar)
 
+    def show_keyboard(self) -> None:
+        ''' Show the virtual keyboard, if possible. '''
+        if self.osk:
+            self.osk.Show()
+
+    def hide_keyboard(self) -> None:
+        ''' Hide the virtual keyboard, if possible. '''
+        if self.osk:
+            self.osk.Hide()
+
     def add_person(self) -> None:
         """ Ask for a new Person and register it, then rebuild the central
         widget. """
+        self.show_keyboard()
         name, ok = QInputDialog.getItem(
             self,
             "Persoon toevoegen",
             0,
             True,
         )
+        self.hide_keyboard()
         if ok and name:
             req = requests.post(
                 urljoin(SERVER_URL, "people"), json={"person": {"name": name}}

setup.py

                 'simpleaudio',
                 'requests',
             ],
+            'osk': [
+                'dbus-python',
+            ],
         },
 
         include_package_data=True,