def keyPressEvent(self, event):
        if event.key() == Qt.Key_Escape:
            self.reset_view()

        if event.key() == Qt.Key_F1:
            self.set_alias_visibility(not self.aliases_visible)

        if event.key() == Qt.Key_F2:
            self.set_port_visibility(not self.ports_visible)

        if event.key() == Qt.Key_F3:
            self.set_subport_visibility(not self.subports_visible)


        if event.key() == Qt.Key_Question:
            help_str = """
            Mouse control:
              Mousewheel: Zoom in and out
              Right-click & drag: Zoom to rectangle
              Middle-click & drag: Pan

            Keyboard shortcuts:
              Esc: Reset view
              F1: Show/hide alias names
              F2: Show/hide ports
              F3: Show/hide subports (ports in underlying references)
            """
            QMessageBox.about(self, 'PHIDL Help', help_str)