Add a checkbox which can be toggled by pressing space bar

src/CMakeLists.txt

@@ -346,6 +346,8 @@ IF(STELLARIUM_GUI_MODE STREQUAL "Standard")
           gui/ObsListDialog.cpp
           gui/ObsListCreateEditDialog.hpp
           gui/ObsListCreateEditDialog.cpp
+          gui/SpaceCheckBox.hpp
+          gui/SpaceCheckBox.cpp
           gui/StelDialog.hpp
           gui/StelDialog_p.hpp
           gui/StelDialog.cpp

src/gui/SpaceCheckBox.cpp

@@ -0,0 +1,37 @@
+/***************************************************************************
+ *   Copyright (C) 2021 Georg Zotti                                        *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Suite 500, Boston, MA  02110-1335, USA.           *
+ ***************************************************************************/
+
+#include "SpaceCheckBox.hpp"
+#include <QKeyEvent>
+
+SpaceCheckBox::SpaceCheckBox(QWidget* parent)
+	: QCheckBox(parent)
+{
+}
+
+void SpaceCheckBox::keyReleaseEvent(QKeyEvent *e)
+{
+	switch (e->key()) {
+	case Qt::Key_Space:
+		toggle();
+		break;
+	default:
+		QCheckBox::keyReleaseEvent(e);
+    }
+}

src/gui/SpaceCheckBox.hpp

@@ -0,0 +1,42 @@
+/*
+ * Stellarium
+ * Copyright (C) 2021 Georg Zotti
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA  02110-1335, USA.
+ */
+
+#ifndef SPACECHECKBOX_HPP
+#define SPACECHECKBOX_HPP
+
+#include <QCheckBox>
+
+//! @class SpaceCheckBox
+//! A QCheckBox which can be toggled by pressing (actually releasing) Space when it has focus.
+//! To use this class in the QtCreator UI designer, add a regular QCheckBox to the UI,
+//! then right-click on it and change its type to SpaceCheckBox.
+//! Then it makes sense to put this checkbox into a useful GUI tab order.
+class SpaceCheckBox : public QCheckBox
+{
+	Q_OBJECT
+public:
+	SpaceCheckBox(QWidget* parent=Q_NULLPTR);
+	~SpaceCheckBox() Q_DECL_OVERRIDE {}
+
+protected:
+    //! This toggles the checkbox on releasing the Space bar.
+    virtual void keyReleaseEvent(QKeyEvent *e) Q_DECL_OVERRIDE;
+};
+
+#endif // SPACECHECKBOX_HPP