Added SubWindow class to compensate for incorrect behavior of normalGeometry() method on X11

include/SubWindow.h

@@ -0,0 +1,56 @@
+/*
+ * SubWindow.h - Implementation of QMdiSubWindow that correctly tracks
+ *   the geometry that windows should be restored to.
+ *   Workaround for https://bugreports.qt.io/browse/QTBUG-256
+ *
+ * Copyright (c) 2015 Colin Wallace <wallace.colin.a@gmail.com>
+ *
+ * This file is part of LMMS - http://lmms.io
+ *
+ * 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 (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+
+#ifndef SUBWINDOW_H
+#define SUBWINDOW_H
+
+
+#include <QMdiSubWindow>
+#include <QRect>
+
+
+class QMoveEvent;
+class QResizeEvent;
+class QWidget;
+
+
+class SubWindow : public QMdiSubWindow
+{
+	Q_OBJECT
+public:
+	SubWindow(QWidget *parent=NULL, Qt::WindowFlags windowFlags=0);
+	// same as QWidet::normalGeometry, but works properly under X11 (see https://bugreports.qt.io/browse/QTBUG-256)
+	QRect getTrueNormalGeometry() const;
+protected:
+	// hook the QWidget move/resize events to update the tracked geometry
+	virtual void moveEvent(QMoveEvent * event);
+	virtual void resizeEvent(QResizeEvent * event);
+private:
+	QRect m_trackedNormalGeom;
+};
+
+#endif