Add possibility to user to choose hdpi round policy

Add combo box in general configuration dialog to let user
choose the round policy to use with hdpi screen.

sources/utils/qetsettings.h

@@ -0,0 +1,37 @@
+/*
+	Copyright 2006-2021 The QElectroTech Team
+	This file is part of QElectroTech.
+
+	QElectroTech 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.
+
+	QElectroTech 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 QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef QETSETTINGS_H
+#define QETSETTINGS_H
+
+#include <Qt>
+
+/**
+ *Interface to use QSettings in QElectroTech
+ *Prefer use this namespace instead of directly QSettings
+ *It's notably usefull when some QSettings value are use in
+ *different part of QElectroTech source code
+ */
+namespace QetSettings
+{
+	void setHdpiScaleFactorRoundingPolicy(const QString &policy_str);
+	void setHdpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy policy);
+	Qt::HighDpiScaleFactorRoundingPolicy hdpiScaleFactorRoundingPolicy(
+			Qt::HighDpiScaleFactorRoundingPolicy default_policy = Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+}
+
+#endif // QETSETTINGS_H