Revamp code

-Move MoveElementsCommand class from diagramcommands file to
movegraphicsitemcommand file.
-Rename the to class MoveGraphicsItemCommand.
-Minor code change to make it more modern.

sources/undocommand/movegraphicsitemcommand.h

@@ -0,0 +1,65 @@
+/*
+	Copyright 2006-2022 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 MOVEGRAPHICSITEMCOMMAND_H
+#define MOVEGRAPHICSITEMCOMMAND_H
+
+#include <QUndoCommand>
+#include <QParallelAnimationGroup>
+#include <QPointer>
+
+#include "../diagramcontent.h"
+
+class Diagram;
+
+/**
+ * @brief The MoveGraphicsItemCommand class
+ * An undo command used for move item(s) in a diagram
+ */
+class MoveGraphicsItemCommand : public QUndoCommand
+{
+	public:
+		MoveGraphicsItemCommand(Diagram *diagram,
+								const DiagramContent &content,
+								const QPointF &movement,
+								QUndoCommand *parent = nullptr);
+
+		~MoveGraphicsItemCommand() {}
+
+	private:
+		MoveGraphicsItemCommand(const MoveGraphicsItemCommand &);
+
+	public:
+		void undo() override;
+		void redo() override;
+
+	private:
+		void move(const QPointF &movement);
+		void setupAnimation(QObject *target,
+							const QByteArray &property_name,
+							const QVariant &start,
+							const QVariant &end);
+
+	private:
+		QPointer<Diagram> m_diagram;
+		DiagramContent m_content;
+		const QPointF m_movement;
+		QParallelAnimationGroup m_anim_group;
+		bool m_first_redo{true};
+};
+
+#endif // MOVEGRAPHICSITEMCOMMAND_H