|  | Home · All Classes · All Functions · Overviews

# commands.cpp Example File
tools/undoframework/commands.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
     ** Commercial Usage
     ** Licensees holding valid Qt Commercial licenses may use this file in
     ** accordance with the Qt Commercial License Agreement provided with the
     ** Software or, alternatively, in accordance with the terms contained in
     ** a written agreement between you and Nokia.
     **
     ** GNU Lesser General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU Lesser
     ** General Public License version 2.1 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.LGPL included in the
     ** packaging of this file.  Please review the following information to
     ** ensure the GNU Lesser General Public License version 2.1 requirements
     ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
     **
     ** In addition, as a special exception, Nokia gives you certain additional
     ** rights.  These rights are described in the Nokia Qt LGPL Exception
     ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
     **
     ** GNU General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License version 3.0 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.GPL included in the
     ** packaging of this file.  Please review the following information to
     ** ensure the GNU General Public License version 3.0 requirements will be
     ** met: http://www.gnu.org/copyleft/gpl.html.
     **
     ** If you have questions regarding the use of this file, please contact
     ** Nokia at qt-info@nokia.com.
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include <QtGui>

     #include "commands.h"
     #include "diagramitem.h"

     MoveCommand::MoveCommand(DiagramItem *diagramItem, const QPointF &oldPos,
                      QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         myDiagramItem = diagramItem;
         newPos = diagramItem->pos();
         myOldPos = oldPos;
     }

     bool MoveCommand::mergeWith(const QUndoCommand *command)
     {
         const MoveCommand *moveCommand = static_cast<const MoveCommand *>(command);
         DiagramItem *item = moveCommand->myDiagramItem;

         if (myDiagramItem != item)
         return false;

         newPos = item->pos();
         setText(QObject::tr("Move %1")
             .arg(createCommandString(myDiagramItem, newPos)));

         return true;
     }

     void MoveCommand::undo()
     {
         myDiagramItem->setPos(myOldPos);
         myDiagramItem->scene()->update();
         setText(QObject::tr("Move %1")
             .arg(createCommandString(myDiagramItem, newPos)));
     }

     void MoveCommand::redo()
     {
         myDiagramItem->setPos(newPos);
         setText(QObject::tr("Move %1")
             .arg(createCommandString(myDiagramItem, newPos)));
     }

     DeleteCommand::DeleteCommand(QGraphicsScene *scene, QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         myGraphicsScene = scene;
         QList<QGraphicsItem *> list = myGraphicsScene->selectedItems();
         list.first()->setSelected(false);
         myDiagramItem = static_cast<DiagramItem *>(list.first());
         setText(QObject::tr("Delete %1")
             .arg(createCommandString(myDiagramItem, myDiagramItem->pos())));
     }

     void DeleteCommand::undo()
     {
         myGraphicsScene->addItem(myDiagramItem);
         myGraphicsScene->update();
     }

     void DeleteCommand::redo()
     {
         myGraphicsScene->removeItem(myDiagramItem);
     }

     AddCommand::AddCommand(DiagramItem::DiagramType addType,
                            QGraphicsScene *scene, QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         static int itemCount = 0;

         myGraphicsScene = scene;
         myDiagramItem = new DiagramItem(addType);
         initialPosition = QPointF((itemCount * 15) % int(scene->width()),
                                   (itemCount * 15) % int(scene->height()));
         scene->update();
         ++itemCount;
         setText(QObject::tr("Add %1")
             .arg(createCommandString(myDiagramItem, initialPosition)));
     }

     void AddCommand::undo()
     {
         myGraphicsScene->removeItem(myDiagramItem);
         myGraphicsScene->update();
     }

     void AddCommand::redo()
     {
         myGraphicsScene->addItem(myDiagramItem);
         myDiagramItem->setPos(initialPosition);
         myGraphicsScene->clearSelection();
         myGraphicsScene->update();
     }

     QString createCommandString(DiagramItem *item, const QPointF &pos)
     {
         return QObject::tr("%1 at (%2, %3)")
             .arg(item->diagramType() == DiagramItem::Box ? "Box" : "Triangle")
             .arg(pos.x()).arg(pos.y());
     }