Home · All Classes · All Functions · Overviews

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

 /****************************************************************************
 **
 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation ([email protected])
 **
 ** 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 [email protected].
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #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());
 }