Qt 4.8: commands.cpp Example File (demos/undo/commands.cpp)

Qt Reference Documentation

# commands.cpp Example File

demos/undo/commands.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the demonstration applications of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
     ** GNU Lesser General Public License Usage
     ** 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.
     **
     ** Other Usage
     ** Alternatively, this file may be used in accordance with the terms and
     ** conditions contained in a signed written agreement between you and Nokia.
     **
     **
     **
     **
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include "commands.h"

     static const int setShapeRectCommandId = 1;
     static const int setShapeColorCommandId = 2;

     /******************************************************************************
     ** AddShapeCommand
     */

     AddShapeCommand::AddShapeCommand(Document *doc, const Shape &shape, QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         m_doc = doc;
         m_shape = shape;
     }

     void AddShapeCommand::undo()
     {
         m_doc->deleteShape(m_shapeName);
     }

     void AddShapeCommand::redo()
     {
         // A shape only gets a name when it is inserted into a document
         m_shapeName = m_doc->addShape(m_shape);
         setText(QObject::tr("Add %1").arg(m_shapeName));
     }

     /******************************************************************************
     ** RemoveShapeCommand
     */

     RemoveShapeCommand::RemoveShapeCommand(Document *doc, const QString &shapeName,
                                             QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         setText(QObject::tr("Remove %1").arg(shapeName));
         m_doc = doc;
         m_shape = doc->shape(shapeName);
         m_shapeName = shapeName;
     }

     void RemoveShapeCommand::undo()
     {
         m_shapeName = m_doc->addShape(m_shape);
     }

     void RemoveShapeCommand::redo()
     {
         m_doc->deleteShape(m_shapeName);
     }

     /******************************************************************************
     ** SetShapeColorCommand
     */

     SetShapeColorCommand::SetShapeColorCommand(Document *doc, const QString &shapeName,
                                                 const QColor &color, QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         setText(QObject::tr("Set %1's color").arg(shapeName));

         m_doc = doc;
         m_shapeName = shapeName;
         m_oldColor = doc->shape(shapeName).color();
         m_newColor = color;
     }

     void SetShapeColorCommand::undo()
     {
         m_doc->setShapeColor(m_shapeName, m_oldColor);
     }

     void SetShapeColorCommand::redo()
     {
         m_doc->setShapeColor(m_shapeName, m_newColor);
     }

     bool SetShapeColorCommand::mergeWith(const QUndoCommand *command)
     {
         if (command->id() != setShapeColorCommandId)
             return false;

         const SetShapeColorCommand *other = static_cast<const SetShapeColorCommand*>(command);
         if (m_shapeName != other->m_shapeName)
             return false;

         m_newColor = other->m_newColor;
         return true;
     }

     int SetShapeColorCommand::id() const
     {
         return setShapeColorCommandId;
     }

     /******************************************************************************
     ** SetShapeRectCommand
     */

     SetShapeRectCommand::SetShapeRectCommand(Document *doc, const QString &shapeName,
                                                 const QRect &rect, QUndoCommand *parent)
         : QUndoCommand(parent)
     {
         setText(QObject::tr("Change %1's geometry").arg(shapeName));

         m_doc = doc;
         m_shapeName = shapeName;
         m_oldRect = doc->shape(shapeName).rect();
         m_newRect = rect;
     }

     void SetShapeRectCommand::undo()
     {
         m_doc->setShapeRect(m_shapeName, m_oldRect);
     }

     void SetShapeRectCommand::redo()
     {
         m_doc->setShapeRect(m_shapeName, m_newRect);
     }

     bool SetShapeRectCommand::mergeWith(const QUndoCommand *command)
     {
         if (command->id() != setShapeRectCommandId)
             return false;

         const SetShapeRectCommand *other = static_cast<const SetShapeRectCommand*>(command);
         if (m_shapeName != other->m_shapeName)
             return false;

         m_newRect = other->m_newRect;
         return true;
     }

     int SetShapeRectCommand::id() const
     {
         return setShapeRectCommandId;
     }