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# commands.cpp Example File

demos/undo/commands.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
     **
     ** This file is part of the demonstration applications of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
     ** Commercial License Usage
     ** Licensees holding valid commercial Qt licenses may use this file in
     ** accordance with the commercial license agreement provided with the
     ** Software or, alternatively, in accordance with the terms contained in
     ** a written agreement between you and The Qt Company. For licensing terms
     ** and conditions see http://www.qt.io/terms-conditions. For further
     ** information use the contact form at http://www.qt.io/contact-us.
     **
     ** 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 or version 3 as published by the Free
     ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
     ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
     ** following information to ensure the GNU Lesser General Public License
     ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
     ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
     **
     ** As a special exception, The Qt Company gives you certain additional
     ** rights. These rights are described in The Qt Company 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.
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #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;
     }