- Qt 5.5
- Qt Widgets
- Undo Framework
- commands.cpp Example File
- Qt 5.5.1 Reference Documentation

# commands.cpp Example File

tools/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.
    **
    ** $QT_BEGIN_LICENSE:LGPL21$
    ** 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.
    **
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    #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;
    }