Qt 4.3: commands.cpp Example File (demos/undo/commands.cpp)

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# commands.cpp Example File
demos/undo/commands.cpp

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    ** included in the packaging of this file.  Alternatively you may (at
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     ****************************************************************************/

     #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;
     }