Initial import of statemachine branch from the old kinetic repository

26 files changed, 1810 insertions, 0 deletions

diff --git a/demos/undo/commands.cpp b/demos/undo/commands.cpp
new file mode 100644
index 0000000..4802e34
--- /dev/null
+++ b/demos/undo/commands.cpp
@@ -0,0 +1,180 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#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;
+}
diff --git a/demos/undo/commands.h b/demos/undo/commands.h
new file mode 100644
index 0000000..f98cb6d
--- /dev/null
+++ b/demos/undo/commands.h
@@ -0,0 +1,112 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef COMMANDS_H
+#define COMMANDS_H
+
+#include <QUndoCommand>
+#include "document.h"
+
+class AddShapeCommand : public QUndoCommand
+{
+public:
+    AddShapeCommand(Document *doc, const Shape &shape, QUndoCommand *parent = 0);
+    void undo();
+    void redo();
+
+private:
+    Document *m_doc;
+    Shape m_shape;
+    QString m_shapeName;
+};
+
+class RemoveShapeCommand : public QUndoCommand
+{
+public:
+    RemoveShapeCommand(Document *doc, const QString &shapeName, QUndoCommand *parent = 0);
+    void undo();
+    void redo();
+
+private:
+    Document *m_doc;
+    Shape m_shape;
+    QString m_shapeName;
+};
+
+class SetShapeColorCommand : public QUndoCommand
+{
+public:
+    SetShapeColorCommand(Document *doc, const QString &shapeName, const QColor &color,
+                            QUndoCommand *parent = 0);
+
+    void undo();
+    void redo();
+
+    bool mergeWith(const QUndoCommand *command);
+    int id() const;
+
+private:
+    Document *m_doc;
+    QString m_shapeName;
+    QColor m_oldColor;
+    QColor m_newColor;
+};
+
+class SetShapeRectCommand : public QUndoCommand
+{
+public:
+    SetShapeRectCommand(Document *doc, const QString &shapeName, const QRect &rect,
+                            QUndoCommand *parent = 0);
+
+    void undo();
+    void redo();
+
+    bool mergeWith(const QUndoCommand *command);
+    int id() const;
+
+private:
+    Document *m_doc;
+    QString m_shapeName;
+    QRect m_oldRect;
+    QRect m_newRect;
+};
+
+#endif // COMMANDS_H
diff --git a/demos/undo/document.cpp b/demos/undo/document.cpp
new file mode 100644
index 0000000..df435fd
--- /dev/null
+++ b/demos/undo/document.cpp
@@ -0,0 +1,445 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qevent.h>
+#include <QPainter>
+#include <QTextStream>
+#include <QUndoStack>
+#include "document.h"
+#include "commands.h"
+
+static const int resizeHandleWidth = 6;
+
+/******************************************************************************
+** Shape
+*/
+
+const QSize Shape::minSize(80, 50);
+
+Shape::Shape(Type type, const QColor &color, const QRect &rect)
+    : m_type(type), m_rect(rect), m_color(color)
+{
+}
+
+Shape::Type Shape::type() const
+{
+    return m_type;
+}
+
+QRect Shape::rect() const
+{
+    return m_rect;
+}
+
+QColor Shape::color() const
+{
+    return m_color;
+}
+
+QString Shape::name() const
+{
+    return m_name;
+}
+
+QRect Shape::resizeHandle() const
+{
+    QPoint br = m_rect.bottomRight();
+    return QRect(br - QPoint(resizeHandleWidth, resizeHandleWidth), br);
+}
+
+QString Shape::typeToString(Type type)
+{
+    QString result;
+
+    switch (type) {
+        case Rectangle:
+            result = QLatin1String("Rectangle");
+            break;
+        case Circle:
+            result = QLatin1String("Circle");
+            break;
+        case Triangle:
+            result = QLatin1String("Triangle");
+            break;
+    }
+
+    return result;
+}
+
+Shape::Type Shape::stringToType(const QString &s, bool *ok)
+{
+    if (ok != 0)
+        *ok = true;
+
+    if (s == QLatin1String("Rectangle"))
+        return Rectangle;
+    if (s == QLatin1String("Circle"))
+        return Circle;
+    if (s == QLatin1String("Triangle"))
+        return Triangle;
+
+    if (ok != 0)
+        *ok = false;
+    return Rectangle;
+}
+
+/******************************************************************************
+** Document
+*/
+
+Document::Document(QWidget *parent)
+    : QWidget(parent), m_currentIndex(-1), m_mousePressIndex(-1), m_resizeHandlePressed(false)
+{
+    m_undoStack = new QUndoStack(this);
+
+    setAutoFillBackground(true);
+    setBackgroundRole(QPalette::Base);
+
+    QPalette pal = palette();
+    pal.setBrush(QPalette::Base, QPixmap(":/icons/background.png"));
+    pal.setColor(QPalette::HighlightedText, Qt::red);
+    setPalette(pal);
+}
+
+QString Document::addShape(const Shape &shape)
+{
+    QString name = Shape::typeToString(shape.type());
+    name = uniqueName(name);
+
+    m_shapeList.append(shape);
+    m_shapeList[m_shapeList.count() - 1].m_name = name;
+    setCurrentShape(m_shapeList.count() - 1);
+
+    return name;
+}
+
+void Document::deleteShape(const QString &shapeName)
+{
+    int index = indexOf(shapeName);
+    if (index == -1)
+        return;
+
+    update(m_shapeList.at(index).rect());
+
+    m_shapeList.removeAt(index);
+
+    if (index <= m_currentIndex) {
+        m_currentIndex = -1;
+        if (index == m_shapeList.count())
+            --index;
+        setCurrentShape(index);
+    }
+}
+
+Shape Document::shape(const QString &shapeName) const
+{
+    int index = indexOf(shapeName);
+    if (index == -1)
+        return Shape();
+    return m_shapeList.at(index);
+}
+
+void Document::setShapeRect(const QString &shapeName, const QRect &rect)
+{
+    int index = indexOf(shapeName);
+    if (index == -1)
+        return;
+
+    Shape &shape = m_shapeList[index];
+
+    update(shape.rect());
+    update(rect);
+
+    shape.m_rect = rect;
+}
+
+void Document::setShapeColor(const QString &shapeName, const QColor &color)
+{
+
+    int index = indexOf(shapeName);
+    if (index == -1)
+        return;
+
+    Shape &shape = m_shapeList[index];
+    shape.m_color = color;
+
+    update(shape.rect());
+}
+
+QUndoStack *Document::undoStack() const
+{
+    return m_undoStack;
+}
+
+bool Document::load(QTextStream &stream)
+{
+    m_shapeList.clear();
+
+    while (!stream.atEnd()) {
+        QString shapeType, shapeName, colorName;
+        int left, top, width, height;
+        stream >> shapeType >> shapeName >> colorName >> left >> top >> width >> height;
+        if (stream.status() != QTextStream::Ok)
+            return false;
+        bool ok;
+        Shape::Type type = Shape::stringToType(shapeType, &ok);
+        if (!ok)
+            return false;
+        QColor color(colorName);
+        if (!color.isValid())
+            return false;
+
+        Shape shape(type);
+        shape.m_name = shapeName;
+        shape.m_color = color;
+        shape.m_rect = QRect(left, top, width, height);
+
+        m_shapeList.append(shape);
+    }
+
+    m_currentIndex = m_shapeList.isEmpty() ? -1 : 0;
+
+    return true;
+}
+
+void Document::save(QTextStream &stream)
+{
+    for (int i = 0; i < m_shapeList.count(); ++i) {
+        const Shape &shape = m_shapeList.at(i);
+        QRect r = shape.rect();
+        stream << Shape::typeToString(shape.type()) << QLatin1Char(' ')
+                << shape.name() << QLatin1Char(' ')
+                << shape.color().name() << QLatin1Char(' ')
+                << r.left() << QLatin1Char(' ')
+                << r.top() << QLatin1Char(' ')
+                << r.width() << QLatin1Char(' ')
+                << r.height();
+        if (i != m_shapeList.count() - 1)
+            stream << QLatin1Char('\n');
+    }
+    m_undoStack->setClean();
+}
+
+QString Document::fileName() const
+{
+    return m_fileName;
+}
+
+void Document::setFileName(const QString &fileName)
+{
+    m_fileName = fileName;
+}
+
+int Document::indexAt(const QPoint &pos) const
+{
+    for (int i = m_shapeList.count() - 1; i >= 0; --i) {
+        if (m_shapeList.at(i).rect().contains(pos))
+            return i;
+    }
+    return -1;
+}
+
+void Document::mousePressEvent(QMouseEvent *event)
+{
+    event->accept();
+    int index = indexAt(event->pos());;
+    if (index != -1) {
+        setCurrentShape(index);
+
+        const Shape &shape = m_shapeList.at(index);
+        m_resizeHandlePressed = shape.resizeHandle().contains(event->pos());
+
+        if (m_resizeHandlePressed)
+            m_mousePressOffset = shape.rect().bottomRight() - event->pos();
+        else
+            m_mousePressOffset = event->pos() - shape.rect().topLeft();
+    }
+    m_mousePressIndex = index;
+}
+
+void Document::mouseReleaseEvent(QMouseEvent *event)
+{
+    event->accept();
+    m_mousePressIndex = -1;
+}
+
+void Document::mouseMoveEvent(QMouseEvent *event)
+{
+    event->accept();
+
+    if (m_mousePressIndex == -1)
+        return;
+
+    const Shape &shape = m_shapeList.at(m_mousePressIndex);
+
+    QRect rect;
+    if (m_resizeHandlePressed) {
+        rect = QRect(shape.rect().topLeft(), event->pos() + m_mousePressOffset);
+    } else {
+        rect = shape.rect();
+        rect.moveTopLeft(event->pos() - m_mousePressOffset);
+    }
+
+    QSize size = rect.size().expandedTo(Shape::minSize);
+    rect.setSize(size);
+
+    m_undoStack->push(new SetShapeRectCommand(this, shape.name(), rect));
+}
+
+static QGradient gradient(const QColor &color, const QRect &rect)
+{
+    QColor c = color;
+    c.setAlpha(160);
+    QLinearGradient result(rect.topLeft(), rect.bottomRight());
+    result.setColorAt(0, c.dark(150));
+    result.setColorAt(0.5, c.light(200));
+    result.setColorAt(1, c.dark(150));
+    return result;
+}
+
+static QPolygon triangle(const QRect &rect)
+{
+    QPolygon result(3);
+    result.setPoint(0, rect.center().x(), rect.top());
+    result.setPoint(1, rect.right(), rect.bottom());
+    result.setPoint(2, rect.left(), rect.bottom());
+    return result;
+}
+
+void Document::paintEvent(QPaintEvent *event)
+{
+    QRegion paintRegion = event->region();
+    QPainter painter(this);
+    QPalette pal = palette();
+
+    for (int i = 0; i < m_shapeList.count(); ++i) {
+        const Shape &shape = m_shapeList.at(i);
+
+        if (!paintRegion.contains(shape.rect()))
+            continue;
+
+        QPen pen = pal.text().color();
+        pen.setWidth(i == m_currentIndex ? 2 : 1);
+        painter.setPen(pen);
+        painter.setBrush(gradient(shape.color(), shape.rect()));
+
+        QRect rect = shape.rect();
+        rect.adjust(1, 1, -resizeHandleWidth/2, -resizeHandleWidth/2);
+
+        // paint the shape
+        switch (shape.type()) {
+            case Shape::Rectangle:
+                painter.drawRect(rect);
+                break;
+            case Shape::Circle:
+                painter.setRenderHint(QPainter::Antialiasing);
+                painter.drawEllipse(rect);
+                painter.setRenderHint(QPainter::Antialiasing, false);
+                break;
+            case Shape::Triangle:
+                painter.setRenderHint(QPainter::Antialiasing);
+                painter.drawPolygon(triangle(rect));
+                painter.setRenderHint(QPainter::Antialiasing, false);
+                break;
+        }
+
+        // paint the resize handle
+        painter.setPen(pal.text().color());
+        painter.setBrush(Qt::white);
+        painter.drawRect(shape.resizeHandle().adjusted(0, 0, -1, -1));
+
+        // paint the shape name
+        painter.setBrush(pal.text());
+        if (shape.type() == Shape::Triangle)
+            rect.adjust(0, rect.height()/2, 0, 0);
+        painter.drawText(rect, Qt::AlignCenter, shape.name());
+    }
+}
+
+void Document::setCurrentShape(int index)
+{
+    QString currentName;
+
+    if (m_currentIndex != -1)
+        update(m_shapeList.at(m_currentIndex).rect());
+
+    m_currentIndex = index;
+
+    if (m_currentIndex != -1) {
+        const Shape &current = m_shapeList.at(m_currentIndex);
+        update(current.rect());
+        currentName = current.name();
+    }
+
+    emit currentShapeChanged(currentName);
+}
+
+int Document::indexOf(const QString &shapeName) const
+{
+    for (int i = 0; i < m_shapeList.count(); ++i) {
+        if (m_shapeList.at(i).name() == shapeName)
+            return i;
+    }
+    return -1;
+}
+
+QString Document::uniqueName(const QString &name) const
+{
+    QString unique;
+
+    for (int i = 0; ; ++i) {
+        unique = name;
+        if (i > 0)
+            unique += QString::number(i);
+        if (indexOf(unique) == -1)
+            break;
+    }
+
+    return unique;
+}
+
+QString Document::currentShapeName() const
+{
+    if (m_currentIndex == -1)
+        return QString();
+    return m_shapeList.at(m_currentIndex).name();
+}
+
diff --git a/demos/undo/document.h b/demos/undo/document.h
new file mode 100644
index 0000000..0b12ad0
--- /dev/null
+++ b/demos/undo/document.h
@@ -0,0 +1,125 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef DOCUMENT_H
+#define DOCUMENT_H
+
+#include <QWidget>
+
+QT_FORWARD_DECLARE_CLASS(QUndoStack)
+QT_FORWARD_DECLARE_CLASS(QTextStream)
+
+class Shape
+{
+public:
+    enum Type { Rectangle, Circle, Triangle };
+
+    Shape(Type type = Rectangle, const QColor &color = Qt::red, const QRect &rect = QRect());
+
+    Type type() const;
+    QString name() const;
+    QRect rect() const;
+    QRect resizeHandle() const;
+    QColor color() const;
+
+    static QString typeToString(Type type);
+    static Type stringToType(const QString &s, bool *ok = 0);
+
+    static const QSize minSize;
+
+private:
+    Type m_type;
+    QRect m_rect;
+    QColor m_color;
+    QString m_name;
+
+    friend class Document;
+};
+
+class Document : public QWidget
+{
+    Q_OBJECT
+
+public:
+    Document(QWidget *parent = 0);
+
+    QString addShape(const Shape &shape);
+    void deleteShape(const QString &shapeName);
+    Shape shape(const QString &shapeName) const;
+    QString currentShapeName() const;
+
+    void setShapeRect(const QString &shapeName, const QRect &rect);
+    void setShapeColor(const QString &shapeName, const QColor &color);
+
+    bool load(QTextStream &stream);
+    void save(QTextStream &stream);
+
+    QString fileName() const;
+    void setFileName(const QString &fileName);
+
+    QUndoStack *undoStack() const;
+
+signals:
+    void currentShapeChanged(const QString &shapeName);
+
+protected:
+    void paintEvent(QPaintEvent *event);
+    void mousePressEvent(QMouseEvent *event);
+    void mouseReleaseEvent(QMouseEvent *event);
+    void mouseMoveEvent(QMouseEvent *event);
+
+private:
+    void setCurrentShape(int index);
+    int indexOf(const QString &shapeName) const;
+    int indexAt(const QPoint &pos) const;
+    QString uniqueName(const QString &name) const;
+
+    QList<Shape> m_shapeList;
+    int m_currentIndex;
+    int m_mousePressIndex;
+    QPoint m_mousePressOffset;
+    bool m_resizeHandlePressed;
+    QString m_fileName;
+
+    QUndoStack *m_undoStack;
+};
+
+#endif // DOCUMENT_H
diff --git a/demos/undo/icons/background.png b/demos/undo/icons/background.png
new file mode 100644
index 0000000..3bc5ed8
--- /dev/null
+++ b/demos/undo/icons/background.png
diff --git a/demos/undo/icons/blue.png b/demos/undo/icons/blue.png
new file mode 100644
index 0000000..4e181bb
--- /dev/null
+++ b/demos/undo/icons/blue.png
diff --git a/demos/undo/icons/circle.png b/demos/undo/icons/circle.png
new file mode 100644
index 0000000..ed16c6e
--- /dev/null
+++ b/demos/undo/icons/circle.png
diff --git a/demos/undo/icons/exit.png b/demos/undo/icons/exit.png
new file mode 100644
index 0000000..539cb2e
--- /dev/null
+++ b/demos/undo/icons/exit.png
diff --git a/demos/undo/icons/fileclose.png b/demos/undo/icons/fileclose.png
new file mode 100644
index 0000000..c5483d1
--- /dev/null
+++ b/demos/undo/icons/fileclose.png
diff --git a/demos/undo/icons/filenew.png b/demos/undo/icons/filenew.png
new file mode 100644
index 0000000..57e57e3
--- /dev/null
+++ b/demos/undo/icons/filenew.png
diff --git a/demos/undo/icons/fileopen.png b/demos/undo/icons/fileopen.png
new file mode 100644
index 0000000..33e0d63
--- /dev/null
+++ b/demos/undo/icons/fileopen.png
diff --git a/demos/undo/icons/filesave.png b/demos/undo/icons/filesave.png
new file mode 100644
index 0000000..57fd5e2
--- /dev/null
+++ b/demos/undo/icons/filesave.png
diff --git a/demos/undo/icons/green.png b/demos/undo/icons/green.png
new file mode 100644
index 0000000..e2e7cc9
--- /dev/null
+++ b/demos/undo/icons/green.png
diff --git a/demos/undo/icons/ok.png b/demos/undo/icons/ok.png
new file mode 100644
index 0000000..e355ea9
--- /dev/null
+++ b/demos/undo/icons/ok.png
diff --git a/demos/undo/icons/rectangle.png b/demos/undo/icons/rectangle.png
new file mode 100644
index 0000000..3a7d979
--- /dev/null
+++ b/demos/undo/icons/rectangle.png
diff --git a/demos/undo/icons/red.png b/demos/undo/icons/red.png
new file mode 100644
index 0000000..58c3e72
--- /dev/null
+++ b/demos/undo/icons/red.png
diff --git a/demos/undo/icons/redo.png b/demos/undo/icons/redo.png
new file mode 100644
index 0000000..5591517
--- /dev/null
+++ b/demos/undo/icons/redo.png
diff --git a/demos/undo/icons/remove.png b/demos/undo/icons/remove.png
new file mode 100644
index 0000000..7a7b048
--- /dev/null
+++ b/demos/undo/icons/remove.png
diff --git a/demos/undo/icons/triangle.png b/demos/undo/icons/triangle.png
new file mode 100644
index 0000000..2969131
--- /dev/null
+++ b/demos/undo/icons/triangle.png
diff --git a/demos/undo/icons/undo.png b/demos/undo/icons/undo.png
new file mode 100644
index 0000000..8cf63a8
--- /dev/null
+++ b/demos/undo/icons/undo.png
diff --git a/demos/undo/main.cpp b/demos/undo/main.cpp
new file mode 100644
index 0000000..f36a6e8
--- /dev/null
+++ b/demos/undo/main.cpp
@@ -0,0 +1,56 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QApplication>
+#include "mainwindow.h"
+
+int main(int argc, char **argv)
+{
+    Q_INIT_RESOURCE(undo);
+
+    QApplication app(argc, argv);
+
+    MainWindow win;
+    win.resize(800, 600);
+    win.show();
+
+    return app.exec();
+};
diff --git a/demos/undo/mainwindow.cpp b/demos/undo/mainwindow.cpp
new file mode 100644
index 0000000..409fd14
--- /dev/null
+++ b/demos/undo/mainwindow.cpp
@@ -0,0 +1,446 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QUndoGroup>
+#include <QUndoStack>
+#include <QFileDialog>
+#include <QMessageBox>
+#include <QTextStream>
+#include <QToolButton>
+#include "document.h"
+#include "mainwindow.h"
+#include "commands.h"
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
+{
+    setupUi(this);
+
+    QWidget *w = documentTabs->widget(0);
+    documentTabs->removeTab(0);
+    delete w;
+
+    connect(actionOpen, SIGNAL(triggered()), this, SLOT(openDocument()));
+    connect(actionClose, SIGNAL(triggered()), this, SLOT(closeDocument()));
+    connect(actionNew, SIGNAL(triggered()), this, SLOT(newDocument()));
+    connect(actionSave, SIGNAL(triggered()), this, SLOT(saveDocument()));
+    connect(actionExit, SIGNAL(triggered()), this, SLOT(close()));
+    connect(actionRed, SIGNAL(triggered()), this, SLOT(setShapeColor()));
+    connect(actionGreen, SIGNAL(triggered()), this, SLOT(setShapeColor()));
+    connect(actionBlue, SIGNAL(triggered()), this, SLOT(setShapeColor()));
+    connect(actionAddCircle, SIGNAL(triggered()), this, SLOT(addShape()));
+    connect(actionAddRectangle, SIGNAL(triggered()), this, SLOT(addShape()));
+    connect(actionAddTriangle, SIGNAL(triggered()), this, SLOT(addShape()));
+    connect(actionRemoveShape, SIGNAL(triggered()), this, SLOT(removeShape()));
+    connect(actionAddRobot, SIGNAL(triggered()), this, SLOT(addRobot()));
+    connect(actionAddSnowman, SIGNAL(triggered()), this, SLOT(addSnowman()));
+    connect(actionAbout, SIGNAL(triggered()), this, SLOT(about()));
+    connect(actionAboutQt, SIGNAL(triggered()), this, SLOT(aboutQt()));
+
+    connect(undoLimit, SIGNAL(valueChanged(int)), this, SLOT(updateActions()));
+    connect(documentTabs, SIGNAL(currentChanged(int)), this, SLOT(updateActions()));
+
+    actionOpen->setShortcut(QString("Ctrl+O"));
+    actionClose->setShortcut(QString("Ctrl+W"));
+    actionNew->setShortcut(QString("Ctrl+N"));
+    actionSave->setShortcut(QString("Ctrl+S"));
+    actionExit->setShortcut(QString("Ctrl+Q"));
+    actionRemoveShape->setShortcut(QString("Del"));
+    actionRed->setShortcut(QString("Alt+R"));
+    actionGreen->setShortcut(QString("Alt+G"));
+    actionBlue->setShortcut(QString("Alt+B"));
+    actionAddCircle->setShortcut(QString("Alt+C"));
+    actionAddRectangle->setShortcut(QString("Alt+L"));
+    actionAddTriangle->setShortcut(QString("Alt+T"));
+
+    m_undoGroup = new QUndoGroup(this);
+    undoView->setGroup(m_undoGroup);
+    undoView->setCleanIcon(QIcon(":/icons/ok.png"));
+
+    QAction *undoAction = m_undoGroup->createUndoAction(this);
+    QAction *redoAction = m_undoGroup->createRedoAction(this);
+    undoAction->setIcon(QIcon(":/icons/undo.png"));
+    redoAction->setIcon(QIcon(":/icons/redo.png"));
+    menuShape->insertAction(menuShape->actions().at(0), undoAction);
+    menuShape->insertAction(undoAction, redoAction);
+
+    toolBar->addAction(undoAction);
+    toolBar->addAction(redoAction);
+
+    newDocument();
+    updateActions();
+};
+
+void MainWindow::updateActions()
+{
+    Document *doc = currentDocument();
+    m_undoGroup->setActiveStack(doc == 0 ? 0 : doc->undoStack());
+    QString shapeName = doc == 0 ? QString() : doc->currentShapeName();
+
+    actionAddRobot->setEnabled(doc != 0);
+    actionAddSnowman->setEnabled(doc != 0);
+    actionAddCircle->setEnabled(doc != 0);
+    actionAddRectangle->setEnabled(doc != 0);
+    actionAddTriangle->setEnabled(doc != 0);
+    actionClose->setEnabled(doc != 0);
+    actionSave->setEnabled(doc != 0 && !doc->undoStack()->isClean());
+    undoLimit->setEnabled(doc != 0 && doc->undoStack()->count() == 0);
+
+    if (shapeName.isEmpty()) {
+        actionRed->setEnabled(false);
+        actionGreen->setEnabled(false);
+        actionBlue->setEnabled(false);
+        actionRemoveShape->setEnabled(false);
+    } else {
+        Shape shape = doc->shape(shapeName);
+        actionRed->setEnabled(shape.color() != Qt::red);
+        actionGreen->setEnabled(shape.color() != Qt::green);
+        actionBlue->setEnabled(shape.color() != Qt::blue);
+        actionRemoveShape->setEnabled(true);
+    }
+
+    if (doc != 0) {
+        int index = documentTabs->indexOf(doc);
+        Q_ASSERT(index != -1);
+        static const QIcon unsavedIcon(":/icons/filesave.png");
+        documentTabs->setTabIcon(index, doc->undoStack()->isClean() ? QIcon() : unsavedIcon);
+
+        if (doc->undoStack()->count() == 0)
+            doc->undoStack()->setUndoLimit(undoLimit->value());
+    }
+}
+
+void MainWindow::openDocument()
+{
+    QString fileName = QFileDialog::getOpenFileName(this);
+    if (fileName.isEmpty())
+        return;
+
+    QFile file(fileName);
+    if (!file.open(QIODevice::ReadOnly)) {
+        QMessageBox::warning(this,
+                            tr("File error"),
+                            tr("Failed to open\n%1").arg(fileName));
+        return;
+    }
+    QTextStream stream(&file);
+
+    Document *doc = new Document();
+    if (!doc->load(stream)) {
+        QMessageBox::warning(this,
+                            tr("Parse error"),
+                            tr("Failed to parse\n%1").arg(fileName));
+        delete doc;
+        return;
+    }
+
+    doc->setFileName(fileName);
+    addDocument(doc);
+}
+
+QString MainWindow::fixedWindowTitle(const Document *doc) const
+{
+    QString title = doc->fileName();
+
+    if (title.isEmpty())
+        title = tr("Unnamed");
+    else
+        title = QFileInfo(title).fileName();
+
+    QString result;
+
+    for (int i = 0; ; ++i) {
+        result = title;
+        if (i > 0)
+            result += QString::number(i);
+
+        bool unique = true;
+        for (int j = 0; j < documentTabs->count(); ++j) {
+            const QWidget *widget = documentTabs->widget(j);
+            if (widget == doc)
+                continue;
+            if (result == documentTabs->tabText(j)) {
+                unique = false;
+                break;
+            }
+        }
+
+        if (unique)
+            break;
+    }
+
+    return result;
+}
+
+void MainWindow::addDocument(Document *doc)
+{
+    if (documentTabs->indexOf(doc) != -1)
+        return;
+    m_undoGroup->addStack(doc->undoStack());
+    documentTabs->addTab(doc, fixedWindowTitle(doc));
+    connect(doc, SIGNAL(currentShapeChanged(QString)), this, SLOT(updateActions()));
+    connect(doc->undoStack(), SIGNAL(indexChanged(int)), this, SLOT(updateActions()));
+    connect(doc->undoStack(), SIGNAL(cleanChanged(bool)), this, SLOT(updateActions()));
+
+    setCurrentDocument(doc);
+}
+
+void MainWindow::setCurrentDocument(Document *doc)
+{
+    documentTabs->setCurrentWidget(doc);
+}
+
+Document *MainWindow::currentDocument() const
+{
+    return qobject_cast<Document*>(documentTabs->currentWidget());
+}
+
+void MainWindow::removeDocument(Document *doc)
+{
+    int index = documentTabs->indexOf(doc);
+    if (index == -1)
+        return;
+
+    documentTabs->removeTab(index);
+    m_undoGroup->removeStack(doc->undoStack());
+    disconnect(doc, SIGNAL(currentShapeChanged(QString)), this, SLOT(updateActions()));
+    disconnect(doc->undoStack(), SIGNAL(indexChanged(int)), this, SLOT(updateActions()));
+    disconnect(doc->undoStack(), SIGNAL(cleanChanged(bool)), this, SLOT(updateActions()));
+
+    if (documentTabs->count() == 0) {
+        newDocument();
+        updateActions();
+    }
+}
+
+void MainWindow::saveDocument()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    for (;;) {
+        QString fileName = doc->fileName();
+
+        if (fileName.isEmpty())
+            fileName = QFileDialog::getSaveFileName(this);
+        if (fileName.isEmpty())
+            break;
+
+        QFile file(fileName);
+        if (!file.open(QIODevice::WriteOnly)) {
+            QMessageBox::warning(this,
+                                tr("File error"),
+                                tr("Failed to open\n%1").arg(fileName));
+            doc->setFileName(QString());
+        } else {
+            QTextStream stream(&file);
+            doc->save(stream);
+            doc->setFileName(fileName);
+
+            int index = documentTabs->indexOf(doc);
+            Q_ASSERT(index != -1);
+            documentTabs->setTabText(index, fixedWindowTitle(doc));
+
+            break;
+        }
+    }
+}
+
+void MainWindow::closeDocument()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    if (!doc->undoStack()->isClean()) {
+        int button
+            = QMessageBox::warning(this,
+                            tr("Unsaved changes"),
+                            tr("Would you like to save this document?"),
+                            QMessageBox::Yes, QMessageBox::No);
+        if (button == QMessageBox::Yes)
+            saveDocument();
+    }
+
+    removeDocument(doc);
+    delete doc;
+}
+
+void MainWindow::newDocument()
+{
+    addDocument(new Document());
+}
+
+static QColor randomColor()
+{
+    int r = (int) (3.0*(rand()/(RAND_MAX + 1.0)));
+    switch (r) {
+        case 0:
+            return Qt::red;
+        case 1:
+            return Qt::green;
+        default:
+            break;
+    }
+    return Qt::blue;
+}
+
+static QRect randomRect(const QSize &s)
+{
+    QSize min = Shape::minSize;
+
+    int left = (int) ((0.0 + s.width() - min.width())*(rand()/(RAND_MAX + 1.0)));
+    int top = (int) ((0.0 + s.height() - min.height())*(rand()/(RAND_MAX + 1.0)));
+    int width = (int) ((0.0 + s.width() - left - min.width())*(rand()/(RAND_MAX + 1.0))) + min.width();
+    int height = (int) ((0.0 + s.height() - top - min.height())*(rand()/(RAND_MAX + 1.0))) + min.height();
+
+    return QRect(left, top, width, height);
+}
+
+void MainWindow::addShape()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    Shape::Type type;
+
+    if (sender() == actionAddCircle)
+        type = Shape::Circle;
+    else if (sender() == actionAddRectangle)
+        type = Shape::Rectangle;
+    else if (sender() == actionAddTriangle)
+        type = Shape::Triangle;
+    else return;
+
+    Shape newShape(type, randomColor(), randomRect(doc->size()));
+    doc->undoStack()->push(new AddShapeCommand(doc, newShape));
+}
+
+void MainWindow::removeShape()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    QString shapeName = doc->currentShapeName();
+    if (shapeName.isEmpty())
+        return;
+
+    doc->undoStack()->push(new RemoveShapeCommand(doc, shapeName));
+}
+
+void MainWindow::setShapeColor()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    QString shapeName = doc->currentShapeName();
+    if (shapeName.isEmpty())
+        return;
+
+    QColor color;
+
+    if (sender() == actionRed)
+        color = Qt::red;
+    else if (sender() == actionGreen)
+        color = Qt::green;
+    else if (sender() == actionBlue)
+        color = Qt::blue;
+    else
+        return;
+
+    if (color == doc->shape(shapeName).color())
+        return;
+
+    doc->undoStack()->push(new SetShapeColorCommand(doc, shapeName, color));
+}
+
+void MainWindow::addSnowman()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    // Create a macro command using beginMacro() and endMacro()
+
+    doc->undoStack()->beginMacro(tr("Add snowman"));
+    doc->undoStack()->push(new AddShapeCommand(doc,
+                            Shape(Shape::Circle, Qt::blue, QRect(51, 30, 97, 95))));
+    doc->undoStack()->push(new AddShapeCommand(doc,
+                            Shape(Shape::Circle, Qt::blue, QRect(27, 123, 150, 133))));
+    doc->undoStack()->push(new AddShapeCommand(doc,
+                            Shape(Shape::Circle, Qt::blue, QRect(11, 253, 188, 146))));
+    doc->undoStack()->endMacro();
+}
+
+void MainWindow::addRobot()
+{
+    Document *doc = currentDocument();
+    if (doc == 0)
+        return;
+
+    // Compose a macro command by explicitly adding children to a parent command
+
+    QUndoCommand *parent = new QUndoCommand(tr("Add robot"));
+
+    new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(115, 15, 81, 70)), parent);
+    new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(82, 89, 148, 188)), parent);
+    new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(76, 280, 80, 165)), parent);
+    new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(163, 280, 80, 164)), parent);
+    new AddShapeCommand(doc, Shape(Shape::Circle, Qt::blue, QRect(116, 25, 80, 50)), parent);
+    new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(232, 92, 80, 127)), parent);
+    new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(2, 92, 80, 125)), parent);
+
+    doc->undoStack()->push(parent);
+}
+
+void MainWindow::about()
+{
+    QMessageBox::about(this, tr("About Undo"), tr("The Undo demonstration shows how to use the Qt Undo framework."));
+}
+
+void MainWindow::aboutQt()
+{
+    QMessageBox::aboutQt(this, tr("About Qt"));
+}
diff --git a/demos/undo/mainwindow.h b/demos/undo/mainwindow.h
new file mode 100644
index 0000000..5340e94
--- /dev/null
+++ b/demos/undo/mainwindow.h
@@ -0,0 +1,87 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, 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 are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QMainWindow>
+#include "ui_mainwindow.h"
+
+class Document;
+
+class MainWindow : public QMainWindow, public Ui::MainWindow
+{
+    Q_OBJECT
+
+public:
+    MainWindow(QWidget *parent = 0);
+
+    void addDocument(Document *doc);
+    void removeDocument(Document *doc);
+    void setCurrentDocument(Document *doc);
+    Document *currentDocument() const;
+
+public slots:
+    void openDocument();
+    void saveDocument();
+    void closeDocument();
+    void newDocument();
+
+    void addShape();
+    void removeShape();
+    void setShapeColor();
+
+    void addSnowman();
+    void addRobot();
+
+    void about();
+    void aboutQt();
+
+private slots:
+    void updateActions();
+
+private:
+    QUndoGroup *m_undoGroup;
+
+    QString fixedWindowTitle(const Document *doc) const;
+};
+
+#endif // MAINWINDOW_H
diff --git a/demos/undo/mainwindow.ui b/demos/undo/mainwindow.ui
new file mode 100644
index 0000000..91a0b43
--- /dev/null
+++ b/demos/undo/mainwindow.ui
@@ -0,0 +1,322 @@
+<ui version="4.0" >
+ <class>MainWindow</class>
+ <widget class="QMainWindow" name="MainWindow" >
+  <property name="geometry" >
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>567</width>
+    <height>600</height>
+   </rect>
+  </property>
+  <property name="iconSize" >
+   <size>
+    <width>32</width>
+    <height>32</height>
+   </size>
+  </property>
+  <widget class="QWidget" name="centralwidget" >
+   <layout class="QVBoxLayout" >
+    <property name="margin" >
+     <number>0</number>
+    </property>
+    <property name="spacing" >
+     <number>0</number>
+    </property>
+    <item>
+     <widget class="QTabWidget" name="documentTabs" >
+      <property name="currentIndex" >
+       <number>0</number>
+      </property>
+      <widget class="QWidget" name="tab" >
+       <attribute name="title" >
+        <string>Tab 1</string>
+       </attribute>
+      </widget>
+     </widget>
+    </item>
+   </layout>
+  </widget>
+  <widget class="QMenuBar" name="menubar" >
+   <property name="geometry" >
+    <rect>
+     <x>0</x>
+     <y>0</y>
+     <width>567</width>
+     <height>27</height>
+    </rect>
+   </property>
+   <widget class="QMenu" name="menuFile" >
+    <property name="title" >
+     <string>File</string>
+    </property>
+    <addaction name="actionNew" />
+    <addaction name="actionOpen" />
+    <addaction name="actionSave" />
+    <addaction name="actionClose" />
+    <addaction name="separator" />
+    <addaction name="actionExit" />
+   </widget>
+   <widget class="QMenu" name="menuShape" >
+    <property name="title" >
+     <string>Edit</string>
+    </property>
+    <widget class="QMenu" name="menuMacros" >
+     <property name="title" >
+      <string>Macros</string>
+     </property>
+     <addaction name="actionAddRobot" />
+     <addaction name="actionAddSnowman" />
+    </widget>
+    <addaction name="separator" />
+    <addaction name="actionAddCircle" />
+    <addaction name="actionAddRectangle" />
+    <addaction name="actionAddTriangle" />
+    <addaction name="actionRemoveShape" />
+    <addaction name="separator" />
+    <addaction name="actionRed" />
+    <addaction name="actionGreen" />
+    <addaction name="actionBlue" />
+    <addaction name="separator" />
+    <addaction name="menuMacros" />
+   </widget>
+   <widget class="QMenu" name="menuHelp" >
+    <property name="title" >
+     <string>Help</string>
+    </property>
+    <addaction name="actionAbout" />
+    <addaction name="actionAboutQt" />
+   </widget>
+   <addaction name="menuFile" />
+   <addaction name="menuShape" />
+   <addaction name="menuHelp" />
+  </widget>
+  <widget class="QStatusBar" name="statusbar" />
+  <widget class="QToolBar" name="toolBar" >
+   <property name="windowTitle" >
+    <string>File actions</string>
+   </property>
+   <property name="orientation" >
+    <enum>Qt::Horizontal</enum>
+   </property>
+   <attribute name="toolBarArea" >
+    <enum>TopToolBarArea</enum>
+   </attribute>
+   <attribute name="toolBarBreak" >
+    <bool>false</bool>
+   </attribute>
+   <addaction name="actionNew" />
+   <addaction name="actionOpen" />
+   <addaction name="actionSave" />
+   <addaction name="actionClose" />
+   <addaction name="separator" />
+  </widget>
+  <widget class="QToolBar" name="shapeToolBar" >
+   <property name="windowTitle" >
+    <string>Shape actions</string>
+   </property>
+   <property name="orientation" >
+    <enum>Qt::Vertical</enum>
+   </property>
+   <attribute name="toolBarArea" >
+    <enum>LeftToolBarArea</enum>
+   </attribute>
+   <attribute name="toolBarBreak" >
+    <bool>false</bool>
+   </attribute>
+   <addaction name="actionAddRectangle" />
+   <addaction name="actionAddCircle" />
+   <addaction name="actionAddTriangle" />
+   <addaction name="actionRemoveShape" />
+   <addaction name="separator" />
+   <addaction name="actionRed" />
+   <addaction name="actionGreen" />
+   <addaction name="actionBlue" />
+  </widget>
+  <widget class="QDockWidget" name="dockWidget" >
+   <property name="windowTitle" >
+    <string>Undo Stack</string>
+   </property>
+   <attribute name="dockWidgetArea" >
+    <number>2</number>
+   </attribute>
+   <widget class="QWidget" name="dockWidgetContents" >
+    <layout class="QVBoxLayout" >
+     <property name="margin" >
+      <number>0</number>
+     </property>
+     <property name="spacing" >
+      <number>4</number>
+     </property>
+     <item>
+      <layout class="QHBoxLayout" >
+       <property name="margin" >
+        <number>0</number>
+       </property>
+       <property name="spacing" >
+        <number>6</number>
+       </property>
+       <item>
+        <spacer>
+         <property name="orientation" >
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" >
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+       <item>
+        <widget class="QLabel" name="label" >
+         <property name="text" >
+          <string>Undo limit</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QSpinBox" name="undoLimit" />
+       </item>
+      </layout>
+     </item>
+     <item>
+      <widget class="QUndoView" name="undoView" >
+       <property name="alternatingRowColors" >
+        <bool>false</bool>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </widget>
+  </widget>
+  <action name="actionOpen" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/fileopen.png</iconset>
+   </property>
+   <property name="text" >
+    <string>&amp;Open</string>
+   </property>
+  </action>
+  <action name="actionClose" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/fileclose.png</iconset>
+   </property>
+   <property name="text" >
+    <string>&amp;Close</string>
+   </property>
+  </action>
+  <action name="actionNew" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/filenew.png</iconset>
+   </property>
+   <property name="text" >
+    <string>&amp;New</string>
+   </property>
+  </action>
+  <action name="actionSave" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/filesave.png</iconset>
+   </property>
+   <property name="text" >
+    <string>&amp;Save</string>
+   </property>
+  </action>
+  <action name="actionExit" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/exit.png</iconset>
+   </property>
+   <property name="text" >
+    <string>E&amp;xit</string>
+   </property>
+  </action>
+  <action name="actionRed" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/red.png</iconset>
+   </property>
+   <property name="text" >
+    <string>Red</string>
+   </property>
+  </action>
+  <action name="actionGreen" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/green.png</iconset>
+   </property>
+   <property name="text" >
+    <string>Green</string>
+   </property>
+  </action>
+  <action name="actionBlue" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/blue.png</iconset>
+   </property>
+   <property name="text" >
+    <string>Blue</string>
+   </property>
+  </action>
+  <action name="actionAddRectangle" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/rectangle.png</iconset>
+   </property>
+   <property name="text" >
+    <string>Add Rectangle</string>
+   </property>
+  </action>
+  <action name="actionAddCircle" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/circle.png</iconset>
+   </property>
+   <property name="text" >
+    <string>Add Circle</string>
+   </property>
+  </action>
+  <action name="actionRemoveShape" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/remove.png</iconset>
+   </property>
+   <property name="text" >
+    <string>Remove Shape</string>
+   </property>
+  </action>
+  <action name="actionAddRobot" >
+   <property name="text" >
+    <string>Add robot</string>
+   </property>
+  </action>
+  <action name="actionAddSnowman" >
+   <property name="text" >
+    <string>Add snowan</string>
+   </property>
+  </action>
+  <action name="actionAddTriangle" >
+   <property name="icon" >
+    <iconset resource="undo.qrc" >:/icons/triangle.png</iconset>
+   </property>
+   <property name="text" >
+    <string>addTriangle</string>
+   </property>
+  </action>
+  <action name="actionAbout" >
+   <property name="text" >
+    <string>About</string>
+   </property>
+  </action>
+  <action name="actionAboutQt" >
+   <property name="text" >
+    <string>About Qt</string>
+   </property>
+  </action>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QUndoView</class>
+   <extends>QListView</extends>
+   <header>qundoview.h</header>
+  </customwidget>
+ </customwidgets>
+ <resources>
+  <include location="undo.qrc" />
+ </resources>
+ <connections/>
+</ui>
diff --git a/demos/undo/undo.pro b/demos/undo/undo.pro
new file mode 100644
index 0000000..e26d07c
--- /dev/null
+++ b/demos/undo/undo.pro
@@ -0,0 +1,17 @@
+SOURCES += main.cpp mainwindow.cpp commands.cpp document.cpp
+HEADERS += mainwindow.h commands.h document.h
+FORMS += mainwindow.ui
+
+build_all:!build_pass {
+    CONFIG -= build_all
+    CONFIG += release
+}
+
+RESOURCES += undo.qrc
+
+# install
+target.path = $$[QT_INSTALL_DEMOS]/undo
+sources.files = $$SOURCES $$HEADERS *.pro icons $$RESOURCES $$FORMS
+sources.path = $$[QT_INSTALL_DEMOS]/undo
+INSTALLS += target sources
+
diff --git a/demos/undo/undo.qrc b/demos/undo/undo.qrc
new file mode 100644
index 0000000..65619b8
--- /dev/null
+++ b/demos/undo/undo.qrc
@@ -0,0 +1,20 @@
+<RCC>
+    <qresource prefix="/" >
+        <file>icons/background.png</file>
+        <file>icons/blue.png</file>
+        <file>icons/circle.png</file>
+        <file>icons/exit.png</file>
+        <file>icons/fileclose.png</file>
+        <file>icons/filenew.png</file>
+        <file>icons/fileopen.png</file>
+        <file>icons/filesave.png</file>
+        <file>icons/green.png</file>
+        <file>icons/ok.png</file>
+        <file>icons/rectangle.png</file>
+        <file>icons/red.png</file>
+        <file>icons/redo.png</file>
+        <file>icons/remove.png</file>
+        <file>icons/triangle.png</file>
+        <file>icons/undo.png</file>
+    </qresource>
+</RCC>