From f568737c20bea96fb79d85681a72e142ec05d66f Mon Sep 17 00:00:00 2001
From: leseb <leseb>
Date: Wed, 10 Jul 2002 21:59:27 +0000
Subject: Undo/redo reimplemented

---
diff --git a/noncore/graphics/drawpad/drawpad.cpp b/noncore/graphics/drawpad/drawpad.cpp
index 4eb47a5..b0a414e 100644
--- a/noncore/graphics/drawpad/drawpad.cpp
+++ b/noncore/graphics/drawpad/drawpad.cpp
@@ -55,9 +55,7 @@ DrawPad::DrawPad(QWidget* parent, const char* name)
 
     m_pDrawPadCanvas = new DrawPadCanvas(this, this);
 
-    connect(m_pDrawPadCanvas, SIGNAL(pagesChanged()), this, SLOT(updateNavigationToolButtons()));
-    connect(m_pDrawPadCanvas, SIGNAL(pagesChanged()), this, SLOT(updateCaption()));
-    connect(m_pDrawPadCanvas, SIGNAL(pageBackupsChanged()), this, SLOT(updateUndoRedoToolButtons()));
+    connect(m_pDrawPadCanvas, SIGNAL(pagesChanged()), this, SLOT(updateView()));
 
     setCentralWidget(m_pDrawPadCanvas);
 
@@ -542,27 +540,21 @@ void DrawPad::changeBrushColor(const QColor& color)
     m_pBrushColorToolButton->popup()->hide();
 }
 
-void DrawPad::updateUndoRedoToolButtons()
-{
-    m_pUndoAction->setEnabled(m_pDrawPadCanvas->undoEnabled());
-    m_pRedoAction->setEnabled(m_pDrawPadCanvas->redoEnabled());
-}
-
-void DrawPad::updateNavigationToolButtons()
-{
-    m_pFirstPageAction->setEnabled(m_pDrawPadCanvas->goPreviousPageEnabled());
-    m_pPreviousPageAction->setEnabled(m_pDrawPadCanvas->goPreviousPageEnabled());
-    m_pNextPageAction->setEnabled(m_pDrawPadCanvas->goNextPageEnabled());
-    m_pLastPageAction->setEnabled(m_pDrawPadCanvas->goNextPageEnabled());
-}
-
-void DrawPad::updateCaption()
+void DrawPad::updateView()
 {
     uint pagePosition = m_pDrawPadCanvas->pagePosition();
     uint pageCount = m_pDrawPadCanvas->pageCount();
 
     setCaption(tr("DrawPad") + " - " + tr("Page") + " "
                + QString::number(pagePosition) + "/" + QString::number(pageCount));
+
+    m_pUndoAction->setEnabled(m_pDrawPadCanvas->currentPage()->undoEnabled());
+    m_pRedoAction->setEnabled(m_pDrawPadCanvas->currentPage()->redoEnabled());
+
+    m_pFirstPageAction->setEnabled(m_pDrawPadCanvas->goPreviousPageEnabled());
+    m_pPreviousPageAction->setEnabled(m_pDrawPadCanvas->goPreviousPageEnabled());
+    m_pNextPageAction->setEnabled(m_pDrawPadCanvas->goNextPageEnabled());
+    m_pLastPageAction->setEnabled(m_pDrawPadCanvas->goNextPageEnabled());
 }
 
 void DrawPad::deleteAll()
diff --git a/noncore/graphics/drawpad/drawpad.h b/noncore/graphics/drawpad/drawpad.h
index c57606c..7306228 100644
--- a/noncore/graphics/drawpad/drawpad.h
+++ b/noncore/graphics/drawpad/drawpad.h
@@ -59,10 +59,8 @@ private slots:
     void changePenWidth(int value);
     void changePenColor(const QColor& color);
     void changeBrushColor(const QColor& color);
-
-    void updateUndoRedoToolButtons();
-    void updateNavigationToolButtons();
-    void updateCaption();
+    
+    void updateView();
 
     void deleteAll();
     void importPage();
diff --git a/noncore/graphics/drawpad/drawpadcanvas.cpp b/noncore/graphics/drawpad/drawpadcanvas.cpp
index 05dd408..025bebb 100644
--- a/noncore/graphics/drawpad/drawpadcanvas.cpp
+++ b/noncore/graphics/drawpad/drawpadcanvas.cpp
@@ -28,8 +28,6 @@
 #include <qtextstream.h>
 #include <qxml.h>
 
-const int PAGE_BACKUPS = 99;
-
 class DrawPadCanvasXmlHandler: public QXmlDefaultHandler
 {
 public:
@@ -149,7 +147,7 @@ bool DrawPadCanvasXmlHandler::characters(const QString& ch)
 
         Page* page = new Page(m_title, image.width(), image.height());
         page->setLastModified(m_date);
-        page->convertFromImage(image);
+        page->pixmap()->convertFromImage(image);
         m_pages.append(page);
     }
 
@@ -161,7 +159,6 @@ DrawPadCanvas::DrawPadCanvas(DrawPad* drawPad, QWidget* parent, const char* name
 {
     m_pDrawPad = drawPad;
     m_pages.setAutoDelete(true);
-    m_pageBackups.setAutoDelete(true);
 
     viewport()->setBackgroundMode(QWidget::NoBackground);
 }
@@ -186,32 +183,24 @@ void DrawPadCanvas::load(QIODevice* ioDevice)
 
     if (m_pages.isEmpty()) {
         m_pages.append(new Page("", contentsRect().size()));
-        m_pages.current()->fill(Qt::white);
+        m_pages.current()->pixmap()->fill(Qt::white);
     }
 
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::initialPage()
 {
     m_pages.append(new Page("", 236, 232));
-    m_pages.current()->fill(Qt::white);
-
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
+    m_pages.current()->pixmap()->fill(Qt::white);
 
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::save(QIODevice* ioDevice)
@@ -227,11 +216,11 @@ void DrawPadCanvas::save(QIODevice* ioDevice)
     for (bufferIterator.toFirst(); bufferIterator.current() != 0; ++bufferIterator) {
         textStream << "        <image>" << endl;
         textStream << "            <title>" << bufferIterator.current()->title() << "</title>" << endl;
-        
+
         int intDate = QDateTime(QDate(1970, 1, 1)).secsTo(bufferIterator.current()->lastModified());
         textStream << "            <date>" << intDate << "</date>" << endl;
 
-        QImage image = bufferIterator.current()->convertToImage();
+        QImage image = bufferIterator.current()->pixmap()->convertToImage();
         QByteArray byteArray;
         QBuffer buffer(byteArray);
         QImageIO imageIO(&buffer, "PNG");
@@ -263,17 +252,13 @@ void DrawPadCanvas::importPage(const QString& fileName)
 {
     Page* importedPage = new Page();
 
-    importedPage->load(fileName);
+    importedPage->pixmap()->load(fileName);
     m_pages.insert(m_pages.at() + 1, importedPage);
 
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::exportPage(uint fromPage, uint toPage, const QString& name,const QString& format)
@@ -289,7 +274,7 @@ void DrawPadCanvas::exportPage(uint fromPage, uint toPage, const QString& name,c
         QIODevice* ioDevice = fileManager.saveFile(docLnk);
         QImageIO imageIO(ioDevice, format);
 
-        QImage image = m_pages.current()->convertToImage();
+        QImage image = m_pages.current()->pixmap()->convertToImage();
         imageIO.setImage(image);
         imageIO.write();
         delete ioDevice;
@@ -305,7 +290,7 @@ void DrawPadCanvas::exportPage(uint fromPage, uint toPage, const QString& name,c
             QIODevice* ioDevice = fileManager.saveFile(docLnk);
             QImageIO imageIO(ioDevice, format);
 
-            QImage image = m_pages.at(i - 1)->convertToImage();
+            QImage image = m_pages.at(i - 1)->pixmap()->convertToImage();
             imageIO.setImage(image);
             imageIO.write();
             delete ioDevice;
@@ -336,45 +321,28 @@ uint DrawPadCanvas::pageCount()
 void DrawPadCanvas::selectPage(Page* page)
 {
     m_pages.findRef(page);
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
 
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
-void DrawPadCanvas::selectPage(uint pagePosition)
+void DrawPadCanvas::backupPage()
 {
-    m_pages.at(pagePosition - 1);
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
-    viewport()->update();
+    m_pages.current()->backup();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
-void DrawPadCanvas::backupPage()
+void DrawPadCanvas::selectPage(uint pagePosition)
 {
-    m_pages.current()->setLastModified(QDateTime::currentDateTime());
-
-    Page* currentBackup = m_pageBackups.current();
-    while (m_pageBackups.last() != currentBackup) {
-        m_pageBackups.removeLast();
-    }
-
-    while (m_pageBackups.count() >= (PAGE_BACKUPS + 1)) {
-        m_pageBackups.removeFirst();
-    }
+    m_pages.at(pagePosition - 1);
 
-    m_pageBackups.append(new Page(*(m_pages.current())));
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
+    viewport()->update();
 
-    emit pageBackupsChanged();
+    emit pagesChanged();
 }
 
 void DrawPadCanvas::deleteAll()
@@ -382,44 +350,31 @@ void DrawPadCanvas::deleteAll()
     m_pages.clear();
 
     m_pages.append(new Page("", contentsRect().size()));
-    m_pages.current()->fill(Qt::white);
+    m_pages.current()->pixmap()->fill(Qt::white);
 
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::newPage(QString title, uint width, uint height, const QColor& color)
 {
     m_pages.insert(m_pages.at() + 1, new Page(title, width, height));
-    m_pages.current()->fill(color);
-
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
+    m_pages.current()->pixmap()->fill(color);
 
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::clearPage()
 {
-    m_pages.current()->fill(Qt::white);
+    m_pages.current()->pixmap()->fill(Qt::white);
 
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
-
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::deletePage()
@@ -428,17 +383,13 @@ void DrawPadCanvas::deletePage()
 
     if (m_pages.isEmpty()) {
         m_pages.append(new Page("", contentsRect().size()));
-        m_pages.current()->fill(Qt::white);
+        m_pages.current()->pixmap()->fill(Qt::white);
     }
 
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::movePageUp()
@@ -459,16 +410,6 @@ void DrawPadCanvas::movePageDown()
     emit pagesChanged();
 }
 
-bool DrawPadCanvas::undoEnabled()
-{
-    return (m_pageBackups.current() != m_pageBackups.getFirst());
-}
-
-bool DrawPadCanvas::redoEnabled()
-{
-    return (m_pageBackups.current() != m_pageBackups.getLast());
-}
-
 bool DrawPadCanvas::goPreviousPageEnabled()
 {
     return (m_pages.current() != m_pages.getFirst());
@@ -481,72 +422,59 @@ bool DrawPadCanvas::goNextPageEnabled()
 
 void DrawPadCanvas::undo()
 {
-    *(m_pages.current()) = *(m_pageBackups.prev());
+    m_pages.current()->undo();
 
     viewport()->update();
 
-    emit pageBackupsChanged();
+    emit pagesChanged();
 }
 
 void DrawPadCanvas::redo()
 {
-    *(m_pages.current()) = *(m_pageBackups.next());
+    m_pages.current()->redo();
 
     viewport()->update();
 
-    emit pageBackupsChanged();
+    emit pagesChanged();
 }
 
 void DrawPadCanvas::goFirstPage()
 {
     m_pages.first();
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
 
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::goPreviousPage()
 {
     m_pages.prev();
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
 
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::goNextPage()
 {
     m_pages.next();
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
-
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::goLastPage()
 {
     m_pages.last();
-    m_pageBackups.clear();
-    m_pageBackups.append(new Page(*(m_pages.current())));
 
-    resizeContents(m_pages.current()->width(), m_pages.current()->height());
+    resizeContents(m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     viewport()->update();
 
     emit pagesChanged();
-    emit pageBackupsChanged();
 }
 
 void DrawPadCanvas::contentsMousePressEvent(QMouseEvent* e)
@@ -567,10 +495,10 @@ void DrawPadCanvas::contentsMouseMoveEvent(QMouseEvent* e)
 void DrawPadCanvas::drawContents(QPainter* p, int cx, int cy, int cw, int ch)
 {
     QRect clipRect(cx, cy, cw, ch);
-    QRect pixmapRect(0, 0, m_pages.current()->width(), m_pages.current()->height());
+    QRect pixmapRect(0, 0, m_pages.current()->pixmap()->width(), m_pages.current()->pixmap()->height());
     QRect drawRect = pixmapRect.intersect(clipRect);
 
-    p->drawPixmap(drawRect.topLeft(), *(m_pages.current()), drawRect);
+    p->drawPixmap(drawRect.topLeft(), *(m_pages.current()->pixmap()), drawRect);
 
     if (drawRect.right() < clipRect.right()) {
         p->fillRect(drawRect.right() + 1, cy, cw - drawRect.width(), ch, colorGroup().dark());
diff --git a/noncore/graphics/drawpad/drawpadcanvas.h b/noncore/graphics/drawpad/drawpadcanvas.h
index 2283e5e..80a2a7e 100644
--- a/noncore/graphics/drawpad/drawpadcanvas.h
+++ b/noncore/graphics/drawpad/drawpadcanvas.h
@@ -37,8 +37,6 @@ public:
     void importPage(const QString& fileName);
     void exportPage(uint fromPage, uint toPage, const QString& name, const QString& format);
 
-    bool undoEnabled();
-    bool redoEnabled();
     bool goPreviousPageEnabled();
     bool goNextPageEnabled();
 
@@ -58,7 +56,7 @@ public slots:
     void deletePage();
     void movePageUp();
     void movePageDown();
-
+    
     void undo();
     void redo();
 
@@ -69,7 +67,6 @@ public slots:
 
 signals:
     void pagesChanged();
-    void pageBackupsChanged();
 
 protected:
     void contentsMousePressEvent(QMouseEvent* e);
@@ -80,7 +77,6 @@ protected:
 private:
     DrawPad* m_pDrawPad;
     QList<Page> m_pages;
-    QList<Page> m_pageBackups;
 };
 
 #endif // DRAWPADCANVAS_H
diff --git a/noncore/graphics/drawpad/erasetool.cpp b/noncore/graphics/drawpad/erasetool.cpp
index f77e038..2326da5 100644
--- a/noncore/graphics/drawpad/erasetool.cpp
+++ b/noncore/graphics/drawpad/erasetool.cpp
@@ -32,6 +32,8 @@ EraseTool::~EraseTool()
 
 void EraseTool::mousePressEvent(QMouseEvent* e)
 {
+    m_pDrawPadCanvas->backupPage();
+
     m_mousePressed = true;
     m_polyline[2] = m_polyline[1] = m_polyline[0] = e->pos();
 }
@@ -41,8 +43,6 @@ void EraseTool::mouseReleaseEvent(QMouseEvent* e)
     Q_UNUSED(e)
 
     m_mousePressed = false;
-
-    m_pDrawPadCanvas->backupPage();
 }
 
 void EraseTool::mouseMoveEvent(QMouseEvent* e)
@@ -50,7 +50,7 @@ void EraseTool::mouseMoveEvent(QMouseEvent* e)
     if (m_mousePressed) {
         QPainter painter;
         QPen pen(Qt::white, m_pDrawPad->pen().width());
-        painter.begin(m_pDrawPadCanvas->currentPage());
+        painter.begin(m_pDrawPadCanvas->currentPage()->pixmap());
         painter.setPen(pen);
         m_polyline[2] = m_polyline[1];
         m_polyline[1] = m_polyline[0];
@@ -69,7 +69,7 @@ void EraseTool::mouseMoveEvent(QMouseEvent* e)
                            m_pDrawPadCanvas->contentsToViewport(r.bottomRight()));
 
         bitBlt(m_pDrawPadCanvas->viewport(), viewportRect.x(), viewportRect.y(),
-               m_pDrawPadCanvas->currentPage(), r.x(), r.y(), r.width(), r.height());
+               m_pDrawPadCanvas->currentPage()->pixmap(), r.x(), r.y(), r.width(), r.height());
 
         m_pDrawPadCanvas->viewport()->update(viewportRect);
     }
diff --git a/noncore/graphics/drawpad/filltool.cpp b/noncore/graphics/drawpad/filltool.cpp
index 0177e1c..2a39d04 100644
--- a/noncore/graphics/drawpad/filltool.cpp
+++ b/noncore/graphics/drawpad/filltool.cpp
@@ -35,11 +35,13 @@ void FillTool::mousePressEvent(QMouseEvent* e)
     int x = e->x();
     int y = e->y();
 
-    m_image = m_pDrawPadCanvas->currentPage()->convertToImage();
+    m_image = m_pDrawPadCanvas->currentPage()->pixmap()->convertToImage();
     m_fillRgb = m_pDrawPad->brush().color().rgb();
     m_oldRgb = m_image.pixel(x, y);
 
     if (m_oldRgb != m_fillRgb) {
+        m_pDrawPadCanvas->backupPage();
+
         if (m_pDrawPad->antiAliasing()) {
             m_mask.create(m_image.width(), m_image.height(), 8, 2);
             m_mask.fill(0);
@@ -58,10 +60,8 @@ void FillTool::mousePressEvent(QMouseEvent* e)
             fillLine(x, y);
         }
 
-        m_pDrawPadCanvas->currentPage()->convertFromImage(m_image);
+        m_pDrawPadCanvas->currentPage()->pixmap()->convertFromImage(m_image);
         m_pDrawPadCanvas->viewport()->update();
-
-        m_pDrawPadCanvas->backupPage();
     }
 }
 
@@ -111,31 +111,31 @@ void FillTool::fillMaskLine(int x, int y)
 {
     if ((x >= 0) && (x < m_image.width()) && (y >= 0) && (y < m_image.height())) {
         if (m_mask.pixelIndex(x, y) == 0) {
-                if (rgbDistance(m_image.pixel(x, y), m_oldRgb) < FILL_THRESHOLD) {
-                int x1, x2;
+            if (rgbDistance(m_image.pixel(x, y), m_oldRgb) < FILL_THRESHOLD) {
+            int x1, x2;
 
-                x1 = x - 1;
-                x2 = x + 1;
+            x1 = x - 1;
+            x2 = x + 1;
 
-                while ((x1 >= 0) && (rgbDistance(m_image.pixel(x1, y), m_oldRgb) < FILL_THRESHOLD)) {
-                    x1--;
-                }
+            while ((x1 >= 0) && (rgbDistance(m_image.pixel(x1, y), m_oldRgb) < FILL_THRESHOLD)) {
+                x1--;
+            }
 
-                while ((x2 < m_image.width()) && (rgbDistance(m_image.pixel(x2, y), m_oldRgb) < FILL_THRESHOLD)) {
-                    x2++;
-                }
+            while ((x2 < m_image.width()) && (rgbDistance(m_image.pixel(x2, y), m_oldRgb) < FILL_THRESHOLD)) {
+                x2++;
+            }
 
-                for (int i = x1 + 1; i < x2; i++) {
-                    m_mask.setPixel(i, y, 1);
-                }
+            for (int i = x1 + 1; i < x2; i++) {
+                m_mask.setPixel(i, y, 1);
+            }
 
-                for (int i = x1 + 1; i < x2; i++) {
-                    fillMaskLine(i, y - 1);
-                }
+            for (int i = x1 + 1; i < x2; i++) {
+                fillMaskLine(i, y - 1);
+            }
 
-                for (int i = x1 + 1; i < x2; i++) {
-                    fillMaskLine(i, y + 1);
-                }
+            for (int i = x1 + 1; i < x2; i++) {
+                fillMaskLine(i, y + 1);
+            }
             }
         }
     }
diff --git a/noncore/graphics/drawpad/page.cpp b/noncore/graphics/drawpad/page.cpp
index 601d1c3..fbf3d01 100644
--- a/noncore/graphics/drawpad/page.cpp
+++ b/noncore/graphics/drawpad/page.cpp
@@ -13,28 +13,41 @@
 
 #include "page.h"
 
+const int PAGE_BACKUPS = 99;
+
 Page::Page()
-    : QPixmap()
 {
+    m_title = "";
     m_lastModified = QDateTime::currentDateTime();
+    m_pPixmap = new QPixmap();
+
+    m_backHistory.setAutoDelete(true);
+    m_forwardHistory.setAutoDelete(true);
 }
 
 Page::Page(QString title, int w, int h)
-    : QPixmap(w, h)
 {
     m_title = title;
     m_lastModified = QDateTime::currentDateTime();
+    m_pPixmap = new QPixmap(w, h);
+
+    m_backHistory.setAutoDelete(true);
+    m_forwardHistory.setAutoDelete(true);
 }
 
 Page::Page(QString title, const QSize& size)
-    : QPixmap(size)
 {
     m_title = title;
     m_lastModified = QDateTime::currentDateTime();
+    m_pPixmap = new QPixmap(size);
+
+    m_backHistory.setAutoDelete(true);
+    m_forwardHistory.setAutoDelete(true);
 }
 
 Page::~Page()
 {
+    delete m_pPixmap;
 }
 
 QString Page::title() const
@@ -47,6 +60,12 @@ QDateTime Page::lastModified() const
     return m_lastModified;
 }
 
+QPixmap* Page::pixmap() const
+
+{
+    return m_pPixmap;
+}
+
 void Page::setTitle(QString title)
 {
     m_title = title;
@@ -57,3 +76,38 @@ void Page::setLastModified(QDateTime lastModified)
     m_lastModified = lastModified;
 }
 
+bool Page::undoEnabled()
+{
+    return (!m_backHistory.isEmpty());
+}
+
+bool Page::redoEnabled()
+{
+    return (!m_forwardHistory.isEmpty());
+}
+
+void Page::backup()
+{
+    setLastModified(QDateTime::currentDateTime());
+
+    while (m_backHistory.count() >= (PAGE_BACKUPS + 1)) {
+        m_backHistory.removeFirst();
+    }
+
+    m_backHistory.append(new QPixmap(*m_pPixmap));
+    m_forwardHistory.clear();
+}
+
+void Page::undo()
+{
+    m_forwardHistory.append(new QPixmap(*m_pPixmap));
+    m_pPixmap = new QPixmap(*(m_backHistory.last()));
+    m_backHistory.removeLast();
+}
+
+void Page::redo()
+{
+    m_backHistory.append(new QPixmap(*m_pPixmap));
+    m_pPixmap = new QPixmap(*(m_forwardHistory.last()));
+    m_forwardHistory.removeLast();
+}
diff --git a/noncore/graphics/drawpad/page.h b/noncore/graphics/drawpad/page.h
index 20a37b5..8ce7bc9 100644
--- a/noncore/graphics/drawpad/page.h
+++ b/noncore/graphics/drawpad/page.h
@@ -14,11 +14,13 @@
 #ifndef PAGE_H
 #define PAGE_H
 
-#include <qpixmap.h>
+#include <qobject.h>
 
 #include <qdatetime.h>
+#include <qlist.h>
+#include <qpixmap.h>
 
-class Page : public QPixmap
+class Page : public QObject
 {
 public:
     Page();
@@ -26,16 +28,28 @@ public:
     Page(QString title, const QSize& size);
 
     ~Page();
-    
+
     QString title() const;
     QDateTime lastModified() const;
+    QPixmap* pixmap() const;
 
     void setTitle(QString title);
     void setLastModified(QDateTime lastModified);
 
+    bool undoEnabled();
+    bool redoEnabled();
+
+    void backup();
+    void undo();
+    void redo();
+
 private:
     QString m_title;
     QDateTime m_lastModified;
+    QPixmap* m_pPixmap;
+
+    QList<QPixmap> m_backHistory;
+    QList<QPixmap> m_forwardHistory;
 };
 
 #endif // PAGE_H
diff --git a/noncore/graphics/drawpad/pageinformationdialog.cpp b/noncore/graphics/drawpad/pageinformationdialog.cpp
index c0d055e..cb14d73 100644
--- a/noncore/graphics/drawpad/pageinformationdialog.cpp
+++ b/noncore/graphics/drawpad/pageinformationdialog.cpp
@@ -43,10 +43,10 @@ PageInformationDialog::PageInformationDialog(Page* page, QWidget* parent, const
     QGroupBox* sizeGroupBox = new QGroupBox(0, Qt::Vertical, tr("Size"), this);
 
     QLabel* widthLabel = new QLabel(tr("Width:"), sizeGroupBox);
-    QLabel* widthValueLabel = new QLabel(QString::number(m_pPage->width()), sizeGroupBox);
+    QLabel* widthValueLabel = new QLabel(QString::number(m_pPage->pixmap()->width()), sizeGroupBox);
 
     QLabel* heightLabel = new QLabel(tr("Height:"), sizeGroupBox);
-    QLabel* heightValueLabel = new QLabel(QString::number(m_pPage->height()), sizeGroupBox);
+    QLabel* heightValueLabel = new QLabel(QString::number(m_pPage->pixmap()->height()), sizeGroupBox);
 
     QVBoxLayout* mainLayout = new QVBoxLayout(this, 4, 4);
     generalGroupBox->layout()->setSpacing(4);
diff --git a/noncore/graphics/drawpad/pointtool.cpp b/noncore/graphics/drawpad/pointtool.cpp
index a4f846e..b9b52bc 100644
--- a/noncore/graphics/drawpad/pointtool.cpp
+++ b/noncore/graphics/drawpad/pointtool.cpp
@@ -33,6 +33,8 @@ PointTool::~PointTool()
 
 void PointTool::mousePressEvent(QMouseEvent* e)
 {
+    m_pDrawPadCanvas->backupPage();
+
     m_mousePressed = true;
     m_polyline[2] = m_polyline[1] = m_polyline[0] = e->pos();
 }
@@ -42,8 +44,6 @@ void PointTool::mouseReleaseEvent(QMouseEvent* e)
     Q_UNUSED(e)
 
     m_mousePressed = false;
-
-    m_pDrawPadCanvas->backupPage();
 }
 
 void PointTool::mouseMoveEvent(QMouseEvent* e)
@@ -61,7 +61,7 @@ void PointTool::mouseMoveEvent(QMouseEvent* e)
         r.setBottom(r.bottom() + m_pDrawPad->pen().width());
 
         QPainter painter;
-        painter.begin(m_pDrawPadCanvas->currentPage());
+        painter.begin(m_pDrawPadCanvas->currentPage()->pixmap());
 
         if (m_pDrawPad->antiAliasing()) {
             QPixmap areaPixmap(r.width(), r.height());
@@ -104,7 +104,7 @@ void PointTool::mouseMoveEvent(QMouseEvent* e)
                            m_pDrawPadCanvas->contentsToViewport(r.bottomRight()));
 
         bitBlt(m_pDrawPadCanvas->viewport(), viewportRect.x(), viewportRect.y(),
-               m_pDrawPadCanvas->currentPage(), r.x(), r.y(), r.width(), r.height());
+               m_pDrawPadCanvas->currentPage()->pixmap(), r.x(), r.y(), r.width(), r.height());
 
         m_pDrawPadCanvas->viewport()->update(viewportRect);
     }
diff --git a/noncore/graphics/drawpad/shapetool.cpp b/noncore/graphics/drawpad/shapetool.cpp
index 8870a78..22e3dd6 100644
--- a/noncore/graphics/drawpad/shapetool.cpp
+++ b/noncore/graphics/drawpad/shapetool.cpp
@@ -32,6 +32,8 @@ ShapeTool::~ShapeTool()
 
 void ShapeTool::mousePressEvent(QMouseEvent* e)
 {
+    m_pDrawPadCanvas->backupPage();
+
     m_mousePressed = true;
     m_polyline[2] = m_polyline[1] = m_polyline[0] = e->pos();
 }
@@ -41,7 +43,7 @@ void ShapeTool::mouseReleaseEvent(QMouseEvent* e)
     Q_UNUSED(e)
 
     QPainter painter;
-    painter.begin(m_pDrawPadCanvas->currentPage());
+    painter.begin(m_pDrawPadCanvas->currentPage()->pixmap());
     drawFinalShape(painter);
     painter.end();
 
@@ -56,13 +58,11 @@ void ShapeTool::mouseReleaseEvent(QMouseEvent* e)
                        m_pDrawPadCanvas->contentsToViewport(r.bottomRight()));
 
     bitBlt(m_pDrawPadCanvas->viewport(), viewportRect.x(), viewportRect.y(),
-           m_pDrawPadCanvas->currentPage(), r.x(), r.y(), r.width(), r.height());
+           m_pDrawPadCanvas->currentPage()->pixmap(), r.x(), r.y(), r.width(), r.height());
 
     m_pDrawPadCanvas->viewport()->update(viewportRect);
 
     m_mousePressed = false;
-
-    m_pDrawPadCanvas->backupPage();
 }
 
 void ShapeTool::mouseMoveEvent(QMouseEvent* e)
@@ -70,7 +70,7 @@ void ShapeTool::mouseMoveEvent(QMouseEvent* e)
     if (m_mousePressed) {
         m_polyline[0] = e->pos();
         QPainter painter;
-        painter.begin(m_pDrawPadCanvas->currentPage());
+        painter.begin(m_pDrawPadCanvas->currentPage()->pixmap());
         drawTemporaryShape(painter);
         painter.end();
 
@@ -85,7 +85,7 @@ void ShapeTool::mouseMoveEvent(QMouseEvent* e)
                            m_pDrawPadCanvas->contentsToViewport(r.bottomRight()));
 
         bitBlt(m_pDrawPadCanvas->viewport(), viewportRect.x(), viewportRect.y(),
-               m_pDrawPadCanvas->currentPage(), r.x(), r.y(), r.width(), r.height());
+               m_pDrawPadCanvas->currentPage()->pixmap(), r.x(), r.y(), r.width(), r.height());
 
         m_pDrawPadCanvas->viewport()->update(viewportRect);
 
diff --git a/noncore/graphics/drawpad/texttool.cpp b/noncore/graphics/drawpad/texttool.cpp
index 34c8a76..9037abd 100644
--- a/noncore/graphics/drawpad/texttool.cpp
+++ b/noncore/graphics/drawpad/texttool.cpp
@@ -56,15 +56,15 @@ void TextTool::mousePressEvent(QMouseEvent* e)
     TextToolDialog textToolDialog(m_pDrawPad);
 
     if (textToolDialog.exec() == QDialog::Accepted && !textToolDialog.text().isEmpty()) {
+        m_pDrawPadCanvas->backupPage();
+
         QPainter painter;
-        painter.begin(m_pDrawPadCanvas->currentPage());
+        painter.begin(m_pDrawPadCanvas->currentPage()->pixmap());
         painter.setPen(m_pDrawPad->pen());
         painter.drawText(e->x(), e->y(), textToolDialog.text());
         painter.end();
 
         m_pDrawPadCanvas->viewport()->update();
-
-        m_pDrawPadCanvas->backupPage();
     }
 }
 
diff --git a/noncore/graphics/drawpad/thumbnailview.cpp b/noncore/graphics/drawpad/thumbnailview.cpp
index 14092bf..9b08ca2 100644
--- a/noncore/graphics/drawpad/thumbnailview.cpp
+++ b/noncore/graphics/drawpad/thumbnailview.cpp
@@ -35,7 +35,7 @@ PageListBoxItem::PageListBoxItem(Page* page, QListBox* parent)
 {
     m_pPage = page;
 
-    QImage image = m_pPage->convertToImage();
+    QImage image = m_pPage->pixmap()->convertToImage();
 
     int previewWidth = THUMBNAIL_SIZE;
     int previewHeight = THUMBNAIL_SIZE;
@@ -57,8 +57,8 @@ PageListBoxItem::PageListBoxItem(Page* page, QListBox* parent)
     m_thumbnail.convertFromImage(thumbnailImage);
 
     m_titleText = QObject::tr("Title:") + " " + m_pPage->title();
-    m_dimensionText = QObject::tr("Dimension:") + " " + QString::number(m_pPage->width())
-                      + "x" + QString::number(m_pPage->height());
+    m_dimensionText = QObject::tr("Dimension:") + " " + QString::number(m_pPage->pixmap()->width())
+                      + "x" + QString::number(m_pPage->pixmap()->height());
     m_dateText = QObject::tr("Date:") + " " + dateTimeString(m_pPage->lastModified());
 
     QColor baseColor = parent->colorGroup().base();
--
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