diff -r 000000000000 -r 1918ee327afb examples/widgets/codeeditor/codeeditor.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/widgets/codeeditor/codeeditor.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,171 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the examples 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 Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtGui>
+
+#include "codeeditor.h"
+
+//![constructor]
+
+CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent)
+{
+    lineNumberArea = new LineNumberArea(this);
+
+    connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
+    connect(this, SIGNAL(updateRequest(const QRect &, int)), this, SLOT(updateLineNumberArea(const QRect &, int)));
+    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));
+
+    updateLineNumberAreaWidth(0);
+    highlightCurrentLine();
+}
+
+//![constructor]
+
+//![extraAreaWidth]
+
+int CodeEditor::lineNumberAreaWidth()
+{
+    int digits = 1;
+    int max = qMax(1, blockCount());
+    while (max >= 10) {
+        max /= 10;
+        ++digits;
+    }
+
+    int space = 3 + fontMetrics().width(QLatin1Char('9')) * digits;
+
+    return space;
+}
+
+//![extraAreaWidth]
+
+//![slotUpdateExtraAreaWidth]
+
+void CodeEditor::updateLineNumberAreaWidth(int /* newBlockCount */)
+{ 
+    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
+}
+
+//![slotUpdateExtraAreaWidth]
+
+//![slotUpdateRequest]
+
+void CodeEditor::updateLineNumberArea(const QRect &rect, int dy)
+{
+    if (dy)
+        lineNumberArea->scroll(0, dy);
+    else
+        lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());
+
+    if (rect.contains(viewport()->rect()))
+        updateLineNumberAreaWidth(0);
+}
+
+//![slotUpdateRequest]
+
+//![resizeEvent]
+
+void CodeEditor::resizeEvent(QResizeEvent *e)
+{
+    QPlainTextEdit::resizeEvent(e);
+
+    QRect cr = contentsRect();
+    lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
+}
+
+//![resizeEvent]
+
+//![cursorPositionChanged]
+
+void CodeEditor::highlightCurrentLine()
+{
+    QList<QTextEdit::ExtraSelection> extraSelections;
+
+    if (!isReadOnly()) {
+        QTextEdit::ExtraSelection selection;
+        
+        QColor lineColor = QColor(Qt::yellow).lighter(160);
+
+        selection.format.setBackground(lineColor);
+        selection.format.setProperty(QTextFormat::FullWidthSelection, true);
+        selection.cursor = textCursor();
+        selection.cursor.clearSelection();
+        extraSelections.append(selection);
+    }
+
+    setExtraSelections(extraSelections);
+}
+
+//![cursorPositionChanged]
+
+//![extraAreaPaintEvent_0]
+
+void CodeEditor::lineNumberAreaPaintEvent(QPaintEvent *event)
+{
+    QPainter painter(lineNumberArea);
+    painter.fillRect(event->rect(), Qt::lightGray);
+
+//![extraAreaPaintEvent_0]
+
+//![extraAreaPaintEvent_1]
+    QTextBlock block = firstVisibleBlock();
+    int blockNumber = block.blockNumber();
+    int top = (int) blockBoundingGeometry(block).translated(contentOffset()).top();
+    int bottom = top + (int) blockBoundingRect(block).height();
+//![extraAreaPaintEvent_1]
+
+//![extraAreaPaintEvent_2]
+    while (block.isValid() && top <= event->rect().bottom()) {
+        if (block.isVisible() && bottom >= event->rect().top()) {
+            QString number = QString::number(blockNumber + 1);
+            painter.setPen(Qt::black);
+            painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
+                             Qt::AlignRight, number);
+        }
+
+        block = block.next();
+        top = bottom;
+        bottom = top + (int) blockBoundingRect(block).height();
+        ++blockNumber;
+    }
+}
+//![extraAreaPaintEvent_2]
+