--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/graphicsview/diagramscene/arrow.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,147 @@
+/****************************************************************************
+**
+** 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 "arrow.h"
+#include <math.h>
+
+const qreal Pi = 3.14;
+
+//! [0]
+Arrow::Arrow(DiagramItem *startItem, DiagramItem *endItem,
+         QGraphicsItem *parent, QGraphicsScene *scene)
+    : QGraphicsLineItem(parent, scene)
+{
+    myStartItem = startItem;
+    myEndItem = endItem;
+    setFlag(QGraphicsItem::ItemIsSelectable, true);
+    myColor = Qt::black;
+    setPen(QPen(myColor, 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
+}
+//! [0]
+
+//! [1]
+QRectF Arrow::boundingRect() const
+{
+    qreal extra = (pen().width() + 20) / 2.0;
+
+    return QRectF(line().p1(), QSizeF(line().p2().x() - line().p1().x(),
+                                      line().p2().y() - line().p1().y()))
+        .normalized()
+        .adjusted(-extra, -extra, extra, extra);
+}
+//! [1]
+
+//! [2]
+QPainterPath Arrow::shape() const
+{
+    QPainterPath path = QGraphicsLineItem::shape();
+    path.addPolygon(arrowHead);
+    return path;
+}
+//! [2]
+
+//! [3]
+void Arrow::updatePosition()
+{
+    QLineF line(mapFromItem(myStartItem, 0, 0), mapFromItem(myEndItem, 0, 0));
+    setLine(line);
+}
+//! [3]
+
+//! [4]
+void Arrow::paint(QPainter *painter, const QStyleOptionGraphicsItem *,
+          QWidget *)
+{
+    if (myStartItem->collidesWithItem(myEndItem))
+        return;
+
+    QPen myPen = pen();
+    myPen.setColor(myColor);
+    qreal arrowSize = 20;
+    painter->setPen(myPen);
+    painter->setBrush(myColor);
+//! [4] //! [5]
+
+    QLineF centerLine(myStartItem->pos(), myEndItem->pos());
+    QPolygonF endPolygon = myEndItem->polygon();
+    QPointF p1 = endPolygon.first() + myEndItem->pos();
+    QPointF p2;
+    QPointF intersectPoint;
+    QLineF polyLine;
+    for (int i = 1; i < endPolygon.count(); ++i) {
+    p2 = endPolygon.at(i) + myEndItem->pos();
+    polyLine = QLineF(p1, p2);
+    QLineF::IntersectType intersectType =
+        polyLine.intersect(centerLine, &intersectPoint);
+    if (intersectType == QLineF::BoundedIntersection)
+        break;
+        p1 = p2;
+    }
+
+    setLine(QLineF(intersectPoint, myStartItem->pos()));
+//! [5] //! [6]
+
+    double angle = ::acos(line().dx() / line().length());
+    if (line().dy() >= 0)
+        angle = (Pi * 2) - angle;
+
+        QPointF arrowP1 = line().p1() + QPointF(sin(angle + Pi / 3) * arrowSize,
+                                        cos(angle + Pi / 3) * arrowSize);
+        QPointF arrowP2 = line().p1() + QPointF(sin(angle + Pi - Pi / 3) * arrowSize,
+                                        cos(angle + Pi - Pi / 3) * arrowSize);
+
+        arrowHead.clear();
+        arrowHead << line().p1() << arrowP1 << arrowP2;
+//! [6] //! [7]
+        painter->drawLine(line());
+        painter->drawPolygon(arrowHead);
+        if (isSelected()) {
+            painter->setPen(QPen(myColor, 1, Qt::DashLine));
+        QLineF myLine = line();
+        myLine.translate(0, 4.0);
+        painter->drawLine(myLine);
+        myLine.translate(0,-8.0);
+        painter->drawLine(myLine);
+    }
+}
+//! [7]