--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/graphicsview/elasticnodes/node.d	Wed Jul 07 22:54:12 2010 +0100
@@ -0,0 +1,203 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Commercial License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Nokia.
+**
+** 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.
+**
+** 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 have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+module node;
+
+import
+    qt.gui.QRadialGradient,
+    qt.gui.QGraphicsItem;
+
+import
+    graphwidget,
+    edge;
+
+class Node : QGraphicsItem
+{
+public:
+    this(GraphWidget graphWidget)
+    {
+        graph = graphWidget;
+        setFlag(ItemIsMovable);
+        setFlag(ItemSendsGeometryChanges);
+        setCacheMode(DeviceCoordinateCache);
+        setZValue(-1);
+    }
+
+    void addEdge(Edge edge)
+    {
+        edgeList ~= edge;
+        edge.adjust();
+    }
+/*    
+    Edge[] edges() const
+    {
+        return edgeList;
+    }
+*/
+    enum { Type = UserType + 1 };
+    int type() const { return Type; }
+
+    void calculateForces()
+    {
+        if (!scene() || scene().mouseGrabberItem() is this) {
+            newPos = pos();
+            return;
+        }
+    
+        // Sum up all forces pushing this item away
+        qreal xvel = 0;
+        qreal yvel = 0;
+        foreach (IQGraphicsItem item; scene().items()) {
+            auto node = cast(Node)item;
+            if (!node)
+                continue;
+
+            auto line = QLineF(mapFromItem(node, 0, 0), QPointF(0, 0));
+            qreal dx = line.dx();
+            qreal dy = line.dy();
+            double l = 2.0 * (dx * dx + dy * dy);
+            if (l > 0) {
+                xvel += (dx * 150.0) / l;
+                yvel += (dy * 150.0) / l;
+            }
+        }
+
+        // Now subtract all forces pulling items together
+        double weight = (edgeList.length + 1) * 10;
+        foreach (Edge edge; edgeList) {
+            QPointF pos;
+            if (edge.sourceNode() == this)
+                pos = mapFromItem(edge.destNode(), 0, 0);
+            else
+                pos = mapFromItem(edge.sourceNode(), 0, 0);
+            xvel += pos.x() / weight;
+            yvel += pos.y() / weight;
+        }
+        
+        if (qAbs(xvel) < 0.1 && qAbs(yvel) < 0.1)
+            xvel = yvel = 0;
+
+        QRectF sceneRect = scene().sceneRect();
+        newPos = pos() + QPointF(xvel, yvel);
+        newPos.x = qMin(qMax(newPos.x(), sceneRect.left() + 10), sceneRect.right() - 10);
+        newPos.y = qMin(qMax(newPos.y(), sceneRect.top() + 10), sceneRect.bottom() - 10);
+
+    }
+    
+    bool advance()
+    {
+        auto pos_ = pos();
+        if (newPos == pos_)
+            return false;
+
+        setPos(newPos);
+        return true;
+    }
+
+    QRectF boundingRect() const
+    {
+        qreal adjust = 2;
+        return QRectF(-10 - adjust, -10 - adjust,
+                      23 + adjust, 23 + adjust);
+    }
+    
+    QPainterPath shape() const
+    {
+        QPainterPath path;
+        path.addEllipse(-10, -10, 20, 20);
+        return path;
+    }
+    
+    override public void paint(QPainter painter, QStyleOptionGraphicsItem option, QWidget widget = null)
+    {
+        painter.setPen(Qt.NoPen);
+        painter.setBrush(new QBrush(Qt.darkGray));
+        painter.drawEllipse(-7, -7, 20, 20);
+
+        auto gradient = new QRadialGradient(-3, -3, 10);
+        if (option.state & QStyle.State_Sunken) {
+            gradient.setCenter(3, 3);
+            gradient.setFocalPoint(3, 3);
+            gradient.setColorAt(1, (new QColor(Qt.yellow)).lighter(120));
+            gradient.setColorAt(0, (new QColor(Qt.darkYellow)).lighter(120));
+        } else {
+            gradient.setColorAt(0, new QColor(Qt.yellow));
+            gradient.setColorAt(1, new QColor(Qt.darkYellow));
+        }
+        painter.setBrush(gradient);
+        painter.setPen(new QPen(new QBrush(Qt.black), 0));
+        painter.drawEllipse(-10, -10, 20, 20);
+    }
+    
+protected:
+    override QVariant itemChange(GraphicsItemChange change, QVariant value)
+    {
+        switch (change)
+        {
+        case ItemPositionHasChanged:
+            foreach (Edge edge; edgeList)
+                edge.adjust();
+            graph.itemMoved();
+            break;
+        default:
+            break;
+        };
+
+        return QGraphicsItem.itemChange(change, value);
+    }
+
+    override void mousePressEvent(QGraphicsSceneMouseEvent event)
+    {
+        update();
+        QGraphicsItem.mousePressEvent(event);
+    }
+
+    override void mouseReleaseEvent(QGraphicsSceneMouseEvent event)
+    {
+        update();
+        QGraphicsItem.mouseReleaseEvent(event);
+    }
+    
+private:
+    Edge[] edgeList;
+    QPointF newPos;
+    GraphWidget graph;
+};