Add the ability to dynamically move nodes.

QGVCore/QGVNode.cpp

@@ -103,6 +103,31 @@ void QGVNode::setIcon(const QImage &icon)
     _icon = icon;
 }
 
+QVariant QGVNode::itemChange (GraphicsItemChange change, const QVariant & value)
+{
+  if (change == ItemPositionChange && _scene) {
+    // value is the new position.
+    QString oldStr = getAttribute(QString::fromLocal8Bit("pos"));
+    qreal gheight = QGVCore::graphHeight(_scene->_graph->graph());
+    QPointF newPos = value.toPointF();
+    qreal width = ND_width(_node->node())*DotDefaultDPI;
+    qreal height = ND_height(_node->node())*DotDefaultDPI;
+    QString newStr = QGVCore::qtToGvPos (QGVCore::centerToOrigin (newPos, -width, -height), gheight);
+
+    if (!newStr.isEmpty()) {
+        qDebug () << newPos;
+        if (oldStr != newStr) {
+            setAttribute ("pos", newStr.toLocal8Bit().data());
+          }
+        return newPos;
+      }
+  } else if (change == ItemPositionHasChanged && _scene) {
+    emit _scene->nodeChanged (this);
+    return value;
+  }
+  return QGraphicsItem::itemChange(change, value);
+}
+
 void QGVNode::updateLayout()
 {
     prepareGeometryChange();

QGVCore/QGVNode.h

@@ -51,6 +51,9 @@ public:
         return Type;
     }
 
+protected:
+    QVariant itemChange (GraphicsItemChange change, const QVariant & value);
+
 private:
     friend class QGVScene;
     friend class QGVSubGraph;

QGVCore/QGVScene.cpp

@@ -231,6 +231,17 @@ void QGVScene::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *mouseEvent)
     QGraphicsScene::mouseDoubleClickEvent(mouseEvent);
 }
 
+void QGVScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent)
+{
+    QGraphicsItem *item = itemAt(mouseEvent->scenePos(), QTransform());
+    if(item)
+    {
+        if(item->type() == QGVNode::Type)
+            emit nodeMouseRelease (qgraphicsitem_cast<QGVNode*>(item));
+    }
+    QGraphicsScene::mouseReleaseEvent(mouseEvent);
+}
+
 #include <QVarLengthArray>
 #include <QPainter>
 void QGVScene::drawBackground(QPainter * painter, const QRectF & rect)

QGVCore/QGVScene.h

@@ -58,6 +58,8 @@ public:
 signals:
     void nodeContextMenu(QGVNode* node);
     void nodeDoubleClick(QGVNode* node);
+    void nodeChanged (QGVNode* node);
+    void nodeMouseRelease (QGVNode* node);
 
     void edgeContextMenu(QGVEdge* edge);
     void edgeDoubleClick(QGVEdge* edge);
@@ -72,6 +74,7 @@ public slots:
 protected:
     virtual void contextMenuEvent(QGraphicsSceneContextMenuEvent * contextMenuEvent);
     virtual void mouseDoubleClickEvent(QGraphicsSceneMouseEvent * mouseEvent);
+    virtual void mouseReleaseEvent(QGraphicsSceneMouseEvent * mouseEvent);
     virtual void drawBackground(QPainter * painter, const QRectF & rect);
 private:
     friend class QGVNode;

QGVCore/private/QGVCore.cpp

@@ -24,6 +24,14 @@ qreal QGVCore::graphHeight(Agraph_t *graph)
     return GD_bb(graph).UR.y;
 }
 
+QString QGVCore::qtToGvPos (QPointF pos, qreal gheight)
+{
+  float x = pos.x();
+  float y = pos.y();
+  //Le repere Y commence du bas dans graphViz et du haut pour Qt !
+  return QString ("%1,%2").arg (x).arg(gheight - y);
+}
+
 QPointF QGVCore::toPoint(pointf p, qreal gheight)
 {
     //Le repere Y commence du bas dans graphViz et du haut pour Qt !

QGVCore/private/QGVCore.h

@@ -38,6 +38,7 @@ class QGVCore
 {
 public:
     static qreal graphHeight(Agraph_t *graph);
+    static QString qtToGvPos (QPointF pos, qreal gheight);
     static QPointF toPoint(pointf p, qreal gheight);
     static QPointF toPoint(point p, qreal gheight);
     static QPointF centerToOrigin(const QPointF &p, qreal width, qreal height);