Documentation for the Elastic Nodes example.

Checked for qdoc errors.

1 files changed, 36 insertions, 10 deletions

diff --git a/examples/graphicsview/elasticnodes/node.cpp b/examples/graphicsview/elasticnodes/node.cpp
index 774046c..495aa89 100644
--- a/examples/graphicsview/elasticnodes/node.cpp
+++ b/examples/graphicsview/elasticnodes/node.cpp
@@ -48,6 +48,7 @@
 #include "node.h"
 #include "graphwidget.h"
 
+//! [0]
 Node::Node(GraphWidget *graphWidget)
     : graph(graphWidget)
 {
@@ -56,7 +57,9 @@ Node::Node(GraphWidget *graphWidget)
     setCacheMode(DeviceCoordinateCache);
     setZValue(-1);
 }
+//! [0]
 
+//! [1]
 void Node::addEdge(Edge *edge)
 {
     edgeList << edge;
@@ -67,14 +70,18 @@ QList<Edge *> Node::edges() const
 {
     return edgeList;
 }
+//! [1]
 
+//! [2]
 void Node::calculateForces()
 {
     if (!scene() || scene()->mouseGrabberItem() == this) {
         newPos = pos();
         return;
     }
-    
+//! [2]
+
+//! [3]
     // Sum up all forces pushing this item away
     qreal xvel = 0;
     qreal yvel = 0;
@@ -83,37 +90,45 @@ void Node::calculateForces()
         if (!node)
             continue;
 
-        QLineF line(mapFromItem(node, 0, 0), QPointF(0, 0));
-        qreal dx = line.dx();
-        qreal dy = line.dy();
+        QPointF vec = mapToItem(node, 0, 0);
+        qreal dx = vec.x();
+        qreal dy = vec.y();
         double l = 2.0 * (dx * dx + dy * dy);
         if (l > 0) {
             xvel += (dx * 150.0) / l;
             yvel += (dy * 150.0) / l;
         }
     }
+//! [3]
 
+//! [4]
     // Now subtract all forces pulling items together
     double weight = (edgeList.size() + 1) * 10;
     foreach (Edge *edge, edgeList) {
-        QPointF pos;
+        QPointF vec;
         if (edge->sourceNode() == this)
-            pos = mapFromItem(edge->destNode(), 0, 0);
+            vec = mapToItem(edge->destNode(), 0, 0);
         else
-            pos = mapFromItem(edge->sourceNode(), 0, 0);
-        xvel += pos.x() / weight;
-        yvel += pos.y() / weight;
+            vec = mapToItem(edge->sourceNode(), 0, 0);
+        xvel -= vec.x() / weight;
+        yvel -= vec.y() / weight;
     }
-    
+//! [4]
+
+//! [5]
     if (qAbs(xvel) < 0.1 && qAbs(yvel) < 0.1)
         xvel = yvel = 0;
+//! [5]
 
+//! [6]
     QRectF sceneRect = scene()->sceneRect();
     newPos = pos() + QPointF(xvel, yvel);
     newPos.setX(qMin(qMax(newPos.x(), sceneRect.left() + 10), sceneRect.right() - 10));
     newPos.setY(qMin(qMax(newPos.y(), sceneRect.top() + 10), sceneRect.bottom() - 10));
 }
+//! [6]
 
+//! [7]
 bool Node::advance()
 {
     if (newPos == pos())
@@ -122,21 +137,27 @@ bool Node::advance()
     setPos(newPos);
     return true;
 }
+//! [7]
 
+//! [8]
 QRectF Node::boundingRect() const
 {
     qreal adjust = 2;
     return QRectF(-10 - adjust, -10 - adjust,
                   23 + adjust, 23 + adjust);
 }
+//! [8]
 
+//! [9]
 QPainterPath Node::shape() const
 {
     QPainterPath path;
     path.addEllipse(-10, -10, 20, 20);
     return path;
 }
+//! [9]
 
+//! [10]
 void Node::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *)
 {
     painter->setPen(Qt::NoPen);
@@ -157,7 +178,9 @@ void Node::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWid
     painter->setPen(QPen(Qt::black, 0));
     painter->drawEllipse(-10, -10, 20, 20);
 }
+//! [10]
 
+//! [11]
 QVariant Node::itemChange(GraphicsItemChange change, const QVariant &value)
 {
     switch (change) {
@@ -172,7 +195,9 @@ QVariant Node::itemChange(GraphicsItemChange change, const QVariant &value)
 
     return QGraphicsItem::itemChange(change, value);
 }
+//! [11]
 
+//! [12]
 void Node::mousePressEvent(QGraphicsSceneMouseEvent *event)
 {
     update();
@@ -184,3 +209,4 @@ void Node::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
     update();
     QGraphicsItem::mouseReleaseEvent(event);
 }
+//! [12]