Documentation for the Elastic Nodes example.

Checked for qdoc errors.

6 files changed, 80 insertions, 42 deletions

diff --git a/examples/graphicsview/elasticnodes/edge.cpp b/examples/graphicsview/elasticnodes/edge.cpp
index 25c769b..634fbee 100644
--- a/examples/graphicsview/elasticnodes/edge.cpp
+++ b/examples/graphicsview/elasticnodes/edge.cpp
@@ -49,6 +49,7 @@
 static const double Pi = 3.14159265358979323846264338327950288419717;
 static double TwoPi = 2.0 * Pi;
 
+//! [0]
 Edge::Edge(Node *sourceNode, Node *destNode)
     : arrowSize(10)
 {
@@ -59,33 +60,21 @@ Edge::Edge(Node *sourceNode, Node *destNode)
     dest->addEdge(this);
     adjust();
 }
+//! [0]
 
-Edge::~Edge()
-{
-}
-
+//! [1]
 Node *Edge::sourceNode() const
 {
     return source;
 }
 
-void Edge::setSourceNode(Node *node)
-{
-    source = node;
-    adjust();
-}
-
 Node *Edge::destNode() const
 {
     return dest;
 }
+//! [1]
 
-void Edge::setDestNode(Node *node)
-{
-    dest = node;
-    adjust();
-}
-
+//! [2]
 void Edge::adjust()
 {
     if (!source || !dest)
@@ -104,7 +93,9 @@ void Edge::adjust()
         sourcePoint = destPoint = line.p1();
     }
 }
+//! [2]
 
+//! [3]
 QRectF Edge::boundingRect() const
 {
     if (!source || !dest)
@@ -118,7 +109,9 @@ QRectF Edge::boundingRect() const
         .normalized()
         .adjusted(-extra, -extra, extra, extra);
 }
+//! [3]
 
+//! [4]
 void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
 {
     if (!source || !dest)
@@ -127,11 +120,15 @@ void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
     QLineF line(sourcePoint, destPoint);
     if (qFuzzyCompare(line.length(), qreal(0.)))
         return;
+//! [4]
 
+//! [5]
     // Draw the line itself
     painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
     painter->drawLine(line);
+//! [5]
 
+//! [6]
     // Draw the arrows
     double angle = ::acos(line.dx() / line.length());
     if (line.dy() >= 0)
@@ -150,3 +147,4 @@ void Edge::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
     painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
     painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);        
 }
+//! [6]
diff --git a/examples/graphicsview/elasticnodes/edge.h b/examples/graphicsview/elasticnodes/edge.h
index b6b951f..58cc89c 100644
--- a/examples/graphicsview/elasticnodes/edge.h
+++ b/examples/graphicsview/elasticnodes/edge.h
@@ -46,17 +46,14 @@
 
 class Node;
 
+//! [0]
 class Edge : public QGraphicsItem
 {
 public:
     Edge(Node *sourceNode, Node *destNode);
-    ~Edge();
 
     Node *sourceNode() const;
-    void setSourceNode(Node *node);
-
     Node *destNode() const;
-    void setDestNode(Node *node);
 
     void adjust();
 
@@ -74,5 +71,6 @@ private:
     QPointF destPoint;
     qreal arrowSize;
 };
+//! [0]
 
 #endif
diff --git a/examples/graphicsview/elasticnodes/graphwidget.cpp b/examples/graphicsview/elasticnodes/graphwidget.cpp
index 7c244be..8b419b8 100644
--- a/examples/graphicsview/elasticnodes/graphwidget.cpp
+++ b/examples/graphicsview/elasticnodes/graphwidget.cpp
@@ -43,14 +43,13 @@
 #include "edge.h"
 #include "node.h"
 
-#include <QDebug>
-#include <QGraphicsScene>
-#include <QWheelEvent>
+#include <QtGui>
 
 #include <math.h>
 
-GraphWidget::GraphWidget()
-    : timerId(0)
+//! [0]
+GraphWidget::GraphWidget(QWidget *parent)
+    : QGraphicsView(parent), timerId(0)
 {
     QGraphicsScene *scene = new QGraphicsScene(this);
     scene->setItemIndexMethod(QGraphicsScene::NoIndex);
@@ -60,8 +59,12 @@ GraphWidget::GraphWidget()
     setViewportUpdateMode(BoundingRectViewportUpdate);
     setRenderHint(QPainter::Antialiasing);
     setTransformationAnchor(AnchorUnderMouse);
-    setResizeAnchor(AnchorViewCenter);
+    scale(qreal(0.8), qreal(0.8));
+    setMinimumSize(400, 400);
+    setWindowTitle(tr("Elastic Nodes"));
+//! [0]
 
+//! [1]
     Node *node1 = new Node(this);
     Node *node2 = new Node(this);
     Node *node3 = new Node(this);
@@ -102,18 +105,18 @@ GraphWidget::GraphWidget()
     node7->setPos(-50, 50);
     node8->setPos(0, 50);
     node9->setPos(50, 50);
-
-    scale(qreal(0.8), qreal(0.8));
-    setMinimumSize(400, 400);
-    setWindowTitle(tr("Elastic Nodes"));
 }
+//! [1]
 
+//! [2]
 void GraphWidget::itemMoved()
 {
     if (!timerId)
         timerId = startTimer(1000 / 25);
 }
+//! [2]
 
+//! [3]
 void GraphWidget::keyPressEvent(QKeyEvent *event)
 {
     switch (event->key()) {
@@ -146,7 +149,9 @@ void GraphWidget::keyPressEvent(QKeyEvent *event)
         QGraphicsView::keyPressEvent(event);
     }
 }
+//! [3]
 
+//! [4]
 void GraphWidget::timerEvent(QTimerEvent *event)
 {
     Q_UNUSED(event);
@@ -171,12 +176,16 @@ void GraphWidget::timerEvent(QTimerEvent *event)
         timerId = 0;
     }
 }
+//! [4]
 
+//! [5]
 void GraphWidget::wheelEvent(QWheelEvent *event)
 {
     scaleView(pow((double)2, -event->delta() / 240.0));
 }
+//! [5]
 
+//! [6]
 void GraphWidget::drawBackground(QPainter *painter, const QRectF &rect)
 {
     Q_UNUSED(rect);
@@ -213,12 +222,15 @@ void GraphWidget::drawBackground(QPainter *painter, const QRectF &rect)
     painter->setPen(Qt::black);
     painter->drawText(textRect, message);
 }
+//! [6]
 
+//! [7]
 void GraphWidget::scaleView(qreal scaleFactor)
 {
-    qreal factor = matrix().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();
+    qreal factor = transform().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();
     if (factor < 0.07 || factor > 100)
         return;
 
     scale(scaleFactor, scaleFactor);
 }
+//! [7]
diff --git a/examples/graphicsview/elasticnodes/graphwidget.h b/examples/graphicsview/elasticnodes/graphwidget.h
index 6f67b4e..3f78a5f 100644
--- a/examples/graphicsview/elasticnodes/graphwidget.h
+++ b/examples/graphicsview/elasticnodes/graphwidget.h
@@ -46,12 +46,13 @@
 
 class Node;
 
+//! [0]
 class GraphWidget : public QGraphicsView
 {
     Q_OBJECT
 
 public:
-    GraphWidget();
+    GraphWidget(QWidget *parent = 0);
 
     void itemMoved();
 
@@ -67,5 +68,6 @@ private:
     int timerId;
     Node *centerNode;
 };
+//! [0]
 
 #endif
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]
diff --git a/examples/graphicsview/elasticnodes/node.h b/examples/graphicsview/elasticnodes/node.h
index 0df579d..990346e 100644
--- a/examples/graphicsview/elasticnodes/node.h
+++ b/examples/graphicsview/elasticnodes/node.h
@@ -51,6 +51,7 @@ QT_BEGIN_NAMESPACE
 class QGraphicsSceneMouseEvent;
 QT_END_NAMESPACE
 
+//! [0]
 class Node : public QGraphicsItem
 {
 public:
@@ -80,5 +81,6 @@ private:
     QPointF newPos;
     GraphWidget *graph;
 };
+//! [0]
 
 #endif