title: QGraphicsScene::clear doesn't change sceneRect
body: <p>I have a QGraphicsScene "scene" and QGraphicsView "graphicsView".</p>
  
  <p>I have a drawing method. When I need redraw all the graphics, I call this method. Everything is OK. But I realized that scene->clear() doesn't change the sceneRect.</p>
  
  <p>Also I tried: </p>
  
  <pre><code>graphicsView-&gt;items().clear();
  scene-&gt;clear();
  graphicsView-&gt;viewport()-&gt;update();
  </code></pre>
  
  <p>After that, if I get the sceneRect by</p>
  
  <pre><code>QRectF bound = scene-&gt;sceneRect();
  qDebug() &lt;&lt; bound.width();
  qDebug() &lt;&lt; bound.height();
  </code></pre>
  
  <p>I expect the bound.width and bound.height to be '0'. But they aren't. I see the previous values everytime. How to clear sceneRect when I clear the scene itself?</p>
  
  <p>It gives some problems that sceneRect remains the same, while using graphicsView->fitInView() method.I use following code:</p>
  
  <pre><code>QRectF bounds = scene-&gt;sceneRect();
  bounds.setWidth(bounds.width()*1.007);          // to give some margins
  bounds.setHeight(bounds.height());              // same as above
  graphicsView-&gt;fitInView(bounds);
  </code></pre>
  
  <p>Although I completely cleared the scene and added only one rather small rectangle, the rectangle didn't fit into view because of sceneRect remains too big. </p>
  
  <p>I hope I could explain my problem.</p>