title: Is it necessary for Qt::paintEvent to be reentrant?
body: <p>Can I put the painter into the class variables? :</p>
  
  <pre><code>protected:
  QPainter *myPainter;
  
  ...
  
  void MyWidget::paintEvent(QPaintEvent *event)
  {
      myPainter = new QPainter(this);
  </code></pre>