title: How to get visible scene rectangle of QGraphicsView?
body: <p>I'm displaying a map built as rectangle of QGraphicsPixmapitem items (each item stands for one map tile). Because my map is quite large (around 30 MB of PNG files) I want to be able to load pixmaps on demand only when they're visible for user in QGraphicsView and unload when they became invisible.</p>
  
  <p>Is there any way to figure out visible scene rectangle?</p>