Matthias Kleine wrote: > On Tue, 2009-01-13 at 09:53 +0100, Gunnar Sletta wrote: >>> First of all I'm wondering whether this is a known problem (with a known >>> solution)? >> Many moving items in a scene is a common degenerate usecase for the >> default configuration of QGraphicsView. You can change the viewport >> update mode to do a full viewport update, in which case less time is >> spent in figuring out collisions etc... > > Unfortunately, this does not help at all as in my case. Yes, I do have > many moving items. Yet, these items are so small that only a tiny > fraction of the graphics view has to be redrawn (imagine many 5x5 pixel > cars on a full screen street map). > Switching to full viewport update mode doesn't make things go any faster > as then too much time is spent on actually redrawing graphics items > (streets) which actually do not have to be redrawn. So I end up with > about the same performance as with the normal update setup. Any > suggestions?
If you replace your moving car items with QGraphicsPixmapItem's, does that solve the performance problem? That would cause the boundingRect() function to be called only on the C++ side, which in turn avoids the somewhat costly boundingRect java call. Its costly because it allocates a java object and two C++ objects while the C++ version does no allocations. - Gunnar _______________________________________________ Qt-jambi-interest mailing list [email protected] http://lists.trolltech.com/mailman/listinfo/qt-jambi-interest
