QGraphicsScene/QGraphicsView performance problems

[bnilsson]

Here is a stripped down version with no loader and a limited set of redundant functions. I did not want to change the UI part so there are some empty action handling methods, please ignore them.

It draws an area set by "chipsize", divided into fields of size "fieldsize", whuch are in turn divided into subfields of size "subfieldsize", and in each subfield there is one rectangle and one polygon. Chip, field and subfield boundaries are drawn in blue color, while the rectangles and polygons are drawn in black.

Chipsize can range from 50,000 microns up to 125,000 microns, the field size is 800 microns, and subfield size is 100 microns. I kept this sceme to be able to relate to my real needs.

Here, 125,000 micron chipsize is beyond the capacity of any of my machines (1 Mac G5 1GB RAM, and 1 amd64 1GB RAM) while 50,000 micron chipsize can be managed with some patience.
Note that Qt4.3.3 has real problems when zooming in on the amd64, the Qt4.4.0 snapshot is much better. They really must have done something there.

Some logs:
Chipsize 50000.000 um, 3844 fields, 246016 subfields, 246016 rects, 246016 polys
Chipsize 100000.000 um, 15625 fields, 1000000 subfields, 1000000 rects, 1000000 polys
Chipsize 125000.000 um, 24336 fields, 1557504 subfields, 1557504 rects, 1557504 polys