QGraphicsScene/QGraphicsView performance problems

[wysota]

What would be your primary platform?

Mine is Linux/x86.

I will have to arrange some way for you to pick up the datafiles, they will be too large for an attachment.

Can't you just provide some small application that would generate such example datafile? They don't have to make sense and they don't have to be larger than a megabyte. It's just a test app.

Here is the project.

It'd be best if you provided something small. It's easier to debug then.

BTW. I just had a quick look at the code you provided and I have some comments:
- I'm not sure if manipulating the update mode the way you do is a good idea, you should set the update mode once and never touch it again
- I'm not sure if beginning by reimplementing the main drawing routine is a good idea. I'd start with the base class implementation first, it's probably trying to be smarter than your implementation
- why do you use the data stream if you only read raw data and seek through the file? Operate on the file directly instead
- try not to fall of the scale with your dimensions, 10nm = 10E-8, pretty close to 32bit precision.