Quote Originally Posted by wysota View Post
Did you enable caching for the items? Also how did you define shape() and boundingRect() for your items? Did you make a QGLWidget the viewport of your view to enable hardware accelleration? To make things faster you can also mark the view as non-interactive, if you can afford it.
I didn't call setCacheMode so it is using NoCache. The graphics is zoomable and the xy scale can be changed interactively, so I suppose caching is not useful.

The shape is not defined, and the bundingRect is properly computed. I don't use QGLWidget and have never used it. Does it work for both Linux and Window?

I don't understand "mark the view as non-interactive". My graphics display is very interactive, such as zoom, scale changes, object selection, pen and brush can also be edited...

When zoom in to small portion, it is fast because I recompute all sub-boundingRect so only render the portion of object really on screen. But not on "view all" mode.