Need advice regarding hierarchy view

[high_flyer]

Hi,

I need to implement a widget that shows a hierarchy in the manner shown in the attached image.
Those of you who know, it is very similar to the way that KProfiler shows the profiling graph.
My question is, which base class should I use?
In a way its exactly like a treeview, only the graphical representation is different (and there is no way to collapse/ expand), so I am thinking to subclass QAbstractItemView, but would like to hear (read) your opinions, may be you know a better class, or a better way.

Thanks in advance.