detecting when layout stop computation (find optimal)

[gg4u]

Hi,
I am trying to play around with UX for graphs in webgl, but with images as textures.

I am not having still good results (as a number of nodes and links opened before I see cluttering, it is <= than SVG, so there is room for improving).

In SVG, I was able to play around with precompute() and postcompute() functions, pausing rendering ad hoc.

Does a layout function return a variable when graph is relaxed ?
As example, settings with theta = 0 will allow reduce number of computations, and I would like to pause rendering each time the graph is relaxed.