[BioC] Rgraphviz edge attributes can't be changed on Mac

[Li.Long at isb-sib.ch]

> Thanks, Herve,
> I updated R , BioConductor and Rgraphviz to the latest
> versions. I still can't customize the edge attributes
> as I mentioned earlier. Any ideas?
> Weijun

Hi,

Since you use "agopen" to prepare the graph for layout and rendering, the
attributes (for both nodes/edges) you could are limited, you can use
"getDefaultAttr" to see which are honored.  This is probably changing un
the near future.

To use "toFile", you could take a look at "agopenSimple" and various
functions that go with it to set all sorts of attributes graphviz
supports.
There's a section in the Rgraphviz vignette (near the end of it) that
shows the work flow.

I don't think the problem you encounter has much to do with Mac OS.

Li