Regarding Adding Merge Lines in Revision graph

Hello

         I would like to work on improving the revision graph feature so that it includes Merge Line. I know its not that easy to add these information as we have to consider many things when coming to that. I was just seeing the source code of TSVN.And I am now stuck up where should I start dealing with...

 Shall I start directly with revsion graph source code or accessing MergeInfo Log and tracking that. ??

Thanks & Regards,
S V Ram