how to make gitk to use specified history information

Hi,

I want to obtain an outline of history information, for example:

  a - b - c - d - h -i -j
   \         /
    e- f - g

I simplify the graph like this:

  a - c - d - j
    \    /
      g

That's to say, I skip all commits that

  * have only one parent, and
  * have only one child, and
  * its child has only one parent

I checked `git help rev-list` but didn't find this feature, so I
write a little script[1] to parse output of `git rev-list --parents
--full-history --sparse --all` and get the simplified history:
j d
d c g
c a
g a

Now how can I make gitk to show this simpilified history? I have tried
GraphViz but the history information is still so large that GraphViz
crashes.


[1] http://jff.googlecode.com/svn/trunk/utils/git-branch-graph.pl

Best regards,

Liu Yubao