How to remove child indentation in GTKTreeView?

[Eric Beuque <eric beuque gmail com>]

Hi,

I'm currently developing a GTK application which need to implements a GTKTreeView.
I read the tutorial at http://scentric.net/tutorial/treeview-tutorial.html which help me very much.

Nevertheless, there's one thing I don't succeed to do !
In fact, I want to remove the indentation in child row below the arrow expander !

I try gtk_tree_view_set_level_indentation() which remove margin left, but the problem is that it
need to pass a pixels value that I'm not able to determine !

For example, I give the value -38, which works nice for me, but when I change the GTK theme, the identation isn't correctly removed.

So do you know if there is a medium to remove properly the indentation disabling it, or if it's possible to calcultate the negative pixels size I have to give to gtk_tree_view_set_level_indentation().

I hope you could help me.

Thanks for your time.

Best regards,
Beuque Eric