Vertical rulers

[Johan Levin <nivel ballyhoo ml org>]

In most graphics-applications (such as gimp) it is desirable to have the
positive axes pointing right and down.
However I would like my positive y-axis to point up. The problem is the
vertical ruler.
It seems the logical way to do this would be:
gtk_ruler_set_range(GTK_RULER(vruler), 50, 0, -1, 50);

But it doesn't work. (The ruler gets all blank.)
Is there any way to get a "inversed" ruler?

/Johan