location of rows/cells in GtkTreeView

["Brian J. Tarricone" <bjt23 cornell edu>]

hi again-

after poring over the gtk API reference, and the very informative gtk 
tree view tutorial 
(http://scentric.net/tutorial/treeview-tutorial.html), i'm still 
stumpedon this...
i have a GtkTreeView using GtkListStore with a large number of rows.  i 
want to be able to figure out if an arbitrary row in the list is visible 
or not (and if not, i want to scroll the list so it _is_ visible).  this 
arbitrary row may or may not be selected - that condition can't be 
counted upon (in fact, most of the time it _won't_ be selected).  i can 
use gtk_tree_view_get_visible_rect() to find the treeview's visible 
area, but there doesn't seem to be a good way to get the location of the 
row in the tree with respect to those coordinates (or in coordinates i 
can convert).  i've tried using gtk_tree_view_get_background_area(), and 
then multiplying rect.height by the row index, but i have two problems 
with that: 1) it doesn't take into account the height of the column 
headers (relatively easy to fix with a fudge factor), and 2) there 
appears to a be a bug[1] that's preventing it from working reliably.  
basically, i'm looking for the inverse of gtk_tree_view_get_path_at_pos().
is there any straightforward (or even convoluted) way of doing this that 
i'm not seeing?
thanks,
brian

[1] in my app, usually one of the rows has PANGO_WEIGHT_BOLD set, which 
increases the height of that row by 1 pixel (with the font/size i'm 
using, anyway).  for some reason, the height returned in 
gtk_tree_view_get_background_area() occasionally has the extra pixel 
included, even when the row path i'm passing _doesn't_ have the bold 
weight set.  it's possible i've screwed something up here (i'll try to 
make a simple testcase), but i've been over this for hours, and it does 
appear to be a bug to me.