setting size of GtkTextView

["Shark" <shark centibyte org>]

Hello,

  I would like to set the maximum height of a GtkTextView to be just
  enough to hold 5 lines of text.  Is this possible?
 If it matters, the GtkTextView is inside a GtkVBox, which also holds a
 GtkTreeView.
A GtkVPaned would allow me to squish the textview down to 5 lines in
height, but that would only be through trial and error and would probably
not work on a computer with different font settings than my own.  The
least I need is a way to figure out how many pixels five lines of text
takes up vertically.
 Thanks!
 -peter