image viewing, geometry...

[eichin-gtk-perl thok org]

I have a simple glade/gtk/gnome/perl application that (once it works)
will put up an image and an editable list of data associated with the
image.  I'm trying to demonstrate this, and finally got as far (using
Gtk::GladeXML) as being able to put a GtkPixmap in an HBox, using
Gtk::Gdk::ImlibImage to load a jpeg, and ->render it to a fixed size.

However, it would be a lot more useful to render it to a size that
fits in the allocation that the GtkPixmap actually got... but I can't
find a way to query that.  Suggestions?  Or do I need to wrap it in an
EventBox and look for Resize events?

(at least half my problem is not really knowing if I've picked the
 wrong objects for accomplishing this kind of thing...)