Browsing gnome theme icons in Ruby-GTK

In my previous post I hard-coded an icon name into the Autotest application hook, using this code:

$tray_icon.icon_name = 'apple-red'

Of course, I'm not sure where that icon comes from or whether it's present in all packagings of GNOME.
So, in order to browse for my own icon easily, I wrote the following script that should run as long as you have the latest version of Ruby-GTK installed (you'll need to chmod +x it):

#!/usr/bin/env ruby

require 'gtk2'

module Gtk
  w = Window.new
  w.signal_connect("destroy") { Gtk.main_quit; exit! }
  sw = ScrolledWindow.new
  w.add(sw)
  icon_list = TreeView.new
  sw.add(icon_list)
  icon_list.model = icons = ListStore.new(String,Gdk::Pixbuf)
  tr = CellRendererText.new
  tcol = TreeViewColumn.new('Name',tr,:text => 0)
  pr = CellRendererPixbuf.new
  pcol = TreeViewColumn.new('Icon',pr,:pixbuf => 1)
  icon_list.append_column(tcol)
  icon_list.append_column(pcol)
  theme = IconTheme.default
  theme.icons.sort.each do |icon| item = icons.append; item[0] = icon; item[1] = theme.load_icon(icon,32,0); end
  w.show_all
  main
end

That'll give you something like this:

Then you can just use the name of the icon you like in place of 'apple-red' in the code. There might be other uses for this too.