#!/usr/bin/env python

import gtk, cairo
import math

class Values(object):
   pass

def expose_event (win, event):
   w, h = win.get_size ()

   cr = win.window.cairo_create ()
   cr.rectangle (*event.area)
   cr.clip ()

   cr.translate (w/2.0, h/2.0)
   cr.scale (min (w/2., h/2.), min (w/2., h/2.))
   cr.scale (1./75, 1./75)

   cr.set_fill_rule (cairo.FILL_RULE_WINDING)
   cr.arc (-20, 0, 30, 0, 2 * math.pi)
   cr.arc_negative (20, 0, 25, 0, 2 * math.pi)
   cr.fill_preserve ()
   cr.stroke ()

   return True


def setup_ui ():
   win = gtk.Window ()
   win.set_default_size (150, 150)

   win.set_events (gtk.gdk.EXPOSURE_MASK)
   win.connect ("expose-event", expose_event)
   win.connect ("delete-event", gtk.main_quit)

   win.show_all ()


if __name__=='__main__':
   setup_ui ()
   gtk.main ()