import pygtk
import gtk, gobject, cairo, math
from gtk import gdk

class Screen( gtk.DrawingArea ):
    """ This class is a Drawing Area"""
    def __init__( self, w, h, speed ):
        super( Screen, self ).__init__( )
        self.connect ( "expose_event", self.do_expose_event )
        gobject.timeout_add( speed, self.tick ) # Go call tick every 'speed' whatsits.
        self.width, self.height = w, h
        self.set_size_request ( w, h )

    def tick ( self ):
        self.alloc = self.get_allocation ( )
        rect = gtk.gdk.Rectangle ( self.alloc.x, self.alloc.y, self.alloc.width, self.alloc.height )
        self.window.invalidate_rect ( rect, True )        
        return True # Causes timeout to tick again.

    def do_expose_event( self, widget, event ):
        self.cr = self.window.cairo_create( )
        self.draw( )


class MyStuff ( Screen ):
    def __init__ ( self, w, h, speed):
        Screen.__init__( self, w, h, speed )

    def draw( self ):
        cr = self.cr # Shabby shortcut.
        cr.set_source_rgba(0.5, 0.1, 0.1, 1)
        cr.set_line_width(200)
        cr.arc(200, 200, 100, 0*(math.pi/180), -60*(math.pi/180))
        cr.stroke()
        #cr.move_to(200, 200)
        #cr.arc(200, 200, 200, 0*(math.pi/180), -60*(math.pi/180))
        #cr.fill()


def run( Widget, w, h, speed ):
    window = gtk.Window()
    #window.move(0, 0)
    window.connect( "delete-event", gtk.main_quit )
    widget = Widget( w, h, speed )
    widget.show( )
    window.add( widget )
    window.present( )
    gtk.main( )

run( MyStuff, 640, 480, speed = 20 )