#!/usr/local/bin/python
##
#   Timer
#   -----
#   Every program can have a timer. This program demonstrates the
#   use of the timer function.
# 
#   Use settimerfn to set the call-back function which is called by
#   the timer. The call-back takes one parameter and returns nothing.
# 
#   Use settimer to start or stop the timer. The number passed to
#   this function is the number of milliseconds between timeouts.
#   In the example, the function draw_something will occur every
#   5 seconds (5000 milliseconds).
# 
#   Because the timer call-back is not associated with a particular
#   window, it must use the drawto function to explicitly allow
#   drawing to a window. Ordinarily a call-back which belongs to a
#   window is set up to draw to the window when it is called.
##

from graphapp import *

global r

def draw_something(w):
	global r
	drawto(w)
	drawellipse(r)
	r.x = r.x + 10
	r.y = r.y + 10

def main():
	global r
	w = newwindow("Timer", rect(20,20,400,300), StandardWindow)
	show(w)

	r = rect(10,10,30,15)

	settimerfn(draw_something, w)
	settimer(2000)
	draw_something(w)
	mainloop()

main()