########################################################################
# similar, but with .after scheduled events, not time.sleep loops;
# because these are scheduled events, this allows both ovals and 
# rectangles to be moving at the _same_ time and does not require
# update calls to refresh the gui (only one time.sleep loop callback
# can be running at once, and blocks others started until it returns);
# the motion gets wild if you press 'o' or 'r' while move in progress,
# though--multiple move updates start firing around the same time;
########################################################################

from Tkinter import *
import canvasDraw_tags

class CanvasEventsDemo(canvasDraw_tags.CanvasEventsDemo):
    def moveEm(self, tag, moremoves):
        (diffx, diffy), moremoves = moremoves[0], moremoves[1:]
        self.canvas.move(tag, diffx, diffy)
        if moremoves: 
            self.canvas.after(250, self.moveEm, tag, moremoves)
    def moveInSquares(self, tag):
        allmoves = [(+20, 0), (0, +20), (-20, 0), (0, -20)] * 5
        self.moveEm(tag, allmoves)

if __name__ == '__main__':
    CanvasEventsDemo()
    mainloop()