## This example draws a green ball.  You must click on the canvas to
## start it moving. click again to stop it.

## Copyright 2005 Boley

from gdraw import *

## build all the basic objects.
circle=fill_oval(20,40,60,80,'green')  ## the ball
stall()                                ## draw it now (might not be needed here)
CanvasDim=get_width(0)                 ## where's the right wall?
counter=[0]                            ## count the steps
paused = [1]                           ## global 'paused' state.

def Move_Ball ():                      ## move the ball 1 step.
    position = get_coords(circle) 
    position[0] += 2 
    position[2] += 2 
    if (position[2] >= CanvasDim[0]):  ## check for wrap-around
        position[0]=20
        position[2]=60 
    set_coords(circle,position) 
    counter[0]=counter[0]+1;
    print "\r ",counter[0],"      ",
    stall()                            ##(might not be needed here)
    return position

def Move_Loop ():                      ## Outer Loop to move ball.
    ## The 'Move_Loop' procedure checks the paused state, moves the ball, 
    ## and finally repeats itself after 50 msec.  
    if paused[0]:
        print "paused"
        return
    Move_Ball() 
    after(50,Move_Loop) 

def toggle (e):                        ## toggle pause/nopause state.
    ## toggle state, then try main task
    paused[0] = not paused[0]
    Move_Loop()

set_binding(0,toggle)                  ## what to do upon mouse click.

textbox = draw_text("Click here to start and stop",200,300);

#CanvasWindow.mainloop()              ## Tell Tk to start processing.
                                      ## (needed only if -i switch omitted)