Moving objects in Tkinter

Matt McCredie mccredie at gmail.com
Fri Oct 12 22:21:19 CEST 2007


On 10/12/07, Evjen Halverson <evjenh at yahoo.com> wrote:
>   I have tried to make a Tkinter program make a rectangle move down the
> window, but did not succeed. All it does is make a rectangle trail.
>    What am I doing wrong?
>
>  from Tkinter import*
>  root = Tk()
>  RectangleColor='orange'
>  Background=tk_rgb = "#%02x%02x%02x" % (100, 255, 100)
>  root.geometry('1000x800+0+0')
>  root.title("Moving Object Test")
>  w = Canvas (root,width=1000,height=800,bg=Background)
>  w.grid()
>  import time
>  t1=time.time()
>  t2=t1
>  ti=t2-t1
>  x=100
>  y=0
>  a=0
> rect=Canvas.create_rectangle(w,x,y,200,100,fill=RectangleColor)
>
>
>
>  def CLS():
>
> cls=Canvas.create_rectangle(w,0,0,1000,800,fill=Background)
>  while ti<10:
>      t2=time.time()
>      ti=t2-t1
>      y=y+10
>
> Canvas.create_rectangle(w,x,y,200,100,fill=RectangleColor)
>
>      st1=time.time()
>      st2=st1
>      subti=st2-st1
>      root.mainloop()
>      time.sleep(100)
>
>      while subti<1:
>          st2=time.time()
>          subti=st2-st1
>          a=a+1
>      CLS()
>
>  #
> rect=Canvas.create_rectangle(w,x,y,1000,800,fill=RectangleColor)
>
>
>
>  root.mainloop()
>
>  quit()

Tkinter canvas works a little different than say, openGL or pygame.
You don't have to draw the rectangle over and over for each frame.
Every time you call create_rectangle you are creating another
rectangle. Another thing to note is that Tkinter has a built in
scheduler. You don't need to use time. The way you are calling Canvas
looks a little funny to me also.

Anyway, here is a simple example:

[code]
import Tkinter as tk

rectanglecolor = 'orange'
background = tk_rgb = "#%02x%02x%02x" % (100, 255, 100)
disty = 6

root = tk.Tk()
root.geometry('1000x800+0+0')
root.title("Moving Object Test")

can = tk.Canvas (root,width=1000,height=800,bg=background)
can.grid()

# note that rect is actually just an integer that is used to identify
that shape in the
# context of the canvas that it was created within.
rect = can.create_rectangle(400,0,600,200,fill=rectanglecolor)

for i in range(100):
    # move the rectangle 0 in the x direction and disty in the y direction.
    can.move(rect, 0, disty)
    root.update() # update the display
    root.after(30) # wait 30 ms

root.mainloop() # this just keeps the window open
[/code]

Matt



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