Mixing Txinter and Pygame

[Eric Brunel]

On Tue, 22 Feb 2005 13:17:37 +1300, Tim Knauf <tim at upperorbit.com> wrote:
> Hi everyone, I'm glad to have found this list.
>
> I've written a small script for my own use which, amongst other things,
> captures mouse click information from a window containing an image. I
> used Pygame to manage the image window, as it was the easiest way to
> implement the functionality I needed. The surrounding interface windows
> (there are two) are constructed with Tkinter.
>
> Despite their unholy union, Pygame and Tkinter seem, generally, to
> cooperate. I'm using this main loop to update one, then the other:
>
> while 1:
>     gameLoop() # This function pumps the Pygame events and checks for
> mouse and keyboard events
>     pygame.time.wait(10)
>     mainwin.update() # mainwin is an instance of Application class,
> which is a child of Tkinter.frame
>
> I have my interface set up so that when *any* of the windows' close
> boxes are clicked, this function will be called:
>
> # This portion of the Pygame loop calls doquit() when it gets a 'QUIT'
> event...
> def gameLoop():
>     pygame.event.pump()
>     for event in pygame.event.get():
>         if event.type == QUIT:
>             doquit()
>             # Etc.
>
>     # And this portion of the Tkinter interface sets the
> WM_DELETE_WINDOW protocol to call doquit()
>     def createWidgets(self):
>         self.title("Region Management")
>         self.geometry('+830+8')
>         self.protocol("WM_DELETE_WINDOW", doquit)
>         # Etc.
>
> # A temporary file is removed, and both Pygame and Tkinter are
> instructed to quit
> def doquit():
>     if os.access('recalc.tmp', os.F_OK):
>         os.remove('recalc.tmp')
>     pygame.quit()
>     mainwin.master.destroy()
>
> Perhaps you've begun to see where I might be having problems. You see,
> if I close the script by closing the Pygame window, I get this exception:
>
> Traceback (most recent call last):
>   File "D:\Development\Python\sludge helpers\addScreenRegion
> helper.pyw", line 363, in ?
>     mainwin.update()
>   File "C:\Python24\lib\lib-tk\Tkinter.py", line 859, in update
>     self.tk.call('update')
> TclError: can't invoke "update" command:  application has been destroyed
>
> Conversely, if I close the application by closing a Tkinter window, I
> get this exception:
>
> Traceback (most recent call last):
>   File "D:\Development\Python\sludge helpers\addScreenRegion
> helper.pyw", line 361, in ?
>     gameLoop()
>   File "D:\Development\Python\sludge helpers\addScreenRegion
> helper.pyw", line 203, in gameLoop
>     pygame.event.pump()
> error: video system not initialized
>
> Obviously, Pygame doesn't like Tkinter telling it to quit (when it's
> trying to do something from its internal loop) and vice versa. Is there
> a simple way that I can avoid getting these exceptions on exit, or have
> I taken the wrong approach? Everything else appears to work fine. Please
> do excuse me if this seems a silly question, as I'm fairly new to Python
> and Pygame, and a total novice when it comes to Tkinter.

Well, since these are just exceptions, a simple try... except block would be fine, and you can even figure out the reason for the exception. Here is what I'd do:
- when you create your Tkinter main window, initialize an attribute that you'll use to see if the application has quit, e.g mainwin.hasQuit = False
- rewrite doquit this way:
def doquit():
     if os.access('recalc.tmp', os.F_OK):
         os.remove('recalc.tmp')
     mainwin.hasQuit = True
     pygame.quit()
- rewrite your custom event loop this way:
while 1:
     gameLoop()
     pygame.time.wait(10)
     try:
       mainwin.update()
     except TclError:
       if not mainwin.hasQuit:
         raise

And: (1) your problem should go away; (2) the "real" exceptions you may get from Tkinter windows should not passed unnoticed.

> On a side note, has anyone else found the Tkinter documentation awfully
> obscure? I've found Python a joy to learn about, and Pygame's tutorials
> are a lot of fun. I can't say the same for Tkinter, and found myself
> having to do many Google searches before I uncovered information I could
> put to use. Has anyone found any high-quality (online) documentation
> that proves me wrong? :^)

Incomplete, but very useful: http://www.pythonware.com/library/tkinter/introduction/index.htm
But the best reference documentation you'll ever find is the tcl/tk man pages, on-line here: http://www.tcl.tk/man/tcl8.4/TkCmd/contents.htm
It unfortunately requires to know how to convert the tcl/tk syntax to Python/Tkinter syntax, but it is actually quite easy (mainly read "option=value" when the tcl/tk documentation says "-option value")

HTH
  - Eric Brunel -