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Python Source  |  1999-06-25  |  2.5 KB  |  93 lines
  1. from Tkinter import *
  2.  
  3.  
  4. class WidgetRedirector:
  5.  
  6.     """Support for redirecting arbitrary widget subcommands."""
  7.  
  8.     def __init__(self, widget):
  9.         self.dict = {}
  10.         self.widget = widget
  11.         self.tk = tk = widget.tk
  12.         w = widget._w
  13.         self.orig = w + "_orig"
  14.         tk.call("rename", w, self.orig)
  15.         tk.createcommand(w, self.dispatch)
  16.  
  17.     def __repr__(self):
  18.         return "WidgetRedirector(%s<%s>)" % (self.widget.__class__.__name__,
  19.                                              self.widget._w)
  20.  
  21.     def close(self):
  22.         for name in self.dict.keys():
  23.             self.unregister(name)
  24.         widget = self.widget; del self.widget
  25.         orig = self.orig; del self.orig
  26.         tk = widget.tk
  27.         w = widget._w
  28.         tk.deletecommand(w)
  29.         tk.call("rename", orig, w)
  30.  
  31.     def register(self, name, function):
  32.         if self.dict.has_key(name):
  33.             previous = dict[name]
  34.         else:
  35.             previous = OriginalCommand(self, name)
  36.         self.dict[name] = function
  37.         setattr(self.widget, name, function)
  38.         return previous
  39.  
  40.     def unregister(self, name):
  41.         if self.dict.has_key(name):
  42.             function = self.dict[name]
  43.             del self.dict[name]
  44.             if hasattr(self.widget, name):
  45.                 delattr(self.widget, name)
  46.             return function
  47.         else:
  48.             return None
  49.  
  50.     def dispatch(self, cmd, *args):
  51.         m = self.dict.get(cmd)
  52.         try:
  53.             if m:
  54.                 return apply(m, args)
  55.             else:
  56.                 return self.tk.call((self.orig, cmd) + args)
  57.         except TclError:
  58.             return ""
  59.  
  60.  
  61. class OriginalCommand:
  62.  
  63.     def __init__(self, redir, name):
  64.         self.redir = redir
  65.         self.name = name
  66.         self.tk = redir.tk
  67.         self.orig = redir.orig
  68.         self.tk_call = self.tk.call
  69.         self.orig_and_name = (self.orig, self.name)
  70.  
  71.     def __repr__(self):
  72.         return "OriginalCommand(%s, %s)" % (`self.redir`, `self.name`)
  73.  
  74.     def __call__(self, *args):
  75.         return self.tk_call(self.orig_and_name + args)
  76.  
  77.  
  78. def main():
  79.     root = Tk()
  80.     text = Text()
  81.     text.pack()
  82.     text.focus_set()
  83.     redir = WidgetRedirector(text)
  84.     global orig_insert
  85.     def my_insert(*args):
  86.         print "insert", args
  87.         apply(orig_insert, args)
  88.     orig_insert = redir.register("insert", my_insert)
  89.     root.mainloop()
  90.  
  91. if __name__ == "__main__":
  92.     main()
  93.