Tkinter callback arguments

Gabriel Genellina gagsl-py2 at
Thu Nov 5 08:34:16 CET 2009

En Wed, 04 Nov 2009 18:08:49 -0300, Alf P. Steinbach <alfps at>  
> * Terry Reedy:
>> Alf P. Steinbach wrote:
>>> However, the natural semantics is that various logical properties,  
>>> such as left, top, right, bottom, width and height, can be varied  
>>> independently.
>>  But they *CANNOT* be varied independently. A rectangle with side  
>> parallel to the axes has exactly 4 degress of freedom, not 6.
> Yes <g>. That's the basic idea of the example I presented up-thread,  
> that's discussed here. With R1's state variables width and heigh can be  
> varied independently by direct modification, with R2 it's right and  
> bottom.
> The public interface must also make this choice, but it's an independent  
> choice: the internal rectangle representation can have the opposite  
> choice.
> And conversely, that means that if the internal representation isn't  
> used directly, then it can be changed without affecting the public  
> interface.

And that's exactly what everyone is saying - so we all agree then!

Gabriel Genellina

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