From: Morton Goldberg <m_goldberg@...>
Date: 2006-09-06T04:00:45+09:00
Subject: Re: How to properly bind context menus to canvas in Ruby/Tk?

On Sep 5, 2006, at 2:00 PM, Josef Wolf wrote:

> On Tue, Sep 05, 2006 at 08:43:01PM +0900, Morton Goldberg wrote:
>
> Thanks for the reply, Morton!
>
>> I tried running your code on my system which is OS X 10.4.7 running
>> Ruby 1.8.2, and I don't see what you report. What I see is following:
>>
>> * Right-clicking away from the the rectangle, the canvas' contextual
>>   menu pops-up.
>> * Right-clicking on the rectangle.
>>     ** The rectangle's contextual menu pops-up.
>>     ** When the rectangle's menu is dismissed, the canvas'
>> contextual menu pops-up.
>
> How do you "dismiss" the menu?  Whatever I do, I never get the  
> second menu.

By left clicking -- either on or off the menu. Which menu don't you  
get, the canvas' or the rect's?

>> With a small tweak, I was able to keep the canvas' contextual menu
>> from popping up when the the rectangle is right-clicked. So what I
>> have now running on my system works as you expected.
>
> Your handled_by_rect flag seems to do the trick.  But this would be a
> global flag in my case since the menus are created from different
> classes. :-(  I would like to avoid such a global flag.

WeLL, I try to avoid globals, too, but sometimes a global is the  
simplest solution. On the other hand you could create a class, say  
CanvasFlag, to manage the flag -- creating a class will solve most  
Ruby design problems ;)

> The Tk::Bind manpage mentions that processing of matching callbacks  
> can
> be controlled by "return" or calling "Tk->break" inside the callback.
> That is, the rectangle's callback should call Tk->break.  But none of
> the involved classes seem to have a break method.  And returning
> false/true/nil/1/0 don't have any effect, too.  Any ideas?

I believe the Ruby/Tk equivalent is Tk.callback_break, but I don't  
think it will help here where we're dealing with an interaction  
between a bind and an itembind.

Regards, Morton