| How to cleanup an object with a non-modal widget method [message #88066] |
Mon, 17 March 2014 14:24  |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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I have an object with a non-modal widget display method. While it is usually used in communication with other objects, I also want to have a simple wrapper to display the widget.
pro displaymap
oAstroMap = obj_new('AstroMap') ;Create the object
oAstroMap.widgetdisplay ;Create the display widget
return
end
While this works, it doesn't clean up after itself, leaving the heap area full. I can't put an OBJ_DESTROY statement before the RETURN because the non-modal widget doesn't wait for the widget to be destroyed, and executes the OBJ_DESTROY right away.
I suppose what I want is for the widget to destroy the underlying object when one presses the Quit button. But my experiments with "OBJ_DESTROY, self " have not been successful. Thanks, --Wayne
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| Re: How to cleanup an object with a non-modal widget method [message #88068 is a reply to message #88066] |
Mon, 17 March 2014 15:15  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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wlandsman writes:
> I have an object with a non-modal widget display method. While it is usually used in communication with other objects, I also want to have a simple wrapper to display the widget.
>
> pro displaymap
>
> oAstroMap = obj_new('AstroMap') ;Create the object
> oAstroMap.widgetdisplay ;Create the display widget
>
> return
> end
>
> While this works, it doesn't clean up after itself, leaving the heap area full. I can't put an OBJ_DESTROY statement before the RETURN because the non-modal widget doesn't wait for the widget to be destroyed, and executes the OBJ_DESTROY right away.
>
> I suppose what I want is for the widget to destroy the underlying object when one presses the Quit button. But my experiments with "OBJ_DESTROY, self " have not been successful.
I would write DisplayMap in such a way that you can get the object
reference back from it (write it as a function, or return the object in
a keyword). Then, I would just make sure I added the object reference to
the info structure of the widget program that calls it, and destroy
along with the other pointers and objects I was cleaning up in the
widget cleanup routine.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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| Re: How to cleanup an object with a non-modal widget method [message #88073 is a reply to message #88066] |
Tue, 18 March 2014 17:58 |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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Mathew, David -- thanks for the suggestions. Sorry if this post appears twice -- Google groups is driving me crazy.
On Monday, March 17, 2014 6:02:00 PM UTC-4, Matthew Argall wrote:
> A simple solution would be to turn "displaymap" into a function so that you can return your oAstroMap object reference. Then, when you are done with it, you can destroy it.
I am trying to write a wrapper for non-IDL users. I want them to be able to type "displaymap" at the IDL prompt and view and manipulate the widget, without them needing to perform any additional cleanup after they click the widget QUIT button.
>
> Maybe more to what you are looking for, check out the TLB_KILL_REQUEST_EVENTS and KILL_NOTIFY keyword to the Widget_Base function. You can have the callback routines kill the object when the top level base is destroyed.
I'll look more closely at these but it still looks like the object has to destroy itself (and not just the widget), and I haven't had much luck with OBJ_DESTROY, self. Perhaps I need to also write the wrapper as an object.
>
> I have another, more complicated solution if neither of these work for you... Is AstroMap object based on function/object graphics? Or is it made from the old widgets?
No, it uses "classic" widgets with Coyote graphics. --Wayne
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| Re: How to cleanup an object with a non-modal widget method [message #88077 is a reply to message #88073] |
Tue, 18 March 2014 20:03 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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wlandsman writes:
>
> Mathew, David -- thanks for the suggestions. Sorry if this post appears twice -- Google groups is driving me crazy.
>
> On Monday, March 17, 2014 6:02:00 PM UTC-4, Matthew Argall wrote:
>> A simple solution would be to turn "displaymap" into a function so that you can return your oAstroMap object reference. Then, when you are done with it, you can destroy it.
>
> I am trying to write a wrapper for non-IDL users. I want them to be able to type "displaymap" at the IDL prompt and view and manipulate the widget, without them needing to perform any additional cleanup after they click the widget QUIT button.
>>
>> Maybe more to what you are looking for, check out the TLB_KILL_REQUEST_EVENTS and KILL_NOTIFY keyword to the Widget_Base function. You can have the callback routines kill the object when the top level base is destroyed.
>
> I'll look more closely at these but it still looks like the object has to destroy itself (and not just the widget), and I haven't had much luck with OBJ_DESTROY, self. Perhaps I need to also write the wrapper as an object.
>>
>> I have another, more complicated solution if neither of these work for you... Is AstroMap object based on function/object graphics? Or is it made from the old widgets?
>
> No, it uses "classic" widgets with Coyote graphics. --Wayne
I guess I still don't understand the problem. The object is created in
association with a widget program, right? The widget program can
(probably does) have a CLEANUP routine that is called when the widget
dies. All you have to do is find a way to put the object reference into
the info structure of the widget. Then, when the widget dies, you get
the info structure, find the object reference, and destroy that. There
is no "self" there. Just the object reference in a widget CLEANUP
routine. I can't imagine how this could cause problems.
PRO Widget_Cleanup, tlb
Widget_Control, tlb, Get_UValue=info
Obj_Destroy, info.objectRef
END
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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| Re: How to cleanup an object with a non-modal widget method [message #88082 is a reply to message #88080] |
Wed, 19 March 2014 05:23 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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wlandsman writes:
> Well, one of the methods of the object creates the widget. So I'd say that the object contains the widget, which is why the widget code refers to self when it needs information from the object (e.g. the top level base ID is stored in self.gui ) I don't have any object reference within the widget method which I can destroy except for self. Thanks, --Wayne
I'm thinking something like this:
oAstroMap = obj_new('AstroMap') ;Create the object
oAstroMap.widgetdisplay ;Create the display widget
So, I write the WidgetDisplay method like this:
PRO AstroMap::WidgetDisplay
tlb = Widget_Base(Title='MyWidget',UValue=self, $
Kill_Notify='Widget_Cleanup')
.... ; Doesn't matter what widget I store the object in, $
.... ; just that it have a kill callback associated with it.
END
And, I write Widget_Cleanup like this:
PRO Widget_Cleanup, widget_that_is_dying
Widget_Control, widget_that_is_dying, Get_UValue=myObject
Obj_Destroy, myObject
END
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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| Re: How to cleanup an object with a non-modal widget method [message #88083 is a reply to message #88082] |
Wed, 19 March 2014 05:29 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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David Fanning writes:
>
> wlandsman writes:
>
>> Well, one of the methods of the object creates the widget. So I'd say that the object contains the widget, which is why the widget code refers to self when it needs information from the object (e.g. the top level base ID is stored in self.gui ) I don't have any object reference within the widget method which I can destroy except for self. Thanks, --Wayne
>
> I'm thinking something like this:
>
> oAstroMap = obj_new('AstroMap') ;Create the object
> oAstroMap.widgetdisplay ;Create the display widget
>
> So, I write the WidgetDisplay method like this:
>
> PRO AstroMap::WidgetDisplay
> tlb = Widget_Base(Title='MyWidget',UValue=self, $
> Kill_Notify='Widget_Cleanup')
> .... ; Doesn't matter what widget I store the object in, $
> .... ; just that it have a kill callback associated with it.
> END
>
> And, I write Widget_Cleanup like this:
>
> PRO Widget_Cleanup, widget_that_is_dying
> Widget_Control, widget_that_is_dying, Get_UValue=myObject
> Obj_Destroy, myObject
> END
Of course, in the Cleanup method of the object, you have to be careful
not to use code that works with widgets, without first testing if the
widget is actually there!
PRO AstroMap::Cleanup
IF Widget_Info(self.gui, /Valid_ID) THEN BEGIN
.... ; Widget cleanup stuff here
ENDIF
....
END
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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| Re: How to cleanup an object with a non-modal widget method [message #88109 is a reply to message #88082] |
Thu, 20 March 2014 15:51 |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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David,
Thanks for this. I think that when destroying an object from a non-modal widget that IDL's automatic garbage collection does not come into play, so that one needs to have proper cleanup methods. And let's just say that my cleanup methods were, um, suboptimal, so it did not appear that the cleanup was working at all. My partial excuse is that automatic garbage collection has made me lazy, but I am also not entirely clear on the concepts.
For example, my map display object includes many other objects which must either be created or passed in via keyword. So my INIT method looks like this:
pro mapdisplay::init,oCoord=oCoord
if obj_valid(oCoord) then self.oCoord = oCoord else self.oCoord = obj_new('Coord')
Now in the cleanup method, I want to destroy self.oCoord if it was created in the ::INIT, but not if it was passed by keyword. How is the Cleanup method supposed to know which is the case? The only solution I can think of is to add a flag to the object, which can be used by ::CLEANUP
pro mapdisplay::init,oCoord=oCoord
if obj_valid(oCoord) then begin
self.oCoord = oCoord
self.destroy_oCoord = 0
endif else begin
self.oCoord = obj_new('oCoord')
self.destroy_oCoord = 1
endelse
Is there a better way than this? Thanks, --Wayne
On Wednesday, March 19, 2014 8:23:10 AM UTC-4, David Fanning wrote:
> wlandsman writes:
>
>
>
>> Well, one of the methods of the object creates the widget. So I'd say that the object contains the widget, which is why the widget code refers to self when it needs information from the object (e.g. the top level base ID is stored in self.gui ) I don't have any object reference within the widget method which I can destroy except for self. Thanks, --Wayne
>
>
>
> I'm thinking something like this:
>
>
>
> oAstroMap = obj_new('AstroMap') ;Create the object
>
> oAstroMap.widgetdisplay ;Create the display widget
>
>
>
> So, I write the WidgetDisplay method like this:
>
>
>
> PRO AstroMap::WidgetDisplay
>
> tlb = Widget_Base(Title='MyWidget',UValue=self, $
>
> Kill_Notify='Widget_Cleanup')
>
> .... ; Doesn't matter what widget I store the object in, $
>
> .... ; just that it have a kill callback associated with it.
>
> END
>
>
>
> And, I write Widget_Cleanup like this:
>
>
>
> PRO Widget_Cleanup, widget_that_is_dying
>
> Widget_Control, widget_that_is_dying, Get_UValue=myObject
>
> Obj_Destroy, myObject
>
> END
>
>
>
> Cheers,
>
>
>
> David
>
> --
>
> David Fanning, Ph.D.
>
> Fanning Software Consulting, Inc.
>
> Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
>
> Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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| Re: How to cleanup an object with a non-modal widget method [message #88110 is a reply to message #88109] |
Thu, 20 March 2014 15:57 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Wayne Landsman writes:
> Thanks for this. I think that when destroying an object from a non-modal widget that IDL's automatic garbage collection does not come into play, so that one needs to have proper cleanup methods. And let's just say that my cleanup methods were, um, suboptimal, so it did not appear that the cleanup was working at all. My partial excuse is that automatic garbage collection has made me lazy, but I am also not entirely clear on the concepts.
>
> For example, my map display object includes many other objects which must either be created or passed in via keyword. So my INIT method looks like this:
>
> pro mapdisplay::init,oCoord=oCoord
> if obj_valid(oCoord) then self.oCoord = oCoord else self.oCoord = obj_new('Coord')
>
> Now in the cleanup method, I want to destroy self.oCoord if it was created in the ::INIT, but not if it was passed by keyword. How is the Cleanup method supposed to know which is the case? The only solution I can think of is to add a flag to the object, which can be used by ::CLEANUP
>
> pro mapdisplay::init,oCoord=oCoord
> if obj_valid(oCoord) then begin
> self.oCoord = oCoord
> self.destroy_oCoord = 0
> endif else begin
> self.oCoord = obj_new('oCoord')
> self.destroy_oCoord = 1
> endelse
>
> Is there a better way than this?
Not to my knowledge. This is the way I do it. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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