nanogui: Thread: focuswp and MwDestroyWindow

Hi,

In microwindows focuswp is a (global) holding the focused window hwnd.

say MwDestroyWindow is called on destroywp for our case.

If destroywp is in focus without parent, everything goes on well,
However if destroywp is in focus (with parent) the check before SetFocus
is not true and the focuswp is not changed even after the window deletion.

The problem is if we create hwnd's with a single parent and want to destroy
one of the hwnds, the focuswp remains unaltered. And on a subsequent
setfocus for
<snip>
   oldfocus = focuswp;
   SendMessage(oldfocus,..)
<snip>
  we get a segfault.


so for a win 32 implemented code we had to apply a check for the same in
MwDestroyWindow.

<snip>
//additional 2 lines follow
% if(wp == focuswp)
% SetFocus(rootwp->children? rootwp->children: rootwp);

if(wp == MwGetTopWindow(focuswp))
SetFocus(rootwp->children? rootwp->children: rootwp);

<snip>

instead of current implementation.

This should take care of maintaining the global focuswp consistently
for destroywindow with or without parent

Has anybody digged this issue deeper, and would like to share their views.

What will be an appropriate microwindows solution.

Please let me know if this needs further clarification.

Regards
Shivaji

Hi...

i came across the same problem some month ago. I solved it that way (maybe not the best solution but up to now it works):

old source:

	/*
	 * Destroy all children, sending WM_DESTROY messages.
	 */
	while (wp->children)
		MwDestroyWindow(wp->children, bSendMsg);

new source:

	/*
	 * Destroy all children, sending WM_DESTROY messages.
	 */
	while (wp->children)
	{
		if (wp->children == focuswp)
			focuswp = MwGetTopWindow(focuswp);
		MwDestroyWindow(wp->children, bSendMsg);
	}

>so for a win 32 implemented code we had to apply a check for the same in
>MwDestroyWindow.

><snip>
>//additional 2 lines follow
>% if(wp == focuswp)
>% SetFocus(rootwp->children? rootwp->children: rootwp);

>if(wp == MwGetTopWindow(focuswp))
>SetFocus(rootwp->children? rootwp->children: rootwp);

I think that your solution to set/correct the focuswp just before the original code should work. But i would focus the parent if there's one instead of the rootwp or 
the first child.

 	// 1) New: If wp is focused set focus to parent (if wp is child)
	if (wp == focuswp)
		SetFocus(MwGetTopWindow(focuswp));

	// 2) Original: If wp is parent of focuswp set focus to other rootwp or first child of rootwp
	if (wp == MwGetTopWindow(focuswp))
		SetFocus(rootwp->children? rootwp->children: rootwp);

Kind regards,

Gerd

Hi,

Can such a fix be taken in the next Microwindows release.

Thanks Gred, for sharing your solution for this issue.

Gred's patch will take care of maintaining focuswp
1. destroying focuswp
2. destroying wp whose child is focuswp
that works and is good enough.

What I would further suggest, is to have one more focus global, say oldfocus,
and set focus to it (after validating oldfocus) instead of setting it to
Top parent window, on destroyWindow.


Regards
Shivaji.


> Hi...
>
> i came across the same problem some month ago. I solved it that way
> (maybe not the best solution but up to now it works):
>
> old source:
>
> 	/*
> 	 * Destroy all children, sending WM_DESTROY messages.
> 	 */
> 	while (wp->children)
> 		MwDestroyWindow(wp->children, bSendMsg);
>
> new source:
>
> 	/*
> 	 * Destroy all children, sending WM_DESTROY messages.
> 	 */
> 	while (wp->children)
> 	{
> 		if (wp->children == focuswp)
> 			focuswp = MwGetTopWindow(focuswp);
> 		MwDestroyWindow(wp->children, bSendMsg);
> 	}
>
>>so for a win 32 implemented code we had to apply a check for the same
>> in MwDestroyWindow.
>
>><snip>
>>//additional 2 lines follow
>>% if(wp == focuswp)
>>% SetFocus(rootwp->children? rootwp->children: rootwp);
>
>>if(wp == MwGetTopWindow(focuswp))
>>SetFocus(rootwp->children? rootwp->children: rootwp);
>
> I think that your solution to set/correct the focuswp just before the
> original code should work. But i would focus the parent if there's one
> instead of the rootwp or  the first child.
>
>  	// 1) New: If wp is focused set focus to parent (if wp is child)
> 	if (wp == focuswp)
> 		SetFocus(MwGetTopWindow(focuswp));
>
> 	// 2) Original: If wp is parent of focuswp set focus to other rootwp
> or
> first child of rootwp if (wp == MwGetTopWindow(focuswp))
> 		SetFocus(rootwp->children? rootwp->children: rootwp);
>
> Kind regards,
>
> Gerd
>
>
>
>
>
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