Re: focus problem

[Fred Kiefer]

Yen-Ju Chen wrote:
> On 8/22/07, Fred Kiefer <fredkiefer@gmx.de> wrote:
>> Let me try to reduce the amount of confusion in this discussion. There
>> are multiple issues with focus setting in GNUstep and Yen-Ju and Andreas
>> are talking about to completely different ones.
>> Andreas has a problem when switching between applications via DO. This
>> should be fixed by my latest change to SVN, but this change introduced a
>> well known race condition when clicking on slow responding applications.
>> Richard and I will be looking into this some more.
>> Yen-Ju is concerned about the focus loss of an application when the last
>> window is closed. His different patches try to solve this.
>> As for the last patch I am a bit surprised that it changes anything. We
>> have similar code already in [NSWindow _lossOfKeyOrMainWindow]. The main
>> difference I see here is that Yen-Ju's code doesn't check if the ordered
>> out window was key before. But why would we have to change the focus
>> when the window being closed wasn't key?
>> The patch may still be valid, I just don't understand it.
> 
>   The _lostOfKeyOrMainWindow is not called when window is closed.
>   When the last document window is closed,
>   it first receives the UnmapNotify, then FocusOut.
>   When FocusOut comes, GNUstep looks for where the focus is.
>   But at the same time, window manager may not prepare the focus yet.
>   So GNUstep cannot find focus on its own window, then deactivate.
>   As in one of my previous patch, which use usleep() to wait 1 second
>   between FocusOut and looking for focused window (XGetInputFocus)
>   in backend, it works fine.
>   So the race is between when window manager transfers the focus
>   and when GNUstep uses XGetInputFocus to get the focused window.
>   To solve this racing issue, GNUstep can transfer focus before the
> window is closed or window manager can do that.
>   No matter which party does so, the correct sequence would be:
>   1. last document window received a close action.
>   2. transfer focus to another window. Since it is the last document,
> it can only transfer to main menu.
>   3. last document window receive UnmapNotify.
>   4. last document window receive FocusOut and check where the current
> focus is. Since the focus is probably on main menu already, it will
> not deactivate.
> 
>   Without step (2), step (4) will deactive the GNUstep application.
>   Since GNUstep knows better about where the focus should go,
>   I believe it may be easier to do step (2) in GNUstep.
> 

If the window manager closes the window without telling GNUstep, then we
really have a problem, but when it goes via [NSWindow close] as your
patch suggest then the next method called will be [NSWindow orderOut:],
which in turn calls [NSWindow orderWindow:relativeTo:]. Here we call
[NSWindow _lossOfKeyOrMainWindow] for the NSWindowOut case. That is why
I thought your patch shouldn't change things to much.

>> Cheers,
>> Fred
>>
>>
>> Yen-Ju Chen wrote:
>>> On 8/22/07, Yen-Ju Chen <yjchenx@gmail.com> wrote:
>>>> On 8/22/07, Yen-Ju Chen <yjchenx@gmail.com> wrote:
>>>>> On 8/22/07, Andreas Höschler <ahoesch@smartsoft.de> wrote:
>>>>>> Hi Yen-Ju,
>>>>>>
>>>>>>> As I said, the first half of the issue is that GNUstep cannot find the
>>>>>>> focused window while it is unmapped. So it deactivates itself.
>>>>>>> This patch transfers the focus to another window in the
>>>>>>> same GNUstep application before it is unmapped,
>>>>>>> therefore, fixes the problem.
>>>>>>>
>>>>>>> The second half of the problem is that after the unmapping,
>>>>>>> window manager tends to actively find another window to focus on,
>>>>>>> therefore, even GNUstep transfers the focus, it still loses it.
>>>>>>> So there is nothing GNUstep can do about it.
>>>>>>> It has to be fixed on window manager.
>>>>>>>
>>>>>>> This patch works for me, but may need to improvement.
>>>>>> Thanks for working on this!
>>>>>>
>>>>>> After applying your patch I can no longer switch between applications
>>>>>> via clicking on application windows. The clicked window is not put to
>>>>>> foreground!? :-(
>>>>   O.K. I can see why it happens. It's another racing issue. :(
>>>>   Well, the patch may need to move to up stream.
>>>   Here is the same patch, but apply on -gui when window is closed.
>>>   Therefore, it will not affect the situation when window loses focus,
>>>   but not closed (application switching).
>>>   The idea is the same: transfer focus to another window before it
>>> gets unmapped.
>>>   This patch does not fix "key focus on wrong window", "window
>>> flicking", nor "menu disappear after last document minimized".
>>>   It only fixes the "menu disappear after last document window closed".
>>>
>>>   Yen-Ju
>>>
>>>>   Yen-Ju
>>>>
>>>>> Do you have latest Azalea from -trunk ?
>>>>> There are a few changes on it to match what GNUstep does.
>>>>> I have no problem switching application by clicking on their windows.
>>>>> But I will run it for a while to see.
>>>>> Fixing such bug has a side-effect that it may introduce another one.  :(
>>>>>
>>>>> I am pretty sure that the problem is as I described.
>>>>> But the fix may not be totally correct.
>>>>> And it doesn't fix the loss of focus during minimization.
>>>>> I am also not sure whether it will break on WindowMaker.
>>>>>
>>>>> Yen-Ju
>>>>>
>>>>>> Regards,
>>>>>>
>>>>>>    Andreas
>>>>>>
>>>>>>
>>>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>> Index: NSWindow.m
>>>> ===================================================================
>>>> --- NSWindow.m       (revision 25410)
>>>> +++ NSWindow.m       (working copy)
>>>> @@ -2455,7 +2455,42 @@
>>>>        _f.has_opened = NO;
>>>>        [NSApp removeWindowsItem: self];
>>>>        [self orderOut: self];
>>>> +#if 1
>>>> +       /* We move focus to another window so that window manager will not
>>>> +          randomly assign the focus. */
>>>> +       NSWindow *key_win = [NSApp keyWindow];
>>>> +       if (key_win == nil)
>>>> +               key_win = [NSApp mainWindow];
>>>> +       if ((key_win == nil) && [[NSApp windows] count])
>>>> +       {
>>>> +               int i, count = [[NSApp windows] count];
>>>> +               for (i = 0; i < count; i++)
>>>> +               {
>>>> +                       key_win = [[NSApp windows] objectAtIndex: i];
>>>> +                       if (key_win  ==  self)
>>>> +                       {
>>>> +                               key_win = nil;
>>>> +                               continue;
>>>> +                       }
>>>> +                       if ([key_win isKindOfClass: [NSWindow class]])
>>>> +                       {
>>>> +                               if ([key_win canBecomeKeyWindow] == NO)
>>>> +                               {
>>>> +                                       /* Get GSCacheWindow or 
>>>> NSIconWindow sometimes */
>>>> +                                       key_win = nil;
>>>> +                                       continue;
>>>> +                               }
>>>> +                       }
>>>> +               }
>>>> +       }
>>>> +       if (key_win == nil)
>>>> +               key_win = [[NSApp mainMenu] window];
>>>> +       int key_num = [key_win windowNumber];
>>>> +NSLog(@"Set Input Focus to %d", key_num);
>>>> +    [GSServerForWindow(key_win) setinputfocus: key_num];
>>>> +#endif
>>>>
>>>> +
>>>>        RELEASE(pool);
>>>>
>>>>        _f.has_closed = YES;
>>
>