Re: Fix, NSView (-releaseGState)

[Fred Kiefer]

Thank you for testing this. I tried to fix it by keeping the value of
_allocate_gstate in a temporary variable. Could you please give that new
code a try?

Thanks
Fred

Am 24.09.2010 03:43, schrieb Georg Fleischmann:
> Hallo Fred,
> 
> I just testes GNUstep GUI from yesterday with Cenon, and now all graphic 
> windows are pitch black, no contents at all.
> 
>> _allocate_gstate will change its value when the view moves to another
>> window. Application code will have to set this again.
> 
> If I remove the [self releaseGState] in [NSView _viewWillMoveToWindow:], it 
> works again.
> It also works if I just keep the _allocate_gstate alive.
> 
> As the Cenon graphics code runs perfectly on OpenStep 4.2 and Apple, I would 
> say, the _allocate_gstate flag should be transferred with the view to the new 
> window.
> 
> Best wishes,
> Georg
> 
> 
> On 15.09.2010, at 16:22, Fred Kiefer wrote:
> 
>> Should be in SVN now. As the logic of undefining a gstate is now a bit
>> more complicated I rather call this method from _viewWillMoveToWindow:
>> instead of duplicating the code. This has the drawback that
>> _allocate_gstate will change its value when the view moves to another
>> window. Application code will have to set this again.
>>
>> Fred
>>
>> Am 13.09.2010 10:05, schrieb Georg Fleischmann:
>>> Hi Fred,
>>>
>>>> if (_gstate)
>>>> if (_window)
>>>>   GSUndefineGState([_window graphicsContext], _gstate);
>>>> _gstate = 0;
>>>
>>> I added this at the beginning of _viewWillMoveToWindow: and played with 
>>> some graphic windows in Cenon.
>>> It will crash, if there is a _gstate but _window has no graphicsContext, 
>>> which seems to be possible here.
>>> If I add an additional test for [_window graphicsContext != nil, then I 
>>> don't get any problems.
>>>
>>> Georg
>>>
>>>
>>> On 11.09.2010, at 20:17, Fred Kiefer wrote:
>>>
>>>> Hi Georg,
>>>>
>>>> thank you for this patch. It surely is correct and I will add it. But as
>>>> you already pointed out there may be a deeper problem here.
>>>> I think that we should always clean up the gstate when the window for a
>>>> view changes, that is in the method _viewWillMoveToWindow:. Something like:
>>>>
>>>> if (_gstate)
>>>> if (_window)
>>>>   GSUndefineGState([_window graphicsContext], _gstate);
>>>> _gstate = 0;
>>>>
>>>> Do you or anybody else on this list, see any problem with that change?
>>>>
>>>> Fred
>>>>
>>>>
>>>> Am 11.09.2010 12:24, schrieb Georg Fleischmann:
>>>>> here is a small patch for NSView (SVN 2010-09-10 and before) to prevent a 
>>>>> crash in Cenon when closing a Graphic Window.
>>>>> The same code of Cenon works on Apple, so I suspect it's an issue with 
>>>>> GNUstep.
>>>>>
>>>>> The crash is in NSView, which has a gstate but no _window (_window = nil) 
>>>>> to get the graphicsContext. This is causing the crash.
>>>>> I simply tested for a _window != nil to prevent the crash, and everything 
>>>>> appears to work.
>>>>>
>>>>> There might be an issue with the order of releasing the hierarchy of 
>>>>> windows and views or something in that line, creating the situation in 
>>>>> the first place, but I'm not deep enough into that to have any idea.
>>>>> I also add the stack of the situation.
>>>>>
>>>>> Best wishes,
>>>>> Georg Fleischmann
>>>>>
>>>>>
>>>>>
>>>>> *** Source/NSView.m.old   2010-09-04 13:30:30.000000000 +0800
>>>>> --- Source/NSView.m       2010-09-11 17:45:22.000000000 +0800
>>>>> ***************
>>>>> *** 2183,2189 ****
>>>>> */
>>>>> - (void) releaseGState
>>>>> {
>>>>> !   if (_allocate_gstate && _gstate)
>>>>>     GSUndefineGState([_window graphicsContext], _gstate);
>>>>>   _gstate = 0;
>>>>>   _allocate_gstate = NO;
>>>>> --- 2183,2189 ----
>>>>> */
>>>>> - (void) releaseGState
>>>>> {
>>>>> !   if (_allocate_gstate && _gstate && _window)
>>>>>     GSUndefineGState([_window graphicsContext], _gstate);
>>>>>   _gstate = 0;
>>>>>   _allocate_gstate = NO;