[Interest] application appearance changing when laptop goes in saving energy mode

[maitai]

Thanks Jason for your help

I have filtered out WM_DISPLAYCHANGE using a QAbstractNativeEventFilter 
and indeed the problem disappeared...

I am now wondering what/if I broke something doing that...

I have opened a bug report (QTBUG-49745)

Thanks
Philippe Lelong

Le 02-12-2015 23:57, Jason H a écrit :
> I'd see what WM_* message(s) are being sent. Specifically
> WM_DISPLAYCHANGE, WM_FONTCHANGE, etc.
> 
> Qt is probably initializing correctly, then when WM_DISPLAYCHANGE
> happens, they get reset back to defaults, without picking up Qt's
> customizations. If you can identify the message, you can filter it
> out.
> 
> 
>> Sent: Wednesday, December 02, 2015 at 6:05 AM
>> From: maitai <maitai at virtual-winds.org>
>> To: Interest at qt-project.org
>> Subject: Re: [Interest] application appearance changing when laptop 
>> goes in saving energy mode
>> 
>> Hello,
>> 
>> Still searching to fix that one.
>> 
>> I can now reproduce it at leasure: If I connect my laptop to an 
>> external
>> monitor, launch the application, then unplug the external monitor and
>> hover the mouse on the windows bar to make it appear (autohide is
>> activated), my application AND QtCreator changes font, palette and
>> style.
>> 
>> Then only way to get normal look back is to restart application.
>> Reloading style, stylesheet, palette and font at application level 
>> does
>> not fix existing widgets once they are corrupted.
>> 
>> I cannot find what trigger this, nor at qApp's event level or at
>> QMainWindow level or at widget's level.
>> 
>> I am using qt 5.5.1 on windows 10. It does not seem to occur on 
>> Windows
>> 7 as far as I can tell.
>> 
>> I have users complaining about that too so it is not just me ;)
>> 
>> Any idea how to catch what is causing that and avoid it? Since it 
>> occurs
>> also in QtCreator maybe I should open a bug report...
>> 
>> Thanks
>> Philippe Lelong
>> 
>> 
>> Le 09-11-2015 16:45, maitai a écrit :
>> > Thanks Robert for your reply,
>> >
>> > In fact I succeeded to reproduce partly the problem. I have a laptop
>> > with 2 graphic cards, switchable. Whenever the PC goes in power-saving
>> > mode, it switches to the intel one. When this happens, my menubar
>> > (regular QMenuBar) is changing font and becomes ugly, and the only way
>> > to get it back to normal is to restart the application. It seems to
>> > happen also from time to time if I switch from external monitor to
>> > laptop monitor.
>> >
>> > This app is not using opengl, it's just a plain QWidget app.
>> >
>> > No signal or event as far as I can see is triggered when this happens,
>> > just a paintEvent it seems.
>> >
>> > The funny thing is that even QtCreator is impacted by that... It also
>> > changes font or style.
>> >
>> > Any clue on what is going on there?
>> >
>> > Thanks
>> > Philippe Lelong
>> >
>> > Le 09-11-2015 12:03, Robert Iakobashvili a écrit :
>> >> On Mon, Nov 9, 2015 at 7:54 AM, maitai <maitai at virtual-winds.org>
>> >> wrote:
>> >>>
>> >>> Hello
>> >>>
>> >>> On Windows, some users are reporting that the application style
>> >>> (font? palette?) is changing when laptop goes in energy saving mode,
>> >>> and becomes more or less unreadable (white font on white background,
>> >>> etc). I have seen that myself also a couple of times but I'm unable
>> >>> to reproduce it.
>> >>>
>> >>> When it occurs, putting the laptop back on power does not fix
>> >>> anything, and the only way to get back the proper appearance is to
>> >>> restart the application. If you start the application when in battery
>> >>> saving mode, no problem. The application is widget-based
>> >>> (QMainWindow, QGraphicalScene, QMenubar, etc), Qt is 5.5.1 but that
>> >>> was reported also with previous Qt versions.
>> >>>
>> >>> As I said this occurs only for a few users, and I cannot reproduce
>> >>> it. Maybe it's connected with the laptop changing GPU, I don't know.
>> >>>
>> >>> Does anyone knows what could possibly trigger this, and if I can
>> >>> catch it somehow either to avoid it or reload style/palette/font/etc
>> >>> when it occurs?
>> >>>
>> >>> Thanks
>> >>> Philippe Lelong
>> >>
>> >>
>> >> Hi,
>> >>
>> >> With which options Qt was configured and built?
>> >>
>> >> Any plugins your software is using?
>> >>
>> >> Is it correlating with any particular Windows versions
>> >> like on Windows-10 or 8.1?
>> >>
>> >> That sounds like an aggressive memory optimization by OS.
>> >> Locking in memory sometimes could help against.
>> >>
>> >> There is a Qt signal
>> >>
>> >> QGuiApplication::on_applicationStateChanged(Qt::ApplicationState
>> >> state);
>> >>
>> >> and using it on Android.
>> >>
>> >> Perhaps, coming to the state:Qt::ApplicationActive from
>> >> somewhere else and reloading fonts, etc could be a work-around?
>> >>
>> >> Kind regards,
>> >> Robert
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