[vlc-devel] [PATCH 1/4] libvlc: Add "fullscreen-monitor" setting

[Steve Lhomme]

On 2019-10-24 21:33, Rémi Denis-Courmont wrote:
> Le torstaina 24. lokakuuta 2019, 18.39.02 EEST Gabriel Luci a écrit :
>> I think you misunderstood my question. This entire patchset was about
>> setting it in the preferences before playback starts. There should be one
>> *setting*, yes. But, from what I see, there are two ways to implement it.
>> (That's what I meant by "2 options")
>>
>> In this patch, I defined a global setting in src/libvlc-module.c. Rémi
>> objected to that approach and said the setting should be defined in the
>> window manager (I assume that means in win32/window.c). But if it's defined
>> there, the setting should be *read* in win32/window.c too.
> 
> I've never written that it should be in the window manager. That makes no
> sense. It has to be in the window provider, which is the only component that
> knows how to enumerate outputs. I've already explained at least three times in
> this thread why it cannot be in the core.
> 
>> My objection to that is that Rémi himself had added an "id" parameter to
>> the vout_ChangeFullscreen() last year, which currently is always NULL.
> 
> Because the UI does not use it yet. Feel free to fix that.
> 
>> That seems to be the place to pass the ID of the monitor to put the
>> fullscreen window on.
> 
> That's kind of the whole point, yes.
> 
>> If I'm correct on that, then the setting needs to be read in
>> src/video_output/vout_intf.c and thus it should be a global setting.
> 
> WTF? How do you handle enumeration with a global setting? How do you handle
> different windowing systems in a global setting? How do you not break the
> existing XDG-shell implementation?

For the record, the capture I sent with the current option in QT is 
listing the possible screens using QGuiApplication::screens(). The text 
presented is the QScreen::name(). It may not be parseable by the 
standalone window (win32/window.c in this case) and may change depending 
on the Qt versions. The documentation doesn't mention any similarity 
with anything existing in the OS.

If we want a stable string we'll have to mimick what Qt does on systems 
where we use Qt (Windows and Linux). I doesn't seem to hard on Windows. 
I don't know about others.

The other option would be to not use QGuiApplication::screens() but 
something else, maybe in the core. We could enumerate screen like we do 
for audio devices. Which uses "XXX-audio-device" to find the list of 
devices when the XXX output is selected. Here the XXX selection would be 
the GUI or a standalone window.

The current selection implies that the Fullscreen Video Device is only 
used when the video is embedded in Qt.