[LV2] Widget-less UI not working

[Stefan Riha]

Thanks, that's a lot of valuable information. Much appreciated.

Yes makes sense, the x11 quirk is not good.

Can't wait to try it next week.
On May 28, 2016 19:10, "Hanspeter Portner" <ventosus at airpost.net> wrote:

> On 28.05.2016 01:27, Stefan Riha wrote:
> > I had time now to try it. I'm not sure if I understood this correctly,
> but ui:idleInterface and ui:showInterface don't
> > seem to solve my problem. Jalv and Ardour don't even call
> extension_data(). They break before that, due to the invalid
> > widget pointer they get from calling instantiate().
>
> Ah, I forgot to tell that not all hosts support ui:showInterface, yet.
> e.g. Ardour does not.
> And jalv needs to be called with a special (undocumented) flag (-s), to
> run in the proper state.
>
> Although ui:showInterface is the 'official' extension to do custom UIs,
> some hosts only support its deprecated
> predecessor extension 'external-ui' [1].
>
> 'external-ui' and ui:showInterface/ui:idleInterface are pretty similar and
> you can actually wrap one into the
> other to support both within the same code [2].
>
> [1] http://kxstudio.linuxaudio.org/ns/lv2ext/external-ui
> [2] https://github.com/ventosus/customui.lv2
>
> Have a look at [2], it should get you going, it runs fine in jalv(1.4.6),
> Ardour(4.7), Qtractor (0.7.5)
>
> Run your host from the console to see whether it works for you (the UI
> prints some debug strings to stdout)
>
> e.g.
> $ jalv -s http://open-music-kontrollers.ch/lv2/customui#test
>
> > However, I noticed that if I declare the widget-less UI as a ui:X11UI in
> the .ttl, then it works! Jalv, Ardour and
> > Qtractor open an empty window, call extension_data() with
> ui:idleInterface. I actually think that's all I need. Probably
> > has something to do with the pointer type for X11 windows (see
> http://lv2plug.in/ns/extensions/ui/#X11UI )
>
> No, that's not what you need. ui:idleInterface can be used apart from
> ui:showInterface. It's readily used with
> ui:X11UI to drive animations, screen updates, etc. as X11 has no main loop
> as e.g. Gtk and Qt.
>
> If your plugin does not create an XWindow, don't declare it as ui:X11UI,
> if your plugin does not create a GtkWidget,
> don't declare it as ui:GtkUI, ...
>
> You're just being lucky here. Hosts expect an ui:X11UI to return an
> XWindow ID. The latter is just a plain Integer.
> Whathever you return as a widget XWindow ID (or whathever resided in
> memory at that time) may just happen to
> already exist in your Xwindow environment. Some hosts may not even check
> the retured value for validity, either.
>
> > On Sat, May 21, 2016 at 5:08 PM, Hanspeter Portner <ventosus at airpost.net
> <mailto:ventosus at airpost.net>> wrote:
> >
> >     On 21.05.2016 06:23, Stefan Riha wrote:
> >     > Hi, I'm a beginner and experimenting with lv2.
> >
> >     Great
> >
> >     > I wrote a simply synth and want a UI without Widget. On the lv2
> page it says
> >     >
> >     >  "There is no requirement that a UI actually be a graphical
> widget."
> >     >  (from: http://lv2plug.in/ns/extensions/ui/ ).
> >
> >     True, an UI can theoretically be anything.
> >
> >     Can you give some more information on what you want to accomplish?
> You may well not need an UI in the first place (but
> >     don't know yet, as you are a beginner).
> >
> >     > Below that, there is a list of subclasses of UI, but all are for
> widgets. So I thought I'd try ui:UI directly instead of
> >     > ui:GtkUI etc. But neither jalv nor Ardour recognises that there is
> a UI.
> >
> >     ui:UI is the parent class which the Widget UIs (ui:GtkUI, ui:Gtk3UI,
> ui:QtUI, ...) derive from. It is en empty shell
> >     really, hosts cannot possibly know what is inside, you have to give
> the host some more information.
> >
> >     > So I used ui:GtkUI instead. In jalv, this yields error messages of
> type Gtk-CRITICAL. Obviously it's because there is no
> >     > actual widget. In Ardour, I can see that the UI is instantiated()
> and immediately cleanedup(), probably because the Gtk
> >     > errors are handled that way.
> >
> >     If you define the UI as an ui:GtkUI, but do not return a valid
> GtkWidget to the host, sure this raises an error.
> >
> >     > How do you do this?
> >     >
> >     > I looked for hours for some example code but couldn't find one. I
> stumbled across Ingen which has some form of
> >     > web-interface (if I understood correctly) and tried to read the
> .ttl files, but don't understand them.
> >
> >     You may be looking for ui:showInterface [1] and ui:idleInterface
> [2], with those you can build arbitrary
> >     UIs.
> >
> >     Here [3] you can find a dummy plugin I use for testing various UIs
> in my humble host.
> >     <test_show.c> implements an as-simple-as-it-gets no-widget UI.
> >
> >     [1] http://lv2plug.in/ns/extensions/ui/#showInterface
> >     [2] http://lv2plug.in/ns/extensions/ui/#idleInterface
> >     [3] https://github.com/ventosus/alluis.lv2
> >
> >     > Thanks a lot for your help,
> >     > Stefan
>
>
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