[LV2] Widget-less UI not working

Stefan Riha hoitaus at gmail.com
Fri Jun 3 19:22:23 PDT 2016 

I should have added that the ui:UI with the additions you suggested works
well with jalv -s, but only if I remove the kx:Window option from the *ttl,
so that jalv doesn't see it at all.


On Sat, Jun 4, 2016 at 12:16 PM, Stefan Riha <hoitaus at gmail.com> wrote:

> Yes, that helped, it works much better now. I tried your "customui.lv2"
> and it works flawlessly.
>
> I structured the *ttl's of my project like yours, and using kx in Ardour
> works. But I still get an error with jalv (with -s). It always wants to use
> the kx:Widget, even though kx is listed as a required feature. Maybe a
> typo, I'll figure it out next week.
>
> The ttl's I use are:
>
> https://github.com/poidl/yassy/blob/master/yassy.lv2/manifest.ttl
> https://github.com/poidl/yassy/blob/master/yassy.lv2/yassy.ttl
> https://github.com/poidl/yassyui/blob/master/yassyui.lv2/yassyui.ttl
>
> I used to have the ui in a separate bundle (that's why the projects are
> different), but I install the
>
> libyassy.so
> libyassyui.so
> manifest.ttl
> yassy.ttl
> yassyui.ttl
>
> files now all to the same .lv2/yassy.lv2 have the exact same *ttl
> structure as customui.lv2.
>
> On Sat, May 28, 2016 at 7:26 PM, Stefan Riha <hoitaus at gmail.com> wrote:
>
>> 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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