[LV2] Widget-less UI not working

Sat Jun 4 12:48:57 PDT 2016

On 04.06.2016 04:22, Stefan Riha wrote:
> 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.

jalv (and many other hosts) just take the first supported UI.
'jalv -s' is kind of broken by that it'll take the first UI it finds no matter whether it is a ui:showInterface or not.

The first here usually means 'first in alphabetical order'.

<http://example.org/yassy#kx> thus comes before <http://example.org/yassy#ui>.
That's why I prefix UI URIs with numbers :-)

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