[LV2] Widget-less UI not working

Hanspeter Portner ventosus at airpost.net
Sun May 22 00:59:16 PDT 2016

On 21.05.2016 13:23, Stefan Riha wrote:
> Great thanks, I will take a look at test_show.c next week!
>>Can you give some more information on what you want to accomplish?
> I would like to make a gui in the browser. Don't know if that makes
> sense, it's just an experiment and I want to learn web-stuff like
> websockets etc. Really just a programming exercise...

In a quest of finding the more-most portable UI without any 
dependencies, I've already experimented with the very same (websocket + 
HTML + JS + JSON) for my moony plugin bundle [1], feel free to get 
inspired. It works quite well, btw.

I've plans to make the web-ui code reusable, but want to migrate things 
to JSON-LD [2] first.

[1] https://openmusickontrollers.github.io/lv2/moony/
[2] http://json-ld.org/

P.s. please reply to the whole list next time, if not, others will miss 
part of the conversation.

> 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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