[LV2] Updating the controls of generic user interface

Hanspeter Portner dev at open-music-kontrollers.ch
Wed Aug 29 12:38:30 PDT 2018

On 8/29/18 9:19 PM, Florian Bihler wrote:
> Hello there!
> I'm looking for a way to update the controls (lv2:InputPort and lv2:ControlPort,
> represented by sliders, drop-down menus, ...) shown in a generic user interface,
> which is automatically created by a plugin host. Sometimes my plugin changes the
> values of certain parameters which are accessible by the generic user interface,
> but the controls are not updated to their new parameter values.

Plugins must *not* update their own input control ports, those are read-only.

That's why you don't see any change. Hosts don't check for changed input values,
as plugins are not allowed to change them :)

P.s. read-write controls are possible with lv2:Parameter [1] and the patch
extension [2], but not many hosts support them.

> The Property "ui:portNotification" seems to require a full-featured graphical
> user interface (GtkUI, Qt4UI, etc.) and does not work with a generic ui, right?
> So, is there a way to update the controls to the current parameter values they
> should represent?

Not relevant for generic UIs, as most hosts by default route all
lv2:ControlPort(lv2:OutputPort) their generic UIs

May only be relevant if you have event ports whose data you want to route to a
custom UI.

[1] http://lv2plug.in/ns/lv2core#Parameter
[2] http://lv2plug.in/ns/ext/patch

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