Subject: Re: [linux-audio-dev] ladspa GUI round 2
From: Werner Schweer (ws_AT_seh.de)
Date: Fri Mar 30 2001 - 13:36:30 EEST
On Friday 30 March 2001 17:48, Robert Jonsson wrote:
> Paul Davis wrote:
> >> I'm not sure what routing you images, but I would like to see:
> >>
> >> ---------- ----------
> >>
> >> | Host |--->| Plugin |
> >>
> >> ---------- ----------
> >> ^ ^
> >>
> >>
> >> ---------- |
> >>
> >> | GUI |<-------/
> >>
> >> ----------
> >>
> >> Obviously the GUI needs to be linked to the plugin in some way, but I
> >
> > why ? the GUI sends control messages to the host, and all it needs is
> > a way to identify the plugin, not to communicate with it.
if the host starts the gui the gui has no need to know anything about
the plugin. The host knows for which plugin he starts the gui and can
route the gui messages to the right plugin.
my picture is:
+------Host----------------+
+-GUI----+ | +------------+ |
| |<-------+------+--<| automation | |
| | | | | | |
| |>-------+---+----->| | |
+--------+ | | | +------------+ |
| | | |
+-Plugin-+ | +-+--+-+ |
| |<-------+-+ add | |
| | | +------+ |
+--------+ +--------------------------+
(hope the mail system does not destroy this pic)
> >
> >> I was imagining that the plugin would only invoke the gui if/when the
> >> host requested it, or mauybe the plugin should just broive the host with
> >> a method or data required to open the custom interface.
> >
> > this brings up a good point. a plugin that was running under a
> > console-only host and has a Qt plugin should probably be advised to
> > not bother starting the GUI process. how best to do that ? do we have
> > the host pro-actively initiate the GUI (allowing it to choose not to
> > do so),
or do we have the host tell the plugin that the run-time
> > environment is <console|xwindows|something-else> ?
> >
> > --p
>
> In my opinion the plugin should not be bothered with any information
> wheter it has a GUI or not. This decision is entirely up to the host.
> Since the GUI will pass information too an fro the plugin through
> standard LADSPA-ports. It is really no difference to the plugin wheter
> it is sending this information to the GUI or if it is a generated
> presentation which the host has constructed.
agreed
>
> If the plugin HAS to know if there is a GUI attached it should be quite
> possible to send a specific value to one of the controlports. If the
> plugin receives this value on this port it knows it's own GUI is available.
> This brings me to a related matter, can you send values to ports which
> hasn't been exported by LADSPA? I was thinking the GUI could send
> controldata on a "hidden" controlport. Which is not exported by the
> plugin but available internally. But I guess it will be a simple NULL
> pointer call....
>
> /Robert
Werner
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