Subject: Re: [linux-audio-dev] ladspa plugin GUI proposal
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: Wed May 24 2000 - 22:48:03 EEST
> an oscilloscope example: I would like to be able to take the
>oscilloscope plugin and connect it to the rest of the system, or
>possibly take oscilloscope-audio and oscilloscope-gui plugins... I don't
>say that audio and gui has to be meshed together, but both audio and
>gui should be 'plug-able', otherwise the oscilloscope is useless, if I
>have to code the gui for it...
I had trouble with the Oscilloscope for Quasimodo when I was trying to
completely sever the backend from the GUI, for reasons related to
this.
My solution was to effectively add a new "type" called a "sink". This
is effectively a "pipe" or FIFO between the audio thread and the GUI
thread, with a name-based lookup. Every time Quasimodo "runs" the
oscilloscope, it writes the data on its audio port to the sink. The
GUI side of things picks data up from the sink, using the name of the
sink to find it, consolidates it into big chunks corresponding to a
sensible screen refresh rate (I do it 10-100 times a second, I think),
and when the appropriate amount of data has accumulated, it (re)draws
the display.
The other part of this is that Quasimodo's XML module DTD includes an
"oscilloscope widget".
--p
This archive was generated by hypermail 2b28 : Thu May 25 2000 - 03:16:53 EEST