Last modified on Sun Oct 24 16:46:50 PDT 1993 by sfreeman

INTERFACE AudioVBT;

IMPORT Filter, Jva, OSError, Thread, VBT;
<* PRAGMA LL *>

All audio streams for a given host in an application share the same connection so the most recent setting is used if there are several AudioVBT.Ts operating on the same source. The meaning of the source string is determined by the underlying audio software.

If mute is true then the audio connection is silent but remains connected.

Unless ignoreMapping is true, the audio connection is muted whenever the T is unmapped, and unmuted when the T is mapped again.

At present, volume is a value in the range [-30..30]. Its default value is 0.

A mute push button can be implemented by wrapping a AudioVBT.T around a child of a TSplit with 2 children. By switching between the children the TSplit will map and unmap the AudioVBT.T, so turning muting on and off.

The T releases its connection to the source when it is deleted. It does not reset the state of the connection before releasing.

TYPE
  T <: Public;
  Public = Filter.T OBJECT
           METHODS
             <* LL < self *>
             init (ch           : VBT.T;
                   source       : TEXT;
                   mute                      := FALSE;
                   ignoreMapping             := FALSE;
                   volume       : Jva.Volume := 0      ): T
                   RAISES {OSError.E, Thread.Alerted};

           END;

<* LL < self *>
PROCEDURE SetMute (t: T; mute: BOOLEAN) RAISES {Thread.Alerted};
PROCEDURE SetIgnoreMapping (t: T; ignore: BOOLEAN) RAISES {Thread.Alerted};
PROCEDURE SetVolume (t: T; volume: Jva.Volume) RAISES {Thread.Alerted};

END AudioVBT.