This command is only available with the Demos installation option. Refer to [a manual with the abbreviation INSTALL] for information on how to install optional software.
gaintool is a SunView demonstration program that controls various characteristics of the SPARCstation 1 audio device, see audio.4s Operations performed by gaintool affect all audio programs; for instance, adjusting the Play Volume instantly changes the output gain, regardless of which program is playing. gaintool also detects audio state changes made by other programs, and updates its display accordingly, keeping gaintool in sync with the current device configuration.
gaintool demonstrates an important principle involved in the integration of audio in the desktop environment: by enabling global control of important characteristics, it is not necessary for every application to provide an interface for these parameters. For instance, since audio output may be paused from the control panel, it is not strictly necessary that output applications display a Pause button of their own. However, such applications may detect that audio output has been paused, and take appropriate action.
If no process has the device open for output when Pause is clicked, gaintool holds the device open itself, thereby denying other processes output access. Audio programs that simply open and write to the audio device will typically be suspended when they attempt to open the device. Programs that asynchronously poll the device will discover that it is ``busy'' and may take appropriate action.
Pressing the PROPS (L3) key brings up a status panel that shows the current state with the its display accordingly, audio applications. Selecting ``Done'' from the panel menu (or pressing the (L7) key) removes the panel.
Ordinarily, the device status is updated only when a SIGPOLL signal is delivered to gaintool (see audio.4s Because of this, the Active and Samples indicators are not necessarily kept up-to-date. However, when the mouse is positioned over the panel, status is continually updated.
Record Volume should be controlled by a separate panel that also provides automatic gain level adjustment capabilities.
This program is furnished on an as is basis as a demonstration of audio applications programming.
Created by unroff & hp-tools. © somebody (See intro for details). All Rights Reserved. Last modified 11/5/97