/**********************************************************************************
Function Name = LeapDesktopAppFull::volumeManipulation
Descriptive Name = Increase/decrease/mute/unmute the volume
Function =
This functions is responsible for performing the actions of increasing/
decreasing/muting/unmuting the volume. Makes use of the available functions on
windows to construct and initialize the interface of audio devices for communication.
Dependencies =
None
Restrictions =
Must have audio devices connected, running and capable of being accessed through the
IMMDeviceEnumerator interface.
Input =
string controlOption - The volume action to be performed, supports the following options:
VOLUME_STEP_UP - This option will increase the volume by 1
VOLUME_STEP_DOWN - This option will decrease the volume by 1
VOLUME_MUTE_UNMUTE - This option will mute or unmute based on
what the state of the volume currently is.
Output =
Currently there are no outputs from this functions as it only performs the action.
Future TODO is to make sure errors are handled and appropriate response is returned.
Normal Return =
N/A
Error Return =
N/A
******************************************************************************/
void LeapDesktopAppFull::volumeManipulation ( string controlOption )
{
// Variable Declaration
HRESULT volumeManipulationResults = NULL ; // Stores detailed information for the volume communication interface
IMMDeviceEnumerator *deviceEnumerator = NULL ; // Stores the interface pointer of enumerating audio devices
IMMDevice *defaultDevice = NULL ; // Stores all the default audio devices resources
IAudioEndpointVolume *endpointVolume = NULL ; // Stores the volume controls on the audio streams
BOOL pbMute = FALSE ; //
// Initialize the COM library on the current thread
CoInitialize ( NULL ) ;
// Create an instance of a single uninitialized object of audio devices, a success instance creation will return "S_OK"
volumeManipulationResults = CoCreateInstance ( __uuidof( MMDeviceEnumerator ), // The CLSID associated with the data and code that is used to create the object
NULL, // Set to NULL to identify that object is not being created as an aggregate
CLSCTX_INPROC_SERVER, // Identifies how the new object will run, in this case it is a DLL that runs in the same process
__uuidof( IMMDeviceEnumerator ), // The identifier of the interface that will be used to communicate with the object
( LPVOID * ) &deviceEnumerator // Pointer that will store the interface pointer that was requested
) ;
// Using the device enumerator interface get the default audio endpoint for the provided data-flow direction
volumeManipulationResults = deviceEnumerator->GetDefaultAudioEndpoint ( eRender, // Set to eRender to represent an audio rendering stream
eConsole, // Set to eConsole to represent the role that is assigned to the endpoint device
&defaultDevice // Pointer to which the device address is stored of the endpoint object
) ;
// No longer need the pointer for the device enumerator interface so release it to free up memory
deviceEnumerator->Release () ;
deviceEnumerator = NULL ; // Force un-initialization
// Activate the device that was retrieved above, a success activation will return "S_OK"
volumeManipulationResults = defaultDevice->Activate ( __uuidof( IAudioEndpointVolume ), // The interface identifier, in this case this is an audio endpoint device
CLSCTX_INPROC_SERVER, // Identifies how the new object will run, in this case it is a DLL that runs in the same process
NULL, // Set to NULL to activate an IAudioEndpointVolume interface on an audio endpoint device
( LPVOID * ) &endpointVolume // Pointer which stores the address of the IAudioEndpointVolume interface
) ;
// No longer need the pointer for the device interface so release it to free up memory
defaultDevice->Release () ;
defaultDevice = NULL ; // Force un-initialization
// From the endpointVolume interface get the mute status
// GetMute returns TRUE for muted and FALSE for the stream not muted
endpointVolume->GetMute ( &pbMute ) ;
// Based on the mute status perform the action of muting or unmuting the stream
if ( ( pbMute && controlOption == VOLUME_MUTE_UNMUTE ) )
{
// Found that the stream is already currently muted so un-mute the stream
volumeManipulationResults = endpointVolume->SetMute ( 0, NULL ) ;
// Display user feed back image based on the action performed
createUserFeedBackWindow ( loadResource ( RES_KEYTAP_IMAGE ), 150, 131 ) ;
}
else if ( !pbMute && controlOption == VOLUME_MUTE_UNMUTE )
{
// Found that the stream is not mute so mute the stream
volumeManipulationResults = endpointVolume->SetMute ( 1, NULL ) ;
// Display user feed back image based on the action performed
createUserFeedBackWindow ( loadResource ( RES_KEYTAPRELEASE_IMAGE ), 150, 131 ) ;
}
// Based on the volume increase/decrease option, perform the appropriate action
if ( controlOption == VOLUME_STEP_UP )
{
// Increase the volume on the stream by one, this also will update any connected system notifications
volumeManipulationResults = endpointVolume->VolumeStepUp ( NULL );
volumeManipulationResults = endpointVolume->VolumeStepUp ( NULL );
volumeManipulationResults = endpointVolume->VolumeStepUp ( NULL );
volumeManipulationResults = endpointVolume->VolumeStepUp ( NULL );
}
else if ( controlOption == VOLUME_STEP_DOWN )
{
// Decrease the volume on the stream by one, this also will update any connected system notifications
volumeManipulationResults = endpointVolume->VolumeStepDown ( NULL );
volumeManipulationResults = endpointVolume->VolumeStepDown ( NULL );
volumeManipulationResults = endpointVolume->VolumeStepDown ( NULL );
volumeManipulationResults = endpointVolume->VolumeStepDown ( NULL );
}
// No longer need the endpointVolume interface so release it to free up memory
endpointVolume->Release ();
// All the actions that are to be performed on the end point device are done so un-initialize the instance
CoUninitialize ();
}
