WoW-Info — информационный World of Warcraft портал

uses
MMSystem;

function GetVolumeControl(aMixer: HMixer; componentType, ctrlType: Longint;
var mxc: TMixerControl): Boolean;
var
mxl: TMixerLine;
mxlc: TMixerLineControls;
rc: Longint;
begin
Result := False;
FillChar(mxl, SizeOf(TMixerLine), 0);
mxl.cbStruct := SizeOf(TMixerLine);
mxl.dwComponentType := componentType;
{Obtain a line corresponding to the component type}
rc := mixerGetLineInfo(aMixer, @mxl, MIXER_GETLINEINFOF_COMPONENTTYPE);
if rc = MMSYSERR_NOERROR then
begin
with mxlc do
begin
cbStruct := SizeOf(TMixerLineControls);
dwLineID := mxl.dwLineID;
dwControlType := ctrlType;
cControls := 1;
cbmxctrl := SizeOf(TMixerLine);
pamxctrl := @mxc;
pamxctrl^.cbStruct := SizeOf(TMixerControl);
end;
mixerGetLineControls(aMixer, @mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);
rc := mixerGetLineControls(aMixer, @mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);
Result := rc = MMSYSERR_NOERROR;
end;
end;

function SetVolumeControl(aMixer: HMixer; mxc: TMixerControl; volume: Longint): Boolean;
var
mxcd: TMixerControlDetails;
vol: TMixerControlDetails_Unsigned;
rc: MMRESULT;
begin
FillChar(mxcd, SizeOf(mxcd), 0);
with mxcd do
begin
cbStruct := SizeOf(TMixerControlDetails);
dwControlID := mxc.dwControlID;
cbDetails := SizeOf(TMixerControlDetails_Unsigned);
paDetails := @vol;
cMultipleItems := 0;
cChannels := 1;
end;
vol.dwValue := volume;
rc := mixerSetControlDetails(aMixer, @mxcd, MIXER_SETCONTROLDETAILSF_VALUE);
Result := rc = MMSYSERR_NOERROR;
end;

function InitMixer: HMixer;
var
Err: MMRESULT;
begin
Err := mixerOpen(@Result, 0, 0, 0, 0);
if Err <> MMSYSERR_NOERROR then
Result := 0;
end;

// Example:

procedure SetMasterVolumeToZero;
var
MyMixerHandle: HMixer;
MyVolCtrl: TMixerControl;
begin
MyMixerHandle := InitMixer;
if MyMixerHandle <> 0 then
try
FillChar(MyVolCtrl, SizeOf(MyVolCtrl), 0);
if GetVolumeControl(MyMixerHandle, MIXERLINE_COMPONENTTYPE_DST_SPEAKERS,
MIXERCONTROL_CONTROLTYPE_VOLUME, MyVolCtrl) then
begin
{The last parameter (0) here is the volume level}
if SetVolumeControl(MyMixerHandle, MyVolCtrl, 0) then
ShowMessage('Volume should now be set to zero');
end;
finally
mixerClose(MyMixerHandle);
end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
SetMasterVolumeToZero
end;