win32volume.cpp

来自「CD播放器源代码 .rar」· C++ 代码 · 共 143 行

#include "win32volume.h"

Win32Volume::Win32Volume()
{
	m_hMixer = NULL;
}

Win32Volume::~Win32Volume(void)
{

}

void Win32Volume::GetVolume(int &left, int &right) 
{
    MIXERCONTROLDETAILS_UNSIGNED mxcdVolume[2];
    MIXERCONTROLDETAILS mxcd;
    int                 ret;
    
    mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
    mxcd.dwControlID = m_dwVolumeControlID;
    mxcd.cChannels = 2;
    mxcd.cMultipleItems = 0;
    mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_UNSIGNED);
    mxcd.paDetails = &mxcdVolume;

    ret = mixerGetControlDetails((HMIXEROBJ)m_hMixer, &mxcd, MIXER_OBJECTF_HMIXER | MIXER_GETCONTROLDETAILSF_VALUE);

    if (ret != MMSYSERR_NOERROR)
        return;

    left = (int)(((float)((mxcdVolume[0].dwValue - m_dwMinimum) * 100) / (float)(m_dwMaximum - m_dwMinimum)) + 0.5); 
    right = (int)(((float)((mxcdVolume[1].dwValue - m_dwMinimum) * 100) / (float)(m_dwMaximum - m_dwMinimum)) + 0.5); 
}

void Win32Volume::SetVolume(int left, int right) 
{
    DWORD dwValLeft, dwValRight;
    
    dwValLeft = (left * (m_dwMaximum - m_dwMinimum) / 100);
    dwValRight = (right * (m_dwMaximum - m_dwMinimum) / 100);

    MIXERCONTROLDETAILS_UNSIGNED mxcdVolume[2];
    MIXERCONTROLDETAILS mxcd;
    
    memcpy(&mxcdVolume[0], &dwValLeft, sizeof(MIXERCONTROLDETAILS_UNSIGNED));
    memcpy(&mxcdVolume[1], &dwValRight, sizeof(MIXERCONTROLDETAILS_UNSIGNED));
    
    mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
    mxcd.dwControlID = m_dwVolumeControlID;
    mxcd.cChannels = 2;
    mxcd.cMultipleItems = 0;
    mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_UNSIGNED);
    mxcd.paDetails = &mxcdVolume;
    
    mixerSetControlDetails((HMIXEROBJ)m_hMixer, &mxcd, MIXER_OBJECTF_HMIXER | MIXER_SETCONTROLDETAILSF_VALUE);
}

bool Win32Volume::InitVolumeControl(HWND hWnd)
{
	MMRESULT mmresult = 0;
	mmresult = mixerOpen(&m_hMixer, 0, (DWORD)hWnd, NULL, MIXER_OBJECTF_MIXER | CALLBACK_WINDOW);
	if (mmresult != MMSYSERR_NOERROR)
	{
		m_hMixer = NULL;
		MessageBox(hWnd, "Unable to open Mixer Controls.", "Volume Control Error", MB_ICONERROR);
    }    

	switch (mmresult)
	{

		case MMSYSERR_NOERROR :
            break;
    
        case MMSYSERR_ALLOCATED :
            m_hMixer = NULL;
            break;

        case MMSYSERR_BADDEVICEID :
            m_hMixer = NULL;
            break;

        case MMSYSERR_INVALFLAG :
            m_hMixer = NULL;
            break;

        case MMSYSERR_INVALHANDLE :
            m_hMixer = NULL;
            break;

        case MMSYSERR_INVALPARAM :
            m_hMixer = NULL;
            break;

        case MMSYSERR_NODRIVER :
            m_hMixer = NULL;
            break;

        case MMSYSERR_NOMEM :
            m_hMixer = NULL;
            break;

        default:
            m_hMixer = NULL;
            break;

    }

    m_oDstLineName = " ";
    m_oVolumeControlName = ' ';

    if (m_hMixer == NULL)
	{
        return FALSE;
	}

    mxl.cbStruct = sizeof(MIXERLINE);
    
	mxl.dwComponentType = MIXERLINE_COMPONENTTYPE_SRC_COMPACTDISC;

    if (mixerGetLineInfo((HMIXEROBJ)m_hMixer, &mxl, MIXER_OBJECTF_HMIXER | MIXER_GETLINEINFOF_COMPONENTTYPE) != MMSYSERR_NOERROR)
	{
        return false;
	}

    mxlc.cbStruct = sizeof(MIXERLINECONTROLS);
    mxlc.dwLineID = mxl.dwLineID;
    mxlc.dwControlType = MIXERCONTROL_CONTROLTYPE_VOLUME;
    mxlc.cControls = 1;
    mxlc.cbmxctrl = sizeof(MIXERCONTROL);
    mxlc.pamxctrl = &mxc;

    if (mixerGetLineControls((HMIXEROBJ)m_hMixer, &mxlc, MIXER_OBJECTF_HMIXER | MIXER_GETLINECONTROLSF_ONEBYTYPE) != MMSYSERR_NOERROR)
        return false;

    // record dwControlID
    m_oDstLineName = mxl.szName;
    m_oVolumeControlName = *mxc.szName;
    m_dwMinimum = mxc.Bounds.dwMinimum;
    m_dwMaximum = mxc.Bounds.dwMaximum;
    m_dwVolumeControlID = mxc.dwControlID;

    return TRUE;
}