多媒体编程

开发平台：
Visual C++

meastool.cpp：源码内容
							//-----------------------------------------------------------------------------
// 文件名: meastool.cpp
//
// 描  述: 实现一个继承自IDirectMusicTool，用以更新一个UI正方形，使其在调节时闪烁红光，
//         在敲击时闪烁绿光。
//-----------------------------------------------------------------------------
#include <dmusici.h>
#include "MeasTool.h"
#include "resource.h"
CMeasureTool* g_pMusicTool = NULL;
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::CMeasureTool()
// 描  述:  
//-----------------------------------------------------------------------------
CMeasureTool::CMeasureTool(HWND hwndParent)
{
    m_cRef = 1;             // // 设置为1，可调用Release()释放
    m_hwndParent = hwndParent;
    g_pMusicTool = this;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::~CMeasureTool()
// 描  述:  
//-----------------------------------------------------------------------------
CMeasureTool::~CMeasureTool()
{
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::QueryInterface()
// 描  述:  
//-----------------------------------------------------------------------------
STDMETHODIMP CMeasureTool::QueryInterface(const IID &iid, void **ppv)
{
    if (iid == IID_IUnknown || iid == IID_IDirectMusicTool)
    {
        *ppv = static_cast<IDirectMusicTool*>(this);
    } 
    else
    {
        *ppv = NULL;
        return E_NOINTERFACE;
    }
    
    reinterpret_cast<IUnknown*>(this)->AddRef();
    return S_OK;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::AddRef()
// 描  述:  
//-----------------------------------------------------------------------------
STDMETHODIMP_(ULONG) CMeasureTool::AddRef()
{
    return InterlockedIncrement(&m_cRef);
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::Release()
// 描  述:  
//-----------------------------------------------------------------------------
STDMETHODIMP_(ULONG) CMeasureTool::Release()
{
    if( 0 == InterlockedDecrement(&m_cRef) )
    {
        delete this;
        return 0;
    }
    return m_cRef;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::Init()
// 描  述:  
//-----------------------------------------------------------------------------
HRESULT STDMETHODCALLTYPE CMeasureTool::Init( IDirectMusicGraph* pGraph )
{
    // 本工具不需要任何初始化
    return E_NOTIMPL;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::GetMsgDeliveryType()
// 描  述:  
//-----------------------------------------------------------------------------
HRESULT STDMETHODCALLTYPE CMeasureTool::GetMsgDeliveryType( DWORD* pdwDeliveryType )
{
    // 本工具需要消息在消息被处理的时刻。 
    // 如此以便"敲击指示器"在敲击时闪烁而不是之前
    *pdwDeliveryType = DMUS_PMSGF_TOOL_ATTIME;
    return S_OK;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::GetMediaTypeArraySize()
// 描  述:  
//-----------------------------------------------------------------------------
HRESULT STDMETHODCALLTYPE CMeasureTool::GetMediaTypeArraySize( DWORD* pdwNumElements )
{
    // 这个工具只需要note、patch、sysex和MIDI四种消息, 
    // 所以*pdwNumElements为4.
    
    *pdwNumElements = 1;
    return S_OK;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::GetMediaTypes()
// 描  述:  
//-----------------------------------------------------------------------------
HRESULT STDMETHODCALLTYPE CMeasureTool::GetMediaTypes( DWORD** padwMediaTypes, 
                                                    DWORD dwNumElements )
{
	// 用本工具想要处理的消息的类型来填充padwMediaTypes数组。
    // 本例中dwNumElements将为3, 因为该数据是从GetMediaTypeArraySize()返回的。 
    
    if( dwNumElements == 1 )
    {
        // 设置数组的元素为DMUS_PMSGT_NOTE,
        // DMUS_PMSGT_MIDI, and DMUS_PMSGT_PATCH
        (*padwMediaTypes)[0] = DMUS_PMSGT_NOTIFICATION;
        return S_OK;
    }
    else
    {
        // 这应该不会发生
        return E_FAIL;
    }
}
// ------------------------------------------------------------------------------
#define DUMPGUID(g)     if (pNotiMsg->guidNotificationType == (g))  OutputDebugString(#g "n")
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::ProcessPMsg()
// 描  述:  
//-----------------------------------------------------------------------------
HRESULT STDMETHODCALLTYPE 
CMeasureTool::ProcessPMsg
( 
    IDirectMusicPerformance* pPerf, 
    DMUS_PMSG*               pPMsg 
)
{
    DMUS_NOTIFICATION_PMSG*  pNotiMsg = (DMUS_NOTIFICATION_PMSG*)pPMsg;
 // 返回S_FREE释放消息. 如果StampPMsg()失败，没有此消息的目的地，因此释放它
    if(( NULL == pPMsg->pGraph ) ||
        FAILED(pPMsg->pGraph->StampPMsg(pPMsg)))
    {
        return DMUS_S_FREE;
    }
    // 本工具被设置只接受DMUS_PMSGT_NOTIFICATION类型的消息
    if (pNotiMsg->guidNotificationType == GUID_NOTIFICATION_MEASUREANDBEAT)
    {
        if (pNotiMsg->dwField1 == 0)
            Blink(eMeasure);
        else
            Blink(eBeat);
    }    
    //返回DMUS_S_REQUEUE，因此原始消息被重新排列 
    return DMUS_S_REQUEUE;
}
//-----------------------------------------------------------------------------
// 函数名: CMeasureTool::Flush()
// 描  述:  
//-----------------------------------------------------------------------------
HRESULT STDMETHODCALLTYPE CMeasureTool::Flush( IDirectMusicPerformance* pPerf, 
                                            DMUS_PMSG* pDMUS_PMSG,
                                            REFERENCE_TIME rt)
{
    // 不需要流
    return E_NOTIMPL;
}
// ------------------------------------------------------------------------------
// 函数名: CMeasureTool::Blink()
// 描  述:  
// ------------------------------------------------------------------------------
void CMeasureTool::Blink(EBeatType eType)
{
    HWND hwndBox = GetDlgItem(m_hwndParent, IDC_BLINKY);
    if (hwndBox)
    {
        HDC         hdcBox = GetDC(hwndBox);
        RECT        rcBox;
        HBRUSH      hbrColored, hbrOld;
        COLORREF    color = RGB(0, 0, 0); 
        UINT        nTimerId = 0;  // 使用'this'作为一个LUID
        
        switch (eType)
        {
            case eOff:
                KillTimer(m_hwndParent, nTimerId);    
                color = GetSysColor(COLOR_3DFACE);
                break;
            case eMeasure:
                SetTimer(m_hwndParent, nTimerId, 100, Unblink);
                color = RGB(255, 0, 0); // 在调节时闪烁红光
                break;
            case eBeat:
                SetTimer(m_hwndParent, nTimerId, 100, Unblink);
                color = RGB(0, 255, 0); // 在敲击时闪烁绿光
        }
        
        hbrColored = (HBRUSH)CreateSolidBrush(color);
        hbrOld = (HBRUSH)SelectObject(hdcBox, hbrColored);
        GetClientRect(hwndBox, &rcBox);
        Rectangle(hdcBox, rcBox.left, rcBox.top, rcBox.right, rcBox.bottom);
        SelectObject(hdcBox, hbrOld);
        DeleteObject(hbrColored);
        ReleaseDC(hwndBox, hdcBox);
    }
}
// ------------------------------------------------------------------------------
// ------------------------------------------------------------------------------
void CALLBACK Unblink
(
    HWND        hwnd,
    UINT        uMsg,
    UINT_PTR    idEvent,
    DWORD       dwTime
)
{
    if( g_pMusicTool )
        g_pMusicTool->Blink(eOff);
}
 

						