C++JPG画像表示

       ::CoInitialize(NULL);  // COM    
	HRESULT hr;
	CFile file;

	file.Open( "c:\\aa.jpg", CFile::modeRead | CFile::shareDenyNone );  //       
	DWORD dwSize = file.GetLength();
	HGLOBAL hMem = ::GlobalAlloc( GMEM_MOVEABLE, dwSize );
	LPVOID lpBuf = ::GlobalLock( hMem );
	file.Read( lpBuf, dwSize );
	file.Close();
	::GlobalUnlock( hMem );

	IStream * pStream = NULL;
	IPicture * pPicture = NULL;

	//   HGLOBAL    IStream，   TRUE      IStream    ，    
	hr = ::CreateStreamOnHGlobal( hMem, TRUE, &pStream );
	ASSERT ( SUCCEEDED(hr) );

	hr = ::OleLoadPicture( pStream, dwSize, TRUE, IID_IPicture, ( LPVOID * )&pPicture );
	ASSERT(hr==S_OK);

	long nWidth,nHeight;  //   ，MM_HIMETRIC   ，   0.01  
	pPicture->get_Width( &nWidth );    //  
	pPicture->get_Height( &nHeight );  //  

	    //
	//CSize sz( nWidth, nHeight );
	//pDC->HIMETRICtoDP( &sz );  //    MM_HIMETRIC       MM_TEXT     
	//pPicture->Render(pDC->m_hDC,0,0,sz.cx,sz.cy,
	//	0,nHeight,nWidth,-nHeight,NULL);

	       
	CRect rect;	GetClientRect(&rect);
	pPicture->Render(pDC->m_hDC,0,0,rect.Width(),rect.Height(),
		0,nHeight,nWidth,-nHeight,NULL);

	if ( pPicture ) pPicture->Release();//    IPicture   
	if ( pStream ) pStream->Release();  //    IStream   ，      hMem

	::CoUninitialize();