C++/(MFC)Save Bitmap To Direct File CDC를 Bitmap으로 저장

void SomeClassDoc::SaveBitmapToDirectFile(CDC* pDC, CRect BitmapSize, int BitCount, CString strFilePath)
{
	CBitmap bmp, *pOldBmp;
    CDC dcMem;  
    BITMAP                  bm;
    BITMAPINFOHEADER        bi;
    LPBITMAPINFOHEADER      lpbi;
    DWORD                   dwLen;
    HANDLE                  handle;
    HANDLE                  hDIB;   
    HPALETTE                hPal=NULL;

/*----- CDC의 내용을 Bitmap으로 전송 ----*/
    dcMem.CreateCompatibleDC(pDC);
    bmp.CreateCompatibleBitmap(pDC ,BitmapSize.Width(),BitmapSize.Height());    
    pOldBmp = (CBitmap*) dcMem.SelectObject(&bmp);
    dcMem.BitBlt( 0,0, BitmapSize.Width(), BitmapSize.Height(), pDC, 0,0, SRCCOPY); 
    dcMem.SelectObject(pOldBmp);

if (strFilePath == "")          return;
    /*------------------------- 비트멥 헤더를 기록함 -------------------------*/
    if (hPal==NULL)
    hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);
    GetObject(HBITMAP(bmp), sizeof(BITMAP), &bm);

bi.biSize               = sizeof(BITMAPINFOHEADER);
    bi.biWidth              = bm.bmWidth;
    bi.biHeight             = bm.bmHeight;
    bi.biPlanes             = 1;
    bi.biBitCount           = 32;       
    bi.biCompression        = BI_RGB;
    bi.biSizeImage          = bm.bmWidth * bm.bmHeight * 3;
    bi.biXPelsPerMeter      = 0;
    bi.biYPelsPerMeter      = 0;
    bi.biClrUsed            = 0;
    bi.biClrImportant       = 0;

int nColors = (1 << bi.biBitCount);
    if( nColors > 256 ) 
        nColors = 0;
    dwLen  = bi.biSize + nColors * sizeof(RGBQUAD);
    hPal = SelectPalette(pDC->GetSafeHdc(),hPal,FALSE);
    RealizePalette(pDC->GetSafeHdc());
    hDIB = GlobalAlloc(GMEM_FIXED,dwLen);
    lpbi = (LPBITMAPINFOHEADER)hDIB;
    *lpbi = bi;
    GetDIBits(pDC->GetSafeHdc(), 
          HBITMAP(bmp), 
          0, 
          (DWORD)bi.biHeight,
          (LPBYTE)NULL, 
          (LPBITMAPINFO)lpbi, 
          (DWORD)DIB_RGB_COLORS);
    bi = *lpbi;
    if (bi.biSizeImage == 0)
    {
        bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8) 
                                        * bi.biHeight;
    }
    dwLen += bi.biSizeImage;
    if (handle = GlobalReAlloc(hDIB, dwLen, GMEM_MOVEABLE))
        hDIB = handle;

lpbi = (LPBITMAPINFOHEADER)hDIB;
    GetDIBits(pDC->GetSafeHdc(), 
             HBITMAP(bmp),
             0,                    
             (DWORD)bi.biHeight,      
             (LPBYTE)lpbi        
             + (bi.biSize + nColors * sizeof(RGBQUAD)),
             (LPBITMAPINFO)lpbi,   
             (DWORD)DIB_RGB_COLORS);

BITMAPFILEHEADER      hdr;
    hdr.bfType        = ((WORD) ('M' << 8) | 'B');        
    hdr.bfSize        = GlobalSize (hDIB) + sizeof(hdr);   
    hdr.bfReserved1   = 0;                                 
    hdr.bfReserved2   = 0;                                 
    hdr.bfOffBits=(DWORD)(sizeof(hdr)+lpbi->biSize + nColors * sizeof(RGBQUAD));
    char* pBmpBuf; 
    DWORD FileSize; 
    FileSize=sizeof(hdr)+GlobalSize(hDIB);
    pBmpBuf = new char[FileSize];
    memcpy(pBmpBuf,&hdr,sizeof(hdr));
    memcpy(pBmpBuf+sizeof(hdr),lpbi,GlobalSize(hDIB));
    /*--------------------- 실제 파일에 기록함 --------------------------*/
    CFile file;
    file.Open(strFilePath, CFile::modeCreate | CFile::modeNoTruncate | CFile::modeWrite);
    file.Write(pBmpBuf,FileSize);
    file.Close();
    /*------------------------ 임시로 할당한 메모리를 해제.. -------------*/
    delete[] pBmpBuf;

if(hDIB) 
    {       
        GlobalFree(hDIB);
    }
    SelectPalette(pDC->GetSafeHdc(),hPal,FALSE);  
}