把MFC程序保存为图片 vc ++

void CCBilinearView::OnFileSave()
{
CDC* pDC = GetWindowDC();
CBitmap bitmap;
CDC memDC ;
CRect rect;
GetClientRect(rect);
memDC.CreateCompatibleDC(pDC);

bitmap.CreateCompatibleBitmap(pDC,rect.Width(),rect.Height());
memDC.SelectObject(&bitmap);
memDC.BitBlt(0,0,rect.Width(),rect.Height(),pDC,0,0,SRCCOPY);

CFileDialog fDlg(FALSE,_T("bmp"),NULL,OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,_T("位图文件|*.bmp"),this);
if (fDlg.DoModal()==IDOK)
{

CString bmpfile = fDlg.GetPathName();

CFile file(bmpfile,CFile::modeCreate|CFile::modeWrite);

BITMAP bInfo;
bitmap.GetBitmap(&bInfo);

//计算调色板大小
int panelsize = 0;
if (bInfo.bmBitsPixel<24) //非真彩色
{
panelsize = pow((double)2,bInfo.bmBitsPixel)*sizeof(RGBQUAD);
}

//定义位图信息
BITMAPINFO*  bMapInfo = (BITMAPINFO*)LocalAlloc(LPTR,sizeof(BITMAPINFO)+panelsize);
bMapInfo->bmiHeader.biBitCount = bInfo.bmBitsPixel;
bMapInfo->bmiHeader.biClrImportant = 0;
bMapInfo->bmiHeader.biCompression = 0;
bMapInfo->bmiHeader.biHeight = bInfo.bmHeight;
bMapInfo->bmiHeader.biPlanes = bInfo.bmPlanes;
bMapInfo->bmiHeader.biSize = sizeof(BITMAPINFO);
bMapInfo->bmiHeader.biSizeImage = bInfo.bmHeight*bInfo.bmWidthBytes;
bMapInfo->bmiHeader.biWidth = bInfo.bmWidth;
bMapInfo->bmiHeader.biXPelsPerMeter = 0;
bMapInfo->bmiHeader.biYPelsPerMeter = 0;

//获取位图的实际数据
char* pData = new char[bMapInfo->bmiHeader.biSizeImage];
int len = GetDIBits(pDC->m_hDC,bitmap,0,bInfo.bmHeight,pData,bMapInfo,DIB_RGB_COLORS);

BITMAPFILEHEADER bFileHeader;
bFileHeader.bfType = 0x4D42;
bFileHeader.bfReserved1 = 0;
bFileHeader.bfReserved2 = 0;
bFileHeader.bfSize = sizeof(BITMAPFILEHEADER);
bFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+panelsize;

//向文件中写入位图数据
file.Write(&bFileHeader,sizeof(BITMAPFILEHEADER));
file.Write(&bMapInfo->bmiHeader,sizeof(BITMAPINFOHEADER));
file.Write(pData,bMapInfo->bmiHeader.biSizeImage+panelsize);
file.Close();
delete pData;
LocalFree(bMapInfo);
}
bitmap.DeleteObject();
memDC.DeleteDC();
}