int oldMapMode = pDC->SetMapMode(MM_LOMETRIC);
int oldBkMode = pDC->SetBkMode(TRANSPARENT);
CRect rcClient;
GetClientRect(&rcClient);
// pDC->DPtoLP(&rcClient);
pDC->SetViewportOrg(rcClient.left, rcClient.bottom);
CDC memDC; // Memory DC.
memDC.CreateCompatibleDC(pDC);
CBitmap memBitmap; // Create memory bitmap.
memBitmap.CreateCompatibleBitmap(&memDC, rcClient.Width(), rcClient.Height() );
memDC.SelectObject(&memBitmap); // Select the bitmap object.
// memDC.FillSolidRect(rcClient, pDC->GetBkColor());
pDC->BitBlt(0, 0, rcClient.Width(), rcClient.Height(), &memDC, 0, 0, SRCCOPY);
memDC.DeleteDC();
memBitmap.DeleteObject();
pDC->SetMapMode(oldMapMode);
pDC->SetBkMode(oldBkMode);