绘制内存位图

一个本科生问我的问题：想保存内存位图，并具有去除部分透明色。void CBitmapView::OnDraw(CDC* pDC){CBitmapDoc* pDoc = GetDocument();ASSERT_VALID(pDoc);if (!pDoc)return;CRect rect;GetClientRect(&rect);pDC ->TransparentBlt (0, 0, rect.Width(), rect.Height(), &m_dcCompatible,0, 0, rect.Width(), rect.Height(),RGB(0,0,0));}

void CBitmapView::OnReadBitmap(){CClientDC dc(this);CBrush *brush = CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));if (!m_dcCompatible.m_hDC){m_dcCompatible.CreateCompatibleDC (&dc);CRect recClient;GetClientRect(&recClient);CBitmap bmCompatible;bmCompatible.CreateCompatibleBitmap (&dc, recClient.Width(), recClient.Height());m_dcCompatible.SelectObject (&bmCompatible);m_dcCompatible.BitBlt (0, 0, recClient.Width(), recClient.Height(), &dc, 0, 0, SRCCOPY);m_dcCompatible.SelectObject(brush);m_dcCompatible.FillRect (recClient, &CBrush(RGB(0,0,0)));CPen pen(PS_SOLID, 2, RGB(255,0,0));m_dcCompatible.SelectObject(&pen);m_dcCompatible.MoveTo (100,100);m_dcCompatible.LineTo (recClient.Width(), recClient.Height());Invalidate();}}