2、创建内存DC， 将位图选进此内存DC
3、调用BitBlt将内存DC的内容拷贝到其它DC(通知是显示DC)
例子（来自MSDN)：
// This OnDraw() handler loads a bitmap from system resources, // centers it in the view, and uses BitBlt() to paint the bitmap // bits. void CBlat2View::OnDraw(CDC* pDC) { CBlat2Doc* pDoc = GetDocument(); ASSERT_VALID(pDoc); // load IDB_BITMAP1 from our resources CBitmap bmp; if (bmp.LoadBitmap(IDB_BITMAP1)) { // Get the size of the bitmap BITMAP bmpInfo; bmp.GetBitmap(&bmpInfo); // Create an in-memory DC compatible with the // display DC we're using to paint CDC dcMemory; dcMemory.CreateCompatibleDC(pDC); // Select the bitmap into the in-memory DC CBitmap* pOldBitmap = dcMemory.SelectObject(&bmp); // Find a centerpoint for the bitmap in the client area CRect rect; GetClientRect(&rect); int nX = rect.left + (rect.Width() - bmpInfo.bmWidth) / 2; int nY = rect.top + (rect.Height() - bmpInfo.bmHeight) / 2; // Copy the bits from the in-memory DC into the on- // screen DC to actually do the painting. Use the centerpoint // we computed for the target offset. pDC->BitBlt(nX, nY, bmpInfo.bmWidth, bmpInfo.bmHeight, &dcMemory, 0, 0, SRCCOPY); dcMemory.SelectObject(pOldBitmap); } else TRACE0("ERROR: Where's IDB_BITMAP1?\n"); }
