显示Bitmap并让适应屏幕改变大小显示

CPaintDC dc(this);

CRect rcClient;
CDC   MemDC;
CBitmap* pOldBitmap;
BITMAP bm;

int nStretchMode;

GetClientRect(&rcClient);
bm.GetBitmap(&bm);

MemDC.CreateCompatibleDC(&dc);
pOldBitmap = MemDC.SelectObject(&m_bitmap); //m_bitmap在其它地方装入的背景位图

//设置缩放模式,防止拉伸后画面失真
nStretchMode = dc.SetStretchBltMode(HALFTONE);

//绘制到窗口
dc.StretchBlt(0, 0, rcClient.Width(), rcClient.Height(), &MemDC, 0, 0, bm.bmWidth, bm.bmHeight, SRCCOPY);

MemDC.SelectObject(pOldBitmap);
MemDC.DeleteDC();
dc.SetStretchBltMode(nStretchMode);