示例程式碼如下

	if (m_hBrushBackground)
	{
		HDC back;
		CRect rcx = rcc;
		back = ::CreateCompatibleDC(dc);
		HBITMAP bmpx;
		bmpx = ::CreateCompatibleBitmap(dc, rcx.Width(), rcx.Height());
		HBITMAP ob = (HBITMAP)::SelectObject(back, bmpx);
		POINT pt2;
		::SetBrushOrgEx(back, m_ptBackBrushOrig.x, m_ptBackBrushOrig.y, &pt2); 
		::FillRect(back, &rcc, m_hBrushBackground);

		BLENDFUNCTION bf;
		bf.BlendOp = AC_SRC_OVER;
		bf.BlendFlags = 0;
		bf.SourceConstantAlpha = 80;
		bf.AlphaFormat = 0;

		GdiAlphaBlend(memDC, 0, 0, rcx.Width(), rcx.Height(), 
			back, 0,  0, rcx.Width(), rcx.Height(), bf);
		::SelectObject(back, ob);
		::DeleteObject(bmpx);
		::DeleteDC(back);
	}