透明画刷 9

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default
    //创建并获得设备描述表
    CClientDC dc(this);
    //绘制一个矩形
    dc.Rectangle(CRect(m_ptOrigin,point));

    CView::OnLButtonUp(nFlags, point);
}