vc画图的一些简单方法演示，各种DC



/*HDC hdc = ::GetDC(this->GetSafeHwnd()); MoveToEx(hdc,m_BtnDown.x,m_BtnDown.y,NULL); LineTo(hdc,point.x,point.y); ::ReleaseDC(this->GetSafeHwnd(),hdc);*/ /*CDC *pDC=GetDC(); pDC->MoveTo(m_BtnDown.x,m_BtnDown.y); pDC->LineTo(point.x,point.y); ReleaseDC(pDC);*/ /*CClientDC dc(this); dc.MoveTo(m_BtnDown); dc.LineTo(point); CView::OnLButtonUp(nFlags, point);*/ /*CWindowDC dc(GetDesktopWindow()); dc.MoveTo(m_BtnDown); dc.LineTo(point);*/ CClientDC dc(this); /*获得空画刷*/ CBrush *bsh = CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH)); CBrush *oldbs = dc.SelectObject(bsh); dc.Rectangle(CRect(m_BtnDown,point)); dc.SelectObject(oldbs);