DC使用入门

本示例在View中 ：

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point) 

{

// TODO: Add your message handler code here and/or call default

//方式1：

HDC hdc;

hdc=::GetDC(m_hWnd);

MoveToEx(hdc,m_ptOrigin.x,m_ptOrigin.y,NULL);

LineTo(hdc,point.x,point.y);

::ReleaseDC(m_hWnd,hdc);:  //释放DC

//方式2：

CDC *pDC=GetDC();

pDC->MoveTo(m_ptOrigin);

pDC->LineTo(point);

ReleaseDC(pDC);   //释放DC

//方式3：

CClientDC dc(this);

//CClientDC dc(GetParent());     //获得父窗口(Frame)DC

dc.MoveTo(m_ptOrigin);

dc.LineTo(point);      

       //方式4：

CWindowDC dc(this);

//CWindowDC dc(GetParent());   //父窗口DC

//CWindowDC dc(GetDesktopWindow());   //桌面DC

dc.MoveTo(m_ptOrigin);

dc.LineTo(point);

CPen pen(PS_DOT,1,RGB(0,255,0));  //创建画笔

CClientDC dc(this);

CPen *pOldPen=dc.SelectObject(&pen);

dc.MoveTo(m_ptOrigin);

dc.LineTo(point);

dc.SelectObject(pOldPen);

CBrush brush(RGB(255,0,0));   //创建红色画刷

CBitmap bitmap;

bitmap.LoadBitmap(IDB_BITMAP1);  

CBrush brush(&bitmap);   //创建位图画刷

CClientDC dc(this);

dc.FillRect(CRect(m_ptOrigin,point),&brush);    //画刷填充矩形区域

//创建透明画刷

CBrush *pBrush=CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));   

CBrush *pOldBrush=dc.SelectObject(pBrush);    //选入DC

dc.Rectangle(CRect(m_ptOrigin,point));

dc.SelectObject(pOldBrush);     //返回原画刷

CView::OnLButtonUp(nFlags, point);

}