画线总结 11

1.绘制线条的起点： 鼠标左键按下

void CDrawView::OnLButtonDown(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default

    m_ptOrigin = point;//线条的起点
    CView::OnLButtonDown(nFlags, point);
}

2.利用SDK全局函数实现画线功能

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default

    //首先获得窗口的设备描述表
    HDC hdc;
    hdc = ::GetDC(m_hWnd);
    //移动到线条的起点
    MoveToEx(hdc,m_ptOrigin.x,m_ptOrigin.y,NULL);
    //画线
    LineTo(hdc,point.x,point.y);
    //释放设备描述符
    ::ReleaseDC(m_hWnd,hdc);
    CView::OnLButtonUp(nFlags, point);
}

3. 利用MFCD的CDC类实现画线功能

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default

    CDC * pDC = GetDC();
    pDC->MoveTo(m_ptOrigin);
    pDC->LineTo(point);
    ReleaseDC(pDC);

    CView::OnLButtonUp(nFlags, point);
}

4.利用MFC的CClientDC类实现画线功能

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default

    CClientDC dc(this);
    dc.MoveTo(m_ptOrigin);
    dc.LineTo(point);

    CView::OnLButtonUp(nFlags, point);
}

5.画彩色线条

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default

    CPen pen(PS_SOLID,10,RGB(255,0,0));
    CClientDC dc(this);
    CPen *pOldPen = dc.SelectObject(&pen);

    dc.MoveTo(m_ptOrigin);
    dc.LineTo(point);
    dc.SelectObject(pOldPen);

    CView::OnLButtonUp(nFlags, point);
}

6.使用画刷绘图

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default
    //创建一个红色画刷
    CBrush brush(RGB(255,0,0));
    //创建并获得设备描述表
    CClientDC dc(this);
    //利用红色画刷填充鼠标拖拽过程中形成的矩形区域
    dc.FillRect(CRect(m_ptOrigin,point),&brush);
    CView::OnLButtonUp(nFlags, point);
}

7.绘制连续线条

void CDrawView::OnLButtonUp(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default
    m_bDraw = FALSE;
    CView::OnLButtonUp(nFlags, point);
}

void CDrawView::OnLButtonDown(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default

    m_ptOrigin = point;//线条的起点
    m_bDraw = TRUE; //判断  左键按下标志，在mouse move 消息函数中使用 标志
    CView::OnLButtonDown(nFlags, point);
}

void CDrawView::OnMouseMove(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default
/*
    CClientDC dc(this);
    if(m_bDraw == TRUE)
    {
        dc.MoveTo(m_ptOrigin);
        dc.LineTo(point);
        //修改线段的起点
        m_ptOrigin =  point;
    }
    CView::OnMouseMove(nFlags, point);

*/
    CClientDC dc(this);
    //创建一个红色的、宽度为1的实现画笔
    CPen pen(PS_SOLID,1,RGB(255,0,0));
    //把创建的画笔选入设备描述表
    CPen *pOldPen = dc.SelectObject(&pen);
    if(m_bDraw == TRUE)
    {
        dc.MoveTo(m_ptOrigin);
        dc.LineTo(point);
        //修改线段的起点
        m_ptOrigin =  point;
    }
    //恢复设备描述表
    dc.SelectObject(pOldPen);

    CView::OnMouseMove(nFlags, point);
}