【作业】简单绘图程序

1.项目名称：简单绘图程序

2.项目内容

        设计一个简单的绘图程序，能够绘制椭圆（圆）、矩形、任意线。

3.功能设计思路

        利用MFC制作这样一个绘图程序！实现绘制椭圆（圆）、矩形、任意线。需要通过菜单按钮实现，可以提高自己对于MFC基本架构的理解，提高自己的VC++编程能力！

4.编码实施

        首先建立一个利用向导生成一个MFC程序名为CTDraw；

        添加菜单绘制图形菜单——画圆ID_MENUYUAN、画矩形ID_MENUJUXING、线段ID_MENUDRAW；

        右击菜单画圆在类向导中为CCTdrawView类添加OnLButtonDown、OnLButtonUp、OnMouseMove事件，为ID_MENUYUAN添加Commond处理函数，为ID_MENUJUXING添加Commond处理函数，为ID_MENUDRAW添加Commond处理函数、添加函数ResetAllFlags()。

添加变量：

         bool m_draw;

         bool m_yuan;

         bool m_juxing;

         CPoint m_start;

         CPoint m_end;

添加代码如下：

void CCTdrawView::ResetAllFlags()
{
    m_draw = false;
    m_juxing = false;
    m_yuan = false;
}

    void CCTdrawView::OnMenudraw() 
{
    // TODO: Add your command handler code here
    ResetAllFlags();
    m_draw = true;
}
void CCTdrawView::OnMenujuxing() 
{
    // TODO: Add your command handler code here
    ResetAllFlags();
    m_juxing = true;
}
void CCTdrawView::OnMenuyuan() 
{
    // TODO: Add your command handler code here
    ResetAllFlags();
    m_yuan = true;
}
void CCTdrawView::OnUpdateMenujuxing(CCmdUI* pCmdUI) 
{
    // TODO: Add your command update UI handler code here
    pCmdUI->SetCheck(m_juxing);
}
void CCTdrawView::OnUpdateMenuyuan(CCmdUI* pCmdUI) 
{
    // TODO: Add your command update UI handler code here
    pCmdUI->SetCheck(m_yuan);
}
void CCTdrawView::OnUpdateMenudraw(CCmdUI* pCmdUI) 
{
    // TODO: Add your command update UI handler code here
    pCmdUI->SetCheck(m_draw);
}
void CCTdrawView::OnLButtonDown(UINT nFlags, CPoint point) 
{
    // TODO: Add your message handler code here and/or call default
    if(m_draw)
    {
        m_start = point;
    }
    if(m_juxing||m_yuan)
    {
        m_start = point;
        m_end = point;
        SetCapture();
    }
    CView::OnLButtonDown(nFlags, point);
}
void CCTdrawView::OnLButtonUp(UINT nFlags, CPoint point) 
{
    // TODO: Add your message handler code here and/or call default
    ReleaseCapture();
    CView::OnLButtonUp(nFlags, point);
}
void CCTdrawView::OnMouseMove(UINT nFlags, CPoint point) 
{
    // TODO: Add your message handler code here and/or call default
    CClientDC dc(this);
    if(m_draw&&(nFlags&&MK_LBUTTON))
    {
        dc.MoveTo(m_start);
        dc.LineTo(point);
        m_start = point;
    }
    if(m_juxing&&(nFlags&&MK_LBUTTON))
    {
        CGdiObject*object = dc.SelectStockObject(NULL_BRUSH);
        int mdoe = dc.GetROP2();
        dc.SetROP2(R2_NOTCOPYPEN);
        dc.Rectangle(m_end.x,m_end.y,m_start.x,m_start.y);
        dc.SetROP2(mdoe);
        dc.Rectangle(m_start.x,m_start.y,point.x,point.y);
        dc.SelectObject(object);
        m_end = point;
    }
    if(m_yuan&&(nFlags&&MK_LBUTTON))
    {
        CGdiObject*object = dc.SelectStockObject(NULL_BRUSH);
        int mdoe = dc.GetROP2();
        dc.SetROP2(R2_NOTCOPYPEN);
        dc.Ellipse(m_end.x,m_end.y,m_start.x,m_start.y);
        dc.SetROP2(mdoe);
        dc.Ellipse(m_start.x,m_start.y,point.x,point.y);
        dc.SelectObject(object);
        m_end = point;
    }
    CView::OnMouseMove(nFlags, point);
}

5.功能实现

 

6.总结

        本设计实现了简单的图形绘制，一个简单的问题就是当视图大小变化时显示的图形就会丢失！再有比如数据的序列化问题，数据的缓冲处理，当数据量很大的时候重绘必须用的缓冲机制。很高。