画图板---画多边形代码

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我是靠谱客的博主忐忑鲜花，最近开发中收集的这篇文章主要介绍画图板---画多边形代码，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

源代码下载

多边形也就是由一些连续的直线组成的，所以绘图的代码还是前面的画直线的那两种算法，只不过在鼠标移动的过程中要特别注意记录终点的位置而已，代码中还是存在着bug,画多边形的时候出现了黄色的阴影线，真是奇怪的问题。为了判别是否是多边形的第一条边，加入了一个新变量：bool m_bIsFirstDone;//是否第一条边

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

    CString str;
    CDC * pDC = GetDC();

     // 状态栏显示坐标值
    str.Format( " X:%d,Y:%d " ,point.x,point.y);
     if ( ! m_pwndStatusBar)
        m_pwndStatusBar = ((CMainFrame * )AfxGetMainWnd()) -> GetStatusBar();
    m_pwndStatusBar -> SetPaneText( 2 ,str, 1 );

     if (m_dsDrawSort == dsNULL)
         return ;
     switch (m_dsDrawSort)
    {
     case dsLine:
        SetCursor(m_hDLCursor);
         break ;
     case dsCircle:
        SetCursor(m_hDCCursor);
         break ;
    }

     // 鼠标放开了
     if ( ! m_bIsMoseDown)
         return ;

    pDC -> SetROP2(R2_NOTXORPEN);

     switch (m_dsDrawSort)
    {
     case dsLine:
        { // 直线
            Line * l1 = new Line(m_startPoint,m_endPoint);
            l1 -> SetDrawLineSort(m_dlsDrawLineSort);
            l1 -> SetPenColor(m_lPenColor);
            Line * l2 = new Line(m_startPoint,point);
            l2 -> SetDrawLineSort(m_dlsDrawLineSort);
            l2 -> SetPenColor(m_lPenColor);
            l1 -> Draw(pDC);
            l2 -> Draw(pDC);
             break ;
        }
     case dsCircle:
        { // 圆
            Line * l1 = new Line(m_startPoint,m_endPoint);
            l1 -> SetDrawLineSort(m_dlsDrawLineSort);
            l1 -> SetPenColor(m_lPenColor);
            Line * l2 = new Line(m_startPoint,point);
            l2 -> SetDrawLineSort(m_dlsDrawLineSort);
            l2 -> SetPenColor(m_lPenColor);
            l1 -> Draw(pDC);
            l2 -> Draw(pDC);

            Circle * c1 = new Circle(m_startPoint,Distance(m_startPoint,m_endPoint));
            c1 -> SetPenColor(m_lPenColor);
            c1 -> Draw(pDC);
            Circle * c2 = new Circle(m_startPoint,Distance(m_startPoint,point));
            c2 -> SetPenColor(m_lPenColor);
            c2 -> Draw(pDC);

             break ;
        }
     case dsPolyGon:
        { // 折线
            Line * l1 = new Line(m_startPoint,m_endPoint);
            l1 -> SetDrawLineSort(m_dlsDrawLineSort);
            l1 -> SetPenColor(m_lPenColor);
            Line * l2 = new Line(m_startPoint,point);
            l2 -> SetDrawLineSort(m_dlsDrawLineSort);
            l2 -> SetPenColor(m_lPenColor);
            l1 -> Draw(pDC);
            l2 -> Draw(pDC);
             break ;
        }

    }

    m_endPoint = point; // 记录下终点,时刻刷新最后的点
    ReleaseDC(pDC);
    CView::OnMouseMove(nFlags, point);
}

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

    m_bIsMoseDown = FALSE; // 鼠标未按下
     if (m_dsDrawSort == dsNULL)
         return ;

    CDC * pDC = GetDC();
    Line lTemp;
     switch (m_dsDrawSort)
    {
     case dsLine:
     case dsPolyGon:
        { // 画直线或折线
            Line * pL1 = new Line(m_startPoint,point);
            pL1 -> SetDrawLineSort(m_dlsDrawLineSort);
            pL1 -> SetPenColor(m_lPenColor);
            pL1 -> Draw(pDC);

            lTemp.SetStartPoint(m_startPoint); // 设置起点
            lTemp.SetEndPoint(point); // 设置终点
            lTemp.SetDrawLineSort(m_dlsDrawLineSort); // 设置画直线方式
            lTemp.SetPenColor(m_lPenColor); // 设置画笔颜色
            m_listAllLines.push_back(lTemp); // 保存此直线
             if (m_dsDrawSort == dsPolyGon)
            {
                m_startPoint = point; // 把鼠标up的那一点作为新的起点
                 if ( ! m_bIsFirstDone)
                { // 第一条边完成
                    m_bIsFirstDone = TRUE;
                }
            }
            SetCursor(m_hDLCursor);
             break ;
        }
     case dsCircle:
        { // 画圆
            Circle cTemp;
             double radius = Distance(m_startPoint,point); // 计算半径大小
            Circle * pC1 = new Circle(m_startPoint,radius);
            pC1 -> SetPenColor(m_lPenColor);
            pC1 -> Draw(pDC);

            cTemp.SetRadis(radius); // 设置半径
            cTemp.SetMidPoint(m_startPoint); // 设置圆心
            cTemp.SetPenColor(m_lPenColor); // 设置画笔颜色
            m_listAllCircles.push_back(cTemp); // 保存此圆

            pDC -> SetROP2(R2_NOTXORPEN); // Pixel is the inverse of the R2_XORPEN color (final pixel = NOT(pen XOR screen pixel)).
            Line * pL1 = new Line(m_startPoint,point);
            pL1 -> SetPenColor(m_lPenColor);
            pL1 -> Draw(pDC);
            SetCursor(m_hDCCursor);
             break ;
        }
    }
    ReleaseDC(pDC);
    CView::OnLButtonUp(nFlags, point);
}

void CMyDrawView::OnLButtonDown(UINT nFlags, CPoint point)
{
     // TODO: Add your message handler code here and/or call default
    m_bIsMoseDown = TRUE; // 鼠标按下了
     if (m_dsDrawSort == dsNULL) // 画图类型未选择
         return ;
    CDC * pDC = GetDC();
    pDC -> SetROP2(R2_NOTXORPEN);

    Line lTemp;

     if (m_dsDrawSort == dsPolyGon && m_bIsFirstDone)
    {
        Line * pL1 = new Line(m_startPoint,point);
        pL1 -> Draw(pDC);

        lTemp.SetStartPoint(m_startPoint);
        lTemp.SetEndPoint(point);
        m_listAllLines.push_back(lTemp);
    }