MFC绘制直角坐标系

void CMyPicoTestDlg::DrawWave(CDC *pDC,CRect &rectPicture)
{

    CPen newPen;                  //用于创建新画笔
    CPen *pOldPen;                  //用于存放旧画笔
    CBrush newBrush;              //用于创建新画笔
    CBrush *pOldBrush;            //用于存放旧画笔        
        newBrush.CreateSolidBrush(RGB(0,0,0));    //新建黑色画刷
    pOldBrush=pDC->SelectObject(&newBrush); //选择新画刷并将旧画刷的指针保存在pOldBrush
    pDC->Rectangle(rectPicture); //黑色画刷为绘图控件，形成黑色背景
    pDC->SelectObject(pOldBrush);//恢复旧画刷
    newBrush.DeleteObject(); //删除新画刷

    newPen.CreatePen(PS_SOLID,1,RGB(0,255,0));  //创建实心画笔，粗度为1，颜色为绿色
    pOldPen=pDC->SelectObject(&newPen);//选择新画笔，并将旧画笔的指针保存在pOldPen
/************************************************************************/
/* 坐标轴                                                               */
/************************************************************************/
//x轴
    pDC->MoveTo(0,rectPicture.Height()/2);
    pDC->LineTo(rectPicture.Width(),rectPicture.Height()/2);
//y轴
    pDC->MoveTo(rectPicture.Width()/2,0);
    pDC->LineTo(rectPicture.Width()/2,rectPicture.Height());
//x轴刻度
    
    for (int32_t i=rectPicture.Width()/2-10;i>0;i-=10)
    {
        pDC->MoveTo(i,rectPicture.Height()/2);
        pDC->LineTo(i,rectPicture.Height()/2-5);
    }
    for (int32_t i=rectPicture.Width()/2+10;i<rectPicture.Width()+1;i+=10)
    {
        pDC->MoveTo(i,rectPicture.Height()/2);
        pDC->LineTo(i,rectPicture.Height()/2-5);

    }
//y轴刻度
    for (int32_t i=rectPicture.Height()/2-10;i>0;i-=10)
    {
        pDC->MoveTo(rectPicture.Width()/2,i);
        pDC->LineTo(rectPicture.Width()/2+5,i);
    }
    for (int32_t     
         i=rectPicture.Height()/2+10;i<rectPicture.Height();i+=10)
    {
        pDC->MoveTo(rectPicture.Width()/2,i);
        pDC->LineTo(rectPicture.Width()/2+5,i);
    }
    pDC->SelectObject(pOldPen);//恢复旧画笔
    newPen.DeleteObject();//删除新画笔
 }

调用

void CMyPicoTestDlg::OnBnClickedButton2()
{
    // TODO: 在此添加控件通知处理程序代码
    
    CRect rectPicture;   
    m_picDraw.GetClientRect(&rectPicture);   
       //绘制坐标系
    DrawWave(m_picDraw.GetDC(), rectPicture);

}