vc画出鼠标一定轨迹

首先添加鼠标的LBUTTONDOWN事件处理函数，记录鼠标按下的位置

void CTestDemoDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
 　// TODO: Add your message handler code here and/or call default
  　m_iPrevX=point.x;
  　m_iPrevY=point.y;
 　return; 
　 //CDialog::OnLButtonDown(nFlags, point);
}

接着添加鼠标的MOUSEMOVE事件处理函数，记录当前鼠标位置，并画线连接上一位置与当前位置

void CMouseDlg::OnMouseMove(UINT nFlags, CPoint point)
{
    // TODO: Add your message handler code here and/or call default
    if((nFlags & MK_LBUTTON)==MK_LBUTTON)
   {
       CClientDC dc(this);
     dc.MoveTo(m_iPrevX,m_iPrevY);
     dc.LineTo(point.x,point.y);
     m_iPrevX=point.x;
     m_iPrevY=point.y;
    //dc.SetPixel(point.x,point.y,RGB(0,0,0));
   }
   CDialog::OnMouseMove(nFlags, point);
}