on.left;
m_wOrigrinHeight = lpwndpl->rcNormalPosition.bottom;
m_wOrigrinHeight -= lpwndpl->rcNormalPosition.top;

LPRECT lpRect1,lpRect2;
lpRect1=new RECT;
lpRect2=new RECT;
GetDlgItem(IDC_PROGRESS_BAR)->GetWindowRect(lpRect1);
GetDlgItem(IDC_STREAM_ID)->GetWindowRect(lpRect2);

lpwndpl->rcNormalPosition.right=(lpRect1->right+lpRect2->left)/2;
m_wReducedWidth = lpwndpl->rcNormalPosition.right;
m_wReducedWidth -= lpwndpl->rcNormalPosition.left;

GetDlgItem(IDC_PROGRESS_BAR)->GetWindowRect(lpRect1);
GetDlgItem(IDC_SEQUENCE_ORDER2)->GetWindowRect(lpRect2);
lpwndpl->rcNormalPosition.bottom=(lpRect1->bottom+lpRect2->top)/2;
m_wReducedHeight = lpwndpl->rcNormalPosition.bottom;
m_wReducedHeight -= lpwndpl->rcNormalPosition.top;

delete lpRect1;
delete lpRect2;

if(m_bHorizontal == TRUE)
{
lpwndpl->rcNormalPosition.right = lpwndpl->rcNormalPosition.left;
lpwndpl->rcNormalPosition.right += m_wOrigrinWidth;

lpwndpl->rcNormalPosition.bottom = lpwndpl->rcNormalPosition.top;
lpwndpl->rcNormalPosition.bottom += m_wReducedHeight;
}
else
{
lpwndpl->rcNormalPosition.right = lpwndpl->rcNormalPosition.left;
lpwndpl->rcNormalPosition.right += m_wReducedWidth;

lpwndpl->rcNormalPosition.bottom = lpwndpl->rcNormalPosition.top;
lpwndpl->rcNormalPosition.bottom += m_wReducedHeight;
}

if(m_bVertical == TRUE)
{
lpwndpl->rcNormalPosition.right = lpwndpl->rcNormalPosition.left;
lpwndpl->rcNormalPosition.right += m_wReducedWidth;

lpwndpl->rcNormalPosition.bottom = lpwndpl->rcNormalPosition.top;
lpwndpl->rcNormalPosition.bottom += m_wOrigrinHeight;
}
else
{

lpwndpl->rcNormalPosition.right = lpwndpl->rcNormalPosition.left;
lpwndpl->rcNormalPosition.right += m_wReducedWidth;

lpwndpl->rcNormalPosition.bottom = lpwndpl->rcNormalPosition.top;
lpwndpl->rcNormalPosition.bottom += m_wReducedHeight;
}

SetWindowPlacement(lpwndpl);

上面这段代码首先将窗口置于屏幕中间，这可以通过函数CenterWindow(GetDesktopWindow()) 来实现，函数 CenterWindow()的用法为：
void CenterWindow( CWnd* pAlternateOwner = NULL );
其中参数pAlternateOwner指向所想居中的窗口的指针。
然后利用函数GetSystemMetrics( int nIndex )得到系统当前设置如屏幕分辨率等。
nIndexs= SM_CXSCREEN 时函数返回屏幕的宽度;返回值单位为像素点。
nIndexs= SM_CYSCREEN 时函数返回屏幕的高度;返回值单位为像素点。
函数BOOL GetWindowPlacement( WINDOWPLACEMENT* lpwndpl ) 是最重要的。他的参数为一个指向结构变量WINDOWPLACEMENT的指针(lpwndpl);其中WINDOWPLACEMENT结构变量数据结构具体为：
typedef struct tagWINDOWPLACEMENT { /* wndpl */
UINT length;
UINT flags;
UINT showCmd;
POINT ptMinPosition;
POINT ptMaxPosition;
RECT rcNormalPosition;
} WINDOWPLACEMENT;
他包含了窗口在屏幕上的定位信息。其中成员变量的含义为：
length：指结构变量的长度，单位字节。
flags: 标志值，控制窗口最小化或窗口还原的方法，可以取如下值：
WPF_SETMINPOSITION：指定窗口最小化时的x位置和y位置。
WPF_RESTORETOMAXIMIZED：指定窗口以最大化方式还原，尽管可能窗口并不是在最大化时最小化的。不改变