图标最小化问题

[procedurecode]

if (IsIconic())
{
CPaintDC dc(this); // device context for painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) /2;
int y = (rect.Height() - cyIcon + 1) /2;

// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}


int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) /2;
int y = (rect.Height() - cyIcon + 1) /2;
能否解释下以上几句，怎么得到图标最小化的坐标