新建单文档工程，命名为SetFont，添加俩个消息处理分别是WM_CREATE,WM_TIMER：在WM_CREATE的消息处理函数中，设置定时器：

SetTimer(1, 100, NULL);

void CSetFontView::OnTimer(UINT_PTR nIDEvent)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值

	m_nWidth += 5;
	CClientDC dc(this);
	TEXTMETRIC tm;
	dc.GetTextMetrics(&tm);
	CRect rect;
	rect.left = 0;
	rect.top = 200;
	rect.right = m_nWidth;
	rect.bottom = rect.top + tm.tmHeight;

	dc.SetTextColor(RGB(255, 0, 0));
	CString str;
	str = "C++技术网";
	dc.DrawText(str, rect, DT_LEFT);

	CSize sz = dc.GetTextExtent(str);
	if (m_nWidth > sz.cx)
	{
		m_nWidth = 0; 
		dc.SetTextColor(RGB(0,255,0));
		dc.TextOutW(0, 200, str);
	}
	CView::OnTimer(nIDEvent);
}

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