C / C++ / MFC

CSize GetMaxCharSize(CDC* pcDC, CFont* pcFont)
{
  CSize csizeResult(0, 0);
  if (pcDC && pcFont) {
    CGdiObject* pcOldFont = pcDC->SelectObject(pcFont);
    TEXTMETRIC tm = {0};
    pDC->GetTextMetrics(&tm);
    csizeResult.cx = tm.tmMaxCharWidth;
    csizeResult.cy = tm.tmHeight;
    pcDC->SelectObject(pcOldFont);
  }
  return csizeResult;
}

/*virtual*/ void CYourView::OnInitialUpdate()
{
  CBaseOfYourView::OnInitialUpdate();

  /*CFont*/ m_cFont.CreatePointFont(120, _T("Arial")); // 12pts * 10
...
}

/*virtual*/ void CYourView::OnDraw(CDC* pDC)
{
  CSize cMaxCharSize(GetMaxCharSize(pDC, &m_cFont));
  CRect cMaxCharRect(CPoint(100, 100), cMaxCharSize);
  pDC->FillSolidRect(cMaxCharRect, RGB(0, 128, 200));
...
}

/*virtual*/ BOOL CLeft(Right)View::PreTranslateMessage(MSG* pMsg) 
{
  if (WM_KEYDOWN == pMsg->message) {
    if (VK_TAB == pMsg->wParam) {
      CWnd* pcWnd = YourFunctionToGetRight(Left)View();
      if (pcWnd) {
        pcWnd->SetFocus(); // :)
      }
      return TRUE;
    }
  }
  return CBaseOfLeft(Right)View::PreTranslateMessage(MSG* pMsg);
}