Call this function to set the paper size for printing this rich edit view.
void SetPaperSize( 
   CSize sizePaper  
);
Parameters
- sizePaper
The new paper size values for printing, measured in MM_TWIPS. 
Remarks
If m_nWordWrap is WrapToTargetDevice, you should call WrapChanged after using this function to adjust printing characteristics.
Example
BOOL CMyRichEditView::OnPreparePrinting(CPrintInfo* pInfo)
{
   // Set the printing margins (720 twips = 1/2 inch).
   SetMargins(CRect(720, 720, 720, 720));
   // Change the paper orientation to landscape mode 
   // See the example for CWinApp::GetPrinterDeviceDefaults
   ((CMyWinApp*)AfxGetApp())->SetLandscapeMode();
   // Change the paper size in the CRichEditView to  
   // reflect landscape mode
   CSize csPaper = GetPaperSize();
   int temp;
   temp = csPaper.cx; csPaper.cx = csPaper.cy; csPaper.cy = temp;
   SetPaperSize(csPaper);
   return DoPreparePrinting(pInfo);
}
Requirements
Header: afxrich.h