从richeditctrl中按“\n”换行显示

方法一：字串超长时不会换行
CString strText=m_txt+"\n";
 int iPos = strText.Find(‘\n‘);
 int iLen=strlen(strText);
 int iAbsPos =0;
 CString str;
 while(iPos > -1){
  str = strText.Mid(0,iPos+1);
  nPosY=3*m_cyPrinter*(12+j);
  j=j+1;
  pDC->TextOut(nPosX,nPosY,str);
   }
  strText = strText.Mid(iPos + 1);  
  iPos = strText.Find(‘\n‘); 
 }

方法二：最有效的

 int nn=m_test.GetLineCount();
 int itPos;
// int j=0;
 for (int i=0;i<nn;i++)
 {
  nPosY=m_cyPrinter*(12+i);
  itPos = m_test.LineLength(i);
  m_test.GetLine(i,str.GetBuffer(itPos));
  str.ReleaseBuffer();
  pDC->TextOut(nPosX,nPosY,str);
 }

方法三：可以得到的矩形区域

FORMATRANGE fr;

// Get the page width and height from the printer.
long lPageWidth =pDC->GetDeviceCaps(PHYSICALWIDTH);// ::MulDiv(pDC->GetDeviceCaps(PHYSICALWIDTH),
1440, pDC->GetDeviceCaps(LOGPIXELSX));
 long lPageHeight =pDC->GetDeviceCaps(PHYSICALHEIGHT); //::MulDiv(pDC->GetDeviceCaps(PHYSICALHEIGHT),
1440, pDC->GetDeviceCaps(LOGPIXELSY));
CRect rcPage(nPosX ,nPosY,lPageWidth,lPageHeight);//lPageWidth, lPageHeight);
pDC->SetMapMode(MM_ANISOTROPIC);

// Format the text and render it to the printer.
fr.hdc = pDC->m_hDC;
fr.hdcTarget = pDC->m_hDC;
fr.rc = rcPage;
fr.rcPage = rcPage;
fr.chrg.cpMin = 0;
fr.chrg.cpMax = -1;
m_test.FormatRange(&fr, TRUE);
m_test.DisplayBand(&rcPage);