//最小二乘法直线拟合
BOOL CalculateLineKB(CFoldPointList *m_FoldList,double &k,double &b)
{
 //最小二乘法直线拟合
 //m_FoldList为关键点(x,y)的链表
 //拟合直线方程(Y=kX+b)

 if(m_FoldList==NULL)return FALSE;
 long lCount=m_FoldList->GetCount();
 if(lCount<2)return FALSE;
 CFoldPoint *pFold;
 double mX,mY,mXX,mXY,n;
 mX=mY=mXX=mXY=0;
 n=lCount;
 POSITION pos=m_FoldList->GetHeadPosition();
 while(pos != NULL)
 {
  pFold=m_FoldList->GetNext(pos);
  mX+=pFold->X;
  mY+=pFold->Y;
  mXX+=pFold->X*pFold->X;
  mXY+=pFold->X*pFold->Y;
 }
 if(mX*mX-mXX*n==0)return FALSE;
 k=(mY*mX-mXY*n)/(mX*mX-mXX*n);
 b=(mY-mX*k)/n;
 return TRUE;
}