一直没弄出的小问题，GDI+相关，绘制弧线

         //draw small parts

	int xCenter = m_rcArea.X + m_rcArea.Width / 2;

	int yCenter = m_rcArea.Y  + m_rcArea.Height / 2;

	int B = m_rcArea.Height / 2;

	int A = m_rcArea.Width / 2;

	PointF lastPt((REAL)A,0);

	REAL lastAngel = 0;		//上次累加的角度

	REAL angel = 0;			//本次角度

	REAL totalPer = 0;		//累加百分比

	REAL totalRadians = 0;	//累加弧度

         //m_vecUNIT只有一个值和颜色信息

	for (unsigned int i = 0 ; i < m_vecUNIT.size() ; ++i)

	{

                  //m_dTotal是整个饼图的值

		angel = m_vecUNIT[i]->dPercent * 360 / m_dTotal;

		totalPer += m_vecUNIT[i]->dPercent;

		if (totalPer >= m_dTotal)

		{

			return ;

		}  

		totalRadians = totalPer * 2 * PIE / m_dTotal ;



		path1.Reset();



		path1.AddLine((REAL)xCenter,(REAL)yCenter,(REAL)lastPt.X + (REAL)xCenter,(REAL)lastPt.Y + (REAL)yCenter);

		path1.AddArc(m_rcArea,lastAngel, angel);

		

		float endX = (REAL)A * cos(totalRadians) + (REAL)xCenter;

		float endY = (REAL)B * sin(totalRadians) + (REAL)yCenter;

		path1.AddLine((REAL)A * cos(totalRadians) + (REAL)xCenter,(REAL)B * sin(totalRadians) + (REAL)yCenter,(REAL)xCenter,(REAL)yCenter);



		

		path1.CloseAllFigures();

		g.DrawPath(&Pen(m_vecUNIT[i]->crContent),&path1);



		BYTE crR = m_vecUNIT[i]->crContent.GetR(); 

		BYTE crG = m_vecUNIT[i]->crContent.GetG();

		BYTE crB = m_vecUNIT[i]->crContent.GetB();

		

	//	g.FillPath(&LinearGradientBrush(m_rcArea,Color(128,crR,crG ,crB ),Color(255,crR ,crG ,crB ),270,LinearGradientModeBackwardDiagonal),&path1);

		

		lastPt.X = A * cos(totalRadians) ;

		lastPt.Y = B * sin(totalRadians) ;

		lastAngel = totalPer * 360 / m_dTotal;

	}