箭头的绘制，这个做过实现，可以很好的绘制出来

//说明：功能在线条尾部（终点）画箭头．

//flSx,flSy）,（flEx,flEy)：分别为线条起点终点坐标．

//flLength：箭头一边的长度．

//flAngle：箭头两边的夹角．

//pDC：图形设备句柄

//GetDistance：得到点点之间距离的函数，其代码在最下方提供．

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if(GetDistance(flSx,flSy,flEx,flEy) == 0) return;

float tmpX = flEx + (flSx-flEx)*flLength/GetDistance(flSx,flSy,flEx,flEy);

float tmpY = flEy + (flSy-flEy)*flLength/GetDistance(flSx,flSy,flEx,flEy);

float fl1X = (tmpX-flEx)*cos(-flAngle/2) - (tmpY-flEy)*sin(-flAngle/2) + flEx;

float fl1Y = (tmpY-flEy)*cos(-flAngle/2) + (tmpX-flEx)*sin(-flAngle/2) + flEy;

float fl2X = (tmpX-flEx)*cos(flAngle/2) - (tmpY-flEy)*sin(flAngle/2) + flEx;

float fl2Y = (tmpY-flEy)*cos(flAngle/2) + (tmpX-flEx)*sin(flAngle/2) + flEy;

pDC-> MoveTo(flEx,flEy);

pDC-> LineTo(fl1X,fl1Y);

pDC-> MoveTo(flEx,flEy);

pDC-> LineTo(fl2X,fl2Y);

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辅助函数GetDistance为一个得距离的方法，代码如下

float GetDistance(float flStartx,float flStarty,float flEndx,float flEndy)

{

float flRlt;

flRlt=(flStartx-flEndx)*(flStartx-flEndx)+(flStarty-flEndy)*(flStarty-flEndy);

flRlt=sqrt(flRlt);

return flRlt;

}