graphics.MeasureString(wName, wName.GetLength(), &font1, PointF(nLINE_LEFT+45, nTop+10), &rtGdiplus);

 

带StringFormat(不带的话测出的值比实际的大)：

RectF rectf;

StringFormat sf;

g.MeasureString(nick.c_str(), nick,size(), &font, ptF2,sf.GenericTypographic(), &rectf);