QT QLineSeries replace 效率远比 append 高

                        series->clear();

                        QList<QPointF> ps;

                        for (i = 0,p1=buffer1; i < num; i++,p1++)

                         {

                             ps.push_back(QPoint((qreal) i, (*p1)*1000));//不扩大1000倍的话，原数会取整，降低精度

                         }

                         series->replace(ps);   
                       // *series << ps;// This << or append() is very slow.