zhangxingjing

``` void showTracer(bool show) { m_isShowTracer = show; if(m_xTracer) m_xTracer->setVisible(m_isShowTracer); ////////////// if(m_yTracer) m_yTracer->setVisible(m_isShowTracer); ///////////// foreach (XxwTracer *tracer, m_dataTracers) { if(tracer) tracer->setVisible(m_isShowTracer); } if(m_lineTracer) m_lineTracer->setVisible(m_isShowTracer); } ```