滑动条在qt时间轴上

基于qwt-6.1实现的时间轴滑动条，主要是slider参数设置技巧，设定起始结束日期，自动绘制时间轴，qwt请自行下载编译，qt我用的版本是5.7.1，vs2013。主要代码如下： QDateTime starData = QDateTime::fromString(dataS, "yyyy-MM-dd"); QDateTime endData = QDateTime::fromString(dataE, "yyyy-MM-dd"); int dayCount = starData.daysTo(endData); _qwtSlider->setScale( QwtDate::toDouble(starData), QwtDate::toDouble(endData) ); _qwtSlider->setTotalSteps(dayCount); _qwtSlider->setPageSteps(30); double space = QwtDate::toDouble(endData) - QwtDate::toDouble(starData); _qwtSlider->setScaleStepSize(space/12); _qwtSlider->setScaleDraw(_qwtDsd); _qwtSlider->setHandleSize(QSize(20, 10));