Qt实现绘制多个设备的流量曲线图详解

//消息过滤，主要用于重绘子控件，过滤Paint事件
 bool QAPRTCurWidget::eventFilter(QObject *watched, QEvent *event)
 {
     if(watched==ui->widget_rxtx && event->type()==QEvent::Paint)
     {
         updateWidgetRTX();
     }
     return QFrame::eventFilter(watched,event);
 }

//绘图操作
 void QAPRTCurWidget::updateWidgetRTX()
 {
     QPainter painter(ui->widget_rxtx);
     painter.setFont(QFont("Times", , QFont::Bold));
     //绘制背景颜色
     painterBackground(painter);
     //画最左边一条虚线，用于和List隔开
     painterLeftDashLine(painter);
     //画纵坐标文本标识
     updateVTextID(painter);
     //画纵坐标文本刻度以及横纵坐标轴
     updateVTextMarkAndCoord(painter);
     //画RX曲线
     paintRXLineInfo(painter);
     //画TX曲线
     paintTXLineInfo(painter);
 }

//画纵坐标文本刻度以及横纵坐标轴
 void QAPRTCurWidget::updateVTextMarkAndCoord(QPainter &painter)
 {
     painter.save();
     //绘图区间的实际高度(部件高度-顶部间隔-底部间隔)
     int nActPaintHeight = ui->widget_rxtx->height()-INTERVAL_WIDGET_TOP-INTERVAL_WIDGET_BOTTOM;
     //每隔的间隔高度
     float fIntervalHeight = ((float)nActPaintHeight)/(m_nVSingleLinePointCount-);
     float fYPointForZero = ui->widget_rxtx->height()-INTERVAL_WIDGET_BOTTOM;
     double dDivideValue = ;
     if(ui->toolButton_rxflow->isChecked())
     {
         dDivideValue = ((double)nRXMaxValue)/(m_nVSingleLinePointCount-);
     }
     if(ui->toolButton_txflow->isChecked())
     {
         dDivideValue = ((double)nTXMaxValue)/(m_nVSingleLinePointCount-);
     }
     for(int nIndex=;nIndex<m_nVSingleLinePointCount;++nIndex)
     {
         //设置文本颜色
         painter.setPen(TEXTCOLOR_WIDGET_PAINT);
         //将原来的字体变小，设置为8
         QFont objFont = painter.font();
         objFont.setPointSize();
         painter.setFont(objFont);
         //画文本，加3的目的是为了是其和横线能保持中间持平
         painter.drawText(INTERVAL_VMARK_LEFT,fYPointForZero-nIndex*fIntervalHeight+,QCommonOP::getKMStrForBit(dDivideValue*nIndex));
         //设置横线颜色
         painter.setPen(COORDCOLOR_WIDGET_PAINT);
         //画横线(第一条和最后一条为实线,中间的为虚线)
         QPen objPen = painter.pen();
         if(==nIndex || (m_nVSingleLinePointCount-)==nIndex)
         {
            objPen.setStyle(Qt::SolidLine);
         }
         else
         {
             objPen.setStyle(Qt::DashLine);
         }
         painter.setPen(objPen);
         float x1 = ui->widget_rxtx->width()-INTERVAL_WIDGET_RIGHT;
         float y1 = fYPointForZero-nIndex*fIntervalHeight;
         painter.drawLine(INTERVAL_HCOORD_LEFT,fYPointForZero-nIndex*fIntervalHeight,x1,y1);
     }
     int nActPaintWidth = ui->widget_rxtx->width()-INTERVAL_HCOORD_LEFT-INTERVAL_WIDGET_RIGHT;
     //每隔的间隔高度--横向:注意使用(float)nActPaintWidth)作为分子，即浮点数
     float fIntervalWidth = ((float)nActPaintWidth)/(m_nHSingleLinePointCount-);
     for(int nIndex=;nIndex<m_nHSingleLinePointCount;++nIndex)
     {
         QPen objPen = painter.pen();
         if(==nIndex || (m_nHSingleLinePointCount-)==nIndex)
         {
            objPen.setStyle(Qt::SolidLine);
         }
         else
         {
             objPen.setStyle(Qt::DashLine);
         }
         painter.setPen(objPen);
         int nXPoint = INTERVAL_HCOORD_LEFT+nIndex*fIntervalWidth;
         painter.drawLine(nXPoint,INTERVAL_WIDGET_TOP,nXPoint,ui->widget_rxtx->height()-INTERVAL_WIDGET_BOTTOM);
     }
     painter.restore();
 }