Qt QChart绘制跟随鼠标的十字线

#include "zchartview.h" ZChartView::ZChartView(ZChart *chart, QWidget *parent): QChartView (chart,parent) { connect(chart,&ZChart::showPointRectSign,this,&ZChartView::showPointRectSlots); setRubberBand(QChartView::RectangleRubberBand); //设置橡皮筋 setRenderHint(QPainter::Antialiasing); //设置平滑曲线 setStyleSheet("background:transparent"); QPen pen; // 定义一个画笔，设置画笔颜色和宽度 pen.setColor("red"); pen.setWidth(1); x_line = new QGraphicsLineItem(); // 定义一个直线图元 x_line->setLine(QLineF(10, 0, 10, this->height())); x_line->setPen(pen); x_line->setEnabled(false); x_line->setVisible(false); scene()->addItem(x_line); y_line = new QGraphicsLineItem(); // 定义一个直线图元 y_line->setLine(QLineF(10, 0, 10, this->height())); y_line->setPen(pen); y_line->setEnabled(false); y_line->setVisible(false); scene()->addItem(y_line); //添加文字背景框矩形 currentPointTextRect = new QGraphicsRectItem(0 , 0 ,100, 60); currentPointTextRect->setBrush(Qt::yellow); currentPointTextRect->setEnabled(false); currentPointTextRect->setVisible(false); scene()->addItem(currentPointTextRect); currentPointText=new QGraphicsTextItem(currentPointTextRect); currentPointText->setHtml(""); currentPointText->setEnabled(false); scene()->addItem(currentPointText); } ZChartView::~ZChartView() { qDebug()<<" 调用了ZChartView的析构函数 "; } void ZChartView::mouseMoveEvent(QMouseEvent *e) { //打印鼠标位置处的点的坐标值 // qDebug()<<"鼠标移入点位"<chart()->mapToValue(e->pos());//把鼠标坐标值转化为画出的图中的坐标 //以防父类的实例接收不到mouseMoveEvent事件。 QChartView::mouseMoveEvent(e);//调用父类的重写方法。本行程序不同于e->ignore()，ignor是把事件继续向父控件（一般其父控件就是ui界面）传递，而不是向父类传递 x_line->setLine(e->x(),0,e->x(),this->height()); y_line->setLine(0,e->y(),this->width(),e->y()); currentPointTextRect->setPos(e->pos()); currentPointText->setHtml("

 "+QString::number(this->chart()->mapToValue(e->pos()).x())+"

 "+QString::number(this->chart()->mapToValue(e->pos()).y())+"

"); currentPointTextRect->setPos(e->pos()); } void ZChartView::enterEvent(QEvent *event) { x_line->setVisible(true); y_line->setVisible(true); currentPointTextRect->setVisible(true); } void ZChartView::leaveEvent(QEvent *event) { x_line->setVisible(false); y_line->setVisible(false); currentPointTextRect->setVisible(false); } void ZChartView::showPointRectSlots(QPointF point, bool state) { // if(state) // { // currentPointTextRect->setVisible(true); // currentPointText->setHtml("

 "+QString::number(point.x())+"

 "+QString::number(point.y())+"

"); // currentPointTextRect->setPos(this->chart()->mapToPosition(point)); // } // else // { // currentPointTextRect->setVisible(false); // } }