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Qt篇——QChartView实现鼠标滚轮缩放、鼠标拖拽平移、鼠标双击重置缩放平移、曲线点击显示坐标_qt chart图表移动缩放返回原点

作者：weixin_40725706 | 2024-04-28 22:33:10

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qt chart图表移动缩放返回原点

话不多说。

 效果：（动图依次展示：①点击曲线显示坐标->②平移->③缩放->④双击还原）

第一步：自定义QChartView，直接搬

FirtCurveChartView.h

  1. #ifndef FITCURVECHARTVIEW_H
  2. #define FITCURVECHARTVIEW_H
  3. #include <QtCharts>
  4.  
  5. class FitCurveChartView : public QChartView {
  6.     Q_OBJECT
  7.  
  8. public:
  9.     FitCurveChartView(QWidget *parent = Q_NULLPTR);
  10.     ~FitCurveChartView();
  11.  
  12. protected:
  13.     void mousePressEvent(QMouseEvent *event);
  14.     void mouseMoveEvent(QMouseEvent *event);
  15.     void mouseReleaseEvent(QMouseEvent *event);
  16.     void mouseDoubleClickEvent(QMouseEvent *event);
  17.     void wheelEvent(QWheelEvent *event);
  18.  
  19. signals:
  20.     void signalMouseEvent(int eventId, QMouseEvent *event);
  21.     void signalWheelEvent(QWheelEvent *event);
  22.  
  23. };
  24.  
  25. #endif // FITCURVECHARTVIEW_H

FirtCurveChartView.cpp

  1. #include "FitCurveChartView.h"
  2.  
  3. FitCurveChartView::FitCurveChartView(QWidget *parent) {
  4.  
  5. }
  6.  
  7. FitCurveChartView::~FitCurveChartView() {
  8.  
  9. }
  10.  
  11. void FitCurveChartView::mousePressEvent(QMouseEvent *event) {
  12.     emit signalMouseEvent(0, event);
  13.     QChartView::mousePressEvent(event);
  14. }
  15.  
  16. void FitCurveChartView::mouseMoveEvent(QMouseEvent *event) {
  17.     emit signalMouseEvent(1, event);
  18.     QChartView::mouseMoveEvent(event);
  19. }
  20.  
  21. void FitCurveChartView::mouseReleaseEvent(QMouseEvent *event) {
  22.     emit signalMouseEvent(2, event);
  23.     QChartView::mouseReleaseEvent(event);
  24. }
  25.  
  26. void FitCurveChartView::mouseDoubleClickEvent(QMouseEvent *event) {
  27.     emit signalMouseEvent(3, event);
  28.     QChartView::mouseDoubleClickEvent(event);
  29. }
  30.  
  31. void FitCurveChartView::wheelEvent(QWheelEvent *event) {
  32.     emit signalWheelEvent(event);
  33.     QChartView::wheelEvent(event);
  34. }

第二步：在主界面代码中使用，我的是在自定义对话框里面，你们可以直接在窗口中使用

举例：fitcurvedialog.h

  1. #ifndef FITCURVEDIALOG_H
  2. #define FITCURVEDIALOG_H
  3.  
  4. #include <QDialog>
  5. #include "FitCurveChartView.h"
  6.  
  7. namespace Ui {
  8. class FitCurveDialog;
  9. }
  10.  
  11. class FitCurveDialog : public QDialog
  12. {
  13.     Q_OBJECT
  14.  
  15. public:
  16.     explicit FitCurveDialog(QWidget *parent = nullptr);
  17.     ~FitCurveDialog();
  18.  
  19.     void initQChartView();
  20.     void updateXYGuideLine();
  21.     void resetZoomAndScroll();
  22.     QVector<int> getAxisRanges();
  23.  
  24. public slots:
  25.     void theSlotMouseEvent(int eventId, QMouseEvent *event);
  26.     void theSlotWheelEvent(QWheelEvent *event);
  27.  
  28. private:
  29.     Ui::FitCurveDialog *ui;
  30.     FitCurveChartView *curveChartView;
  31.     QChart *curveChart;
  32.     QSplineSeries* fitPointsSeriesS;    //要显示的曲线原始数据
  33.     QScatterSeries* tipSeries;
  34.     QSplineSeries* xGuideSeries;    //鼠标悬浮位置点的x轴辅助线
  35.     QSplineSeries* yGuideSeries;    //鼠标悬浮位置点的y轴辅助线
  36.     bool isPressed = false;         //图标是否在拖拽中
  37.     QPoint pressedPoint;            //鼠标拖拽起点
  38.  
  39. };
  40.  
  41. #endif // FITCURVEDIALOG_H

fitcurvedialog.cpp    (UI文件里面就放了一个水平布局chartLayout)

  1. #include "fitcurvedialog.h"
  2. #include "ui_fitcurvedialog.h"
  3.  
  4. FitCurveDialog::FitCurveDialog(QWidget *parent) :
  5.     QDialog(parent),
  6.     ui(new Ui::FitCurveDialog)
  7. {
  8.     ui->setupUi(this);
  9.  
  10.     qApp->setOverrideCursor(Qt::ArrowCursor);       //允许系统弹窗、提示
  11.     initQChartView();
  12. }
  13.  
  14. void FitCurveDialog::initQChartView() {
  15.     //创建图表框架
  16.     curveChartView = new FitCurveChartView(this);
  17.     curveChartView->setMaximumWidth(1730);
  18.     curveChartView->setMinimumHeight(480);
  19.     curveChart = new QChart();
  20.     curveChart->setTheme(QChart::ChartThemeBlueIcy);
  21.     curveChart->setContentsMargins(0, 0, 0, 0);             //设置外边界全部为0, 根据自己实际情况设置
  22.     curveChart->setMargins(QMargins(5, -30, 5, 10));        //设置内边界, 根据自己实际情况设置
  23.     curveChart->setBackgroundRoundness(0);                  //设置表格边框圆角半径
  24.     curveChartView->setChart(curveChart);
  25.  
  26.     //创建折线序列
  27.     fitPointsSeriesS = new QSplineSeries(this);               //原始数据曲线
  28.     fitPointsSeriesS->setUseOpenGL(true);
  29.     xGuideSeries = new QSplineSeries(this);
  30.     yGuideSeries = new QSplineSeries(this);
  31.     tipSeries =  new QScatterSeries();                      // 创建一个散点数据集对象,用于显示
  32.     tipSeries->setMarkerShape(QScatterSeries::MarkerShapeCircle);  // 设置绘制的散点的样式为圆
  33.     tipSeries->setMarkerSize(10);
  34.  
  35.     QObject::connect(fitPointsSeriesS, &QSplineSeries::clicked, [=](const QPointF &point)mutable{
  36.         QPointF tempPoint;
  37.         QVector<QPointF> tempList(fitPointsSeriesS->pointsVector());  //复制曲线中的数据进行计算, 因为直接使用会导致卡顿
  38.         int tempX = qRound(point.x());
  39.         int tempY = -999;
  40.         for (int i = 0; i < tempList.size(); i++) {
  41.             if (tempList[i].x() == tempX) {
  42.                 tempY = tempList[i].y();
  43.                 tempPoint.setX(tempX);
  44.                 tempPoint.setY(tempY);
  45.                 break;
  46.             }
  47.         }
  48.         if (tempY != -999) {
  49.             QToolTip::showText(QCursor::pos(), QString("(%1,%2)").arg(tempX).arg(tempY));
  50.             QVector<QPointF> tipList;
  51.             tipList.append(tempPoint);
  52.             tipSeries->replace(tipList);
  53.             updateXYGuideLine();
  54.         }
  55.     });
  56.     curveChart->addSeries(xGuideSeries);
  57.     curveChart->addSeries(yGuideSeries);
  58.     curveChart->addSeries(fitPointsSeriesS);
  59.     curveChart->addSeries(tipSeries);
  60.     //添加数据绘制
  61.     size_t count = 20000;
  62.     QVector<QPointF> list;
  63.     for (size_t i = 0; i < count; i++) {
  64.         list.append(QPoint(i, int(i / 40)));
  65.     }
  66.     fitPointsSeriesS->replace(list);
  67.  
  68.     //创建坐标轴
  69.     QValueAxis* axisX = new QValueAxis;
  70.     axisX->setRange(0, 20000);
  71.     axisX->setTickCount(21);
  72.     axisX->setLabelFormat("%d");
  73.     axisX->setLabelsAngle(-90);      //坐标刻度文字显示角度
  74.     curveChart->addAxis(axisX,Qt::AlignBottom);
  75.  
  76.     xGuideSeries->attachAxis(axisX);
  77.     yGuideSeries->attachAxis(axisX);
  78.     fitPointsSeriesS->attachAxis(axisX);
  79.     tipSeries->attachAxis(axisX);
  80.  
  81.     QValueAxis* axisY = new QValueAxis;
  82.     axisY->setRange(0, 500);
  83.     axisY->setTickCount(11);
  84.     axisY->setLabelFormat("%d");
  85.     curveChart->addAxis(axisY,Qt::AlignLeft);
  86.  
  87.     xGuideSeries->attachAxis(axisY);
  88.     yGuideSeries->attachAxis(axisY);
  89.     fitPointsSeriesS->attachAxis(axisY);
  90.     tipSeries->attachAxis(axisY);
  91.  
  92. //    axisX->setGridLineVisible(false);   //隐藏背景网格X轴框线
  93. //    axisY->setGridLineVisible(false);   //隐藏背景网格Y轴框线
  94.     curveChart->legend()->markers()[0]->setVisible(false);
  95.     curveChart->legend()->markers()[1]->setVisible(false);
  96.     curveChart->legend()->markers()[2]->setVisible(false);
  97.     curveChart->legend()->markers()[3]->setVisible(false);
  98.     curveChartView->setRenderHint(QPainter::Antialiasing);  //除锯齿
  99.     connect(curveChartView, &FitCurveChartView::signalMouseEvent, this, &FitCurveDialog::theSlotMouseEvent);
  100.     connect(curveChartView, &FitCurveChartView::signalWheelEvent, this, &FitCurveDialog::theSlotWheelEvent);
  101.     ui->chartLayout->addWidget(curveChartView);
  102. }
  103.  
  104. void FitCurveDialog::theSlotMouseEvent(int eventId, QMouseEvent *event) {
  105.     if (eventId == 0){  //单击按下
  106.         isPressed = true;
  107.         QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
  108.         pressedPoint = mouseEvent->pos();
  109.     } else if (eventId == 1) {  //鼠标移动
  110.         if (isPressed) {
  111.             QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
  112.             curveChart->scroll(-(mouseEvent->pos().x() - pressedPoint.x()) / 10,
  113.                                (mouseEvent->pos().y() - pressedPoint.y()) / 10);
  114.             updateXYGuideLine();
  115.         }
  116.     } else if (eventId == 2) {  //单击抬起
  117.         isPressed = false;
  118.     } else if (eventId == 3) {  //双击
  119.         resetZoomAndScroll();
  120.         updateXYGuideLine();
  121.     }
  122. }
  123.  
  124. void FitCurveDialog::theSlotWheelEvent(QWheelEvent *event) {
  125.     int delta = event->angleDelta().y();
  126.     if (delta > 0) {
  127.         curveChart->zoom(0.95);
  128.     } else {
  129.         curveChart->zoom(1.05);
  130.     }
  131.     updateXYGuideLine();
  132. }
  133.  
  134. void FitCurveDialog::updateXYGuideLine() {
  135.     if (tipSeries->points().size() > 0) {
  136.         QVector<int> axisRanges = getAxisRanges();
  137.         QVector<QPointF> xGuideList, yGuideList;
  138.         int tempX = tipSeries->points()[0].x();
  139.         int tempY = tipSeries->points()[0].y();
  140.         xGuideList.append(QPointF(tempX, axisRanges[2]));
  141.         xGuideList.append(QPointF(tempX, tempY));
  142.         yGuideList.append(QPointF(axisRanges[0], tempY));
  143.         yGuideList.append(QPointF(tempX, tempY));
  144.         xGuideSeries->replace(xGuideList);
  145.         yGuideSeries->replace(yGuideList);
  146.     }
  147. }
  148.  
  149. void FitCurveDialog::resetZoomAndScroll() {
  150.     curveChart->zoomReset();
  151.     QList<QAbstractAxis*> axesX, axesY;
  152.     axesX = curveChart->axes(Qt::Horizontal);
  153.     axesY = curveChart->axes(Qt::Vertical);
  154.     QValueAxis *curAxisX = (QValueAxis*)axesX[0];
  155.     QValueAxis *curAxisY = (QValueAxis*)axesY[0];
  156.     curAxisX->setRange(0, 20000);
  157.     curAxisY->setRange(0, 500);
  158. }
  159.  
  160. QVector<int> FitCurveDialog::getAxisRanges() {
  161.     QList<QAbstractAxis*> axesX, axesY;
  162.     axesX = curveChart->axes(Qt::Horizontal);
  163.     axesY = curveChart->axes(Qt::Vertical);
  164.     QValueAxis *curAxisX = (QValueAxis*)axesX[0];
  165.     QValueAxis *curAxisY = (QValueAxis*)axesY[0];
  166.     QVector<int> ranges = {int(curAxisX->min()), int(curAxisX->max()), int(curAxisY->min()), int(curAxisY->max())};
  167.     return ranges;
  168. }
  169.  
  170. FitCurveDialog::~FitCurveDialog()
  171. {
  172.     delete ui;
  173. }
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