利用QCustomPlot在图上画点并实现滚轮缩放和鼠标拖动

效果如图所示：

步骤如下：

1. 新建工程，并添加qcustomplot.h，qcustomplot.cpp

并在工程的pro文件添加printsupport

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport

2. 在ui里面添加一个Widget, 并提升为QCustomPlot，在这里我将这个Widget命名为plot

3. 开始写代码。

在此附上源码及注释。

 

// mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

    void addPoint(double x, double y);
    void clearData();
    void plot();


private slots:

    void clickedGraph(QMouseEvent *event);

private:
    Ui::MainWindow *ui;

    QVector qv_x, qv_y;

};

#endif // MAINWINDOW_H

// mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    ui->plot->setInteraction(QCP::iRangeDrag, true); //鼠标单击拖动
    ui->plot->setInteraction(QCP::iRangeZoom, true); //滚轮滑动缩放
    ui->plot->addGraph();
    ui->plot->graph(0)->setScatterStyle(QCPScatterStyle::ssCircle);
    ui->plot->graph(0)->setLineStyle(QCPGraph::lsNone);

    //connect(ui->plot, SIGNAL(mousePress(QMouseEvent*)), SLOT(clickedGraph(QMouseEvent*))); //单击
    connect(ui->plot, SIGNAL(mouseDoubleClick(QMouseEvent*)), SLOT(clickedGraph(QMouseEvent*))); //双击
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::addPoint(double x, double y)
{
    qv_x.append(x);
    qv_y.append(y);
}

void MainWindow::clearData()
{
    qv_x.clear();
    qv_y.clear();
}

void MainWindow::plot()
{
    ui->plot->graph(0)->setData(qv_x,qv_y);
    ui->plot->replot();
    ui->plot->update();
}


void MainWindow::clickedGraph(QMouseEvent *event)
{
    QPoint point = event->pos();
    qDebug()<plot->xAxis->pixelToCoord(point.x())<plot->yAxis->pixelToCoord(point.y());
    addPoint(ui->plot->xAxis->pixelToCoord(point.x()), ui->plot->yAxis->pixelToCoord(point.y()));
    plot();
}