How can I set the plot points through the mouse cursor?

Blackzero

How to set up up and down on each plot point through the mouse cursor, I mean how the cursor can pull up and down on the plot point and get a value when the cursor pulls the point up or down.

Screenshot 2024-06-18 111619.png

#include "plot2d.h"
#include "ui_plot2d.h"
#include <QStringList>

Plot2D::Plot2D(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::Plot2D)

{
    ui->setupUi(this);
    Plot2D::makeplot();
}

Plot2D::~Plot2D()
{
    delete ui;
}

void Plot2D::makeplot()
{

    // Add new data points
    QVector<double> x2 = {0, 1, 2, 3, 4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29}; // Example x values
    QVector<double> y2 = {1000
                          ,1200
                          ,1400
                          ,1500
                          ,1600
                          ,1650
                          ,1700
                          ,1800
                          ,1900
                          ,2000
                          ,2250
                          ,2500
                          ,2750
                          ,3000
                          ,3250
                          ,3500
                          ,3750
                          ,4000
                          ,4500
                         , 5000
                          ,5500
                          ,6000
                          ,6500
                          ,7000
                          ,7500
                          ,8000
                          ,8500
                          ,9000
                          ,11500}; // Given y values

    QCPGraph *graph2 = ui->customPlot->addGraph();
    graph2->setData(x2, y2);
    graph2->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssSquare, QPen(Qt::red, 1.5), QBrush(Qt::red), 9));
    graph2->setPen(QPen(QColor(200, 50, 50), 2));

    // move bars above graphs and grid below bars:
    ui->customPlot->addLayer("abovemain", ui->customPlot->layer("main"), QCustomPlot::limAbove);
    ui->customPlot->addLayer("belowmain", ui->customPlot->layer("main"), QCustomPlot::limBelow);
    graph2->setLayer("abovemain");
    ui->customPlot->xAxis->grid()->setLayer("belowmain");
    ui->customPlot->yAxis->grid()->setLayer("belowmain");

    // set some pens, brushes and backgrounds:
    ui->customPlot->xAxis->setBasePen(QPen(Qt::white, 1));
    ui->customPlot->yAxis->setBasePen(QPen(Qt::white, 1));
    ui->customPlot->xAxis->setTickPen(QPen(Qt::white, 1));
    ui->customPlot->yAxis->setTickPen(QPen(Qt::white, 1));
    ui->customPlot->xAxis->setSubTickPen(QPen(Qt::white, 1));
    ui->customPlot->yAxis->setSubTickPen(QPen(Qt::white, 1));
    ui->customPlot->xAxis->setTickLabelColor(Qt::white);
    ui->customPlot->yAxis->setTickLabelColor(Qt::white);
    ui->customPlot->xAxis->grid()->setPen(QPen(QColor(140, 140, 140), 1, Qt::DotLine));
    ui->customPlot->yAxis->grid()->setPen(QPen(QColor(140, 140, 140), 1, Qt::DotLine));
    ui->customPlot->xAxis->grid()->setSubGridPen(QPen(QColor(80, 80, 80), 1, Qt::DotLine));
    ui->customPlot->yAxis->grid()->setSubGridPen(QPen(QColor(80, 80, 80), 1, Qt::DotLine));
    ui->customPlot->xAxis->grid()->setSubGridVisible(true);
    ui->customPlot->yAxis->grid()->setSubGridVisible(true);
    ui->customPlot->xAxis->grid()->setZeroLinePen(Qt::NoPen);
    ui->customPlot->yAxis->grid()->setZeroLinePen(Qt::NoPen);
    ui->customPlot->xAxis->setUpperEnding(QCPLineEnding::esSpikeArrow);
    ui->customPlot->yAxis->setUpperEnding(QCPLineEnding::esSpikeArrow);
    QLinearGradient plotGradient;
    plotGradient.setStart(0, 0);
    plotGradient.setFinalStop(0, 350);
    plotGradient.setColorAt(0, QColor(80, 80, 80));
    plotGradient.setColorAt(1, QColor(50, 50, 50));
    ui->customPlot->setBackground(plotGradient);
    QLinearGradient axisRectGradient;
    axisRectGradient.setStart(0, 0);
    axisRectGradient.setFinalStop(0, 350);
    axisRectGradient.setColorAt(0, QColor(80, 80, 80));
    axisRectGradient.setColorAt(1, QColor(30, 30, 30));
    ui->customPlot->axisRect()->setBackground(axisRectGradient);

    // Adjust axes to fit the new data
    ui->customPlot->rescaleAxes();
    ui->customPlot->yAxis->setRange(*std::min_element(y2.constBegin(), y2.constEnd()), *std::max_element(y2.constBegin(), y2.constEnd()));
    ui->customPlot->replot();
}

SGaist

Hi,

You should start with the user interactions tutorials from the QCustomPlot documentation.

For further help, you should check with the QCustomPlot community as they will likely be more knowledgeable about this module.