Tutorial (JKQTPlotter): Using a JKQTPlotter inside a Qt User Interface Designer (UI) File

This project (see ./examples/ui/) demonstrates how to create add a JKQTPlotter inside the Qt Form Editor (e.g. called from of Qt Creator) into a widget.

Instructions on how to use JKQTPlotter in the Qt Form Designer

For this to work you have to follow the steps shown below:

1. add a new UI-file to your project and open it in the Form Editor. Then right-click the form and select Promote Widgets ...:
   
2. In the dialog that opens, you have to define JKQTPlotter as a promotion to QWidget as shown below. Finally store the settings by clicking Add and closing the dialog with Close.
   
3. Now you can add a QWidgetfrom the side-bar to the form and then promote it to JKQTPlotter, by selecting and right-clicking the QWidget and then selecting Promote To | JKQTPlotter:
   

In the example, there is a main CPP-file (shown below) and a formwithjkqtplotter.ui-file with the formwithjkqtplotter.cpp/.h-files that are used to implement the functionality behind the form (see next chapter).

The source code of the main application is simply instanciating the Form class FormWithJKQTPlotter from formwithjkqtplotter.ui/.h/.cpp:

#include <QApplication>
#include "formwithjkqtplotter.h"
 
 
int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
 
    FormWithJKQTPlotter plot;
    plot.show();
    plot.resize(600,400);
 
    return app.exec();
}

Form Class FormWithJKQTPlotter

The Form was designed in the Qt Form Designer within Qt Creator, using the method described above (see formwithjkqtplotter.ui):

In addition the example implements some simple functionality in the formwithjkqtplotter.cpp/.h-files. A single graph, which parses and plots a function (from a QLineEdit) is added to the plot in the constructor:

#include "formwithjkqtplotter.h"
#include "ui_formwithjkqtplotter.h"
 
FormWithJKQTPlotter::FormWithJKQTPlotter(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::FormWithJKQTPlotter)
{
    ui->setupUi(this);
    graph=new JKQTPXParsedFunctionLineGraph(ui->plot);
    graph->setFunction(ui->edtEquation->text());
    graph->setTitle(ui->edtEquation->text());
    ui->plot->addGraph(graph);
    ui->plot->setXY(-10,10,-10,10);
}

Then three slots react to user interactions. First two interactions set the x- or y-axis to linear or logarithmic, depending on the state of the two check-boxes. It also sets the scaling of the axes to meaningful default values:

void FormWithJKQTPlotter::on_chkLogX_toggled(bool checked)
{
    ui->plot->getXAxis()->setLogAxis(checked);
    if (checked) {
        ui->plot->setX(1e-3,10);
    } else {
        ui->plot->setX(-10,10);
    }
}
 
void FormWithJKQTPlotter::on_chkLogY_toggled(bool checked)
{
    ui->plot->getYAxis()->setLogAxis(checked);
    if (checked) {
        ui->plot->setY(1e-3,10);
    } else {
        ui->plot->setY(-10,10);
    }
}

A third slot is connected to the clicked()-event of the QPushButton labeled "REPLOT!". This slot reads the function from the QLineEdit and updates the plot with it:

void FormWithJKQTPlotter::on_btnReplot_clicked()
{
    graph->setFunction(ui->edtEquation->text());
    graph->setTitle(ui->edtEquation->text());
    ui->plot->redrawPlot();
}

The result looks like this:

If you set both axes to logarithmic and modify the plotted function a bit, you get: