Auto scale, but no plot data

Hi all,

This is my first time posting, and my first time trying to use Qwt. I am presently working on Win7 with Qt 5.5.1, and Qwt 6.1.2. I am compiling with VS2013 32. Everything seems to be installed properly, and I am using creator with the Qwt plugin.

I haven't found a lot of examples, but pieced a test program together with what I found and the Qwt documentation.

Current issue...
My program compiles and runs with no warnings.
When I call (update plot), the plot will auto scale the axis to my data but the plot doesn't show any data. It is completely blank.

I have a feeling it is something I am overlooking, or don't know about.
I am stuck and would appreciate any pointers.

Code:

---

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    ui->qwtPlot->setTitle("Plot 1");
    ui->qwtPlot->setAxisTitle(QwtPlot::xBottom, "X axis");
    ui->qwtPlot->setAxisTitle(QwtPlot::yLeft, "Y axis");
    ui->qwtPlot->setCanvasBackground(Qt::white);
 
    QwtPlotCurve testCurve("Test Curve");
 
    QVector<double> x;
    QVector<double> y;
 
    for(int i = 0; i<500; i++)
    {
        x.push_back(i);
        y.push_back(i*i);
    }
 
    testCurve.setSamples(x, y);
    //testCurve.setRawSamples(x.data(), y.data(), y.size());
 
    myCurve.setPen(QPen(Qt::red));
 
    testCurve.attach(ui->qwtPlot);
 
    ui->qwtPlot->replot();
    //ui->qwtPlot->show();
 
}

---

Also, I just set up another computer exactly the same as previously described, but with VS2010. Same results.

Thanks

testCurve is on the stack and therefore gone, when you leave the constructor of MainWindow.
Concerning examples: there are several in the official tarball.

Uwe

Uwe,

I knew it was something I was overlooking. My plot looks great now.

Thanks for the excellent library, and the assistance.