I found this example hidden in the code as commented, but it cannot be compiled. This looks to be a simple application of Qwt, and it is almost what I need to start with and to learn some basics.

Qt Code: 
  1. #include <cmath>
  2. #include <qwt_series_data.h>
  3. #include <qwt_plot_curve.h>
  4. #include <qwt_plot.h>
  5. #include <qapplication.h>
  6.  
  7. class SinusData: public QwtSyntheticPointData
  8. {
  9. public:
  10.     SinusData():
  11.         QwtSyntheticPointData(100)
  12.     {
  13.     }
  14.     virtual double y(double x) const
  15.     {
  16.         return qSin(x);
  17.     }
  18. };
  19.  
  20. int main(int argc, char **argv)
  21. {
  22.     QApplication a(argc, argv);
  23.  
  24.     QwtPlot plot;
  25.     plot.setAxisScale(QwtPlot::xBottom, 0.0, 10.0);
  26.     plot.setAxisScale(QwtPlot::yLeft, -1.0, 1.0);
  27.  
  28.     QwtPlotCurve *curve = new QwtPlotCurve("y = sin(x)");
  29.     curve->setData(SinusData());
  30.     curve->attach(&plot);
  31.  
  32.     plot.show();
  33.     return a.exec();
  34. }
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This is what I get as error:

..\sinus\main.cpp: In function 'int qMain(int, char**)':
..\sinus\main.cpp:29: error: no matching function for call to 'QwtPlotCurve::setData(SinusData)'
..\sinus\libraries\qwt/qwt_plot_seriesitem.h:146: note: candidates are: void QwtPlotSeriesItem<T>::setData(QwtSeriesData<T>*) [with T = QPointF]
mingw32-make[1]: *** [release/main.o] Error 1

If you can fix this code for me, I think I will be able to extend it with more. Thanx in advance!