I have a main window and in that main window is a qwidget which I promoted to my class based on qwtplot. In the constructor of that class I have defined two arrays which were then added to my plotcurve. When running in Fedora Core 12 the plot comes up fine but missing the plot curve. When I run the same program in Windows 7 all is well with a plot containing the curve. Qt version is 4.6.2 on both platforms with qwt5.1.2 which I subversioned over and built on both machines. My constructor which does all of the work is below... Thanks very much for any insight into what I might be lacking here.

Qt Code:
  1. #include "myplot.h"
  2. #include <qwt_symbol.h>
  3.  
  4. MyPlot::MyPlot(QWidget *gv) : QwtPlot ( gv)
  5. {
  6.  
  7. int i ;
  8.  
  9. setTitle ("junk") ;
  10. QwtPlotCurve *curve1 = new QwtPlotCurve("Curve 1");
  11. curve1->attach(this);
  12. // alloc memory for data arrays
  13. xdata = new double [100] ;
  14. ydata = new double [100] ;
  15.  
  16. // load arrays for display
  17. for (i = 0; i < 100; i++)
  18. {
  19. xdata[i] = i ;
  20. ydata[i] = i ;
  21. }
  22.  
  23. curve1->setData(xdata, ydata, 100);
  24. curve1->setPen(QPen(Qt::red, 3));
  25. curve1->setStyle (QwtPlotCurve::Lines) ;
  26.  
  27.  
  28. replot() ;
  29.  
  30. }
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