Updating QwtPlot from QThread

**boudie** · 5th April 2011, 13:33

Stick to one thread and call processEvents in the loop.
That will make your gui responsive again.

**JohannesMunk** · 5th April 2011, 13:54

I'm having the exact same situation here. Real-Time-Data-Acquisition-Oscilloscope !

You should leave the acquisition in a separate thread with higher priority. To reduce the load for the gui thread you could prepare a QwtSeriesData and pass it through a signal to your gui thread. There you use a QwtPlotDirectPainter to plot only the data that just arrived and avoid replotting everything.

If that is still not fast enough, qwt provides the QwtWeedingCurveFitter. With it you can subsample your data to make plotting faster. http://www.qtcentre.org/threads/2843...ng-application

Let me know if you need more details,

HIH

Johannes

**lamle** · 5th April 2012, 08:05

Originally Posted by JohannesMunk

I'm having the exact same situation here. Real-Time-Data-Acquisition-Oscilloscope !

You should leave the acquisition in a separate thread with higher priority. To reduce the load for the gui thread you could prepare a QwtSeriesData and pass it through a signal to your gui thread. There you use a QwtPlotDirectPainter to plot only the data that just arrived and avoid replotting everything.

If that is still not fast enough, qwt provides the QwtWeedingCurveFitter. With it you can subsample your data to make plotting faster. http://www.qtcentre.org/threads/2843...ng-application

Let me know if you need more details,

HIH

Johannes

Hi Johannes,
I am having exactly the same issue, can you provide more details please
Thanks,Lam