Hello!

I have wrote simple program which captures sound samples from sound card in one thread and writes them to circular buffer. Another thread takes samples from buffer and process them (calculate FFT). The output (double*) is added in beggining of QList<double* > (last item is removed) and than signal is emmited to main thread that new data is ready to display.
In main thread i have two plots: simple qwtplot which plots current spectrum and second qwtspectrogram which plots spectrogram from QList.
The problem is that it works very slow - about 2 FPS. When I remove spectrogram from GUI and leave only qwtplot I have about 22 FPS.
So my question is: how to speed up generating/drawing spectrogram ?

Misza