Qwt: Is it possible to perform GUI operations from a separate QProcess?

[seanj]

In any case, you should not perform your screen updates based on some QTimer or similar mechanism that establishes an update rate. Instead, you should use Qt's signal and slot mechanism to let the image creation thread tell the main thread that a new image is ready and to update the on-screen display. Otherwise, you run the risk of either wasting a lot of time in inappropriate polling or seeing glitches due to incompletely rendered images.

Currently, my first plot paints onto a widget still, but I plan on modifying my code to paint onto a QImage in a separate thread later on. Before I do that though, I am just curious, how could I use the signal and slot mechanism to notify when I am finished painting? Would I need to re-implement paintEvent and emit a signal after calling painter.end() ?

Thank you, I greatly appreciate your help.

---

Added after 4 minutes:

Better use Qwt 6.2 from SVN ( being released soon ) as it has a significant optimization ( QwtPlotCurve::FilterPointsAggressive ), that might be relevant for your usecase.

Uwe

Awesome! Thanks for the reply. I will check it out soon.
How does this compare with QwtPlotCurve::FilterPoints? When I set QwtPlotCurve::FilterPoints to true, my frame rate drops from 16.5 FPS to 14.5 FPS.