I've noticed that QCustomPlot slows down greatly when drawing a high frequency sine wave with fill... even if the number of points is fixed to 256.
Is the calculation of the fill area for a graph a huge performance bottleneck? In my example above, lowering the frequency of the sine wave which reduces the number of zero line crossings greatly increases the frame rate.
Are there any knobs I can tweak to speed things up? I already have the QCustomPlot widget inside of an OpenGl widget to (hopefully) reduce the time spent painting the image. Not sure what to do if the control code is too slow though.