I would like something like this example's bullets:
http://www.qcustomplot.com/index.php/demos/styleddemo
but the bullets to be placed only on Local Extremes. Which means, only where:
y0 < f(x) < y1
x0 < x < x1

Or the complete opposite. Is it possible to achieve that through that library? I've already done some basic drawing with this library and it's fun I have to say, but is it possible to do such thing?