Draw on a QChart

[Totoro]

Hi.

I built a simple candlestick graph with Qt Chart (in Python, but it's ok to have answers in C++ or in other languages), and it works well. I used a QChartView to show the content I drew on the QChart.
I zoom and pan the graph with the zoomIn(QRect) and scroll functions of the QChart.

Now, I'd like to draw some indicators (like arrows or other simple drawings) on or near specific candlesticks, but I really doesn't know very well the graphics view framework and Qt Chart, and I was not able to understand if there is a simple way to do that, or even a way that does not make me crazy.
I'd like to have graphics that moves with my candlestick, and preferably I'd like to choose if they will resize together with zoom or they will have the same screen size at each zoom level.

Thanks in advance!