@Joe-von-Habsburg
Yes you can draw lines on a QGraphicsScene, I never suggested you not use a QChart (or equivalent, QChart is not considered wonderful and it is being replaced by QtGraphs, for all I know that may be better here) for drawing charts, there is a reason that is its own component.

Since I don't know anything about QCharts and zooming I would not know about axes and what the consequences might be. I only know what I wrote and the links I referred you to, which may have alternative approaches.

@timob256
There is nothing more to say. Code like the stuff you are using. Replace new QPushButton with code for new QChartView plus its own QChart as above.

@Davide00 said in QtCharts and QDialog:

can I show a chart in a QDialog?

Yes

"And if yes, how can i do it?" - what exactly is the problem? Simply add your chart as child widget in your dialog.