Hi,

I am trying to inherit QwtPlotZoomer and overload the zoom() function. I want to make a small modification to the function, but I don't have access to PrivateData* d_data. How can I properly overload this function?

And then this leads to my next question, what is the purpose of PrivateData? What's the difference between doing like this vs placing those variables (public member variables from class PrivateData) directly into QwtPlotZoomer's private data?

Thanks