QCustomPlot Discussion and Comments

Multiple zero linesReturn to overview

I have to display multiple graphs on a single QCPAxisRect, is it possible to have multiple zero lines, one for each graph

You can have any number of "virtual" 0 lines, it all depends on which Y value you consider as the 0 crossing line.
If instead you mean having multiple Axes then this is possible too (have a look at the documentation on QCPAxis).

In addition to what t3sty said: You can also look at the "advanced axes demo" code in the examples project to find out how to work with multiple axes.