QCustomPlot Discussion and Comments

In one-point-at-a-time spectroscopies it is a frequent case that the measurement is performed in sections,
(characteristic peaks far from each other), and even the scales of the sections are different. For an example see
http://tex.stackexchange.com/questions/277343/photoelectron-spectroscopy-scan-simulation

I.e. it would be useful to add a sectioned graph, where a list of ranges rather than a single range is available, with independent scaling. It would be great if the vertical scale could be given as a multiplier relative to the leftmost scale.

I'm currently writing up a use case tutorial doing exactly that. It comes down to creating two axis rects next to each other (i.e. add one to the right of the main axis rect) and hiding the yAxis of the right axis rect. For convenience, connect the ranges of the main yAxis and the yAxis of the right axis rect. Finally, you create two QCPGraph instances, one in the left, one in the right axis rect. They can share a mutual data container if you like (you can put non-signaling NaNs to create gaps between separated peaks).
To create that diagonal dash on the axis end, use axis->setLowerEnding(QCPLineEnding::esSkewedBar); and setUpperEnding, respectively.