When exporting a QCustomPlot as a QPixmap, an arbitrary size can be given to the toPixmap() method to control the viewport size.
I would prefer to set a size for the axis rect so that exported figures can be comparable independently of the axis label font.

For example, if I have 3 plots with similar data:
- 1st plot with short y axis title
- 2nd plot with long y axis title => smaller font required
- 3rd plot with y axis + y2 axis titles

is there a way to ensure that the axis rect is always the same ?