QCustomPlot Discussion and Comments

At first , congratulation for such a nice library. It is a pleasure to use the library.
My problem is not specifically on QCustomplot, it's a general problem.
I want to plot vacuum reading as histogram in positive Y axis. Vacuum is low pressure and lower the pressure , better the vacuum. So 1E-5 mBar should be taller than 1E-3 mBar . Moreover Y axis must be in log scale to cover 1E03 to 1E-10. Not very sure how to achieve it because highest value ( 1E03) must be on X Axis and lowest value 1E-10 will be at the topmost position of Y Axis.
Any help is appreciated. Please excuse me if the problem is very dumb or trivial.

Check the documentation for these methods: QCPAxis::setRangeReversed (set to true) and QCPAxis::setScaleType (set to QCPAxis::ScaleType::stLogarithmic ) together with QCPAxis::setRange (set to your values) should do the trick for you.

Is it necessary for you to show good vacuum referring maximum on the plot?
You can also show not the pressure values graph, but 1/pressure values.
The highest value ( 1E03) must be on X Axis: X-axis is always in the bottom or top position on the plot, so you just call setRange, as written above.