Discrete frequencies mode

[TF3RDL]

Basically the mapping mode for the transform algorithm "FFT", where all magnitude of raw FFT bins (which is linearly-spaced) within the specified range are displayed, but the graph is still scaled with arbitrary frequency scale provided by "Linear" frequency distribution and usual parameters (except number of bands, which applies to anything other than the proposed "Discrete frequencies" mapping mode), and it would look like this for the bars mode:

When paired with curves drawing mode, it would look similar to Enhanced Spectrum analyzer (foo_enhanced_spectrum_analyzer) like this:

[stuerp]

I don't understand what needs to be changed or fixed...