[Feature request] Simulate an experimental slit as a post-process method

[erwanp]

Hello,

As I understand it, currently the Simulate an experimental slit checkbox changes the input parameter and recomputes the spectrum. Therefore, the slit is only applied at the spectrum calculation time (here in backend.py ).

It would be interesting to be able to simulate the experimental slit on a pre-computed spectrum. This is because on large databases, calculating the spectrum can take ~10-20s (or minutes / hours in other spectral codes!), whereas applying the slit is instantaneous.

This would allow :

• users to apply and adjust (one parametrized Parameterize experimental slit #47 ) a slit after they have computed the spectrum. Which is something all equivalent softwares (ex: https://spectraplot.com) cannot do, although it's very useful for experimentalists !
• to include alternative post-processing functions. For instance, many experimentalists want to plot the transmittance or the opacity instead of the radiance. Radis computes everything, and switching from emission mode ("radiance") to the absorption mode ("transmittance") or opacity ("abscoeff") would become as simple as ticking a checkbox.

Implementation wise, it requires to store the Spectrum object after it is computed, and apply a post-processing function + replot after .

• @suzil is this hard given the current architecture ?