This example is the one we use to come up with new features. That means, that the code is maybe a bit convoluted, but it aims to showcase what the foleys_gui_magic can do.
This project has 6 IIR filters (juce out of the box), where all the parameters are exposed to the host, so they can be automised and knobs can be attached to each parameter.
It shows how to create frequency response curves from the IIR coefficients, and also shows an analyser plot before and after the processing.