If you want a clean solution, you'll have to wait untill I add the code to the library, or add it yourself. You could make your own Analog class, as explained on the Wiki. Take a look at Analog.h and Analog.cpp for inspiration. First try to understand how the code I posted works.
If you don't have that much time, just create the HystFilters manually, and use the Analog::map(std::function<int(int)>) function to apply them to all potentiometers. That's exactly what happens in the code I posted. Try to understand it first, and ask questions if you don't understand how it works.
Here are some comments:
[b][color=#d35400]Analog[/color][/b] [color=#000000]potentiometers[/color][color=#000000][[/color][color=#000000]][/color] [color=#434f54]=[/color] [color=#000000]{[/color] [color=#434f54]// Create an array of 4 new Analog objects[/color]
[color=#000000]{[/color][color=#000000]multiplexer[/color][color=#434f54].[/color][color=#d35400]pin[/color][color=#000000]([/color][color=#000000]0[/color][color=#000000])[/color][color=#434f54],[/color] [b][color=#d35400]MIDI_CC[/color][/b][color=#434f54]:[/color][color=#434f54]:[/color][color=#00979c]Channel_Volume[/color][color=#434f54],[/color] [color=#000000]1[/color][color=#000000]}[/color][color=#434f54],[/color]
[color=#000000]{[/color][color=#000000]multiplexer[/color][color=#434f54].[/color][color=#d35400]pin[/color][color=#000000]([/color][color=#000000]1[/color][color=#000000])[/color][color=#434f54],[/color] [b][color=#d35400]MIDI_CC[/color][/b][color=#434f54]:[/color][color=#434f54]:[/color][color=#00979c]Channel_Volume[/color][color=#434f54],[/color] [color=#000000]2[/color][color=#000000]}[/color][color=#434f54],[/color]
[color=#000000]{[/color][color=#000000]multiplexer[/color][color=#434f54].[/color][color=#d35400]pin[/color][color=#000000]([/color][color=#000000]2[/color][color=#000000])[/color][color=#434f54],[/color] [b][color=#d35400]MIDI_CC[/color][/b][color=#434f54]:[/color][color=#434f54]:[/color][color=#00979c]Channel_Volume[/color][color=#434f54],[/color] [color=#000000]3[/color][color=#000000]}[/color][color=#434f54],[/color]
[color=#000000]{[/color][color=#000000]multiplexer[/color][color=#434f54].[/color][color=#d35400]pin[/color][color=#000000]([/color][color=#000000]3[/color][color=#000000])[/color][color=#434f54],[/color] [b][color=#d35400]MIDI_CC[/color][/b][color=#434f54]:[/color][color=#434f54]:[/color][color=#00979c]Channel_Volume[/color][color=#434f54],[/color] [color=#000000]4[/color][color=#000000]}[/color][color=#434f54],[/color]
[color=#000000]}[/color][color=#000000];[/color]
[color=#000000]HystFilter[/color] [color=#000000]hystFilters[/color][color=#000000][[/color][color=#000000]4[/color][color=#000000]][/color][color=#000000];[/color] [color=#434f54]// Create an array of 4 new HystFilter objects[/color]
[color=#434f54]// Make sure that the number of HystFilters and the number of Analog potentiometers are the same[/color]
[color=#00979c]const[/color] [b][color=#d35400]size_t[/color][/b] [color=#000000]nb_pots[/color] [color=#434f54]=[/color] [color=#00979c]sizeof[/color][color=#000000]([/color][color=#000000]potentiometers[/color][color=#000000])[/color] [color=#434f54]/[/color] [color=#00979c]sizeof[/color][color=#000000]([/color][color=#000000]potentiometers[/color][color=#000000][[/color][color=#000000]0[/color][color=#000000]][/color][color=#000000])[/color][color=#000000];[/color]
[color=#00979c]const[/color] [b][color=#d35400]size_t[/color][/b] [color=#000000]nb_hyst[/color] [color=#434f54]=[/color] [color=#00979c]sizeof[/color][color=#000000]([/color][color=#000000]hystFilters[/color][color=#000000])[/color] [color=#434f54]/[/color] [color=#00979c]sizeof[/color][color=#000000]([/color][color=#000000]hystFilters[/color][color=#000000][[/color][color=#000000]0[/color][color=#000000]][/color][color=#000000])[/color][color=#000000];[/color]
[color=#000000]static_assert[/color][color=#000000]([/color][color=#000000]nb_pots[/color] [color=#434f54]==[/color] [color=#000000]nb_hyst[/color][color=#434f54],[/color] [color=#005c5f]"Error: number of Analog potentiometers should be the same as the number of HystFilters"[/color][color=#000000])[/color][color=#000000];[/color]
[color=#00979c]void[/color] [color=#5e6d03]setup[/color][color=#000000]([/color][color=#000000])[/color] [color=#000000]{[/color]
[color=#5e6d03]for[/color] [color=#000000]([/color][b][color=#d35400]size_t[/color][/b] [color=#000000]i[/color] [color=#434f54]=[/color] [color=#000000]0[/color][color=#000000];[/color] [color=#000000]i[/color] [color=#434f54]<[/color] [color=#000000]nb_pots[/color][color=#000000];[/color] [color=#000000]i[/color][color=#434f54]++[/color][color=#000000])[/color] [color=#434f54]// For all potentiometers[/color]
[color=#434f54]// Apply a HystFilter to the analog value before sending it over MIDI[/color]
[color=#000000]potentiometers[/color][color=#000000][[/color][color=#000000]i[/color][color=#000000]][/color][color=#434f54].[/color][color=#d35400]map[/color][color=#000000]([/color][color=#000000][[/color][color=#000000]i[/color][color=#000000]][/color][color=#000000]([/color][color=#00979c]int[/color] [color=#000000]raw[/color][color=#000000])[/color][color=#000000]{[/color] [color=#5e6d03]return[/color] [color=#000000]([/color][color=#00979c]int[/color][color=#000000])[/color] [color=#000000]hystFilters[/color][color=#000000][[/color][color=#000000]i[/color][color=#000000]][/color][color=#434f54].[/color][color=#000000]getOutputLevel[/color][color=#000000]([/color][color=#000000]raw[/color][color=#000000])[/color][color=#000000];[/color] [color=#000000]}[/color][color=#000000])[/color][color=#000000];[/color]
[color=#434f54]// Note that you need a different HystFilter for each potentiometer[/color]
[color=#000000]}[/color]
If you don't understand the [nobbc]potentiometers[i].map(...)[/nobbc] part, it's a capturing lambda expression (google it).