Is imadjust a Matlab-only library? If so, can it be replaced?
The imadjust in Matlab includes 4 arguments as well. You always need to specify the shape of the curve (gamma), and map the values in I to new values in J such that values between low_in and high_in map to values between low_out and high_out.

You can try the link you found yourself, or try this version.