Function object for compression (Maximus clone)

I'm trying to make a complex comressor which will essentially work like Maximus from image-line (fl-studio).

Instead of a simple ratio and threshold control, this plugin has an XY grid where you can create your own function, the X axis represents Input level and the Y axis output level. So if at x=0 dB you place a point with y= -3 dB, you'll have a 2/1 ratio at input level 0 dB. If your function is a simple diagonal line (X = Y), then the ratio is 1/1. It allows placement of points and curves between them similar to the function object.

So...is there a way to input the amplitude of a signal into the function object as X coordinates, so that it outputs the corresponding Y values? The closest thing I found to what I want is the "nth" message, which outputs the Y value of an X POINT. But nothing inbetween the points, which is what I need.

Since I know that the function generator is meant mostly for envelope related tasks, if what I'm asking is impossible, then is there maybe another way to create functions like that in Max? Maybe through Jitter?