How does graydist work?

What does each element of the gray dist transfrom mean with repect to the imputs? How is each element calculated. I think i have use case for a weighted distance transfrom, but I cant understand the function.

% Please note this is part of the example included in the MATLAB
% documentation.
A= magic(3)
A = 3×3    
     8     1     6
     3     5     7
     4     9     2

T1 = graydist(A,1,1)
T1 = 3×3    
         0    4.5000    8.0000
    5.5000    6.5000    8.5000
    9.0000   11.5000   10.0000

Prework,

1. I double checked Digital Image Processing By Rafael Gonzalez. The book only discusses the binary distance transfrom. I understand the binary distance transform.
2. I searched google/ youtube.
3. I searched for the cited article but my company does not have access to it.
4. I looked at the algorithm section. The formula has no disciption of the variables.