Default shift: Documentation error?

[aloboa]

The help page ?glcm initially states:
"The default textures are calculated using a 45 degree shift. "
But in the example, it says (twice):
"Calculate using default 90 degree shift"

Which is thus the default?

Also, I'm confused on the actual nature of the "shift". Initially, I understood it was setting the jump of the slicing window,
but after reading the help page I tend to think that it refers to the way the adjacency is defined within the window, that is
for shift = c(1,1) the co-occurrence is checked between pixel (i,i) and pixel (i+1, i+1) within the window.
If this is the case (please confirm), I understand that the slicing window always moves by jumping to next column and then to the next row (please confirm as well). For large images and large windows, moving the window by more than 1 pixel could be an acceptable simplification with a considerable gain of speed.