Complex Linear Functions

The function is w = az+b. The blue grid is in the z = x+iy domain, the red image is in the w = u+iv domain.

We will consider w = (1-i) z+(2+i).

Along the real axis, think how w = az+b is
(1-i) t + (2+i) = [t+2, -t+1]
Which yields the path y = -x + 3.

However, along the imaginary axis, w = az+b is
(1-i) it + (2+i) = [t+2, t+1]
Which yields the path y = x - 1.