Rotating a section of a two dimensional array.

Question

I've read this SO question on how to rotate a two-dimensional array many times, and I was curious as to how you could expand this situation to work with a section of a two-dimensional array. I've thought about it for a while, and I can't seem to come up with a good equation. Essentially what I'm wanting to do is something like this:

1  2  3  4  5  6            13 7  1  4  5  6
7  8  9  10 11 12           14 8  2  10 11 12
13 14 15 16 17 18           15 9  3  16 17 18
19 20 21 22 23 24   ---->   19 20 21 22 23 24
25 26 27 28 29 30           25 26 27 28 29 30
31 32 33 34 35 36           31 32 33 34 35 36

I'm writing this in Ruby, currently, but I don't particularly care what language the solution to this kind of problem would be. I'm just curious as to how you'd go about solving this kind of problem.

Edit: To add some more specifics, the basic parameters for a function that could do this would be something that looked like this

def rotate(array, times=1, x=0, y=0, len=nil)
  ...
end

Answer 1

Something like that?

def rotate a,len,ii=0,jj=0,t=1
    t.times do
        a = a.map.with_index do |line,i|
            line.map.with_index do |e,j|
                (ii...(ii+len))===i && (jj...(jj+len))===j ?
                    a[ii+jj+len-j-1][jj+i-ii] : e
            end
        end
    end
    a
end

t = (1..6).map{|i|(1..6).map{|j|j+6*i-6}}
t.each { |i| p i }

rotate(t,3,2,1).each { |i| p i }
rotate(t,6).each { |i| p i }
rotate(t,3,2,1,4).each { |i| p i }
rotate(t,6,0,0,4).each { |i| p i }
rotate(t,2,2,2,3).each { |i| p i }