)) &lt;&lt; <span class="number">2</span>
        
        r_sum += (r_in_sum += (stackIn.r = pixels[p]))
        g_sum += (g_in_sum += (stackIn.g = pixels[p + <span class="number">1</span>]))
        b_sum += (b_in_sum += (stackIn.b = pixels[p + <span class="number">2</span>]))
        
        stackIn = stackIn.next
        
        r_out_sum += (pr = stackOut.r)
        g_out_sum += (pg = stackOut.g)
        b_out_sum += (pb = stackOut.b)
        
        r_in_sum -= pr
        g_in_sum -= pg
        b_i