

        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_in_sum -= pb

        stackOut = stackOut.next

        yi += <span class="number">4</span>
        
      yw += width
      
    <span class="keyword">for</span> x <span class="keyword">in</span> [<span class="number">0.</span>..width]
      g_in_sum = b_in_sum = r_in_sum = g_sum = b_sum = r_sum = <span class="number">0</span>

     