     // iterative thinning algorithm
     unsigned int iterations = 0;
     // do {
-    //     skeletonize_pass<<<grid_dim, block_dim>>>(src_bitmap->data, dst_bitmap->data, src_bitmap->width, src_bitmap->height, padding_amounts);
+    //     skeletonize_pass<<<grid_dim, block_dim>>>(src_bitmap->data, dst_bitmap->data, src_bitmap->width, src_bitmap->height, padding);
     //     swap_bitmaps(&src_bitmap, &dst_bitmap);
 
     //     iterations++;


    // Remove extra padding that was added to the images (don't care about
    // src_bitmap, so only need to unpad dst_bitmap)
    unpad_binary_bitmap(&dst_bitmap, padding_amounts);

    // save 8-bit binary-valued grayscale version of dst_bitmap to dst_fname
    binary_to_grayscale(dst_bitmap);


#define PAD_TOP 2
#define PAD_LEFT 2
#define PAD_BOTTOM 1
#define PAD_RIGHT 1

#define P2(data, row, col, width) ((data)[((row)-1) * width +  (col)   ])
#define P3(data, row, col, width) ((data)[((row)-1) * width + ((col)-1)])
