Neat! In my experience jump flooding on the GPU is faster than any CPU side approach for images bigger than a few hundred pixels. It's O(n ^ 2 log n) which sounds really expensive, but it requires just O(log n) draw calls.

The link you provided also describes a GPU amenable approach, but it says that jump flooding on the GPU is faster.

> For a more efficient GPU-amenable method, see also jump flooding by Rong and Tan. Their method generates a closest point coordinate field from which a distance field can be derived.