Marching Squares: Boundary detection

A little code for a change.

Sakri was working on this, and I ported a class from Java which I believe he adapted into his final implementation. It’s a basic tool for morphing, 3D surface reconstruction, and vectorization.

I’ve cleaned up my version of it and I offer it here. The important function signature looks like this:

public static function perimeter(data:BitmapData, x:int, y:int):Vector.<Point>

It returns a list of pixels representing the boundary between opaque and transparent pixels, starting from a single boundary point that you provide.

You can get a boundary point using Sakri’s and Mario’s EdgeFinder class.

Download the source.

How it works: Marching Squares on Wikipedia