Looking for a Paintbucket / Fill shader

vvvv beta question
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Hallo Coders, I got a little request for a shader, but no idea where to to start. I want to be able to fill a colouring page, for black/white drawings.
A bit like the Paint Bucket Tool in Photoshop. I tried to use UNC’s awesome Growth (EX9.Texture Filter), the result is fun, but not exactly what I was looking for. Hope some one is nice enough to pick up the challenge.

Needs XY (mouse) and color input I think.

https://vvvv.org/sites/default/files/imagecache/large/images/Colour-Drawing.jpg

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