Darn, looks like you indeed found a way to speed floodfill up, it's lightning fast
. The program seems great to me-- when I was younger and played with paint programs a lot, it frustrated me that when you filled in a black outline with black, and then filled it with something else, you'd lose the whole outline... excellent that you fixed that. I assume the paint-black is RGB 1,1,1 and the outline black is 0,0,0, and you just didn't allow that color to be painted... smart...
Well done indeed
Famous Fighting Furball