flood fill (scanline)

http://simulations.narod.ru/
This is flood fill or paint bucket tool in matlab. scanline algoritm used because it fast. Seeds shown as red dots. The function itslef is flood_fill.m
rest files:
zz_flood_fill_test.m - run it to test flood_fill.m
zz_flood_fill_test_movie.m - run it to get animation
zz_flood_fill_movie.m used in animation
explane.png - this picture explane how scanline works
smile.png - used in flood fill test

The idea is fill the object with horizontal lines. during line scan the line set seeds up and down if there is a place (explane.png). In next iteration new scan lines start from seeds. seed accumulated to a stack.