I am trying for a coloring app and to figure out floodfill in objective c anybody did this before..???I am reading all pixel data in a picture and i can change it also..but
Theres lots of source code available for flood fill algos. You can probably find a good one and throw it in a method
http://www.google.co.uk/search?q=c+flood+fill+algorithm
If its been written in C/C++ you can use it in Objective-C
I figured it out myself This link really helped me to identify the black and white dot in particular pixels.flood filling is explained here.