How to flood-fill part of a bitmap enclosed by a black border with my chosen color?

Question

I want to programmatically modify a bitmap using python but don\'t really need a thorough grounding in the subject, so would like to concentrate on learning just what I need

Answer 1

PIL has an undocumented function ImageDraw.floodfill:

>>> import ImageDraw
>>> help(ImageDraw.floodfill)
Help on function floodfill in module ImageDraw:

floodfill(image, xy, value, border=None)
    Fill bounded region.

(Flood-filling should generally be a last resort because it interacts poorly with anti-aliased lines. It is usually better to get the actual boundary data for the counties and then draw a filled polygon. However, PIL doesn't support anti-aliased line drawing so this advice is useless unless you switch your drawing module to something more capable like PythonMagick or pycairo.)