> Could someone let me know where to find an algorithm that will find the
> points along the edge of a region of color (similar to flood fill but
> only return the boundary). Paint Shop Pro does this with their "magic
> wand" tool.
It's quite simple. How do you mark the border of a lake if you're
started swimming in it? You swim to shore, and take a walk around the
lake. That's really all there is to it. The only tricky parts are to
set up a useful definition of the "shore", and how to trace the shore,
always keeping water to your left, and land to your right.
Even if all the snow were burnt, ashes would remain.