Was the movie 'All Dogs Go To Heaven' based on a book?

I recently bought this movie for my iPod to take a trip down memory
lane. I remember watching this when I was a kid and being terribly
creeped out by the perilous and deadly situations that Charlie got
into. (Not to mention the dreaded dream sequence. It still gives me
chills!)

Watching this movie as an adult gave me a new perspective on the
movie, and a new appreciation for the sheer uniqueness of it. Gambling
dogs? Horrifying images accompanied by unusually cheerful musical
numbers?

It makes me wonder. Was this movie based off of a book, or did Don
Bluth concieve the idea by himself? Usually, bizarre films like this
come from a book, and they are not the result of holywood executives
brainstorming different plot ideas.