Actually - learning to draw, one of first thing to learn is proportions.
Distance between eyes is equal to one additional eye; nose lies on a line that connects it to bottom of the ear; mouth are about halfway between chin and nose; body is about seven heads tall, etc.
I'd say constraint solving is pretty much in line with that kind of thinking.
You're right. The drawing canons are, in a way, constraints.
However, it's not relevant for this, I think. Drawing is very different, goal-wise, from design. Designers do learn how to draw early on their education, but I think it's more a matter of learning how to "see" and developing other useful skills. The approach to drawing doesn't translate directly to the approach used while designing.
Distance between eyes is equal to one additional eye; nose lies on a line that connects it to bottom of the ear; mouth are about halfway between chin and nose; body is about seven heads tall, etc.
I'd say constraint solving is pretty much in line with that kind of thinking.