I think I see what you might be trying to go for but shouldn't it be:
glTranslatef(cpBodyGetPos(ball.body).x/size.width - 0.5*viewAspect, cpBodyGetPos(ball.body).y/size.height - 0.5, 0.0)

I don't know what "size" is referring to though.

Also, I still think you want the inverse of the ball motion.

Thanks. I solved it. The answer is glTranslatef(0.5*viewAspect - cpBodyGetPos(ball.body).x/size.height, 0.5 - cpBodyGetPos(ball.body).y/size.height, 0.0).