Speaking of Max Fleischer, there was an interesting thing about the Betty Boop cartoon... Big Band leader Cab Calloway* was filmed dancing for Minnie the Moocher. One of the cartoon characters was animated by drawing the cells over the frames of Cab dancing in a process called Rotoscope. So, the animation reflected Cab's actual movement. The Rotoscope process was invented by the Fleishers.
* For you younger guys, Cab Calloway was the custodial engineer at the orphanage in the original Blues Brothers movie... who later in the movie sang his band's theme song onstage "Minnie the Moocher" with the Blues Brothers band.
http://www.heptune.com/minnbett.html