The Markov pen: online synthesis of free-hand drawing styles

Learning expressive curve styles from example is crucial for interactive or computer-based narrative illustrations. We propose a method for online synthesis of free-hand drawing styles along arbitrary base paths by means of an autoregressive Markov Model. Choice on further curve progression is made while drawing, by sampling from a series of previously learned feature distributions subject to local curvature. The algorithm requires no user-adjustable parameters other than one short example style. It may be used as a custom "random brush" designer in any task that requires rapid placement of a large number of detail-rich shapes that are tedious to create manually.