  Image-guided drawing can compensate for the lack of skills but often requires
a significant number of repetitive strokes to create textures. Existing
automatic stroke synthesis methods are usually limited to predefined styles or
require indirect manipulation that may break the spontaneous flow of drawing.
We present a method to autocomplete repetitive short strokes during users'
normal drawing process. Users can draw over a reference image as usual. At the
same time, our system silently analyzes the input strokes and the reference to
infer strokes that follow users' input style when certain repetition is
detected. Users can accept, modify, or ignore the system predictions and
continue drawing, thus maintaining the fluid control of drawing. Our key idea
is to jointly analyze image regions and operation history for detecting and
predicting repetitions. The proposed system can effectively reduce users'
workload in drawing repetitive short strokes and facilitates users in creating
results with rich patterns.
