start drawing after cursor has moved at least four pixels
start drawing after cursor has moved at least four pixels

darcs-hash:20080730065258-a887e-481eb7146c385e740ae6c2a1fd24e68d71dfd70e.gz

RaphaelRochet/easystroke,RaphaelRochet/easystroke,thjaeger/easystroke,thjaeger/easystroke