Layout problems arise in a number of domains and one common strategy is to use optimization techniques to find a layout that sat- isfies domain-specific criteria. Researchers have applied this op- timization approach to circuit board layout [Sarrafzadeh and Lee 1993], graph layout [Tollis et al. 1998], component layout in prod- uct design [Cagan et al. 2002], document layout [Jacobs et al. 2003; Hurst et al. 2009], UI layout [Lok and Feiner 2001; Gajos et al. 2010], label layout [Christensen et al. 1995; Vollick et al. 2007], and architectural floor plan layout [Merrell et al. 2010]. Most of these approaches were developed for off-line layout and do not sup- port.
