11. The method of claim 10 , wherein the identifying of at least one boundary additionally comprises reversing the extending for ones of the extended bounding rectangles with at least one layout relationship that changed as a result of the extending.
11. The method of claim 10 , wherein the identifying of at least one boundary additionally comprises reversing the extending for ones of the extended bounding rectangles with at least one layout relationship that changed as a result of the extending. 12. The method of claim 11 , wherein the identifying of at least one boundary additionally comprises identifying one or more additional candidate boundaries aligned with respective maximal edges of respective groups of the bounding rectangles subject to the extending, and repeating the extending and the reversing for each of the groups.