Canonical Ordering for Triangulations on the Cylinder, with Applications to Periodic Straight-line Drawings
Luca Castelli Aleardi, Olivier Devillers, Éric Fusy · 2012
Abstract. We extend the notion of canonical orderings to cylindric triangula-tions. This allows us to extend the incremental straight-line drawing algorithm of de Fraysseix, Pach and Pollack to this setting. Our algorithm yields in linear time a crossing-free straight-line drawing of a cylindric triangulation G with n vertices on a regular grid Z/wZ × [0..h], with w ≤ 2n and h ≤ n(2d+1), where d is the (graph-) distance between the two boundaries. As a by-product, we can also obtain in linear time a crossing-free straight-line drawing of a toroidal triangulation with n vertices on a periodic regular grid Z/wZ × Z/hZ, with w ≤ 2n and h ≤ 1 + n(2c + 1), where c is the length of a shortest non-contractible cycle. Since c ≤ √2n, the grid area is O(n5/2). Our algorithms apply to any triangulation (whether on the cylinder or on the torus) with no loops nor multiple edges in the periodic representation. 1.