Shear Based Bijective Digital Rotation in Hexagonal Grids.

In this paper, a new bijective digital rotation algorithm for the hexagonal grid is proposed. The method is based on an decomposition of rotations into shear transforms. It works for any angle with an hexagonal centroid as rotation center and is easily invertible. The algorithm achieves an average distance between the digital rotated point and the continuous rotated point of about 0.42 (for 1.0 the distance between two neighboring hexagon centroids).