Bulge, shear and squash: a representation for the general conic arc

Abstract There is a need for a well conditioned representation of a general conic arc, for use in computer graphics and elswehere. An extension is proposed to Sabin's ‘bulge-factor’ for the circular arc, by adding two more factors, ‘shearlrs and ‘squash’. These can continuously cover the entire spectrum of conic arcs, from elliptic to hyperbolic. Integer representation, for display files or for transmission to an ‘intelligent terminal’, is also considered.