Interactive Graphics Systems Group
Department of Computer Science
Technische Universität Darmstadt
Rundeturmstr. 6, 64283 Darmstadt, Germany
Scan-conversion of Archimedes' spiral
(a straight line in polar coordinates) is investigated.
It is shown that an exact algorithm requires transcendental functions and, thus, cannot have a fast and exact integer implementation. Piecewise polynomial approximations are discussed and a simple algorithm based on piecewise circular approximation is derived. Variations of the algorithms allow to scan convert other types of spirals.