A Linear Algorithm for Incremental Digital Display of Circular Arcs
Circular arcs can be drawn on an incremental
display device such as a cathode ray tube, digital 
plotter, or matrix prin ter using only sign testing and
elementary addition and subtraction.  This paper 
describes methodology for producing dot or
step patterns closet to the true circle.
CACM February, 1977
Bresenham, J.
