A note on discrete representation of lines

In raster graphics a line must be drawn as a “discrete segment”, a set of integer grid points that lie close to the line. Equivalence classes of identically drawn lines are described in terms of Farey series; this treatment notably simplifies previous work of Dorst and Smeulders. A log n algorithm serves to identify a line's equivalence class. Using it to choose among precomputed n-pixel discrete segments, we may draw lines in n-pixel blocks rather than the customary single-pixel steps.