6x13 fixed Review

6x13 is the classic fixed monospace bitmap font that is expected to be available on every X server. It is part of the misc-fixed family. These fonts were handcrafted for readability in a terminal.

Why bitmap fonts? At a small text size each character has a limited resolution. A character size of 6x13 pixels means only 78 pixels per character. Modern fonts are designed to be scalable, and are less legible at these small sizes. Using bitmap fonts increases legibility by eliminating scaling and sub-pixel aliasing artifacts. Some scalable fonts include "ppems" embedded bitmaps for this reason.

With a fixed 6x13 font, the number of characters in a terminal is easy to compute. Every character is 6x13 pixels, so a 1440x900 pixel display will render 240x69 characters. 6x13 is semi-condensed, meaning the characters are slightly thinner than usual so that more can be printed on a line.

The disadvantage of misc-fixed fonts is that they don't scale, which can cause problems with displays that vary wildly from traditional pixel density. Although 6x13 is the traditional fixed font, there are numerous other sizes ranging from 5x7 to 10x20.