Fonts & Encodings

Appendix A. Bitmap Font Formats

Without a doubt, bitmap font formats are things of the past. Aside from a few visionaries such as Luc Devroye [117], who dreams of the perfect rendition of a font in bitmap form with a pixel having the size of a molecule of ink (!), few people give serious consideration to bitmap fonts today, since all operating systems, without exception, have switched to vector fonts.

Yet bitmap fonts are practical for display on screen. First, they are rendered more cleanly: as much as we sing the praises of vector fonts, a good, sturdy bitmap font is more efficient than the most beautiful Aldine for displaying text on the screen as it is typed, especially at a small size. Moreover, bitmap fonts are easy to modify and adapt to changing needs. Creating a new glyph takes less than a minute; modifying it is a matter of a few clicks to enable or disable a handful of pixels.

Bitmap fonts can always be useful in any application oriented towards reading on a screen rather than towards printing, such as the Unix console that we use every day but hardly ever print out.

Next, there are also bitmap fonts that go with vector fonts. An intelligent operating system can take advantage of them to display certain actual sizes optimally while using vector fonts for printing.

Below we shall examine the most common bitmap font formats. Most of them are surprisingly simple, unlike those for vector fonts.