This document describes the support for fonts in XFree86. Installing fonts is aimed at the casual user wishing to install fonts in XFree86; the rest of the document describes the font support in more detail.
We assume some familiarity with digital fonts. If anything is not clear to you, please consult Appendix: Background at the end of this document for background information.
XFree86 includes two font systems: the core X11 fonts system, which is present in all implementations of X11, and the Xft fonts system, which is not currently distributed with implementations of X11 that are not based on XFree86 but will hopefully be included by them in the future
The core X11 fonts system is directly derived from the fonts system included with X11R1 in 1987, which could only use monochrome bitmap fonts. Over the years, it has been more or less happily coerced into dealing with scalable fonts and rotated glyphs.
Xft was designed from the start to provide good support for scalable fonts, and do so efficiently. Unlike the core fonts system, it supports features such as anti-aliasing and sub-pixel rasterisation. Perhaps more importantly, it gives applications full control over the way glyphs are rendered, making fine typesetting and WYSIWIG display possible. Finally, it allows applications to use fonts that are not installed system-wide for displaying documents with embedded fonts.
Xft is not compatible with the core fonts system: usage of Xft requires making fairly extensive changes to toolkits (user-interface libraries). While XFree86 will continue to maintain the core fonts system, toolkit authors are encouraged to switch to Xft as soon as possible.