X-Face

File Format
Name	X-Face
Ontology	Electronic File Formats Graphics X-Face
Extension(s)	.face, .xface
Spec	https://purl.org/x-face-spec
Released	~1990

X-Face is a compressed image format that can be placed in an email or Usenet newsgroup message header. It is expected to contain the sender's picture or avatar. It is a 48×48 bi-level (apart from its extensions to support color, bigger images, and animation) image. The format appears to be fairly complex, and probably uses arithmetic coding.

Discussion

Although X-Face data is often expected to be stored in a file, there isn't really a standard X-Face file format. The main thing to be aware of is that sometimes the "X-Face:" header name is stored in the file, and sometimes it is not (a behavior that can potentially break the format's improvement extensions). Different software has different requirements.

File extensions .face and .xface have both been suggested. Sometimes, X-Face data will be in a file named ".face" in the user's home directory.

Most or all X-Face code is based on James Ashton's Compface software, and Compface's code is fairly opaque. A specification has been written by reverse-engineering Compface.

Compface intermediate format

The Compface software by default converts X-Face to and from the Ikon format. It only supports 48×48 images with a bit depth of 1. Most implementations use 16-bit words but one implementation[1] uses 8-bit words.

Software

• Compface
  • compface-1.4.tar.gz (uncompface -X to convert to XBM format)
  • compface-1.5.2.tar.gz
  • compface-25Jan90.tar.gz
  • X-Faces for Windows 95/NT
• FFmpeg
• Deark
• Online X-Face Converter
• x-face-el — extends the format, in a manner unsupported by other software, adding colour/greyscale pixels, animation, and larger image sizes
  • https://web.archive.org/web/20051029080636/http://www.jpl.org/elips/ - Additional Emacs Lisp scripts that handle X-Face, plus examples of extended X-Face.

• Datula - A Japanese e-mail client which supported plugins in versions such as 1.52.01.01, two of which involved extended X-Face.
  • Datula DFaceEX X-Face Plugin - An X-Face viewer plugin for Datula capable of viewing extended X-Faces.
  • XFacePlugin with FaceMake - Another viewer plugin by the same author (saku/Saku works) which includes a program called FaceMake which, on the latest version (Datula's is, but the version of FaceMake shipped in X-FaceTool004, a version for e-mail clients like EdMax and Eudora, among others, isn't) combines the X-Face-el extensions into a unified format of 24-bit RGB with animation (needs to be done frame-by-frame, but the decoder will happily decode it, at least where Datula is concerned) and beyond-48x48px. The 24-bit support in FaceMake doesn't exist in the build bundled with X-FaceTool004, unlike the FaceMake for Datula's X-Face plugin that it is bundled with. FaceMake is also picky.

Samples

• https://dev.mutt.org/trac/wiki/MuttGuide/XFace - Search for "compface tao.xbm".
• WinFace1_3-src.zip → WinFace/default_face.txt
• faces man page, "XFACE SUPPORT" section, has an example.

• https://stgiga.github.io/X-FacePlusFaceAll48pxHeaders.txt - Sample of regular X-Face, Face (Base64+PNG), & the 48x48 x-face-el extended X-Face types (8-bit grayscale & animated 3bpp RGB).
  • https://stgiga.github.io/X-FacePlusFaceAll48pxHeadersFix.txt - Sample of regular X-Face, Face (Base64+PNG), & the 48x48 x-face-el extended X-Face types (8-bit grayscale & animated 3bpp RGB, in a way that works on Datula).
• https://stgiga.github.io/QuadFace.gif - A GIFski GIF rendering of the above, assembled into a 96x96 square cell (useful if everything is 48x48) that modern UIs would prefer.

• https://stgiga.github.io/X-FacePlusFaceAllHeaders.txt - Sample of regular X-Face, Face (Base64+PNG), & the x-face-el extended X-Face types (8-bit grayscale & animated 3bpp RGB, including going beyond 48x48px).
  • https://stgiga.github.io/X-FacePlusFaceAllHeadersFix.txt - Sample of regular X-Face, Face (Base64+PNG), & the x-face-el extended X-Face types (8-bit grayscale & animated 3bpp RGB, including going beyond 48x48px, and in the way that works on Datula).
• https://stgiga.github.io/TallFace.gif - A GIFski GIF rendering of the above, assembled into a 96x144 cell that modern UIs would prefer over stringing them side-by-side like x-face-el does, or in a tiny gallery like Datula does.

• https://stgiga.github.io/X-FacePlusFaceAllHeadersPlus24bitFixOG.txt - Sample of regular X-Face, Face (Base64+PNG), & the x-face-el and Datula extended X-Face types (Datula's animated 24-bit RGB, plus x-face-el's 8-bit grayscale & animated 3bpp RGB, including going beyond 48x48px.)
• https://stgiga.github.io/LushFace.gif - A GIFski GIF rendering of the above, assembled into a 96x144 cell that modern UIs would prefer over stringing them side-by-side like x-face-el does, or in a tiny gallery like Datula does.

• https://web.archive.org/web/20051029080349/http://www.jpl.org/elips/image/x-faces.gif - Many samples of X-Face and X-Face-el (extended mode is known as X-Face-Xmas internally) from long ago.
  • https://web.archive.org/web/19980630075245/http://www.jpl.org/elips/image/x-faces.gif - Oldest (1998) archived version of the collage, featuring beyond-48x48px X-Face-el/X-Face-Xmas X-Faces from long ago in addition to the RGB ones, even mixing the two modes.

• dexvert samples — image/xface

Links

• Faces Archive - Lists some X-Face resources
  • [2] - Archived page
• faces man page
• Wikipedia: X-Face