Exploring the Charm of X-Face Headers
=====================================

Inspired by Mick's article "Custom Headers in Claws Mail"
(https://baldric.net/2023/03/23/custom-headers-in-claws-mail/),
I played with X-Face again just for fun. A few mail clients,
like Claws Mail, still display these tiny portraits, although
most modern mail applications ignore them. Even if X-Face has
mostly disappeared, experimenting with it again is a nostalgic
reminder of how inventive early Internet tools were.


matrix.dat
----------

	3 3
	0.0  -1.0   0.0
	-1.0  5.0  -1.0
	0.0  -1.0   0.0


Creating the X-Face Header
--------------------------

	#!/bin/bash

	jpegtopnm images.jpg \
		| pnmscale -xsize 48 -ysize 48 \
		| pnmconvol -matrixfile matrix.dat \
		| ppmtopgm \
		| pgmtopbm -fs \
		| pbmtoxbm \
		| compface


Notes
-----

X-Face is a small monochrome image format originally designed
for displaying user portraits in email headers. The format was
popular in Unix mail environments and Usenet during the early
Internet era. Today only a few mail clients still support it,
but the simplicity of the format makes it an interesting piece
of computing history.