X-Face headers describe a 48x48 pixel black-and-white (1 bit
depth) image that’s supposed to represent the author of the message.
It seems to be supported by an ever-growing number of mail and news
readers.
Viewing an X-Face header either requires an Emacs that has
‘compface’ support, or that you
have suitable conversion or display programs installed. If your Emacs
has image support the default action is to display the face before the
From header. If there’s no native X-Face support, Gnus
will try to convert the X-Face header using external programs
from the pbmplus package and friends, see below. The
default action under Emacs without image support is to fork off the
display program.
On a GNU/Linux system, the display program is included in the
ImageMagick package. For external conversion programs look for packages
with names like netpbm, libgr-progs and compface.
On Windows, you may use the packages netpbm and compface
from https://gnuwin32.sourceforge.net. You need to add the
bin directory to your PATH environment variable.
The variable gnus-article-x-face-command controls which programs
are used to display the X-Face header. If this variable is a
string, this string will be executed in a sub-shell. If it is a
function, this function will be called with the face as the argument.
If gnus-article-x-face-too-ugly (which is a regexp) matches the
From header, the face will not be shown.
(Note: x-face is used in the variable/function names, not
xface).
Face and variable:
gnus-x-face ¶Face to show X-Face. The colors from this face are used as the foreground and background colors of the displayed X-Faces. The default colors are black and white.
gnus-face-properties-alist ¶Alist of image types and properties applied to Face (see Face) and
X-Face images. The default value is ((pbm . (:face gnus-x-face))
(png . nil)). Here are examples:
;; Specify the altitude of Face and X-Face images in the From header.
(setq gnus-face-properties-alist
'((pbm . (:face gnus-x-face :ascent 80))
(png . (:ascent 80))))
;; Show Face and X-Face images as pressed buttons.
(setq gnus-face-properties-alist
'((pbm . (:face gnus-x-face :relief -2))
(png . (:relief -2))))
See Image Descriptors in The Emacs Lisp Reference Manual,
for the valid properties for various image types. Currently,
pbm is used for X-Face images and png is used for Face
images in Emacs.
If you use posting styles, you can use an x-face-file entry in
gnus-posting-styles, See Posting Styles. If you don’t, Gnus
provides a few convenience functions and variables to allow easier
insertion of X-Face headers in outgoing messages. You also need the
above mentioned ImageMagick, netpbm or other image conversion packages
(depending the values of the variables below) for these functions.
gnus-random-x-face goes through all the ‘pbm’ files in
gnus-x-face-directory and picks one at random, and then
converts it to the X-Face format by using the
gnus-convert-pbm-to-x-face-command shell command. The
‘pbm’ files should be 48x48 pixels big. It returns the X-Face
header data as a string.
gnus-insert-random-x-face-header calls
gnus-random-x-face and inserts a ‘X-Face’ header with the
randomly generated data.
gnus-x-face-from-file takes a GIF file as the parameter, and then
converts the file to X-Face format by using the
gnus-convert-image-to-x-face-command shell command.
Here’s how you would typically use the first function. Put something like the following in your ~/.gnus.el file:
(setq message-required-news-headers
(nconc message-required-news-headers
(list '(X-Face . gnus-random-x-face))))
Using the last function would be something like this:
(setq message-required-news-headers
(nconc message-required-news-headers
(list '(X-Face . (lambda ()
(gnus-x-face-from-file
"~/My-face.gif"))))))