bug#13691: 24.3.50; Problem with glyphs in unibyte buffers

[Eduardo Ochs]

In Emacs24 if I run the code below to define glyphs for the characters
171 and 187 the effect is different on unibyte (i.e., "coding:
raw-text-unix") and non-unibyte buffers, as shown in the attached
screenshot.

My guess is that for some range of characteres that includes 171 and
187 - but not 15, see the screenshot - the glyph lookup is either
disabled in unibyte buffers or it is done using some range translation
that I wasn't able to figure out what is.

Here is the test code:

--snip--snip--

cat > /tmp/g <<'%%%'
(progn

(menu-bar-mode 0)
(tool-bar-mode 0)
(scroll-bar-mode -1)

(defun eepitch-set-glyph (pos &optional char face)
  (aset standard-display-table pos
        (if char (vector (make-glyph-code char face)))))

(if (not standard-display-table)
    (setq standard-display-table (make-display-table)))

(defface eepitch-star-face
  '((t (:foreground "red")))
  "Face used for the red star glyph (char 15).")

(defface eev-glyph-face-green
  '((t (:foreground "green")))
  "Face used for the green glyphs (`<<' and `>>', chars 171 and 187).")

(eepitch-set-glyph ?\^O ?* 'eepitch-star-face)
(eepitch-set-glyph 171 171 'eev-glyph-face-green)
(eepitch-set-glyph 187 187 'eev-glyph-face-green)

(insert "\n;; " 15 171 187)

)


;; Local Variables:
;; coding:            raw-text-unix
;; End:
%%%

emacs23          -fg bisque -bg black -fn 6x13 -Q /tmp/g
emacs24-from-git -fg bisque -bg black -fn 6x13 -Q /tmp/g

--snip--snip--

  Cheers, thanks in advance =),
    Eduardo Ochs
    eduardoochs@gmail.com
    http://angg.twu.net/
    http://angg.twu.net/#eev



P.S.: I use glyphs a lot in my personal files (see
<http://angg.twu.net/glyphs.html>), and a few glyphs - 3, actually -
in a package that I would like to include in Emacs in a few more
months or years: <http://angg.twu.net/#eev>... I tried to keep this
first bug report quite concise, but I may have tests ready for several
other related cases where the behaviors of Emacs24 were a bit
unexpected to me...

P.P.S.: the Emacs23 used for comparison was the standard one in Debian
Squeeze,

  GNU Emacs 23.2.1 (i486-pc-linux-gnu, GTK+ Version 2.20.1) of
    2013-01-08 on murphy, modified by Debian

and the extra info for my Emacs24 from the git repository (I ran it
with "-Q") follows below.




In GNU Emacs 24.3.50.2 (i686-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2013-02-11 on varda
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
System Description:     Debian GNU/Linux 6.0.6 (squeeze)

Important settings:
  value of $LANG: C
  locale-coding-system: nil
  default enable-multibyte-characters: t

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils time-date tooltip ediff-hook vc-hooks
lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment lisp-mode register page menu-bar
rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax
facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak
czech european ethiopic indian cyrillic chinese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer loaddefs button faces
cus-face macroexp files text-properties overlay sha1 md5 base64 format
env code-pages mule custom widget hashtable-print-readable backquote
make-network-process dbusbind inotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty emacs)

glyph-bug-screenshot.png
Description: PNG image