bug#21846: 25.0.50; emacs hebrew script bidi nikud rendering bug

[Mark H. David]

emacs -Q
C-x C-f ytest-emacs.txt RET

This was using the default font and no other changes or customizations.

You see numerous glaring rendering bugs.

First case:
  Upper right first sequence (bounded by space)
  Sequence description: mem double-yud pasekh sof-nun
  Paste of character sequence: מײַן
  Problem: a "base character standin" glyph appears between what should
  be the 2nd/3rd of 3 bounding boxes, the second of which comprises two
  Unicode characters:
    05F2;HEBREW LIGATURE YIDDISH DOUBLE YOD
    05B7;HEBREW POINT PATAH

Second case: 
  Upper right 5th sequence (bounded by space)
  Sequence description: alef pasekh pey rofe reysh yud ayin
  Paste of character sequence:  אַפֿריקע
  Problem: the base character alef and pey are separated from
    their following nikuds


Many more could be described. I'll stop at two for now.  Should they all
be combined, or should they all be divided?

I could send screen shots, both of how it should look and how it
actually looks, but how do I do that? I don't see a way with this bug
report. Can you give instructions on how to do that if it's useful?

Thanks,

-Mark





In GNU Emacs 25.0.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2015-11-05
Repository revision: 54e2ed97bf904eda2ee5ae9b7822288e10b3abc5
Windowing system distributor 'The X.Org Foundation', version 11.0.11701000
System Description:     Ubuntu 14.04.3 LTS

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Text

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-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

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message dired format-spec
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util help-fns help-mode easymenu cl-loaddefs pcase cl-lib mail-prsvr
mail-utils time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan
thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote dbusbind inotify
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 81228 5903)
 (symbols 48 19102 0)
 (miscs 40 287 135)
 (strings 32 12876 4236)
 (string-bytes 1 378178)
 (vectors 16 15082)
 (vector-slots 8 458413 6458)
 (floats 8 133 86)
 (intervals 56 192 0)
 (buffers 976 12)
 (heap 1024 30041 988))