[Bug 952724] [NEW] status area scrolled out infinitely (tmux-backend with libvte + VTE_CJK_WIDTH=1)

[Launchpad Bug Tracker]

You have been subscribed to a public bug by Vibhav Pant (vibhavp):

When environment varibable "VTE_CJK_WIDTH=1" is set, byobu-tmux is
scroll-out infinitely.

How to reproduce:

 1) install precise.
 2) open gnome-terminal
 3) exec:
    $ export VTE_CJK_WIDTH=1; gnome-terminal --disable-factory 

    Notes: if you exec gnome-terminal without disable-factory, gnome-
terminal will take over the environment variable of parents' initial
condition, so VTE_CJK_WIDTH will be ignored.

 3') another aproach:
   create  /etc/profile.d/vte_cjk_width.sh file as follows, and session restart(log-out and log-in)
   ------------------------------------------
   $ cat /etc/profile.d/vte_cjk_width.sh
    export VTE_CJK_WIDTH=1
   ------------------------------------------

 4) exec:
    byobu-tmux (or byobu)

Workaround:
 disable "logo" indicator from byobu-config.
  (if you want edit config directoly,  edit you .byobu/status::tmux_left : "logo" -> "#logo" )

Root cause:
 byobu-tmux(byobu with tmux backends) use the Ubuntu Logo character from Ubuntu Fonts. Ubuntu Logo char hits "East Asian Ambiguous" problem, that have ambigous-wide, so that switch the wide of rendering at run-time. 

When VTE_CJK_WIDTH=0 or not set, the Ubuntu Logo wide is 1, but,
when VTE_CJK_WIDTH=1, the Ubuntu Logo wide is 2. So that cause the scrolling problem.


Background: 
  For historical reason, "VTE_CJK_WIDTH=1" is libvte's workaround of Unicode::"East Asian Ambiguous width" problem, when VTE_CJK_WIDTH=0, the ambigous wide char's wide is 1, therefor VTE_CJK_WIDTH=1 is set, the ambigous wide char's wide is 2.
  In CJK environment(ESP Japanese), that workaround is important for CLI/terminal sessions. If that is not set, the ambigous wide char render without correctness wide. So, I believe that many CLI/terminal users enable the VTE_CJK_WIDTH=1 in their /etc/profile.d/ at Japan.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: byobu 5.16-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-18.28-generic-pae 3.2.9
Uname: Linux 3.2.0-18-generic-pae i686
ApportVersion: 1.94.1-0ubuntu2
Architecture: i386
Date: Mon Mar 12 13:20:24 2012
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
PackageArchitecture: all
ScreenRC:
 
SourcePackage: byobu
UpgradeStatus: Upgraded to precise on 2012-03-12 (0 days ago)

** Affects: byobu
     Importance: Low
         Status: Fix Committed

** Affects: byobu (Ubuntu)
     Importance: Low
         Status: Confirmed


** Tags: apport-bug i386 precise
-- 
status area scrolled out infinitely (tmux-backend with libvte + VTE_CJK_WIDTH=1)
https://bugs.launchpad.net/bugs/952724
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