Please file all relevant information in gnome bugzilla instead of just pointing to another bug tracker.

The original bug information as requested:


-------------------------------BEGIN--------------------------------
Package: libvte9
Version: 1:0.20.1-1
Severity: important

Greetings,

 Recent upload of vte breaks the GNU screen display in GBK encoded
terminals. Please try to cat the attach file (GBK encoded) in a normal
terminal emulator set to GBK encoding, then in GNU screen set
":encoding gbk" and cat the file to see the differences. Thanks!

Difei


-- System Information:
Debian Release: squeeze/sid
 APT prefers unstable
 APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.28-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=zh_CN.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages libvte9 depends on:
ii  libatk1.0-0               1.24.0-2       The ATK accessibility toolkit
ii  libc6                     2.9-7          GNU C Library: Shared libraries
ii  libcairo2                 1.8.6-2+b1     The Cairo 2D vector graphics libra
ii  libfontconfig1            2.6.0-3        generic font configuration library
ii  libfreetype6              2.3.9-4        FreeType 2 font engine, shared lib
ii  libglib2.0-0              2.20.1-1       The GLib library of C routines
ii  libgtk2.0-0               2.16.1-2       The GTK+ graphical user interface
ii  libncurses5               5.7+20090404-1 shared libraries for terminal hand
ii  libpango1.0-0             1.24.0-3+b1    Layout and rendering of internatio
ii  libvte-common             1:0.20.1-1     Terminal emulator widget for GTK+

libvte9 recommends no packages.

libvte9 suggests no packages.

-- no debconf information

---------------------------------END---------------------------------

The attachment can be found at http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=vte-gbk;att=1;bug=525374

Plus, downgrading the Debian package to version 0.17.4-2+b1 (0.17.4 as upstream version) makes the symptom disappear.

It looks like that the font priority messed up, as '━' character is picked from a wide character fonts that takes a 2-narrow-character space, which leads to the mess up.  It also seems that the font I choose from profile settings - DejaVu Sans Mono - is not picked, but the other non-mono variant.  HTH.

Created attachment 134199 [details]
normal display

The normal display of aptitude.

Created attachment 134200 [details]
garbled display

This is the garbled display.

Please note that the fonts are different in garbled.png too, so it looks like the font preference is not evaluated in screen.  HTH.

It looks like the symptom is related to the problem reported in bug#435000.  Maybe the pangocairo backend doesn't pick the correct fonts as expected.

pangocairo backend is irrelevant AFAIU.  Are you running under CJK locale?

Yes, I'm under zh_CN.UTF-8.  I'll check whether it works in en_US.UTF-8 later today.  But it used to work smoothly under zh_CN.UTF-8 FTR.

No luck under en_US.UTF-8 either, same problem :(

After another try, it indeed doesn't happen under en_US.UTF-8: the correct "-" is chosen and display is no longer garbled.  Maybe then it is caused by the default font chosen under different locale?  If so, does this problem lie in pango or the font?

That character is U+2501 BOX DRAWINGS HEAVY HORIZONTAL, which has ambiguous width in Unicode and assumes double width under CJK locales.  I don't think using that character is justified.  Not sure though.

(In reply to comment #11)
> That character is U+2501 BOX DRAWINGS HEAVY HORIZONTAL, which has ambiguous
> width in Unicode and assumes double width under CJK locales.  I don't think
> using that character is justified.  Not sure though.
> 

Thanks for the explanation.  AIUI this bug is not related to vte any more, or at least not where the real cause resides.  Any idea where it belongs?

Please bring it up with the application causing it.  It may be an issue in slang or ncurses.  Not sure.