URL:
<http://savannah.gnu.org/bugs/?33756>
Summary: Cursor positioning fails due to incorrect width
assumptions
Project: GNU Screen
Submitted by: towo
Submitted on: Tue 12 Jul 2011 16:36:12 GMT
Category: Program Logic
Severity: 3 - Normal
Priority: 5 - Normal
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Release: 4.0.2
Fixed Release: None
Planned Release: None
Work Required: None
_______________________________________________________
Details:
Apparently screen transforms absolute cursor positioning escape sequences
from the application into relative ones towards the host terminal.
This is fatal practice whenever screen's assumption of character width
does not reflect the actual width on the terminal.
This is particularly the case if screen is invoked with a locale environment
not matching the terminal character encoding, e.g. with LC_ALL=C in a
UTF-8 terminal, see screenshot menu1.png where screen fails miserably
to position the menu borders (which are properly placed by the application).
Note that this (arguably misconfigured) environment is not unlikely to
occur in a network after remote login.
The problem occurs, however, also if locale setup is proper, due to the
many different versions of Unicode character width data. So around
double-width characters the problem may still occur and spoil the
display layout, see screenshot menu2.png.
I don't think this transformation (probably to save a few bytes occasionally)
is a proper thing to do, it is not transparent handling of the application's
escape sequences in any case. Please change it.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Tue 12 Jul 2011 16:36:12 GMT Name: menu1.png Size: 26kB By: towo
<http://savannah.gnu.org/bugs/download.php?file_id=23645>
-------------------------------------------------------
Date: Tue 12 Jul 2011 16:36:12 GMT Name: menu2.png Size: 25kB By: towo
<http://savannah.gnu.org/bugs/download.php?file_id=23646>
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?33756>
_______________________________________________
Message sent via/by Savannah
http://savannah.gnu.org/
