bugGNU Screen - Bugs: bug #33756, Cursor positioning fails due to...


bug #33756: Cursor positioning fails due to incorrect width assumptions

Submitted by:  Thomas Wolff <towo>
Submitted on:  Tue Jul 12 16:36:12 2011  
Category: Program LogicSeverity: 3 - Normal
Priority: 5 - NormalStatus: None
Privacy: PublicAssigned to: None
Open/Closed: OpenRelease: 4.0.2
Fixed Release: NonePlanned Release: None
Work Required: None

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Tue Jul 12 16:36:12 2011, original submission:

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.

Thomas Wolff <towo>


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):

Attached Files
file #23645:  menu1.png added by towo (26kB - image/png)
file #23646:  menu2.png added by towo (25kB - image/png)


Depends on the following items: None found

Items that depend on this one: None found


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  • -unavailable- added by towo (Submitted the item)
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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Tue Jul 12 16:36:12 2011towoAttached File-=>Added menu1.png, #23645
      Attached File-=>Added menu2.png, #23646
      Carbon-Copy-=>Added towo

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