Does not display VT-100 control codes correctly/consistently

Bug #1770494 reported by Scott on 2018-05-10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
gnome-terminal (Ubuntu)

Bug Description

I'm writing a shell script that draws in color to any VT-100 terminal. The terminal in Ubuntu consistently and randomly drops out of graphics mode producing huge glitches. This does not occur in Xterm or Gnome Terminal on CentOS.

  The image from the file below should look like a color filled square, what you see is a "glitch" which looks like the second half of an escape command followed by a lot of "a"'s where the graphical checkerboard character should be rendered (in Ubuntu Gnome terminal it is rendered as a cursor that is the color of a 50% blend between the background and foreground color, making it the best appearing terminal I've used)

It is 100% reproducible with the instructions below.

To reproduce:
  Using the attached screen-capture.txt file:

  In Gnome-Terminal try "cat screen-capture.txt" over and over to see the error.

  In Gnome-Terminal try "less -r screen-capture.txt" and scale the terminal window to see variation

   I don't know if there is a problem where characters are dropped from stdin, or if the pipe is getting reset, or if the emulator can't keep up with the commands, or if there is a(n inconsisent) limit to the number of command codes that can be sent to the terminal. Or if it is being interrupted, or if it randomly resets...

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: gnome-terminal 3.6.2-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-147.196-generic 3.13.11-ckt39
Uname: Linux 3.13.0-147-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.27
Architecture: amd64
CurrentDesktop: Unity
Date: Thu May 10 15:10:57 2018
InstallationDate: Installed on 2014-12-02 (1255 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
SourcePackage: gnome-terminal
UpgradeStatus: No upgrade log present (probably fresh install)

Scott (spot1984) wrote :
Scott (spot1984) wrote :

All the excape codes were stripped from the description, please use the attached screen-capture.txt file.

Scott (spot1984) on 2018-05-11
description: updated
Egmont Koblinger (egmont-gmail) wrote :

What's the version of GNOME Terminal on CentOS that you're referring to, where you don't face these issues?

GNOME Terminal (more precisely, the underlying VTE widget) was improved a lot during the last 4 years, tons of emulation (and other) bugs were fixed. The most relevant one is probably

I can't reproduce the issues on Ubuntu 18.04 (gnome-terminal 3.28, vte 0.52).

I personally recommend to you to upgrade to 18.04 soon (14.04 will EOL in a year anyway). It's pretty unlikely that these emulation fixes will be backported to 14.04. (My guess is that GNOME Terminal in Ubuntu 16.04 is most likely already fixed.) (Disclaimer: I'm a GNOME Terminal / VTE guy, but not an Ubuntu developer, so it's not Ubuntu's recommendation to you to upgrade.)

> in Ubuntu Gnome terminal it is rendered as a cursor that is the color of a 50% blend between the background and foreground color, making it the best appearing terminal I've used

Thanks; not everyone shares your opinion though, see :)

Scott (spot1984) wrote :

This appears fixed in Ubuntu 18.04. I just checked in a virtualbox VM. This can be closed.

Scott (spot1984) on 2018-05-14
Changed in gnome-terminal (Ubuntu):
status: New → Fix Released
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