Tag Archives: ubuntu

Ubuntu Yielding Noisy Black/White Scans

I did a fresh install of Ubuntu 14.10 today with Cinnamon as a desktop and am pleased with the interface.

I noticed something when scanning some documents in lineart mode, though: the resulting images had a ton of noise, noise that I did not see in scans prior to my upgrade. After snooping around the various options in the gscan2pdf application, I stumbled upon this one which, when toggled, causes the noise to disappear: Disable dynamic lineart. After checking that box, my scans seem to be noise free.

Ubuntu and VNC

I seem to occasionally find myself sparring with Ubuntu on getting VNC server configured correctly. I use the default (RealVNC) vncserver package included with Ubuntu. There are two main points of configuration I seem to rediscover each time:

Make sure vncserver is looking in the right place for configuration

For my setup, the “right” place means ~/.vnc/xstartup. I’ve seen vncserver look to /etc/X11/Xsession by default. To change this, make sure the following line is in /etc/vnc.conf:

$vncStartup = "~/.vnc/xstartup";

Now you need to make sure the configuration exists in your user home directory. Following is the contents of ~/.vnc/xstartup (note: there are several commented lines I leave there for posterity:

#!/bin/sh
# Uncomment the following two lines for normal desktop:
unset SESSION_MANAGER
#exec /etc/X11/xinit/xinitrc
#gnome-session --session=gnome-classic &
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
#x-terminal-emulator -geometry 1280x1024+10+10 -ls -title "$VNCDESKTOP Desktop" &
#x-window-manager &
startxfce4 &

Then I just have a simple script in my home directory to start a vnc session, looks something like this:

#!/bin/bash
vncserver :1 -geometry 1440x900 -depth 16 -name my_lil_desktop

 

EDIT (2015-01-23) : Today I installed version 14.10 of Ubuntu. By default, it uses the ‘vino’ application for remote desktop tasks. It did not work out of the box for me, and this seemed to be the case for many, based on what I read online. At any rate, I fell back to the configuration described in this post but had to install vnc4server first, as it was not installed along with 14.10. I initially tried tightvncserver but it did not work with this configuration; vnc4server, however, did.

Ubuntu and VNC

Ubuntu has been my Linux of choice for sometime now. Currently using Ubuntu 7.10 (Gutsy) with default VNC package. Along the way I have found some issues.

Keyboard Malfunction

I recently ran into a problem while upgrading distributions. In short, the keyboard mapping was completely messed up when connected over VNC. Typing characters over VNC returned seemingly random characters on the other end. The problem has been discussed and a work-around solution proposed here:

https://bugs.launchpad.net/ubuntu/feisty/+source/vino/+bug/112955

Two posts by “wjs” on that page got me up and running (I am using a U.S. keyboard). The correct characters are now carried over VNC. Evidently, this bug is still not fixed, and has been experienced with multiple Ubuntu distributions. Check out the link above for more information.

Disappearing Desktop

I have also found an issue related to the display of the desktop and menus which seems to affect the operation of the keyboard and mouse, as well. Whenever I would try to connect to a VNC session, the login process would begin, the menu bars at the top and
bottom would flash, but disappear. I was left with only the trademark Ubuntu brown desktop (my current background) and no menus. The mouse and keyboard also seemed inoperable. I began to think something in gnome was broken, but could not track down the problem. In the end, I discovered that specifying a color depth when starting the VNC server corrected the problem. Instead of just

vncserver -geometry 1024x768 :1

which would give me an inoperable desktop, I used

vncserver -geometry 1024x768 -depth 16 :1

and the desktop loaded fine. I have not looked around much online regarding this problem.