Posts Tagged ‘xserver’

Adding Teamviewer to auto start on Linux GNOME login

Friday, February 1st, 2013

Administrating Linux via graphical interface is not common, however sometimes it is necessery. There are plenty of ways to remotely administrate with GUI Linux. You can connect to remote Xserver and launch X session via xinit, connect via (Gnome Display Manager) GDM, use nomachine NX server / client (if you're on slow connection line) or use the good old Teamviewer.

As Teamviewer works pretty well on both Windows and Linux in last times I like using teamviewer as a standard. It is freeware and it often disconnects with the annoying Trial message, but in general for managing something quick on remote desktop it is nice.

To use teamviewer, you need to have it installed on the Linux host via deb or rpm:

Whether on Debian / Ubuntu use:

# wget http://www.teamviewer.com/download/version_8x/teamviewer_linux_x64.deb
.....
# dpkg -i teamviewer_linux_x64.deb
...
....

 

On Fedora, CentOS, RHEL run:

# wget -q http://www.teamviewer.com/download/teamviewer_linux.rpm
# rpm -Uvh teamviewer_linux.rpm
.....

Once package is installed teamviewer is installed in /opt/teamviewer/* there is a tiny wrapper run script in /usr/bin/teamviewer – evoking TeamViewer to be run via wine emulation.

Hence to make TeamViewer start on certain user GNOME login the script has to run on GNOME user login session.
In both GNOME 2 and GNOME 3 what is run on user login is managed through gnome-session-properties thus /usr/bin/teamviewer has to be set to run through gnome-session-properties (to run it press ALT+F2 or type it directly in gnome-terminal)

user@linux:~$ gnome-session-properties

A window like in below screenshot pops up and from there Add TeamViewer.

Adding Teamviewer to auto start on Linux Debian Fedora CentOS GNOME non privileged user

To be able to later connect via a Remote host with another TeamViewer peer launch TeamViewer and configure permanent password through menus:

Extras -> Options -> Security

teamviewer extras options security configuring teamviewier permanent password for ID

All left is to write down your Teamviewer Remote Connect ID and permanent set password

Teamviewer remote connect ID screnshot Linux

After next succesful GNOME login teamviewer will just pop-up. Enjoy

Viewing JPEG,GIF and PNG in ASCII with cacaview on GNU / Linux – Review on caca-utils text mode graphics utilities

Thursday, May 17th, 2012

Stitch 80x45 libcaca mascot cacaview viewing JPG, PNG, GIF images as ASCII on Linux libcaca

Probably, many don't know that it is possible to view normal graphical pictures (JPG, PNG, GIF, BMP) etc. in plain console tty.

Being able to view pictures in ASCII is something really nice especially for console geeks like me.
The images produced sometimes are a bit unreadable, if compared to the original graphics, but anyways most of the pictures looks pretty decent 🙂

Viewing in console / terminal images on GNU / Linux is possible thanks to a library called libcaca, caca labs libcaca project official website here.
Below is a shot description of libcaca:
hipo@noah:~$ apt-cache show libcaca0|grep 'Description' -A 4
Description: colour ASCII art library
libcaca is the Colour AsCii Art library. It provides high level functions
for colour text drawing, simple primitives for line, polygon and ellipse
drawing, as well as powerful image to text conversion routines.

In Debian, Ubuntu and other deb Linux distros viewing GUI images with no need for Xserver or any kind of window manager in plain ASCII is possible with cacaview.

cacaview is part of a package called caca-utils. caca-utils is providing few other great utilities for ASCII freaks 🙂 along with cacaview console ascii viewer prog.
The package> is available for Debian distributins since many years, so even on a very old Debians like Debian – (Potato, Woody, Sarge) the package is available in default free package repositories ready to install via apt

To install apt-get it as usual:

noah:~# apt-get --yes install caca-utils

Here is a list of the binaries the package provides:

hipo@noah:~$ dpkg -L caca-utils|grep -i /usr/bin/
/usr/bin/cacaserver
/usr/bin/cacaplay
/usr/bin/cacafire
/usr/bin/cacademo
/usr/bin/cacaview
/usr/bin/img2txt

1. cacaserver a tiny program allowing network streaming of applications written in caca

Belkow is a chop, from man cacaserver
 

cacaserver reads libcaca animation files in its standard input and
serves them as ANSI art on network port 51914. These animations can be
created by any libcaca program by setting the CACA_DRIVER environment
variable to raw and piping the program's standard output to cacaserver.

Clients can then connect to port 51914 using telnet or netcat to see
the output.

The example section of the manual points 1 example use of cacaserver to stream the console output from cacademo.
cacademo binary is a short presentation ASCII DEMO in the spirit of the old school assembly demos (demoscene) .
To run it to bind on port 51914 one has to type in bash shell:
hipo@noah:~$ CACA_DRIVER=raw cacademo | cacaserver
initialised network, listening on port 51914

Then to check out how the demo looks, open telnet connection to the cacaserver host; In my case the cacaserver is binded and streamed over IP 192.168.0.2:

hipo@debian:~$ telnet 192.168.0.2 51914

Immediately you got the demo shining; Below are two screenshots of the demo played after succesful telnet connection:

Cacaserver - caca for the network screenshot Matrix cacademo

cacademo running over telnet network connection – Matrix

cacaserver running on Debian GNU / Linux drug addict like spots streamed via telnet

Blur spots cacademo shot of cacademo streamed via network

You see the demo looks quite awesome 🙂

2. Running cacafire to stream over network

Another possible example use of cacaserver is in conjunction with cacafire libcaca test application:

noah:~# CACA_DRIVER=raw cacafire | cacaserver
initialised network, listening on port 51914
cacafire is a short application written to render ASCII via libcaca and is just displaying a screen with ASCII (moving) burning fire.
It is quite spectacular if you, ask an unexpecting friend to connect to your host to 51914 🙂

Cacafire Screenshot Debian GNU / Linux cacaserver streaming ASCII demo via network port 51914

Besides that bored sys admins, could run cacafire in console to hypnotize themselves watching dumb the burning fire screen for few hoursor just use it as a screensaver 😉

3. cacaview a program to display a graphic images in console using ASCII art

cacaview takes just one argument – the picture to be displayed.

Below is a screenshot of cacaview ran from my gnome-terminal displaying a ASCII text version of the MySQL server logo

hipo@noah:~$ cd /disk/pictures
hipo@noah:/disk/pictures$ cacaview mysql_logo.png

 

cacaview displaying MySQL database logo in ASCII using caca for X

Whether cacaview is invoked in GUI, the libcaca X support is used, so the text image is visualized in new window with graphics, if however it is invoked in plain let's say tty1 libcaca displays the graphics pictures drawing it with only text characters.

Here is also a screenshot, I've made while viewing a GIF website logo in ASCII in plain tty console:

hipo@noah:~$ cacaview /disk/pictures/logo.gif

cacaview plain tty console screenshot of a website logo graphics pictures 17-05-2012

The logo is in cyrillic, so for latin speaking people some of the characters in the two words seen will be unreadable 🙂

cacaview even supports viewing, the next and previous picture in line, like in any modern graphics image viewer program.
To view a bunch of graphic pictures in ASCII with cacaview pass it *.*:

hipo@noah:~$ cacaview /disk/pictures/*.*

For simplicity the common unix * is also supported, so I find it quicker to do:

hipo@noah:~$ cacaview /disk/pictures/*

Showing pictures forward and backward (Previous / Next) picture is done with n and p kbd keys, whether;
n - next;
p - previous

cacaview doesn't crash or stop but skip unknown file formats – if for instance encounters filenames which are not images; lets say you have *.rar archive files along with other pictures.

The complete list of keys cacaview supports are:
br />

KEYS
? show the help screen

n, p switch to next image, previous image

Left, Right, Up, Down or h, l, k, j
scroll the image around

+, – zoom in and out

z reset the zoom level to normal

f switch fullscreen mode (hide/show menu and status bars)

d toggle the dithering mode (no dithering, 4×4 ordered dithering, 8×8 ordered dithering and random dithering)

q exit the program

4. Converting graphics images to ASCII art like (plain text pictures)

The tool that does "the trick" is img2txt. img2txt has a bit more options while compared to the rest of the aforementioned tools.The following list of arguments are recognized:

  • the size (font, height)
  • brightness
  • contrast
  • gamma and dither
  • format type of out the output pic

Anyways I found that the basic just in / out arguments passed are enough to produce pretty good results:

hipo@noah:~$ img2txt hipo_avatar.gif >hipo_avatar_pic.txt

The original hipo_avatar.gif file looks like so:

hipo avatar gif picture before img2txt convertion to text

After above img2txt command is run and hipo_avatar_pic.txt to see the colorful output ASCII art img2txt produces, cat it:

hipo@noah:~$ cat hipo_avatar_pic.txt

The image result if screenshot looks quite beautiful and even, can be considered or used as an ART effect image (filter) 🙂

Console Screenshot hipo avatar pic ASCII img2txt output picture

The picture colors are plain ANSI color, so in order to display properly the picture with colors on another computers or Operating System you will need at least basic support for ANSI colors.

Plenty of output file formats are supported by img2txt

Here is the complete list of supported output formats:
 

ansi : coloured ANSI
caca : internal libcaca format
utf8 : UTF8 with CR
utf8 : UTF8 with CRLF (MS Windows)
html : HTML with CSS and DIV support
html3 : Pure HTML3 with tables
irc : IRC with ctrl-k codes
bbfr : BBCode (French)
ps : Postscript
svg : Scalable Vector Graphics
tga : Targa Image

libcaca is available for FreeBSD too, but the caca-utils is not available as a port yet, though probably the deb or rpm packages can easily be ported to BSD.

Well that's all, Enjoy.

How to install Nvidia GeForce FX 5500 on Ubuntu 11.04

Tuesday, July 19th, 2011

Nvidia Tux GeForce GNU / Linux

Yesterday I was at a friend of mine who has recently installed Ubuntu 11.04 to his already oldish Desktop computer.

The system was 1.4Ghz (amd) with 512 RAM and some kind of Dell Trinitron 19 inch monitor
Even though he tried hard to make his NVIDIA GeForce FX 5500 ‘s drive to work properly with Ubuntu Natty Narwhal, he just has messed it even more.
As I always like helping people and I’m joyful for people who want to migrate to Linux, I took some time to make his NVIDIA GeForce work with this Ubuntu release.

First I tried to make it work by using some of the official NVIDIA Linux drivers located on nvidia.com following some online tutorial for Ubuntu claiming that it works but actually it didn’t, so finally after a bit of experimentation I found a way to make this video card work.
Here is how:

1. Install the following Ubuntu packages

root@ubuntu:~# apt-get install nouveau-firmware nvidia-173 nvidia-173-kernel-source
nvidia-cg-toolkit nvidia-common nvidia-current nvidia-glx-173 nvidia-settings
...

2. Load in the kernel and set to be auto loaded on boot nvidia’s driver kernel module nvidia-173

root@ubuntu:~# depmod -a;
root@ubutnu:~# modprobe nvidia-173
root@ubuntu:~# echo nvidia-173 >> /etc/modules

3. Stop temporary (Gnome dipsplay manager) gdm

root@ubuntu:~# service gdm stop
...

4. Use nvidia-xconfig to generate a working version of /etc/X11/xorg.conf for Nvidia

root@ubuntu:~# nvidia-xconfig
..

nvidia-xconfig will generate new /etc/X11/xorg.conf configuration corresponding to the Nvidia GeForce Fx 5500 and will move the old xorg.conf to xorg.conf.backup.

5. Start the gdm manager to be running again

root@ubuntu:~# service gdm start
...

Now the Xserver will start in a terrible mode of 640×480, probably because Ubuntu was unable to define correct VerticalSync and HorizontalSync for the 19 inch Dell Trinitron monitor or for some other weird reason, to fix this it’s quite easy though.
The fix to the NVIDIA GeForce 5500 running in 640×480 mode is done straigh via Gnome menus.

6. Use Gnome’s System -> Preferences -> Monitors to set raise up the Xserver resolution

Navigate to Gnome’s menus:

System -> Preferences -> Monitors

Gnome System Preferences Monitors Nvidia GeForce 5500 Ubuntu

Here you will have to select more appropriate resolution and a different refresh rate, which in my case was 1024×768 and further on to store the settings press the Apply button.

One oddity here was that according to the Monitor Preferences the refresh rate was running on 54 Hz which I don’t believe was the case as I guess it’s some kind of Gnome or Ubuntu bug. I changed the 54 Hz Refresh Rate to 50 Hz as using the 54 Hz refresh rate as the screen had a minor vibrations observable if one takes a thorough look on the screen.

Setting the NVIDIA GeForce 5500 driver to work with 50 Hz Refresh Rate in Gnome loooked like the Windows’s 85 Hz RR and looked quite nice so I left it this way.

Finally to test the newly installed driver 3D acceleration I used glxgears.

7. Install glxgears in order to be able to test that 3D acceleration on Nvidia works fine

root@ubuntu:~# apt-get install mesa-utils

After installing mesa-utils which nowdays contains glxgears executable one needs to execute the glxgears binary.

root@ubuntu:~# glxgears

Immediately after a window containing the glxgears should popup on the screen, like shown in below screenshot
Benchmark 3d Acceleration Linu glxgears

glxgears showed 3d acceleration works fine as the performance for 3d rendering shown was quite good and therefore 3D acceleration was running fine.

And that was it now the video works like and my friends, can enjoy the fun to have a generally virus Free OS 😉

What is Xorg’s server DPMS module for? And how to use it to reduce your computer power consumption

Thursday, April 21st, 2011

As I’m manually configuring a Xserver via xorg.conf I have noticed a block of code in:

Section "Monitor"
Identified "Generic Monitor"
Option "DPMS"
EndSection
That triggered my curiousity to research further what is DPMS . A very quick google search revealed that DPMS’s purpose is to communicate to communicate between the monitor and the computer, to make the computer turn off the (CRT or LED) based monitor if the computer is not used

Thus in short to rephrase DPMS is a power saving handy Xorg feature. I many custom configured xorg.conf like the mine I’m building right now does not include DPMS as many people doesn’t have idea what DPMS is and how to enable it.

DPMS is also an interface to the Energy start power-saving capability if not all, most of the modern day monitor screens.

DPMS enables the Xserver to control automatically the computer screen and thus reduces the overall computer power consumption.

To enable the use of DPMS on my Linux, all I had to do is place a couple of configuration directives in my xorg.conf .:
Here is how I enabled DPMS in my Xorg server:

1. Edit with a text editor /etc/X11/xorg.conf

2. Find the Monitor Section , e.g.:

Section "Monitor"
....
EndSection

3. Add inside the Monitor Section Options "DPMS" "true"

4. Lookup for the ServeryLayout section , e.g.:

Section "ServerLayout"
...
EndSection

5. Place inside the ServerLayout section For instance the following options:

Option "StandbyTime" "20"
Option "SuspendTime" "10"
Option "OffTime "25"

You might like to change the options StandbyTime, SuspendTIme or OffTime to match your likings.
6. As a last step restart the Xorg server.

Press Ctrl+Alt+BackSpace or by issuing:

host:~# pkill -HUP X

Test that DPMS is loaded properly by reviewing /var/log/Xorg.0.log for example:

host:~# grep -i /var/log/Xorg.0.log
(II) Loading extensions DPMS

Xserver kill sequenze not working anymore via Dontzap option in Debian Unstable

Saturday, October 3rd, 2009

The Xkill sequence in Debian unstable is not working again
even though the:
Option “DontZap” “off”in my xorg.conf
Fix comes to adding to xorg.conf:
Option “DontZap” “off”
END—–