Posts Tagged ‘Desktop’

Improve default picture viewing on Slackware Linux with XFCE as Desktop environment

Saturday, March 17th, 2012

Default XFce picture viewer on Slackware Linux is GIMP (GNU Image Manipulation Program). Though GIMP is great for picture editting, it is rather strange why Patrick Volkerding compiled XFCE to use GIMP as a default picture viewer? The downsides of GIMP being default picture viewing program for Slackware's XFCE are the same like Xubuntu's XFCE risterroro, you can't switch easily pictures back and forward with some keyboard keys (left, right arrow keys, backspace or space etc.). Besides that another disadvantage of using GIMP are;
a) picture opening time in GIMP loading is significantly higher if compared to a simple picture viewer program like Gnome's default, eye of the gnomeeog.

b) GIMP is more CPU intensive and puts high load on each picture opening

A default Slackware install comes with two good picture viewing programs substitute for GIMP:
 

  • Gwenview

    Gwenview on Slackware Linux picture screenshot XFCE

  •  
  • Geeqie
  • Geeqie Slackware Linux Screenshot XFCE

    Both of the programs support picture changing, so if you open a picture you can switch to the other ones in the same directory as the first opened one.
    I personally liked more Gwenview because it has more intutive picture switching controls. With it you can switch with keyboard keys space and backspace

    To change GIMP's default PNG, JPEG opening I had with mouse right button over a pic and in properties change, Open With: program.

    XFCE4 Slackware Linux picture file properties window

    If you're curious about the picture on on all screenshots, this is Church – Saint George (situated in the city center of Dobrich, Bulgaria).
    St. Georgi / St. George Church is built in 1842 and is the oldest Orthodox Church in Dobrich.
    In the Crimean War (1853-1856) the church was burned down and was restored to its present form in 1864.

    gpicview is another cool picture viewing program, I like. Unfortunately on Slackware, there is no prebuild package and the only option is either to convert it with alien from deb package or to download source and compile as usual with ./configure && make && make install .
    Downloading and compiling from source went just fine on Slackware Linux 13.37gpicview has more modern looking interface, than gwenview and geeqie. and is great for people who want to be in pace with desktop fashion 🙂

How to take area screenshots in GNOME – Take quick area selection screenshots in G* / Linux and BSD

Thursday, March 15th, 2012

Quick Area screenshot in GNOME how to make quick area selection screenshots in Linux and FreeBSD gnome-screenshot shot

Often when, you do something on your PC, you need to make a quick screenshot of a screen area.. Yes GNOME's feature to take complete screenshots of Screen with Print Screen SysRQ and consequential picture edit with GIMP is one way, but this is far away from quick. This method to chop out of a complete display screenshot usually takes from 40 secs to 1 minute to properly cut and save a selection of the whole picture.
Another common use, that I love in GNOME is the ALT + Print Screen SysRQ key combination. alt+ print scr sysrq is handy while taking a single window screenshot is desired. Anyways often you only need to make a screenshot of a tiny area of the screen. Many people might think this is not possible currently in GNOME, but they will be wrong as there are no impossible but hard things to achieve on Linux / FreeBSD 😉

There are at least two ways using a predefined command for taking quick area screen snapshot.

1. Taking quick area screenshot by using ImageMagick's import command

To use import you will need to have installed ImageMagickswiss army knife of command line image manipulation 😉
For area screenshot with import, press ALT+F2 and type inside Run Application box:

Screenshot GNOME run application GNU / Linux Debian ImageMagick import area screenshot

import -frame screenshot.png

Now make the selection of the exact screen area you would like to screeshot in file screenshot.png
Note that screenshot.png file will be saved by default in your home directory as it is read from $HOME shell variable:

hipo@noah:~$ echo $HOME/home/hipo
hipo@noah:~$ ls -al screenshot.png
-rw-r--r-- 1 hipo hipo 4950 Mar 14 21:11 screenshot.png

You see my $HOME equals /home/hipo, therefore screenshot.png just grabbed is saved in there.

One downside of taking the screenshot with import is that picture snapshot is not further edittable, if it has to be further processed with GIMP or some other graphic editor program.

In the screenshot, below I show you one screen area of my XMMS taken with import -frame screenshot.png cmd:

XMMS Screen Area Screenshot import screenshot

Trying to open the screenshot.png, file with GIMP displays the following error in GIMP:

PNG image message PNG the file specifies offset that caused the layer to be positioned outiside image GIMP screenshot

Not all area snapshots taken with import -frame, create this issue sometimes screenshots are opening in GIMP but only area of the screenshot.png is visible in gimp.

Thanksfull, there is work around to this issue by converting the import generated PNG format picture to JPEG with ImageMagick's convert and then edit the .JPEG with GIMP etc.:

hipo@noah:~$ convert screenshot.png screenshot.jpg

Hence to permanently work around it, in case you intend to apply (GIMP modifications), once area snapshot is made instruct import to save its output picture in .jpeg, e.g.:

hipo@noah:~$ import -frame screenshot.jpeg

2. Taking quick area screenshot using gnome-screenshot cmd

Once again invoke the GNOME command Launcher by pressing Alt+F2 (holding alt and pressing F2) and type in the launch box:

gnome-screenshot -a

gnome-screenshot Run Application in GNOME 2.30 on Debian GNU / Linux

Below is a small area from my desktop, chopped with gnome-screenshot 🙂

GNOME desktop area chop screenshot with gnome-screenshot on my home Debian Linux

You see on above screenshot a tiny (picture) icon one of the greatest, if not the greatest bulgarian saint – saint John of Rila. St. John's lived as hermit for many years in Rila mountain and by God's grace possessed incorruptable body. His incorruptable body is still kept and can be venerated in Rila Monastery. The monastery is located 160 km from Bulgaria's capital city Sofia

St. Johns first Bulgarian established monastery Rila Monastery is currently the biggest functioing monastery in Bulgaria. The saints monastery is considered one of the most holy places in Bulgaria. If you have a travel or plan a holiday in Bulgaria, I warmly recommend you go there and venerate the saint incorruptable relics.

3. Binding keys to allow quick area screenshot taking with gnome-screenshot in GNOME

This configuration is for GNOME 2.x and is tested to work on my Debian (Squeeze 6.0), GNOME ver. 2.30.2, it should work in earlier Ubuntu versions shipped with GNOME 2.2.xx too. As I've red on the Internet it works well with Ubuntu 10.10Binding a key for screenshot area grab, should be working properly also on any GNOME 2.2.x supporting OS, including the BSD family OSes (FreeBSD, OpenBSD, NetBSD)

a) setting gnome-screenshot key binding for interactive screenshot area grab

Navigate the mouse cursor to GNOME main menus panel in left top, where you see (Applications, Places, System).
Therein use menus:

System -> Preferences -> Keybord Shortcuts -> Add ->

Alternatively if you prefer you can directly invoke the Keyboard Shortcuts configuration with command:

hipo@noah:~$ gnome-keybinding-properties

Further on, assign a shortcut by filling in something like:

name: grab-screen-area
command: gnome-screenshot -i -a

GNOME add keyboard shortcut map key for area interactive screenshot

press Apply and next map a key to the new defined key binding:

GNOME add keyboard shortcut map key

Under the Shortcut column click on Disabled and assign some key combination to invoke the cmd for example Ctrl+F4

The command gnome-screenshot -i makes gnome-screenshot, show interactive make screenshot dialog like the one in below screenshot.

GNOME screenshot interactive screenshot select area grab shot

b) creating gnome-screenshot -a area screenshot key binding for quick area screenshots "on the fly"

The procedure is precisely the same as with adding interactive screenshot; Under Keyboard Shortcuts GNOME config assign new key binding by pressing Add button and adding:

name: grab-screen-area1
command: gnome-screenshot -a

Once again in Shortcut column in line starting with grab-screen-area1 add your desired key switch. I personally like Ctrl+Print Screen SysRQ as it is close to the default GNOME key combination assigned for taking screenshot for a Windows Alt+Print SysRq

It was logical, that this key binding should work and a direct selection mouse cursor to appear once Alt+Print SysRQ is pressed, however for some reason this is not working (hmm, maybe due to bug) ??

Thanksfully it is always possible to substitute the just assigned gnome-screenshot -a key binding with import -frame /home/hipo/Desktop/screenshot.png

If you have followed literally my article so far and you did tried to place a bind for gnome-screenshot -a, modifty grab-screen-area1 to be something like:

name: grab-screen-area1
command: import -frame /home/hipo/Desktop/screenshot.png

Where modify the path /home/hipo/Desktop/screenshot.png, to wherever you prefer the region screep capture to be stored.

c) bind keys for delayed screenshot

This also a handy binding, especially if you every now and then need to make screenshots of screen with a few secs interval.
Add one more keyboard shortcut;

name: grab-screen-area2
command: gnome-screenshot -d 5

Assign a key to make a screenshot of the active display after a delay of 5 seconds. I prefer Ctrl+F5

Onwards every time you would like to make an area screenshot, just use the defined keys:

Ctrl+F4 - will prompt you interactively for the precise type of screenshot you would like to take
Ctrl+Print SysRQ - will prompt you for a direct area to select and once selected will immediately screenshot it
Ctrl+F5 - would do delayed screenshot of entire screen after a delay of 5 seconds

4. Adding border and drop shadow effects with gnome-screenshot Actually, there is plenty of interesting things to do with Screenshots which I never thought were possible.
While reading gnome-screenshot's man page, I've stumbled to an interesting argument:

-e, --effect=EFFECT,
Add an effect to the outside of the screenshot border. EFFECT can be ``shadow'' (adding drop shadow), ``border'' (adding
rectangular space around the screenshot) or ``none'' (no effect). Default is ``none''.

This would have been a nice feature but as of time of writting this article, untofrtunately it is not working in GNOME 2.30.2. I'm not sure if this is a local Debian bug, however I suspect on other Linux distributions with different GNOME build configuration, this features might be working well. My guess here is drop shadow effect and border effect are not working because, gnome-screenshot was compiled without (support for ImageMagick?).
Anyways the way the feature is supposed to be work is by invoking commands:
:

hipo@noah:~$ gnome-screenshot --border-effect=shadow
hipo@noah:~$ nome-screenshot --border-effect=border

The same basic effects, are also available through GIMP's menus:

Image -> Effects

5. Setting default behaviour of gnome-screenshot in gconf-editor GConf (Gnome config registry db)

Experienced, GNOME users should already know about the existence of gconf-editor and the gnome registry database. For those who have don't, coming from MS-Windows background gconf-editor is GNOME (graphical environment) equivalent to Microsoft Windows registry regedit command

gconf-editor can be used to atune the way the screenshots are taken by default. To do so, launch gconf-editor cmd and follow to sub-structure:

/ -> apps -> gnome-screenshot

gconf-editor GNOME screenshot border effect none default gnome-screenshot gnome behaviour

The settings in above screenshot are configurations which are used by default by gnome-screenshot, right after install.
You can play with the options to change the default way PrintScreen SysRQ key press will take screenshots.
Here is one example for changing the gnome-screenshot default GNOME behaviour:

GConf Editor GNOME screenshot, border effect drop shadow and include border option set on Linux Debian

As you can see in above screenshot, I've changed my default gnome-screenshot snap taking to include a drop shadow effect:
Name | Value
border_effect | shadow include_border | (tick on)
last_save_directory | file://home/hipo/Desktop

As you see you can also control, where by default gnome-screenshot will save its screenshots, by default, its saved in $HOME/Desktop
. If you prefer some custom directory to only contain Screenshots taken for instance $HOME/Screenshots, create the directory:
hipo@noah:~$ mkdir ~/Screenshots

and then change the value for last_save_directory gconf var:

last_save_directory | file://home/hipo/Screenshots

Once settings are applied screenshots with Print Screen SysRQ key will be made with Shadow Border effect and saved in /home/hipo/Screenshots

Strangely enough, changing gnome-screenshot default screenshotting values to include screenshot effects like drop shadow or screenshot border effect works just fine.
Even though gnome-screenshot –border-effect=shadow and gnome-screenshot –border-effect=border doesn't directly affect the current screenshot to be made, I've later noticed writting this two commands in the gnome-terminal, does change the border settings for gconf-editor screenshot border.

If you enjoyed, this article and you intend to become "a professional screnshotter" :), you might also enjoy my two other articles:

Happy screenshotting 😉

How to install GNOME server on Ubuntu 10.04.2 LTS Lucid

Wednesday, April 20th, 2011

After some upgrades of Ubuntu from 9.10 to Ubuntu 10.04.2, I faced problems during apt-get upgrade && apt-get dist-upgrade

I had to fix it up with apt-get upgrade -f , however the “fix” which was targetting a fix up to the apt-get dist-upgrade removed about 260 packages, among which were the grub boot loader , xorg-server and even gnome

As in order to fix the package mishap the apt-get update -f was my only possible solution I went by and confirmed that I would like to wipe out all the packages.

Logically afterwards it was required that I install my missing xorg-server and gnome in order to make the Ubuntu desktop work again.

Here is how:

ubuntu:~# apt-get update && apt-get xorg-server ubuntu-desktop

The ubuntu-desktop is a meta package which installs the GNOME environment.

How to fix transmission unable to download and connect to torrent tracker on Ubuntu Maverick 10.10

Wednesday, April 27th, 2011

As you can read in my few previous posts I have just installed a new Ubuntu 10.10 on a Toshiba Satellite L40 notebook.

Most of the things which are necessery for a fully working Linux desktop are already installed and the machine works fine, however I just noticed there is an issue with the default torrent gnome client and transmission unable to download files from torrent trackers.

Few minutes of playing with the transmission’s settings has revealed what was causing my torrent download problems.

It seems on Ubuntu 10.10 (probably on other Ubuntus and Debians) by default the transmission bittorrent client is trying to use for torrent download connections an incoming port 53636 number.

As the computer is behind a firewall and does not have a real IP address seeders cannot properly connect to the notebook port 53636 and hence the transmission bittorrent client could not initialize any torrent downloads.

Fixing up the issue is rather easy to fix it I had to change the settings in transmission from the menus:

Edit -> Settings -> Network

You need to select the options:
 

  • Pick a random port on startup
  • Use UPnP or NAT-PMP to redirect connections

Next I had to restart transmission and my torrent downloads started 😉

Alternative way to kill X in Linux with Alt + Printscreen + K

Sunday, October 31st, 2010

I’ve recently realized that the CTRL + ALT + BACKSPACE keyboard combination is no longer working in Debian unstable.

This good old well known keyboard combination to restart X is not working with my xorg 7.5+8 under my Gnome 2.30 desktop
However thanksfully there is another combination to kill the X server if for instance if your Gnome desktop hangs.

If that happens simply press ALT + PRINTSCREEN + K this will kill your X and then reload the (Gnome Display manager) gdm.

Another suggestion I’ve red in the forums of a way to enable back CTRL+ALT+BACKSPACE is to put in either .bashrc or .xinitrc the following command

setxkbmap -option terminate:ctrl_alt_bksp

BTW It’s better that the above command is placed in ~/.xinitrc.

I’ve also red on some forums that in newer releases of Ubuntu. The CTRL+ALT+BACKSPACE can be enabled using a specific command, e.g. with:

dontzap -disable
 

How to fix clock on Slackware / Slackware and this old incorrect BIOS time troubles

Friday, February 24th, 2012

There two main reasons which cause incorrect clock settings on Slackware Linux.
One common reason for incorrectly set time is improper clock and timezone settings during Slackware install.

On install, one of the ncruses install menus asks an ambigious dialog question reading

HARDWARE CLOCK SET TO UTC?
Is the hardware clock set to Coordinated Universal Time (UTC/GMT)?

Some newbie Slackware users make the mistake to choose YES here, resulting in incorrectly set clock.

Second possibility for improper time is incorrect time on BIOS level. This is not so common among laptop and modern desktop PCs. However in the past impoper system BIOS hardware clock was usual.
In any case it is a good practice to check the system PC BIOS clock settings.

To check BIOS battery hardware clock from command line use:

bash-4.1# hwclock --show
Fri 24 Feb 2012 01:24:18 AM EET -0.469279 seconds

The system clock on Slackware is set via a script called timeconfig. To fix slack's incorrect host time run:

bash-4.1# timeconfig

Slackware Linux timeconfig set to UTC ncurses dialog clock setting

Slackware Linux timeConfig Country Selection dialog

Running timeconfig once should configure a proper timezone to be set on next system reboot, however the system time will probably still be not ok.
To manually set time to right time, use date command. To set manually the system wide time to 12:00:00 with date:

bash-4.1# date -s "12:00:00"

Anyways for time accuracy the ntpdate should be used to feth time from NTP internet time server:

bash-4.1# ntpdate time.nist.gov
...

Finally to make the new set right time permanent also for the BIOS battery clock issue:

bash-4.1# hwclock --systohc

By the way its curious fact Slackware Linux is the oldest still existent GNU / Linux based distribution. Its up and running since the very day GNU and Linux came to merge at one Free OS 😉

Create PDF file from (png, jpg, gif ) images / pictures in Linux

Tuesday, September 14th, 2010

I’ve recently received a number of images in JPEG format as a feedback on a project plan that was constructed by a team I’m participating at the university where I study.

Somebody from my project group has scanned or taken snapshots of each of the hard copy paper feedback and has sent it to my mail.

I’ve received 13 images so I had to open them one by one to get each of the Project Plan to read the feedback on the page this was really unhandy, so I decided to give it a try on how to generate a common PDF file from all my picture files.

Thanksfully it happened to be very easy and trivial using the good old Image Magick

In order to complete the task of generating one PDF from a number of pictures all I did was.1. Switch to the directory where I have saved all my jpeg images

debian:~# cd /home/hipo/Desktop/my_images_directory/

2. Use the convert binary part of imagemagick package to generate the actual PDF file from the group of images

debian:~# convert *.jpg outputpdffile.pdf

If the images are numbered and contain many scanned pages of course you can always pass by all the images to the /usr/bin/convert binary, like for instance:

debian:~# convert 1.jpg 2.jpg 3.jpg 4.jpg 5.jpg outputpdffile.pdf
Even though in my case I had to convert to PDF from multiple JPEG (JPG) pictures, convertion with convert is not restricted to convert only from JPEG, but you can also convert to PDF by using other graphical file formats.

For instance to convert multiple PNG pictures to a single PDF file the command will be absolutely the same except you change the file extension of the graphic files e.g.:

debian:~# convert 1.PNG 2.PNG 3.PNG 4.PNG 5.PNG OUTPUT-PDF-FILE.PDF

I was quite happy eventually to know Linux is so flexible and such a trivial things are able to be completed in such an easy way.

How to fix upside-down / inverted web camera laptop Asus K51AC issue on Ubuntu Linux and Debian GNU / Linux

Monday, February 13th, 2012

Skype Video Inverted bat like linux screenshot

Does your camera show video correctly in cheese but shows captured video upside-down (inverted) in skype ?
This is an issue a friend of mine experienced on his Asus K51AC-SX037D laptop on both Ubuntu and Debian Linux.
As you can see in the picture above it is funny as with this bug the person looks like a batman 😉
As the webcam upside-down issue was present on both latest Ubuntu 11.10 and latest stable Debian Squeeze 6.02, my guess was other GNU / Linux rpm based distro like Fedora might have applied a fix to this weird Skype inverted video (bat human like) issue.
Unfortunately testing the webcam with Skype on latest both Fedora 16 and Linux Mint 12 appeared to produce the same webcam bug.

A bit of research for the issue online and try outs of a number of suggested methods to resolve the issue led finally to a work around, thanks to this post
Here is few steps to follow to make the webcam show video like it should:

1. Install libv4l-0 package

root@linux:~# apt-get --yes install libv4-0
...

Onwards to start skype directly from terminal and test the camera type:

hipo@linux:~$ LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype

This is the work around for 32 bit Linux install, most people however will probably have installed 64 bit Linux, for 64bit Linux installs the above command should be little different:

hipo@linux:~$ LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so skype

Once skype is launched test the camera and see if the camera capture is now uninverted, through menus:

S -> Options -> Video Devices -> Test

Skype Options Video devices screenshot

2. Create a skype Wrapper script Launcher

To make skype launch everytime with exported shell variable:
LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so

A new skype wrapper bash shell script should be created in /usr/local/bin/skype , the file should contain:

#!/bin/sh
LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so
/usr/bin/skype

To create the script with echo in a root terminal issue;

root@linux:~# echo '#!/bin/sh' >> /usr/local/bin/skype
root@linux:~# echo 'LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so' >> /usr/local/bin/skype
root@linux:~# echo '/usr/bin/skype' >> /usr/local/bin/skype
root@linux:~# chmod +x /usr/local/bin/skype

3. Edit the Skype gnome menu to substitute /usr/bin/skype Skype Launcher with /usr/local/bin/skype

Gnome 2 has a handy menu launcher, allowing to edit and add new menus and submenus (menus and items) to the Application menu, to launch the editor one has to click over Applications with last mouse button (right button) and choose Edit Menus

GNOME Edit menus screenshot

The menu editor like the one in the below screenshot will appear:

GNOME 2 Menu Editor Screenshot

In the preceeding Launcher properties window, Command: skype has to be substituted with:

GNOME2 Skype screenshot Launcher properties

Command: /usr/local/bin/skype

For console freaks who doesn't want to bother in editting Skype Launcher via GUI /usr/share/applications/skype.desktop file can be editted in terminal. Inside skype.desktop substitute:

Exec=skype

with

Exec=/usr/local/bin/skype

Skype fixed inverted bat like screenshot

As one can imagine the upside-down video image in Skype is not a problem because of Linux, but rather another bug in Skype (non-free) software program.
By the way everyone, who is using his computer with Free Software operating system FreeBSD, Linux etc. knows pretty well by experience, that Skype is a very problematic software; It is often a cause for system unexpected increased system loads, problems with (microphone not capturing), camera issues, issues with pulseaudio, problem with audio playbacks … Besides the long list of bugs there are unexpected display bugs in skype tray icon, bugs in skype messanger windows and at some rare occasions the program completely hangs and had to be killed with kill command and re-launched again.

Another worrying fact is Skype's versions available for GNU / Linux and BSD is completely out of date with its "competitor" operating systems MS Windows, MacOS X etc.
For people like me and my friend who want to use free operating system the latest available skype version is not even stable … current version fod download from skype's website is (Skype 2.2Beta)!

On FreeBSD the skype situation is even worser, freebsd have only option to run Skype ver 1.3 or v. 2.0 at best, as far as I know skype 2.2 and 2.2beta is not there.

Just as matter of comparison the latest Skype version on Windows is 5.x. Windows release is ages ahead its Linux and BSD ver. From a functional point of view the difference between Linux's 2.x and Windows 5.x is not that much different, what makes difference is is the amount of bugs which Linux and BSD skype versions contain…
Skype was about 6 months ago bought by Microsoft, therefore the prognosis for Skype Linux support in future is probably even darker. Microsoft will not probably bother to release new version of Skype for their competitor free as in freedom OSes.

I would like to thank my friend and brother in Christ Stelian for supplying me with the Skype screenshots, as well as for being kind to share how he fixed his camera with me.