Posts Tagged ‘png’

Optimize WordPress Pictures with EWWW Image Optimizer, Async JS and CSS and Autoptimize for better Search Engine Ranking

Tuesday, December 9th, 2014

 


wordpress-ewww-image-optimizer_settings_screenshot-plugin-seo-for-images-wp_3

While optimizing picture performance with console tools optipng, jpegoptin, jpegtran, pngcrush (could save you a lot of server space and make pictures downloads faster (and hence increase your website responsiveness and SEO – check out), still for Blogs and WebSites based on WordPress its not worthy to loose time with console acrobatics but simply use EWWW Image Optimizer to Optimize all old or new uploaded Images.

To work EWWW Image Optimizer needs jpegtran, optipng, pngout and gifsicle to be installed on the Linux / BSD server. EWWW Image Optimizer can load the command line tools also from a Cloud, if a cloud service is running on the server. Once installed the plugin does scan all the imported WordPress Media files and can be run to optimize picture files on present blog psot / pages.

EWWW Image Opitimizer plugin does a good job in reducing file size on  NextGEN, GRAND FlAGallery galleries.

wordpress-ewww-image-optimizer_settings_screenshot-plugin-seo-for-images-wp

Here is how EWWW Image Optimizer works taken from plugin's website:
How are JPGs optimized?

Lossless optimization is done with the command jpegtran -copy all -optimize -progressive -outfile optimized-file original-file. Optionally, the -copy switch gets the 'none' parameter if you choose to strip metadata from your JPGs on the options page. Lossy optimization is done using the outstanding JPEGmini utility.
It is better if the server has not the jpegtran, pngout, gifsicle utilities installed as the plugin provides an uptodate static compiled Linux binaries.

How are PNGs optimized?

There are three parts (and all are optional). First, using the command pngquant original-file, then using the commands pngout-static -s2 original-file and optipng -o2 original-file. You can adjust the optimization levels for both tools on the settings page. Optipng is an automated derivative of pngcrush, which is another widely used png optimization utility.

How are GIFs optimized?

Using the command gifsicle -b -O3 –careful original file. This is particularly useful for animated GIFs, and can also streamline your color palette. That said, if your GIF is not animated, you should strongly consider converting it to a PNG. PNG files are almost always smaller, they just don't do animations. The following command would do this for you on a Linux system with imagemagickconvert somefile.gif somefile.png

wordpress-ewww-image-optimizer_settings_screenshot-plugin-seo-for-images-wp

Some othe plugins that could strenghten your WordPress Search Engine Optimization ranking worthy to check are:
 

  • Async JS and CSS
     

Most importantly plugin solves "Render-blocking JavaScript and CSS" warning shown during site audit with  Google Developers PageSpeed InsightBy the way Google PageSpeed Insight is a precious tool so I recommend you check if you already haven't, Google's suggestions could often double or triple daily site visitors 

What Async JS and CSS does is:

Converts render-blocking CSS and JS files into NON-render-blocking, improving performance of web page

async_js_and_css_wordpress-plugin_configuration_menu

The plugin makes ALL scripts loaded by other plugins to be loaded in asynchronous. All CSS files will be inserted inline into the document code or moved from the document beginning to the end, just before closing BODY tag (or just where you placed wp_foot() function). There are various methods to do that via plugin configuration page.
 

  • Autoptimize

     

     

     

    Wordpress-Autoptimize-screenshot-a-plugin-to-minify-wordpress-html-js-and-css-scripts

Autoptimize speeds up your website and helps you save bandwidth by aggregating and minimizing JS, CSS and HTML.

What does the plugin do to help speed up site?

It concatenates all scripts and styles, minifies and compresses them, adds expires headers, caches them, and moves styles to the page head, and scripts to the footer. It also minifies the HTML code itself, making your page really lightweight. Autoptimize is very much like WP Mnify (CSS / JS) minifaction WP plugin. The only difference and reason why you might want to use WP Mnify is it does HTML minification – something that WP Minify does not. Both plugins play nice together the only thing to be careful is not to configure CSS / JS minification in both Autoptimize and WP Minifyas this might slower instead of fasten the WP site.

A great bunch of other useful WP plugins to make a WordPress Blog friendly to Search Engines is here.

Improve Websites SEO: Optimize images to Increase website loading performance on Linux server – Image Compress tools

Friday, December 5th, 2014

Optimize-website-images-pictures-to-Increase-website-loading-performance-on-Linux-server_Image_Compress_tools-Improve-Websites_SEO
Part of our daily life as Web hosting system adminstrators is to constantly strive to better utilize our Linux / Windows hosting servers hardware.
Therefore it is our constant task to look for new better ways to optimize our Apache Sites and Webservers in order to return served application content light fast to keep the Boss and customers happy 🙂

There are things to tune up for better server performance and better CPU / memory utilization on both server Application server side as well as the website programming code backend, html and pictures / images

Thus it is critically important to not only keep the Webserver / PHP engine optimized but keep hosted sites  stored images and source code clean and efficient.

We as admins usually couldn't directly interfere with clearning the source code and often we have to host a crappy written sites with picture upload forms with un-optimized Image files that was  produced on old Photo Cameras, "Ancient" Mobile Mobiles, Win XP MS Paint, various versions Photoshop, Gimp etc.).

It is a well known fact that a big part from a Website User Experience is how fast the user loads a page, thus if HTML / CSS loaded images loads slow has a negative impact on user look & feel about website

Therefore by optimizing the size of hosted sites Images, you Save Network bandwidth and in some cases when Large Gallery sites HDD disk space.

On Linux, there are already a many command line tools to inspect and optimize (compress) the size of PNG, JPEG, GIF, BMP, PNM, Tiff Images, most famous ones are:

  • optipng – PNG optimizer that recompresses image files to a smaller size, without losing any information.
  • jpegoptim –   lossless JPEG optimization (based on optimizing the Huffman tables) and "lossy" optimization based on setting a maximum quality factor.
  • pngcrush – Recommended tool to use by Stoyan Stefanov (Yahoo Yslow Developer)
  • jpegtran – Recommended to use by Google 
  • gifsicle –  command-line tool for creating, editing, and getting information about GIF images and animations. 

It is hence useful to first run manually availale Linux image optimization tools (to get an idea what they do) and later automate them to run as scripts to optimize server stored images size and make pictures load faster on websites and thus improve End Users Experience and speed up Image content delivery to GoogleBot / YahooBot / Bing Crawlers which will make Search Engines to position server hosted sites better (more SEO Friendly).

 

  • How much percents of  space (Mega / Gigabytes ) Pictures compress can save you?

If you run it on 500MB image directory, you can probably save about 20 to 50MB of size, so don't expect extraordinary file reduce, however 5% to 10% reduce in size is not bad too. If you host 100 sites each with half gigas of data this would mean saving of 5GB of data and some 5GB from backups 🙂 At extraordinary cases you can expect 20% to 30% of storage reduce. For even better image compression you can try out GIMP's – Save for Web option.
 

  • Installing jpegtran, optpng, jpegoptim, pngcrush gifsicle on Debian / Ubuntu (deb based) Linux
     

apt-get install –yes libjpeg-progs optipng jpegoptim pngcrush gifsicle

 

  • Installing  jpegtran, optpng, jpegoptim, pngcrush, gifsicle on Fedora / CentOS / RHEL (RPM based distros)
     

yum -y install pngcrush libjpeg-turbo-utils opt-jpg opt-png opt-gif


gifsicle is not availale by default on Redhacks 🙂 but there is a RPM package for fedora from http://pkgs.repoforge.org/gifsicle/

 

Some examples of running image compression on GNU / Linux

  • optipng and jpegoptim optimize for all files in directory
     

cd /home/sites/

find . -iname '*.png' -print0 | xargs -0 optipng -o7 -preserve
find . -iname '*.jpg' -print0 |
 xargs -0 jpegoptim –max=90 –strip-all –preserve –totals


In jpegoptim command, the option –strip-all will strip any metadata including Exif data from images. For websites JPEG metadata is usually not needed, so usually its ok to strip them.

Above jpegoptim example will decrease slightly JPEG image quality to 90%. quality level of 90 is still high enough and website visitors are unlikely to spot any visible quality reduction / defects in the image.

 

  • pngcrush all files in a directory example
     

cd /home/sites/

for png in `find $IMG_DIR -iname "*.png"`; do
    echo "crushing $png …"
        pngcrush -rem alla -reduce -brute "$png" temp.png

 

    # preserve original on error
    if [ $? = 0 ]; then
        mv -f temp.png $png
        else
        rm temp.png
        fi
done

  • Run jpegtran on sites directory
     

find /home/sites -name "*.jpg" -type f -exec jpegtran -copy none -optimize -outfile {} {} ;

 

  • Set a script to compress / reduce size of Sites Images


Here is a basic optimize_images.sh which I used earlier before and was reducing the overall images size just 5 to 10%, then I found the much improved version of optimize images shell script  (useful to  clear up EXIF picture data / And Comments from JPG / PNG files). The script execution could take very long time on large image directories and thus could cause a high HDD disk I/O, however if ran once a week at night time its not such a big deal. 

To set it to run on your server as a cronjob:
 

cd /usr/sbin/
wget -q http://www.pc-freak.net/bshscr/optimize_images2.sh
crontab -u root -e 


Sample cron job to run once a month on 10th and 27th in 3 o'clock AM:
 

 00 3 10,27 * * /usr/sbin/optimize_images2.sh 2>&1 >/dev/null


Also if you need to further optimize million of tiny sized PNG files Yahoo Smush.it service could be helpful. For compression maniacs its worthy to check out also TinyPNG Service (however be awre that this service compresses files with significant quality loss) making picture quality visibly deteriorated.

Besides optimizing server stored Pictures, here are some other stuff that helps in increasing server utilization / lower webpages loading time.

Starting up with the installation (when site is to use Apache + PHP) for its backend, the first thing to on the freshlyinstalled Linux server is to implement the following list of Apache common Timeout variables that help better scale the webserver for the CMS-es hosted, enable Webserver caching with (mod_deflate), enable eAccelerator tune PHP common php variable etc.

Other thing  I sometimes use to speed-up performance of Apache child responce time up to 20-30  is to Include into Virtualhost / httpd.conf Apache configuration any htacces mod_rewrite rules.

On too heavily loaded sites On-line stores / Large Company website portals with more than 60 000 – 100 000 unique IP visitors a day it is useful tip to disable completely Apache logging in access.log / error.log.

Often when old architecture websites are moved from older Linux OS version to a newer one with newer versions of Apache / PHP often sites are working without major code rework, but use many functions which are already obsolete and thus many WARNING messages crap is logged into php_error.log / error.log. Thus to save disk space and decrease hard disk I/O operations it is good to Disable PHP Notices and Warnings messages
 

Linux: Rename all files extension from upper to lower cases

Friday, February 14th, 2014

Lets say you're an admin involved in webhosting and due to a programmer's mistake, you end up with directory full with files with extension in upper cases but for actual version of website (all pictures are red only in lower cases), hence would like to transform these to lower cases.
To give an example, to illustrate what I mean, lets say you have in a directory files like;

filename.JPG, picture.PNG, new-picture.GIF

and you would like all files to be renamed to lower extension characters, i.e.:

filename.jpg, picture.png, new-picture.gif.
 

# find . -name '*.*' -exec sh -c 'a=$(echo {} | sed -r "s/([^.]*)\$/\L\1/"); [ "$a" != "{}" ] && mv "{}" "$a" ' \;

That's all enjoy 🙂

Converting JPEG Images to ASCII Art text (picture) in Microsoft Windows (2000 / XP / Vista / 7)

Friday, May 18th, 2012

A friend of mine, just mentioned about a program ASCIIPic – capable of converting graphic images in JPEG to plain text ASCII in Microsoft Windows OSes.
Yesterday I blogged about caca-utils (img2txt) – console tool to convert picture graphics to plain text ASCII , so knowing of the Windows freeware ASCIIPic existence catched my attention and I decided to give it a try to get idea what is situation with Images to ASCII text convertion in Windows? 🙂.

1. Generating ASCII from JPEG images with ASCII Pic

As I don't have a Microsoft Windows OS at hand, I downloaded it and run it on my Debian notebook with WINE (Wine Is Not an Emulator) MS-Windows emulator.

For my surprise the program run succesfuly its GUI interface and worked pretty smooth even emulated on Linux.

ASCII Pic 2.0 JPG PNG GIF to ASCII text MS Windows Convertor screenshot

As of time of writting, the latest version of the freeware program available is 2.0. You see in above screenshot the program is pretty intutive to use. You select an Input file, an Output file and you're ready to Process the image to TXT.
One small note to make here is the program couldn't recognize as Input files images in PNG or GIF formats, it seems the only image formats the program recognizes as input are JPEG and BMP.

ASCII Pic Windows image to ASCII program picture shot

The converted images to ASCII results are quite unsatisfactory, I tried converting few pictures originally in size 1024×768 but the produced ASCII was messy huge (the program didn't automatically set height / width dimensions to 60×80 and therefore, when I revied the produced pictures, they were very ugly and hardly readable. It could be the same image looks better if reviewed in MS-Windows Notepad but I seriously doubt that …

I thought some improvement to the produced ASCII image might be possible from the app options so I played around with the Zoom, Negation, Brightness and Monochrome options, none of them had a drastic change on the output. Using any of the program options didn't make the output TXT "image" to look closer riginal JPEGs..

ASCII Pic 2.0 Windows picture to ASCII Program options screenshot

ASCII Pic official website contains a number of other tiny tools, like WinKill and RemoteShut, however most of the tools are already too obslete and useless just like ASCII Pic

If I have to compare ASCIIPic produced ASCII Images to libcaca's Linux img2txt, asciipic's ASCII images are a piece of crap.

2. jp2a command line tool image to ASCII generator

As of time of writting a good alternative program I found for Windows is jp2a
jp2a is a free GPL-ed software available for all major operating system architectures Linux, BSD, Mac OS X, Windows.
jp2a is a command line tool and lacks any GUI interface but if compared to ASCII Pic the output ASCII image is awesome.

jp2a Windows binary can be downloaded from here , also I've made a mirror of windows jp2a bin in case if it disappears here

3. ASCII Generator 2 (asc2gen) – Windows GUI Images to ASCII generator

ASC 2 Gen is actually the best I can find program to convert images to ascii in Win as of time of writting.
Just like img2txt it generates pretty decent looking text images.

ASC2Gen failed to run emulated on my Linux host with wine version 1.0.1, hence to test it I used a a Windows host via teamviewer.

Below are few screenshots illustrating most of the options ASCII2GEN provides:

asc2gen Microsoft Windows image to ascii generator inverted penguins screenshot

asc2gen penguins in inverted color set (black color text background)

ASC2Gen backhead penguins ascii picture screenshot

ASC2GEN flipped backhed generated image to ASCII

ascii2gen generate images to ascii in colors Microsoft Windows shot

Picture to ASCII text converted with ASCII colors

Dithering Windows image to ascii text generated picture ASCII

ascii2gen dithering level option shot

asc2gen jpeg, png, gif to plain text ascii brightness contrast screenshot pic

asc2gen contrast / brigthness atune shot

ascii2gen penguins converted images to plain text inverted with capital letters for picture

asc2gen save as options shot

Something else nice is it supports a lot of image file formats as input including (BMP and GIF) images.
I've also made a mirror of asc2gen v. 2.0.0 here

While researching online, I found plenty of other Image to ASCII geneartors, however as I didn't tested them I can't say if they are  better ones.
Anyways I will be happy to hear if anyone knows other good ASCII generator alternative progs for Winblows?

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 make screenshot in /dev/tty console on GNU / Linux – Taking picture JPEG / PNG snapshot of text console in systems without graphical environment

Monday, April 30th, 2012

I'm used to making picture screenshots in GNOME desktop environment. As I've said in my prior posts, I'm starting to return to my old habits of using console ttys for regular daily jobs in order to increase my work efficiency. In that manner of thoughts sometimes I need to take a screenshot of what I'm seeing in my physical (TTY consoles) to be able to later reuse this. I did some experimenting and this is how this article got born.

In this post, I will shortly explain how a picture of a command running in console or terminal in GNU / Linux can be made

Before proceeding to the core of the article, I will say few words on ttys as I believe they might be helpful someone.
The abbreviation of tty comes after TeleTYpewritter phrase and is dating back somewhere near the 1960s. The TTY was invented to help people with impaired eyesight or hearing to use a telephone like typing interface.

In Unix / Linux / BSD ttys are the physical consoles, where one logs in (typing in his user/password). There are physical ttys and virtual vtys in today *nixes. Today ttys, are used everywhere in a modern Unixes or Unix like operating system with or without graphical environments.
Various Linux distributions have different number of physical consoles (TTYs) (terminals connected to standard output) and this depends mostly on the distro major contributors, developers or surrounding OS community philosophy.
Most modern Linux distributions have at least 5 to 7 physical ttys. Some Linux distributions like Debian for instance as of time of writting this, had 7 active by default physical consoles.
Adding 3 more ttys in Debian / Ubuntu Linux is done by adding the following lines in /etc/inittab:
 

7:23:respawn:/sbin/getty 38400 tty7
8:23:respawn:/sbin/getty 38400 tty8
9:23:respawn:/sbin/getty 38400 tty9

On some Linux distributions like Fedora version 9 and newer ones, new ttys can no longer be added via /etc/inittab,as the RedHat guys changed it for some weird reason, but I guess this is too broad issue to discuss ….

In graphical environments ttys are called methaphorically "virtual". For instance in gnome-terminal or while connecting to a remote SSH server, a common tty naming would be /dev/pts/8 etc.

tty command in Linux and BSDs can be used to learn which tty, one is operating in.

Here is output from my tty command, issued on 3rd TTY (ALT+F3) on my notebook:
 

noah:~# tty
/dev/tty3

A tty cmd output from mlterm GUI terminal is like so:
 

hipo@noah:~$ tty/dev/pts/9

Now as mentioned few basic things on ttys I will proceed further to explain how I managed to:

a) Take screenshot of a plain text tty screen into .txt file format
b) take a (picture) JPG / PNG screenshot of my Linux TTY consoles content

1. Take screenshot of plain text tty screen into a plain (ASCII) .txt file:

To take a screenshot of tty1, tty2 and tty3 text consoles in a txt plain text format, cat + a standard UNIX redirect is all necessery:
 

noah:~# cat /dev/vcs1 > /home/hipo/tty1_text_screenshot.txt
noah:~# cat /dev/vcs2 > /home/hipo/tty2_text_screenshot.txt
noah:~# cat /dev/vcs3 > /home/hipo/tty3_text_screenshot.txt

This will dump the text content of the console into the respective files, if however you try to dump an ncurses library like text interactive interfaces you will end up with a bunch of unreadable mess.
In order to read the produced text 'shots' onwards less command can be used …
 

noah:~# less /home/hipo/tty1_text_screenshot.txt
noah:~# less /home/hipo/tty2_text_screenshot.txt
noah:~# less /home/hipo/tty3_text_screenshot.txt

2. Take picture JPG / PNG snapshot of Linux TTY console content

To take a screenshot of my notebook tty consoles I had to first install a "third party program" snapscreenshot . There is no deb / rpm package available as of time of writting this post for the 4 major desktop linux distributions Ubuntu, Debian, Fedora and Slackware.
Hence to install snapscreenshot,I had to manually download the latest program tar ball source and compile e.g.:
 

noah:~# cd /usr/local/src
noah:/usr/local/src# wget -q http://bisqwit.iki.fi/src/arch/snapscreenshot-1.0.14.3.tar.bz2
noah:/usr/local/src# tar -jxvvvf snapscreenshot-1.0.14.3.tar.bz2

noah:/usr/local/src# cd snapscreenshot-1.0.14.3
noah:/usr/local/src/snapscreenshot-1.0.14# ./configure && make && make install
Configuring…
Fine. Done. make.
make: Nothing to be done for `all'.
if [ ! "/usr/local/bin" = "" ]; then mkdir –parents /usr/local/bin 2>/dev/null; mkdir /usr/local/bin 2>/dev/null; \
for s in snapscreenshot ""; do if [ ! "$s" = "" ]; then \
install -c -s -o bin -g bin -m 755 "$s" /usr/local/bin/"$s";fi;\
done; \
fi; \
if [ ! "/usr/local/man" = "" ]; then mkdir –parents /usr/local/man 2>/dev/null; mkdir /usr/local/man 2>/dev/null; \
for s in snapscreenshot.1 ""; do if [ ! "$s" = "" ]; then \
install -m 644 "$s" /usr/local/man/man"`echo "$s"|sed 's/.*\.//'`"/"$s";fi;\
done; \
fi

By default snapscreenshot command is made to take screenshot in a tga image format, this format is readable by most picture viewing programs available today, however it is not too common and not so standartized for the web as the JPEG and PNG.
Therefore to make the text console tty snapshot taken in PNG or JPEG one needs to use ImageMagick's convert tool. The convert example is also shown in snapscreenshot manual page Example section.

To take a .png image format screenshot of lets say Midnight Commander interactive console file manager running in console tty1, I used the command:
 

noah:/home/hipo# snapscreenshot -c1 -x1 > ~/console-screenshot.tga && convert ~/console-screenshot.tga console-screenshot.png

Linux text console tty mc screenshot with snapscreenshot terminal / console snapshotting program

Note that you need to have read/write permissions to the /dev/vcs* otherwise the snapscreenshot will be unable to read the tty and produce an error:
 

hipo@noah:~/Desktop$ snapscreenshot -c2 -x1 > snap.tga && convert snap.tga snap.pngGeometry will be: 1x2Reading font…/dev/console: Permission denied

To take simultaneous picture screenshot of everything contained in all text consoles, ranging from tty1 to tty5, issue:
 

noah:/home/hipo# snapscreenshot -c5 -x1 > ~/console-screenshot.tga && convert ~/console-screenshot.tga console-screenshot.png

Here is a resized 480×320 pixels version of the original screenshot the command produces:

All text Consoles tty1 to tty5 merged screenshot png image with snapscreenshot taken on Debian GNU / Linux

Storing a picture shot of the text (console) screen in JPEG (JPG) format is done analogously just the convert command output extension has to be changed to jpeg i.e.:
 

noah:/home/hipo# snapscreenshot -c5 -x1 > ~/console-screenshot.tga && convert ~/console-screenshot.tga console-screenshot.jpeg

I've also written a tiny wrapper shell script, to facilitate myself picture picture taking as I didn't like to type each time I want to take a screenshot of a tty the above long line.

Here is the wrapper script I wrote:
 

#!/bin/sh
### Config
# .tga produced file name
output_f_name='console-screenshot.tga';
# gets current date
cur_date=$(date +%d_%m_%Y|sed -e 's/^ *//');
# png output f name
png_f_name="console-screenshot-$cur_date.png";
### END Config
snapscreenshot -c$arg1 -x1 > $output_f_name && convert $output_f_name $png_f_name;
echo "Output png screenshot from tty1 console produced in";
echo "$PWD/$png_f_name";
/bin/rm -f $output_f_name;

You can also download my console-screenshot.sh snapscreenshot wrapper script here

The script is quite simplistic to use, it takes just one argument which is the number of the tty you would like to screenshot.
To use my script download it in /usr/local/bin and set it executable flag:
 

noah:~# cd /usr/local/bin
noah:/usr/local/bin# wget -q http://www.pc-freak.net/~bshscr/console-screenshot.sh
noah:/usr/local/bin# chmod +x console-screenshot.sh

Onwards to use the script to snapshot console terminal (tty1) type:
 

noan:~# console-screenshot.sh

I've made also mirror of latest version of snapscreenshot-1.0.14.3.tar.bz2 here just in case this nice little program disappears from the net in future times.

 

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 🙂

Convert single PDF pages to multiple SVG files on Debian Linux with pdf2svg

Sunday, February 26th, 2012

In my last article, I've explained How to create PNG, JPG, GIF pictures from one single PDF document
Convertion of PDF to images is useful, however as PNG and JPEG graphic formats are raster graphics the image quality gets crappy if the picture is zoomed to lets say 300%.
This means convertion to PNG / GIF etc. is not a good practice especially if image quality is targetted.

I myself am not a quality freak but it was interesting to find out if it is possible to convert the PDF pages to SVG (Scalable Vector Graphics) graphics format.

Converting PDF to SVG is very easy as for GNU / Linux there is a command line tool called pdf2svg
pdf2svg's official page is here

The traditional source way compile and install is described on the homepage. For Debian users pdf2svg has already existing a deb package.

To install pdf2svg on Debian use:

debian:~# apt-get install --yes pdf2svg
...

Once installed usage of pdf2svg to convert PDF to multiple SVG files is analogous to imagemagick's convert .
To convert the 44 pages Projects.pdf to multiple SVG pages – (each PDF page to a separate SVG file) issue:

debian:~/project-pdf-to-images$ for i in $(seq 1 44); do \
pdf2svg Projects.pdf Projects-$i.SVG $i; \
done

This little loop tells each page number from the 44 PDF document to be stored in separate SVG vector graphics file:

debian:~/project-pdf-to-images$ ls -1 *.svg|wc -l
44

For BSD users and in particular FreeBSD ones png2svg has a bsd port in:

/usr/ports/graphics/pdf2svg

Installing on BSD is possible directly via the port and convertion of PDF to SVG on FreeBSD, should be working in the same manner. The only requirement is that bash shell is used for the above little bash loop, as by default FreeBSD runs the csh. 
On FreeBSD launch /usr/local/bin/bash, before following the Linux instructions if you're not already in bash.

Now the output SVG files are perfect for editting with Inkscape or Scribus and the picture quality is way superior to old rasterized (JPEG, PNG) images

Create PNG, JPG, GIF pictures / images from PDF on Linux

Saturday, February 25th, 2012

I've received a PDF file with a plan for development of a bundle of projects, My task was to evaluate this plan and give feeback on the 44 pages PDF document.

Since don't know of program to directly be able edit PDF files on GNU / Linux ?, my initial idea was to open and convert the PDF to ODT / DOC with OpenOffice (Libre Office) and then edit the ODT file.
Unfortunately Open Office oowrite program was unable to open / visualize the PDF file. My assumption is OO failure to open the PDF is because the PDF was generated on Microsoft Windows with Adobe illustrator or smth.

The idea that came to my mind as alternative, way to edit the PDF file was to convert it in pictures edit and then convert the pictures to PDF.
In other words to follow these 3 steps:
1. Convert the PDF document to multiple images
2. Edit each of the images with GIMP or Inkscape
3. Convert back all images to a single PDF file

Some time ago, I've written an article how to create PDF file from many image files in JPEG, PNG or GIF on Linux

. This prior article was exactly describing how to complete Step 3.Therefore all left was to find a way to convert the PDF file to multiple JPEG / PNG / GIF images.

convert command to convert PDF document to multiple pictures which you can take from my earlier article is:

$ convert *.jpg outputpdffile.pdf
Actually in Step 1 I was aiming to do the opposite of what I've previously done.

Hence, in order to convert the singe Project.PDF file to multiple PNG images, I just switched convert IN / OUT arguments order.

hipo@noah:~/project-pdf-to-images$ convert Project.pdf Project.png
...

I've done the PDF to pictures conversion on my notebook running Debian Squeeze (6.0.2) GNU / Linux.Convertion of the PDF file to 44 images, took 25 seconds on my dual core 1.8 Ghz / 2GB RAM Thinkpad r61.
Afterwards, I've had at hand 44 PNG files generated, e.g.:

hipo@noah:~/project-pdf-to-images$ ls -al Project-*.png |wc -l
44

convert was also smart enough to produce correct file naming. The output file names were:
Project-1.png
Project-2.png
etc.

Nicely each number (-1.png) was corresponding to the respective PDF page. For instance Project-10.png was corresponding to page 10 of the Projects.PDF file

Rather ironically, after convertion of the PDF to pictures, while opening the Project-1.png, I've noticed The GIMP – (The GNU Image Manipulation Program) is capable of directly reading PDF files. GIMP has both the option to open files in layers or separate images 😉
Anyways even if GIMP is used to modify the different PDF pages as layers, once completed GIMP doesn't have the ability to save the file as PDF and therefore once saved the file if merging of layers is done the resulting picture becomes ONE BIG MESS.
Therefore it seems my the 3 steps way e.g.:

1. convertion PDF to pictures
2. picture edit with GIMP or Inkscape
3. convertion of pictures back to PDF

is still the only way to "modify PDF" in Linux or BSDs. I will be glad to hear if someone has come up with a better solution?