DEV Community: ListNUX

Fun with ImageMagick

ListNUX — Wed, 17 Jul 2019 23:20:06 +0000

ImageMagick is an amazing software suite, with tools for displaying images, editing, converting from one format to another and it works with both bitmap (raster) images and vector images. It can read over 100 major file formats, including RAW files from various camera models, video files such as AVI or MPEG and more.

Being command-line mostly tool, and ubiquitous, makes it the ideal tool to bundle with other software that needs image editing. It can be scripted - and some people have created some amazing script collections like Fred and Snibgo.

This post is a compilation of some of my random notes and various examples from ImageMagick usage pages. I provide no explanation for the various tools and options, the official site (especially the usage pages) and the man-pages explain it much better than I can.

ImageMagick command-line tools.

Here is the full list of all ImageMagick command-line tools. Some common tools are:

convert: image editing.
mogrify: image editing, mostly used for batch editing.
import: screenshot utility.
display: ImageMagick GUI.
animate: animates an image on a GUI window.

1. Create a text logo:

Check available fonts:



convert -list font

and then:



convert -background DarkSlateBlue -strokewidth 2 -stroke turquoise1 -font Aka-AcidGR-LivingSword -pointsize 256 -density 90 label:ListNUX test.png

List of colour names.

Result:

2. Resize images:

Let's download some penguin images from Wikipedia:



mkdir -p penguins && cd "$_"
cat>"url_list.txt"<<EOF
https://upload.wikimedia.org/wikipedia/commons/0/08/South_Shetland-2016-Deception_Island%E2%80%93Chinstrap_penguin_%28Pygoscelis_antarctica%29_04.jpg
https://upload.wikimedia.org/wikipedia/commons/1/1d/Penguin_in_Antarctica_jumping_out_of_the_water.jpg
https://upload.wikimedia.org/wikipedia/commons/f/fd/Antarctic_adelie_penguins_%28js%29_21.jpg
https://upload.wikimedia.org/wikipedia/commons/4/49/Pygoscelis_antarcticus_-Cooper_Bay%2C_South_Georgia%2C_British_Overseas_Territories%2C_UK-8.jpg
https://upload.wikimedia.org/wikipedia/commons/9/9e/Penguins_walking_-Moltke_Harbour%2C_South_Georgia%2C_British_overseas_territory%2C_UK-8.jpg
https://upload.wikimedia.org/wikipedia/commons/4/4f/Yellow-eyed_Penguin_MC.jpg
EOF
wget -i url_list.txt

First, let's resize all photos so that the biggest size (height or width, whichever is largest) is at maximum 800px. We will also reduce quality to 90%, for smaller file sizes.



for i in *.jpg; do
  convert $i -resize "800x800>" -strip -quality 90 _${i};
  rm ${i};
done

3. Crop images from center:

And let's crop them all to 500x500px squares:



for i in *.jpg; do
  convert ${i} -gravity center -crop 500x500+0+0 +repage _${i};
  rm ${i};
done

Now, let's rename them all to pengu01, pengu02, etc.



num=1
for i in *.jpg; do
  new=$(printf "pengu%02d.jpg" "$num");
  mv -- "$i" "$new"
  let num=num+1
done

5. Combine multiple images into a gif:

And now, time to animate!



# pop-up a window with all the images with 90sec delay
animate -delay 90 *.jpg
# write the previous animation to a gif image
convert -delay 90 *.jpg test.gif

6. Create a gradient:



# simple linear gradient, two colours
convert -size 600x400 gradient:blue-red linear_gradient.png
# simple radiant gradient, two colours
convert -size 600x400 radial-gradient:blue-red radial_gradient.png
# a more complex, multi-colour gradient with bicubic interpolation
convert \( -size 600x400 gradient: -interpolate Bicubic -rotate 180 \
  \( +size xc:firebrick4 xc:crimson xc:MediumPurple xc:DarkSlateBlue -append \) \
  -clut \) \
  gradient.png

7. Create a text logo with a 3D effect:



convert gradient.png -background purple -alpha shape \
  -font Aka-AcidGR-ScrachThis -pointsize 192 -fill firebrick2 \
  -stroke black -gravity Center \
  -annotate 0 "ListNUX" logo_simple.png

Overlay the text:



convert logo_simple.png -alpha extract -blur 0x6 -shade 580x80 -normalize \
  logo_simple.png -compose Overlay -composite \
  logo_simple.png -alpha on -compose Dst_In -composite \
  logo_v1.png

... and then add some shadow



convert logo_v1.png \
  \( +clone -background CornflowerBlue -shadow 80x4+20+20 \) \
  +swap -background MidnightBlue -layers merge +repage \
  logo.png

8. Stars:

Let's create an image with stars. We will create background noise, then delete and blur the excess noise, and use motion blur to create starbrusts.



convert -size 500x500 xc: +noise Random -channel R -threshold 0.07% \
  -negate -channel RGB -separate plasma:DarkOrchid1 \
  +channel \( +clone \) -compose multiply -flatten \
  -virtual-pixel tile  -blur 0x.5 \
  \( -clone 0  -motion-blur 0x20+15 -motion-blur 0x20+195 \) \
  \( -clone 0  -motion-blur 0x20-45  -motion-blur 0x20+135 \) \
  -compose screen -background black -flatten \
  -normalize stars.png

Credits

ImageMagick logo Wikimedia Commons under ImageMagick License
Examples of ImageMagick usage
Fonts used: Aka-acid fonts, specifically:
- Living sword font
- Scratch this font

Seven ridiculously good command line tools

ListNUX — Wed, 03 Jul 2019 19:09:47 +0000

Originally posted on listnux.com

You are coding in Python. Your screen is filled up with terminals of various sizes and lenghts, and you have a deadline. It is 2.00 am, winter, the room is chilly, and there is a storm outside.

You have a big dictionary, and you want to sort it by a numeric value. How to do this? You turn your head around the screen, to spot your favourite browser, and to ask your friends, Google, or StackOverflow. You know the browser is there, it has always been there for you. But all the terminals all over the screen cover it completely. You curse your decision to use a window manager without taskbar and frantically start moving and minimising terminals.

Well, you are in luck. You might not need to.

Ridiculously good command line tools

Contents
cheat.sh
Rebound
mycli
Bat
Fiche - termbin.com
GRV
GoAccess

1. cheat.sh - the only cheat sheet you need

A cheatsheet that let's you access not only actual cheatsheets and simple overviews of various commands and programming languages, but it even queries Stack Overflow for answers? And automatically selects the most upvoted thread that matches your search term? Yes, that's cheat.sh.

To find out what Stack Overflow has to say about our previous question, without leaving the terminal, is as simple as:

curl cheat.sh/python/sort+dictionary+by+value|more
# OR
curl cht.sh/python/sort+dictionary+by+value|more

Alternatively,you can install the command line client, cht.sh, so that you don't even have to type curl, or add + between the terms:

cht.sh python sort dictionary by value

Notice the link at the end (so/q/613183)? It stands for https://stackoverflow.com/q/613183 and it is the most upvoted question in Stack Overflow that contains the queried terms. Say, though, the most upvoted question does not answer your specific issue (though this particular answer is excellent)? Simply extend a /1 or /2 or any number at the end of your query. For instance:

curl cht.sh/python/sort+dictionary+by+value/1
#or
cht.sh python sort dictionary by value/1

will return the top answer to this Stack Overflow question

cheat.sh • View on GitHub

2. Rebound - Command-line tool that instantly fetches Stack Overflow results

So, with the help of cht.sh, you figured out the answer of your question and finished a part of your project. So you run it, and, whoa... compile error. You can still type the error for cht.sh to fetch an answered question from StackOverflow, but, why waste time typing a long error, when you can use Rebound?

Rebound is a fantastic Python tool, that allows you to simply execute the file and directly pull the error message and find related Stack Overflow questions. It works with Python, Ruby, Java, Goland and Node.js and it is as simple as:

# instead of typing:
python app.py
# you simply type:
rebound app.py

And here is what happens:

Once you press enter, you get a list of related Stack Overflow threads:

Fantastic? Absolutely!

View on GitHub

3. mycli - A terminal client for MySQL

mycli.net, at first glance, might not seem as sexy as the previous tools, but it is insanely handy when you are working with MySQL databases.

It packs auto-completion for SQL keywords and tables, views or columns, logs, colourful tabular data, multiline queries and more.

But what's more, it permits you to save complex (or simple) queries as aliases for future use. It allows parameter substitution for your saved queries, so you can reuse them whenever applicable.

For example, I have saved a query, which generates a DROP statement for tables starting with a certain string:

\fs cleardb SELECT CONCAT( 'DROP TABLE ', 
                            GROUP_CONCAT(table_name) , ';' ) AS statement FROM
                            information_schema.tables WHERE table_schema = '$1'
                            AND table_name LIKE '$2__%';

with $1 being my database name and $2 the string I want my query to match on the table name. Simply invoking the alias with:

\f cleardb "my_database" "my_string_"

will return the drop statement I need. You really don't realise how much you are missing a tool like this, before you actually try it.

Also see the pgcli project for Postgres

mycli.net • View on GitHub

4. Bat - a cat clone with winds

Bat is a Rust tool that aims to be the better, prettier and more handy replacement of cat(1). It features syntax highlithing, line numbering, theming, pagers, and it communicates with Git to display file modifications.

Bat can completely replace cat and it can be used in pipes (bat .bash_profile |grep PATH), or with find: find -type f -name README.md -exec bat {} +

View on GitHub

5. Fiche - termbin.com

You were still coding that Python script, remember? And decided to share a file with your friend.

Now, you can login to GitHub and post a gist, or to GitLab and post a snippet, or to Pastebin. But, yeah, your browser is hidden below a few stacks of terminals. So, what can you do?

This:

cat test_howdoi.py | nc termbin.com 9999 # or 'bat test_howdoi.py...'

The terminal returns a simple URL: https://termbin.com/wf6u in the above case. You text this URL to your friend, and, behold, you just shared your file, without ever leaving your terminal. (In case you are wondering, I shared a file from howdoi, a fantastic command-line tool, which is not in the current list, as it has a bit similar function with the first two tools listed).

Termbin.com is a public pastebin server that works with the commandline pastebin tool fiche. It is very quick, keeps pastebins for a month and even has syntax highlighting (try the above link with l.termbin instead of termbin: l.termbin.com/wf6u).

What's more, you can install fiche and self-host your own pastebin server.

termbin.com • View on GitHub

6. GRV - terminal interface for git

Sometimes you don't know anymore what's going on on your local git repo. You remember that your last few commits were "Fix #1999", "Prev fix broke things, revert to #1998", "Fix #2000", "revert Fix #2000", "final fix", "%#&@ this I go to sleep", but you need to see what files you changed on each commit, the diffs, the commit messages.

And of course git allows you to do all of this. And of course, there is an even easier way, to see all your commits, diffs and refs on a nice, easy to browse table.

"Yes, *I know* ", you say, "it is called *GitHub*. I need to dig out that browser".

Or you can simply use GRV. It presents all the above info on a nice table right on your terminal. It has tabs and splits and custom views, queries, and your terminal refreshes automatically whenever there is a change on the filesystem.

GRV is a tool you don't realise how much you need it, until you actually use it. It makes the presentation of your git repo so easy to grasp and browse, that it is a must-have tool if you work with Git a lot (and you should work with Git all the time, if you are coding).

View on GitHub

7. GoAccess - real-time web log analyzer

One of these things is not like the others. The last tool on today's list is not going to help you in your coding adventures. But, if you have a website, it will analyse the logs of your web server and allow you to view them directly on your terminal.

This is awesome, cause the access.log logs on most servers are hard to read and even harder to analyse quickly. GoAccess will allow you to have visitor statistics for your website without tracking your visitors, compromising their privacy and sharing their browser habits with big Internet monopolies.

It's meant to satisfy a simple curiosity about how many people visit your site and what pages they view. It's not a tool to replace Google Analytics, or Piwiq/Matomo, or Statcounter. It is meant to simply present nicely the logs your web server already keeps.

GoAccess • View on GitHub

[Bonus] wttr.in - the right way to check the weather

So, is this storm still going outside? You can't hear any rain dropping on your windows, but you can't be sure without leaving that terminal (or that chair). Why don't you simply curl wttr.in or curl wttr.in/YOUR-LOCATION?

Nope, not a single cloud. Nice!

wttr.in • View on GitHub