Image magic

I've been facing the task of manipulating images for web apps and websites from time to time - like cropping, scaling and reducing file size. While some of these tasks can be done with a handy GUI tool like Photoshop (you have to pay for it), Photopea (a very powerful web-based photoshop-like editor that works with a multitude of formats including .psd) or Paint.net, sometimes a shell-based tool will do so much better. 

There is a tool like that and it's called Imagemagick. 

The thing let's you manipulate various raster images in different ways. I would most often use it for resizing and compressing images in batches and sometimes for cropping (here a visual tool may be better, but really depends on the scenario). 

For my own and other's reference, here are some of my usecases. Of course, there is an extensive documentation on the tool's website. 

(Since I'm on windows, I use image magick in Powershell to process many files at once).

Crop

Crop all files in the current directory and save them with a .crop suffix. This one reduces the size of the images to 1080x1732 cutting off 62px on the top (android screenshot).

Get-ChildItem -File | Foreach {convert $_.fullname -crop 1080x1732+0+62 $_.fullname.replace(".png",".crop.png")}

Scale

Scale all files in a directory down to 50% their dimensions (preserves aspect ratio):

Get-ChildItem -File | % {convert -resize 50% $_.fullname $_.fullname}

Compress

Based on this stackoverflow discussion.

Just one file, saving a copy:

convert -strip -interlace Plane -quality 85% .\banner_1.jpg .\banner_1.comp.jpg

All files in the current directory, replacing the originals:

Get-ChildItem -File | % {convert -strip -interlace Plane -quality 85% $_.fullname $_.fullname}

A lot of other usecases - do explore them!

Clojure: Barnsley Fern

In addition to other pleasurable events, the last month I got as a gift yet another book devoted to the Chaos Theory – ‘Simply Chaos’ by Sergey Demenok (in Russian). This one vaguely reminds me of ‘Chaos: Making a New Science’ by James Gleick, since both aim mostly at attracting readers to science, explaining it to them and showing how beautiful it can be. Still they differ a lot, with ‘Simply Chaos’ being more joyful reading balancing on the boundary between historical and scientifical truth on one side and myth and fantasy on the other. This way the last book was a great and funny refresher, making me remember of some things, that fascinated me while I was reading the Gleick’s ‘Chaos’ a year and a half ago. Most notably, I faced the idea of Barnsley Fern once more.