Thor VS RMagick

Ruby has always been a great general-purpose scripting language and is often used to create command-line utilities. Many of these use the excellent Thor gem to parse command-line options, but there's no escaping one fact: command-line utilities just aren't interesting. Never have been, never will be.

All public methods in the generator will be called one after the other. Private methods will not be called but are available in your public methods like regular Ruby classes.

ruby: http://whatisthor.com

I will add that if you want to develop a CLI tool that gives you various commands that you can run, I would have a look at something like thor to keep it organised and documented. But this is completely unnecessary as a first step - you can simply create a Ruby file that does a thing you want and invoke it directly.

Not to be confused with generator functions (which you might be familiar with from Python or Javascript), Rails generators are custom Thor commands that focus on, well, generating things.

I wanted to provide a command-line interface for the user that was easy to use, and I also wanted to provide the flexibility with the options used to render the animation. After looking around online I found that Thor was a good tool to utilize. It allowed me to easily create a number of options that make this program much more versatile. An example below shows how a user can select which folder the source images are in, as well as what the background and foreground colors should be:

I've used Thor a lot, but it's kind of terrible. It uses a custom non-POSIX-compliant option parser (ex: method_option :list, type: :array -> --list one two three, where as the POSIX way is --list one,two,three or --item one -- item two --item three) and will not error on unknown options or exit with -1 when not enough args are given. If you want a better CLI library, checkout dry-rb, command_kit, or cmdparse.

And Thor might be worth looking at if you have complex scripts: https://github.com/erikhuda/thor

require 'rmagick' include Magick module LambdaFunction class Handler def self.process(event:, context:) image_url = event['image_url'] my_image = ImageList.new(image_url) # TODO: Use rmagick to make your image transformations # Docs: https://rmagick.github.io { "success": true } end end end

mini_magick is much slower than YOLO. I hear that rmagick is well maintained these days, so you may want to use that.

To accomplish this project, I knew I would need some way to process the input images. Resizing the images was the easy bit. The more complex (and more important) task was to find the best way to relate a pixel's color in the source image to a dot's size in final animation. I felt that the relative luminance as described in this W3 accessibility document was a logical property to use in this case, and can be easily calculated with a color's RGB components. After determining what tasks I needed to fulfill, I determined that the RMagick library would be a good choice for this project.