Site does not render without JS enabled. At all. You get a flat white page. Enabling JS lets it render, but also scrolls crippling slowly. If I could downvote right now I would.
But it gets worse.
Nothing in here is about graph theory. It is a massive over complication. He is just trying to resize to a new aspect ratio by cropping the least amount. While dragging in calculus? This is really very simple and common. Imagemagick even has a dedicated option for it:
-resize <size>^ -gravity center -extent <size>
That caret does all the heavy lifting. (see
http://www.imagemagick.org/Usage/resize/#fill for more)
To add insult to injury, he then uses Imagemagick to do the resize! The article is misleading, poorly written and hosted on a horrible platform to boot.