Haxe port of Pixel Sprite Generator by zfedoran.
SWF - https://pub.darekgreenly.com/github/pixel-sprite-generator/PixelSpriteGenerator.swf
HTML/JS - https://pub.darekgreenly.com/github/pixel-sprite-generator/index.html
haxelib install pixel-sprite-generator
The sprites are generated by using a two dimensional mask. The values in the mask are then randomized and mirrored. The resulting template is rendered to a canvas element.
The algorithm is explained in more detail on Dave Bollinger's website.