This is a collection of various Acorn plugins.

Acorn is a great image editor for the Mac from Flying Meat, and you can grab it from here: http://flyingmeat.com/acorn/

Official documentation on writing plugins is also available, but you might find it easiest to look through the samples.

This repository contains samples written in JSTalk, as well as in Objective-C. You'll find various examples, as well as code for reading composites of Acorn images, as well as reading the layer information.