Collision Detection Kit is a package of classes for pixel-precise, shape-based collision detection for all display objects. It comes with several features to control how collisions are detected, and provides data for the user of the kit so they can do something about the collision.
Features include setting alpha thresholds and color exclusions, retrieving information on the pixels involved in the collision, and a returned angle of collision calculated from the shapes of the display objects at the site of the collision.