FreedomsFlame

I've been hunting through the class files and honestly have probably looked past it a thousand times, but where is the event for when something is within the player's reach (when if it's a block it puts the frame around it)? I'm trying to make a reactive crosshair mod that will change the crosshair based on what you are aiming at and what item you are wielding (pickaxe icon, axe icon, sword icon when mobs are within reach, hammer when holding and aiming at a block, hand icon when aiming at a usable object like a button, door or lever, and a looting icon when aiming at chests). Help would be much appreciated!