I've been following a tutorial on Tuts+ (linked from the WordPress Codex) on how to interact with the TinyMCE editor to add buttons. Following the example code on that article, I have a JS file which adds the buttons to TinyMCE. The relevant snipped of JS that adds the icon is:
title : 'DropCap',
cmd : 'dropcap',
image : url + '/dropcap.png'
Now this was fine pre WP 3.8, however since Dashicons were introduced it looks outdated to use static PNG's for TinyMCE buttons... Since 3.8 I've updated my custom post types to use Dashicons, but was wondering what is the correct way to get TinyMCE buttons using Dashicons as well? There's a handy guide from James Coster on how to use Dashicons which may be relevant (though I assume there's no need to place calls to enqueue the Dashicons scripts as they'll already be loaded in the back-end).