Allows you to dynamically determine if your code is being used in a plugin or a theme

wp_code_context.php

<?php
function wp_code_context() {
	$theme = strpos( __DIR__, 'themes' );
	return ( $theme ) ? 'theme' : 'plugin';
}
function get_directory_by_context() {
	$context = wp_code_context();
	switch( $context ) {
		case 'theme':
			$local_dir = get_template_directory();
			break;
		case 'plugin':
			$local_dir = plugin_dir_path(__FILE__);
			break;
		default:
			$local_dir = false;
	}
	return $local_dir;
}

function get_directory_url_by_context() {
	$context = wp_code_context();
	switch( $context ) {
		case 'theme':
			$local_url = get_template_directory();
			break;
		case 'plugin':
			$local_url = plugin_dir_path(__FILE__);
			break;
		default:
			$local_url = false;
	}
	return $local_url;
}