Customize Wordpress TinyMCE Editor

customize-wp-tinymce.php

<?php
// Make TinyMCE editor awesome!
function make_mce_awesome( $init ) {
    $init['theme_advanced_blockformats'] = 'h2,h3,h4,p';
    $init['theme_advanced_buttons1_add'] = 'copy, cut, paste, redo, undo';
    $init['theme_advanced_buttons2_add'] = 'anchor, hr, sub, sup';
    $init['theme_advanced_disable'] = 'wp_help';
    return $init;
}
 
add_filter('tiny_mce_before_init', 'make_mce_awesome');

add_filter( 'mce_buttons_2', 'my_mce_buttons_2' );

function my_mce_buttons_2( $buttons ) {
    array_unshift( $buttons, 'styleselect' );
    return $buttons;
}

add_filter( 'tiny_mce_before_init', 'my_mce_before_init' );
function my_mce_before_init( $settings ) {
    $style_formats = array(
    	array(
    		'title' => 'Button',
    		'selector' => 'a',
    		'classes' => 'btn'
    	),
        array(
        	'title' => 'Callout Box',
        	'block' => 'div',
        	'classes' => 'callout',
        	'wrapper' => true
        ),
        array(
        	'title' => 'Bold Red Text',
        	'inline' => 'span',
        	'styles' => array(
        		'color' => '#f00',
        		'fontWeight' => 'bold'
        	)
        )
    );
    $settings['style_formats'] = json_encode( $style_formats );
    return $settings;
}
add_editor_style('path/to/custom/admin-styles.css');
?>