Code Snippet: Integrate Custom Fonts into Oxygen

Version: 3.2.4 (Oct 26, 2021)



Oxygen Builder allows you to select standard web-safe font combinations, Google Fonts and even TypeKit fonts.
Custom fonts, such as fonts licensed by the customer, are not available here.

Of course you can upload your own fonts to the server and then embed them by CSS yourself. But in Oxygen such a font is still not available for selection.


There are several plugins that allow integrating custom fonts into Oxygen:

Those plugins work perfectly. 
However, you'll have to upload each single font file and register with name, weight, and style.

Code Snippet

For a customer project, I had to use a font licensed by the customer to comply with the CI, but I didn't want to install another plugin for just this one font.

Since I already had installed the plugin "Code Snippets" anyway in order to implement several other features in this project, I developed a solution, which can be integrated as code snippet.

The Code Snippet can also automate the deployment of fonts as far as possible and, since version 3, also optimally integrate Google Fonts. For the easy download of Google Fonts I have developed the Web Font Loader.



  1. Install and activate the Code Snippet (see Download)
  2. The snippet automatically creates a new folder on your server: wp-content/uploads/fonts as soon as you have accessed the Appearance > Custom Fonts page or the frontend once after activating the snippet. Of course, you can also create this folder yourself.
  3. Upload your font files (eot, otf, svg, ttf, woff, woff2) into this fonts folder.
    Alternatively, you can download Google Fonts via my Web Font Loader to host them locally on your server.
    Please extract the ZIP file and upload the complete extracted folder, named like your font, and all of its contents to the folder on the server.

The snippet will find all font files, make them available for selection in Oxygen and generate CSS code in the frontend.

Font Files, Names, Weights and Styles

With Google Fonts, which you have downloaded via my Web Font Loader, all available font files, weights, styles and also the available character sets are automatically detected. The necessary information is read from the enclosed JSON file. You can skip this chapter.

For your own fonts from other sources, these details are determined based on the file names.

The snippet supports the font formats EOT, OTF, SVG, TTF, WOFF, WOFF2.

The filename of the font file will be used as font name.
So for the font file "Matthias Altmann.woff2" Oxygen will display the font name "Matthias Altmann".

If the file name contains keywords for font weights, these are recognized and not included in the font name, but noted in the generated CSS code accordingly.
The following weights and styles are currently recognized:

Font WeightKeywords
200ExtraLight, UltraLight
400Normal, Regular, Book
600Demi, DemiBold, SemiBold
800ExtraBold, UltraBold

The keywords are not case sensitive and may contain hyphens between the keyword parts.
ExtraLight is therefore recognized in the same way as extra-light.

Numeric values (100, 200, ...) in the file names are also recognized as font weights.

Furthermore, the keywords "italic" and "oblique" are recognized for the italic font style. Also here, the capitalization and a leading hyphen are irrelevant.

If there are multiple font files with the same name but different font formats (eot, otf, svg, ttf, woff, woff2), Oxygen will display the font name only once. However, the generated CSS will contain all available font formats. The browser will choose the preferred one by itself.

Fonts with variable weights are also supported: If the keyword VariableFont (case-insensitive) is recognized in the file name, the CSS is automatically adjusted for fonts with variable weights.

Testing the fonts

The snippet implements a test function that outputs a list of all fonts, weights and styles recognized and registered by the snippet. Here you can check the integration and display of the fonts, also in different font sizes.

Test with Admin Function

In the WordPress administration there is a new menu item "Custom Fonts" under Appearance
Here you get a quick overview of the fonts registered by the snippet

Test by Shortcode

The snippet provides a shortcode [maltmann_custom_font_test].
This shortcode can be easily entered on a new page in the Gutenberg Editor. The page does not even need to be made public. A preview gives you a quick overview of the fonts registered by the snippet.


While developing the script I paid a lot of attention to efficiency and performance. Detecting existing fonts and generating the CSS code takes only milliseconds on an average server.

The CSS code for the fonts is linked as CSS file or emitted at the end of each page, no matter if one of the fonts is used on that page or not.
However, the browser loads a font only when it is really needed, and then only in the one preferred format.


So far, I know of three WordPress plugins that integrate custom fonts into Oxygen in a similar way: "Elegant Custom Fonts", "Use Any Font", and "Swiss Knife".
Since the way of implementation or the technical approach to integrate fonts into Oxygen are similar in these plugins and my code snippet, these solutions are not compatible. You have to choose one of these solutions. So please deactivate these plugins, or in case of "Swiss Knife", deactivate the "Font Manager" before using my Code Snippet.

Oxygen offers the possibility to embed Google Fonts directly.
If you want to use this code snippet to host Google Fonts locally on your own server, I recommend disabling Google Fonts support in Oxygen: Oxygen > Settings > Bloat Eliminator > Disable Google Fonts

FAQ - Frequently Asked Questions

What are the different font file formats (TTF, EOT, OTF, SVG, WOFF, WOFF2) all about?

Since the 1990s, the "True Type" format (TTF) has been available for installing fonts on a computer.
In 1996, Microsoft developed the "Embedded Open Type" (EOT) format to provide compressed and thus smaller font files for Internet Explorer.
Starting in the 2010s, other increasingly optimized font file formats were developed for use on the web, namely OTF, SVG, WOFF, and WOFF2.

WOFF2 is currently the most advanced format and is supported by all modern browsers.
Only a few older devices, such as iPhones and iPads of the very early generations, cannot use it and need WOFF.

The following table shows the file sizes of the individual file formats using the "Dinot" font:

FormatFile Size

Since a font can consist of several files for the different weights and styles, it quickly becomes clear that with modern formats such as WOFF and WOFF2, significantly less data needs to be transferred.

So if you have your own font only in TTF format, it is recommended to convert it to WOFF or WOFF2.
You can find numerous free online services for this on the Internet under the search term "Font Converter".

Can I host Google Fonts locally with this Code Snippet?

For downloading Google Fonts in modern web formats, I have developed my own service Web Font Loader, which is perfectly adapted for use with this snippet.

Please note:

My Code Snippet will search for font files and add them to the Oxygen font list.
However, Oxygen offers some Google Fonts in the font list by itself.

For example, if we download the Google Font "Roboto" and host it locally, my Code Snippet will add it to the font list.
Oxygen adds the Google Font "Roboto" itself.
So "Roboto" is now included twice in the list: Once as local font /listed in light blue) and once as Google Font (listed in white).

To make matters worse, even with the option "Disable Google Fonts" enabled, Oxygen still displays 20 Google fonts in the font selector, and offers Google Fonts when searching for fonts. This is known to the Oxygen team, but there is currently no solution for this.

I recommend to disable Google Fonts support in Oxygen: Oxygen > Settings > Bloat Eliminator > Disable Google Fonts

Why are there no font weights available for my custom font in Oxygen Global Settings?

In Oxygen Global Settings you can define the font weights for Google Fonts to be embedded. This way you can limit which font weights are loaded from Google Fonts Server and thus reduce the file size if only a few font weights are used.

For our own fonts, which we embed using this Code Snippet, we decide ourselves which font files we place in the "fonts" folder. Usually there is a separate font file for each font weight. All these font files provided by us and thus the different font weights are offered to the browser. However, the browser only loads the font files with the font weights that are really needed to display the page.

So there is no reason to limit the font sizes for our own fonts in the Oxygen Global Settings.


The Code Snippet is available for download here:

Version 3.2.4, 2021-10-26

For installation and use of the downloaded JSON file you will need the plugin Code Snippets or Advanced Scripts.
You can install the JSON file using the "Import" function of the plugin. 
Don't forget to activate the snippet after import.

Alternative: At the end of this page you can view and copy the complete source code of the snippet.

New functionalities and bug fixes are documented in the change log.
A few small things about compatibility should be noted.


I have developed and tested the code snippet to the best of my knowledge under WordPress 5.8.1 and Oxygen 3.8.1.
I provide the code snippet for free use.
I cannot give a guarantee for the functionality in all conceivable WordPress environments.
Download and use of this code snippet is at your own risk and responsibility.


I enjoy developing code snippets and solving requirements with them. I provide the snippets free of charge.

If you like, you can honor my many hours of work with a small coffee donation via PayPal.

  When clicking the button, a connection to PayPal is established.

Your donation will of course be taxed properly by me.

Change Log

See Source Code.

Source Code

Plugin Name:  MA Oxygen Custom Fonts
Description:  Load custom fonts and inject to Oxygen
Author:       <a href="">Matthias Altmann</a>
Project:      Code Snippet: Load custom fonts and inject to Oxygen
Version:      3.2.4
Plugin URI:
Description:  en:
Copyright:    © 2020-2021, Matthias Altmann

Version History:
Date		Version		Description
2021-10-26	3.2.4		Changes:
						- Deferred initialization to hook wp_loaded, after incompatibility checks
						- Gutenberg: Apply custom fonts for new posts also
						- Renamed IDs (for scripts and styles) and CSS classes (for font test) for consistency
						- Avoid unneccessary init by separating admin/frontend and more detailed checks 
						- Fixed an issue comparing hashes for code and file
						  (Thanks to David Sitniansky for reporting)
						- Emit styles for Gutenberg correctly if $cssoutput is configured as 'html'
2021-10-15	3.2.3		Changes:
						- Gutenberg: Use display font for post title
						  (Thanks to Sunny Trochaniak for reporting)
						- Fonts preview: Changed sample text size from 15 to 16 px which is browser standard 
						- Fonts preview: Shortcode output uses WP system fonts for UI instead of custom fonts
						- CSS file link now contains ?ver=... instead of ?hash only
						- Only create CSS file if contents (font configuration) have changed 
						- Removed itemprop="stylesheet" from <link rel="stylesheet" ...>
						  (Thanks to Max Gottschalk for reporting and testing)
						- Proper quoting for font families
2021-08-02	3.2.2		Changes:
						- Using scheme-less URL to avoid issues with wrong WordPress URL configuration
						- Added admin notice if folder wp-content/uploads/fonts is not writable.
						- Fixed issue with uppercase font file extensions.
2021-06-18	3.2.1		Fixes: 
						- Fixed typo in CSS for Gutenberg
2021-06-18	3.2.0		New Features:
						- Display Custom Fonts in Gutenberg (enqueue ma_customfonts.css for font definitions, 
						  add custom style for display and text font from Oxygen global settings)
						- Auto-create folder /wp-content/uploads/fonts
2021-05-17	3.1.3		Changes:
						- Optimized init sequence
						- Emit implementation and version in CSS
						- Reversed Version History order
2021-05-16	3.1.2		Changes:
						- Avoid font swap: Load ma-customfonts.css early; default font-display now "block"
						New Features:
						- Allow space in addition to dashes to detect font weights and styles
2021-03-21	3.1.1		Fixes:
						- Fixed font loading in Gutenberg editor (with Oxygen Gutenberg Integration)
2021-03-20	3.1.0		New Features:
						- "Oblique" in font file name is now detected as italic style
						- Custom Fonts test: Option to show font weights/styles without files as browser would 
						- Output Custom Font CSS in head instead of footer to prevent font swap
						- Custom Fonts test: Changed logic for output font samples and related file info
						- Custom Fonts test: Fixed font file count for fonts provided by Web Font Loader
2021-03-08	3.0.2		Fix:
						- Compatibility with Windows server and local dev environments.
						  (Thanks to Franz Müller for reporting and testing)
2021-02-23	3.0.1		Fixes:
						- Compatibility with WordPress 5.6.2 (doesn't set REQUEST::action anymore)
						- Compatibility check with Swiss Knife's Font Manager feature
						- Compatibility with Swiss Knife (font lists did not display custom fonts light blue)
2021-02-18	3.0.0		New Features:
						- Support for font packages from Web Font Loader (
						- New configuration option: CSS output as inline CSS or external CSS file (cacheable)
						- New configuration option: CSS minimize (was controlled by debug switch before)
						- Changed configuration option: font-display may now be specified as desired, 
						  default is now 'auto'
2021-01-24 	2.5.2		New Features:
						- Custom Fonts test (via Admin panel and shortcode) now allows custom sample text
2021-01-23	2.5.1		Fix:
						- Changed compatibility check process: 
						  Changed Hook for plugin compatibility check from plugins_loaded to init
						  Check only if admin and function is_plugin_active exists
						  (Thanks to Sebastian Albert for reporting and testing)
2021-01-23	2.5.0		New features:
						- WP Admin Menu: Appearance > Custom Fonts 
						  Shows a list of all registered custom fonts, including samples, weights, formats
						  with adaptable sample font size 
						- Detect font weight terms "Book" (400) and "Demi" (600) 
						- Redesign of classes (MA_CustomFonts, ECF_Plugin)
						- Font swap is now a configuration option
						- Cut "-webfont" from font name
2020-12-08	2.2.5		Changes:
						- In CSS, font sources are now listed in a prioritized order (eot,woff2,woff,ttf,otf,svg)
						  (Thanks to Viorel Cosmin Miron for reporting)
						- Test shortcode now also displays available font formats
2020-11-27	2.2.4		Fix:
						- Corrected typo in variable name (2 occurrences) that could cause repeated search 
						  for font files. (Thanks to Viorel Cosmin Miron for reporting)
2020-11-25	2.2.3		Changes:
						- In Oxygen font selectors the custom fonts are now displayed in lightblue 
						  to distinguish from default, websafe and Google Fonts 
2020-11-25	2.2.2		New features:
						- Partial support for fonts with variable weights, detected by "VariableFont" in 
						  filename. CSS output as font-weight:100 900;
2020-11-24	2.2.1		New features:
						- Shortcode [ maltmann_custom_font_test ] for listing all custom fonts with their weights 
						  and styles
						- Fonts are now sorted alphabetically for e.g. CSS output
						- Added more request rules to skipping code execution when not needed
2020-11-23	2.2.0		New features:
						- Detection of font weight from number values 
						- CSS now contains font-display:swap;
2020-10-03 	2.1.1		Fix:
						- Handle empty fonts folder correctly. 
						  (Thanks to Mario Peischl for reporting)
						- Corrected title and file name (typo "cutsom") of Code Snippet
2020-09-16	2.1.0		New features:
						- Detection of font weight and style from file name
						- EOT: Typo in extension detection
						- EOT: Missing quote in style output
2020-09-15	2.0.0		Improved version
						- Finds all font files (eot, otf, svg, ttf, woff, woff2) in directory wp-content/uploads/fonts/
						- Optionally recursive
						- Takes font name from file name
						- Emits optimized CSS with alternative font formats
						- Special handling for EOT for Internet Explorer
2020-04-10	1.0.0		Initial Release for customer project

if (!class_exists('MA_CustomFonts')) :
class MA_CustomFonts {

	const TITLE     	= 'MA Custom Fonts';
	const VERSION   	= '3.2.4';

	// ===== CONFIGURATION =====
	public static $recursive 		= true; 	// enables recursive file scan
	public static $parsename 		= true; 	// enables parsing font weight and style from file name
	public static $fontdisplay		= 'block';	// set font-display to auto, block, swap, fallback, optional or '' (disable)
	public static $cssoutput		= 'file';	// set to 'html' to output CSS inline into page, 
												// set to 'file' to create and reference a CSS file (cacheable by browser)
	public static $cssminimize		= true; 	// minimize CSS (true) or pretty print (false)

	public static $timing			= false; 	// write timing info (a lot!) to wordpress debug.log if WP_DEBUG enabled		
	public static $debug			= false; 	// write debug info (a lot!) to wordpress debug.log if WP_DEBUG enabled	
	public static $sample_text 		= 'The quick brown fox jumps over the lazy dog.';	

	// ===== INTERNAL =====
	public 	static $prioritized_formats	= ['eot','woff2','woff','ttf','otf','svg'];
	private static $fonts 				= null;	// will be populated with fonts and related files we found
	private static $fonts_details_cache	= [];	// cache for already parsed font details
	private static $font_files_cnt		= 0;	// number of font files parsed
	private static $font_css			= null;	// temp storage for custom font css
	private static $guten_oxy_font_css	= null;	// temp storage for Gutenberg css defining oxygen fonts
	static function init() {

		if (!defined('MA_CustomFonts_Version')) define('MA_CustomFonts_Version',self::VERSION);

		// Pre-fill font definitions
		// Pre-fill custom font css, and optionally write file
		self::$font_css = self::get_font_css();

		// Frontend: Emit custom font css in head 
		add_action( 'wp_head', function(){ 
			echo self::$font_css; 

		// Backend
		if (is_admin()) {
			// Load CSS for calls using Gutenberg Editor. 
			// Requires ma_customfont.css (for font loading) and some Oxygen settings (for font assignment)
			global $pagenow;
			if ( ($pagenow === 'post-new.php') || ($pagenow === 'post.php' && @$_REQUEST['action']==='edit') ) {
				// set up fonts dir and url
				$fonts_base = self::get_fonts_base(); 
				if (!$fonts_base) 	{return false;}

				// enqueue or embed ma_customfonts.css
				if (self::$cssoutput == 'file') {
					wp_enqueue_style('ma-customfonts', $fonts_base->url.'/ma_customfonts.css'); 
				} else {
					$plain_css = self::get_font_css(true); 
					add_action( 'admin_head', function(){ 
						echo self::get_font_css(); 

				if (defined("CT_VERSION")) { // Oxygen installed and active?
					// create custom style for body, h1-h6 from Oxygen global settings
					$ct_global_settings = ct_get_global_settings();
					self::$guten_oxy_font_css = sprintf(
						'body .editor-styles-wrapper {font-family:%1$s;}'.
						'body .editor-styles-wrapper :is(h1,h2,h3,h4,h5,h6,.editor-post-title) {font-family:%2$s;}',
						self::quote_font_names($ct_global_settings['fonts']['Text']), 	// text font
						self::quote_font_names($ct_global_settings['fonts']['Display'])	// heading font
					// add custom style to overwrite Gutenberg's default font
					if (self::$cssoutput == 'file') {
					} else {
						add_action( 'admin_head', function(){ 
							echo '<style id="ma-customfonts-oxygen">'.self::$guten_oxy_font_css.'</style>'; 
		// Shortcode for testing custom fonts (listing all fonts with their formats, weights, styles)
		add_shortcode('maltmann_custom_font_test', function( $atts, $content, $shortcode_tag ) {
			return self::get_font_samples('shortcode');

	static function init_admin_menu() {
		$st = microtime(true);
		// Add submenu page to the Appearance menu.
		add_action('admin_menu', function(){
			add_submenu_page(	'themes.php', 										// parent slug of "Appearance"
								_x('Custom Fonts','page title','ma_customfonts'), 	// page title
								_x('Custom Fonts','menu title','ma_customfonts'), 	// menu title
								'manage_options',									// capabilitiy
								'ma_customfonts',									// menu slug
								[__CLASS__, 'admin_customfonts']					// function
		$et = microtime(true);
		if (WP_DEBUG && self::$timing) {error_log(sprintf('%s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
	// Proper quoting for font families: Detect multiple families and quote individually if required
	static function quote_font_names($font_spec) {
		$fonts = preg_split('/,\s*/', $font_spec, -1, PREG_SPLIT_NO_EMPTY);
		$fonts = array_map(function($name){
			return preg_match('/[^A-Za-z\-]/',$name) ? '"'.$name.'"' : $name;
		$retval = implode(', ',$fonts);
		return $retval;

	static function get_script_version() {
		$implementation = basename(__FILE__) == 'ma-oxygen-custom-fonts.php' ? 'Plugin' : 'Code Snippet';
		return sprintf('%s, %s', $implementation, self::VERSION);
	// Admin function Appearance > Custom Fonts to display samples of all detected fonts
	static function admin_customfonts() {
		$output =	'<div class="wrap">'.
						'<h1>' . esc_html(get_admin_page_title()) . '</h1>'.
		echo $output;
		echo self::get_font_css();
	// parses weight from a font file name (not used for Web Font Loader packages)
	static function parse_font_name($name) {
		// already in cache?
		if (array_key_exists($name,self::$fonts_details_cache)) {return self::$fonts_details_cache[$name];}
		$retval = (object)['name'=>$name, 'weight'=>400, 'style'=>'normal'];
		if (!self::$parsename) {return $retval;}
		$st = microtime(true);
		if (WP_DEBUG && self::$debug) {error_log(sprintf('%s::%s() parsing font file name: "%s"',__CLASS__,__FUNCTION__, $retval->name));}
		$weights = (object)[ // must match from more to less specific !!
			// more specific
			200 => '/[ \-]?(200|((extra|ultra)\-?light))/i',
			800 => '/[ \-]?(800|((extra|ultra)\-?bold))/i',
			600 => '/[ \-]?(600|([ds]emi(\-?bold)?))/i',
			// less specific
			100 => '/[ \-]?(100|thin)/i',
			300 => '/[ \-]?(300|light)/i',
			400 => '/[ \-]?(400|normal|regular|book)/i',
			500 => '/[ \-]?(500|medium)/i',
			700 => '/[ \-]?(700|bold)/i',
			900 => '/[ \-]?(900|black|heavy)/i',
			'var' => '/[ \-]?(VariableFont)/i',
		$count = 0;
		// detect & cut style
		$new_name = preg_replace('/[ \-]?(italic|oblique)/i', '', $retval->name, -1, $count); 
		if ($new_name && $count) {
			$retval->name = $new_name;
			$retval->style = 'italic';
			if (WP_DEBUG && self::$debug) {error_log(sprintf('%s::%s() detected italic, new font family name: "%s"',__CLASS__,__FUNCTION__, $retval->name));}
		// detect & cut weight
		foreach ($weights as $weight => $pattern) {
			$new_name = preg_replace($pattern, '', $retval->name, -1, $count);
			if ($new_name && $count) {
				$retval->name = $new_name;
				$retval->weight = $weight;
				if (WP_DEBUG && self::$debug) {error_log(sprintf('%s::%s() detected weight %s, new font family name: "%s"',__CLASS__,__FUNCTION__, $retval->weight, $retval->name));}
		// cut -webfont
		$retval->name = preg_replace('/[ \-]?webfont$/i', '', $retval->name); 
		// variable font: detect & cut specifica
		if ($retval->weight == 'var') {
			$retval->name = preg_replace('/_(opsz,wght|opsz|wght)$/i', '', $retval->name); 
		if (WP_DEBUG && self::$debug) {error_log(sprintf('%s::%s() retval: [name:"%s", weigh:%d, style:%s]',__CLASS__,__FUNCTION__, $retval->name, $retval->weight, $retval->style));}
		// store to cache
		self::$fonts_details_cache[$name] = $retval;
		$et = microtime(true);
		if (WP_DEBUG && self::$timing) {error_log(sprintf(' %s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
		return $retval;
	// construct CSS block from CSS properties stored in JSON from Web Font Loader
	static 	function create_css_from_ruleset($css_ruleset) {
		$retval = '';
		if (isset($css_ruleset)) {
			if (isset($css_ruleset->{'comment'})) {$retval .= sprintf("/* %s */\n",$css_ruleset->{'comment'});}
			$retval .= "@font-face {\n";
			$retval .= sprintf("\tfont-family: '%s';\n",$css_ruleset->{'font-family'});
			$retval .= sprintf("\tfont-style: %s;\n",$css_ruleset->{'font-style'});
			$retval .= sprintf("\tfont-weight: %s;\n",$css_ruleset->{'font-weight'});
			$retval .= sprintf("\tsrc: url('%s') format('%s');\n",$css_ruleset->{'url'}, $css_ruleset->{'format'});
			if (isset($css_ruleset->{'unicode-range'})) {$retval .= sprintf("\tunicode-range: %s;\n", $css_ruleset->{'unicode-range'});}
			if (self::$fontdisplay) {
				$retval .= sprintf("\tfont-display: %s;\n",self::$fontdisplay);
			$retval .= '}';
		return $retval;
	// return base dir/url for fonts. Create directory if necessary
	private static function get_fonts_base() {
		$retval = (object)['dir'=>null,'url'=>''];
		$fonts_dir_info = wp_get_upload_dir();
		$retval->dir = $fonts_dir_info['basedir'].'/fonts';
		$retval->url = $fonts_dir_info['baseurl'].'/fonts';
		// create fonts folder if not exists
		if (!file_exists($retval->dir)) {
			if (!@mkdir($retval->dir)) {
				add_action('admin_notices', function(){
					echo '<div class="notice notice-error"><p>['.self::TITLE.'] Error creating fonts base folder <code>wp-content/uploads/fonts</code>.</p></div>';
				error_log(sprintf('%s::%s() Error creating fonts base folder.', __CLASS__, __FUNCTION__)); 
				return null;
		if (!is_writable($retval->dir)) {
			add_action('admin_notices', function(){
				echo '<div class="notice notice-error"><p>['.self::TITLE.'] Folder <code>wp-content/uploads/fonts</code> is not writable. Please correct folder permissions.</p></div>';
		// V3.2.2, create scheme-less URL
		$retval->url = preg_replace('/^https?\:/','',$retval->url);

		return $retval;
	// find font files in font folder
	static function find_fonts() {
		$st = microtime(true);
		if (isset(self::$fonts)) return;
		self::$fonts = [];
		// set up fonts dir and url
		$fonts_base = self::get_fonts_base(); 
		if (!$fonts_base) 	{return false;}
		// property $recursive either recursive or flat file scan
		if (self::$recursive) {
			// recursive scan for font files (including subdirectories)
			$directory_iterator = new RecursiveDirectoryIterator($fonts_base->dir,  RecursiveDirectoryIterator::SKIP_DOTS | RecursiveDirectoryIterator::UNIX_PATHS);
			$file_iterator = new RecursiveIteratorIterator($directory_iterator);
		} else {
			// flat scan for font files (no subdirectories)
			$file_iterator = new FilesystemIterator($fonts_base->dir);
		// loop through files and collect font and JSON files
		$font_splfiles = [];
		$json_splfiles = [];
		foreach( $file_iterator as $file) {
			// V3: A JSON file might be available from Web Font Loader
			if ($file->getExtension() == 'json') {
				$json_splfiles[] = $file;
			if (in_array(strtolower($file->getExtension()), self::$prioritized_formats)) {
				$font_splfiles[] = $file;
		// V3: check JSON files. If it defines "family" read the font name and CSS
		$json_font_families = [];
		foreach ($json_splfiles as $json_splfile) {
			if ($font_details = @json_decode(@file_get_contents($json_splfile->getPathname()))) {
				// It's a JSON from Web Font Loader?
				if (isset($font_details->creator) && (strpos($font_details->creator, 'Web Font Loader')=== 0)) {
					// store font family name 
					$json_font_families[$json_splfile->getBasename('.json')] = $font_details->family;
					// drop all collected font files for that font since they are listed in JSON file
					$font_path = $json_splfile->getPath().'/';
					foreach ($font_splfiles as $idx => $font_splfile) {
						if (strpos($font_splfile->getPath().'/',$font_path) === 0) {
							self::$font_files_cnt ++;
					$font_path = str_replace($fonts_base->dir,'',$font_path);
					// encode every single path element since we might have spaces or special chars 
					$font_path = implode('/',array_map('rawurlencode',explode('/',$font_path)));
					// add CSS blocks (could be multiple unicode ranges) to fonts list

					$font_baseurl = $fonts_base->url . $font_path;
					foreach ($font_details->css as $css_ruleset) {
						self::$fonts[$css_ruleset->{'font-family'}][$css_ruleset->{'font-weight'}.'/'.$css_ruleset->{'font-style'}]['has_css'] = true;
						// only formats woff and woff2, so just use format as file extension slot
						if (!isset(self::$fonts[$css_ruleset->{'font-family'}][$css_ruleset->{'font-weight'}.'/'.$css_ruleset->{'font-style'}][$css_ruleset->{'format'}])) {
							self::$fonts[$css_ruleset->{'font-family'}][$css_ruleset->{'font-weight'}.'/'.$css_ruleset->{'font-style'}][$css_ruleset->{'format'}] = [];	
						$css_ruleset->url = $font_baseurl . $css_ruleset->url;

						$css_block = self::create_css_from_ruleset($css_ruleset);
						self::$fonts[$css_ruleset->{'font-family'}][$css_ruleset->{'font-weight'}.'/'.$css_ruleset->{'font-style'}][$css_ruleset->{'format'}][] = $css_block;
		// collect font definitions
		foreach ($font_splfiles as $font_splfile) {
			self::$font_files_cnt ++;
			$font_ext = $font_splfile->getExtension();
			$font_details = self::parse_font_name($font_splfile->getbasename('.'.$font_ext));
			$font_name = $font_details->name;
			if (in_array($font_name,array_values($json_font_families))) {
				// already found this font from Web Font Loader. Skip.
			$font_weight = $font_details->weight;
			$font_style = $font_details->style;
			$font_path = str_replace($fonts_base->dir,'',$font_splfile->getPath());
			// encode every single path element since we might have spaces or special chars 
			$font_path = implode('/',array_map('rawurlencode',explode('/',$font_path)));
			// create entry for this font name
			if (!array_key_exists($font_name,self::$fonts)) {self::$fonts[$font_name] = [];}
			// create entry for this font weight/style 
			if (!array_key_exists($font_weight.'/'.$font_style,self::$fonts[$font_name])) {self::$fonts[$font_name][$font_weight.'/'.$font_style] = [];}
			// store font details for this file
			self::$fonts[$font_name][$font_weight.'/'.$font_style][strtolower($font_ext)] = $fonts_base->url . $font_path . '/' . rawurlencode($font_splfile->getBasename());
		ksort(self::$fonts, SORT_NATURAL | SORT_FLAG_CASE);
		if (WP_DEBUG && self::$debug) {error_log(sprintf('%s::%s() final fonts: %s]',__CLASS__,__FUNCTION__, print_r(self::$fonts,true)));}
		$et = microtime(true);
		if (WP_DEBUG && self::$timing) {error_log(sprintf('%s::%s() %d font files, %d font families.',__CLASS__,__FUNCTION__, self::$font_files_cnt, count(self::$fonts)));}
		if (WP_DEBUG && self::$timing) {error_log(sprintf('%s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
	// returns a list of font families
	static function get_font_families() {
		if (!isset(self::$fonts)) self::find_fonts();
		$st = microtime(true);
		$font_family_list = [];
		foreach (array_keys(self::$fonts) as $font_name) {
			$font_family_list[] = $font_name;
		$et = microtime(true);
		if (WP_DEBUG && self::$timing) {error_log(sprintf('%s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
		return $font_family_list;
	// we call this function from footer emitter to get font definitions for emitting required files
	static function get_font_definitions() {
		return self::$fonts;
	// creates CSS for custom fonts. 
	// For $cssoutput 'file', return <link rel="stylesheet" ...>, for 'html' <style>...</style>
	// If $plaincss is true, return plain css instead
	static function get_font_css($plaincss = false) {
		// emit CSS for fonts in footer
		$version = self::get_script_version();
		$style = '';
		// set up fonts dir and url
		$fonts_base = self::get_fonts_base(); 
		if (!$fonts_base) 	{return false;}
		$st = microtime(true);
		foreach (self::$fonts as $font_name => $font_details) {
			foreach ($font_details as $weight_style => $file_list) {
				list ($font_weight,$font_style) = explode('/',$weight_style);

				if (isset($file_list['has_css'])) {
					// V3: Google Font package CSS from Web Font Loader already has CSS
					foreach (array_reverse(self::$prioritized_formats) as $font_ext) {
						// we only have woff and woff2
						if (!isset($file_list[$font_ext])) { continue; }
						foreach ($file_list[$font_ext] as $css) {
							$style .= trim($css).PHP_EOL;
				} else {
					// V2: Only have font info and file names. Build CSS
					if ($font_weight == 'var') {
						$font_weight_output = '100 900';
					} else {
						$font_weight_output = $font_weight;
					$style .= 	'@font-face{'.PHP_EOL.
								'  font-family:"'.$font_name.'";'.PHP_EOL.
								'  font-weight:'.$font_weight_output.';'.PHP_EOL.
								'  font-style:'.$font_style.';'.PHP_EOL;
								// .eot needs special handling for IE9 Compat Mode
					if (array_key_exists('eot',$file_list)) {$style .= '  src:url("'.$file_list['eot'].'");'.PHP_EOL;}
					$urls = [];

					// output font sources in prioritized order
					foreach (self::$prioritized_formats as $font_ext) {
						if (array_key_exists($font_ext,$file_list)) {
							$font_url = $file_list[$font_ext];
							$format = '';
							switch ($font_ext) {
								case 'eot': $format = 'embedded-opentype'; break;
								case 'otf': $format = 'opentype'; break;
								case 'ttf': $format = 'truetype'; break;
								// others have same format as extension (svg, woff, woff2)
								default:	$format = strtolower($font_ext);
							if ($font_ext == 'eot') {
								// IE6-IE8
								$urls[] = 'url("'.$font_url.'?#iefix") format("'.$format.'")';
							} else {
								$urls[] = 'url("'.$font_url.'") format("'.$format.'")';
					$style .= '  src:' . join(','.PHP_EOL.'      ',$urls) . ';'.PHP_EOL;
					if (self::$fontdisplay) {
						$style .= sprintf('  font-display: %s;'.PHP_EOL,self::$fontdisplay);
					$style .= '}'.PHP_EOL;
		// if Oxygen Builder is active, emit CSS to show custom fonts in light blue.
		$builder_style = defined('SHOW_CT_BUILDER') ? '[ng-repeat*="elegantCustomFonts"] {color:lightblue !important;}' : '';
		if (WP_DEBUG && self::$debug) {error_log(sprintf('%s::%s() style: %s]',__CLASS__,__FUNCTION__, $style));}
		// minimize string if configured
		if (self::$cssminimize) {
			$style = preg_replace('/\r?\n */','',$style); 

		$retval = '';
		if (self::$cssoutput == 'file') {
			// option: write CSS to file
			$css_path = $fonts_base->dir.'/ma_customfonts.css';
			$css_code = '/* Version: '.$version.' */'.PHP_EOL.$style;
			$css_hash_code = hash('CRC32', $css_code, false);
			$css_hash_file = file_exists($css_path) ? hash_file('CRC32', $css_path, false) : 0;
			if ($css_hash_code !== $css_hash_file) {
				if (WP_DEBUG && (self::$timing || self::$debug)) {error_log(sprintf('%s::%s() Writing CSS file "%s"',__CLASS__,__FUNCTION__,$css_path));}
				$status = file_put_contents($css_path, $css_code);
				if ($status === false) {error_log(sprintf('%s::%s() Error writing CSS file "%s"',__CLASS__,__FUNCTION__,$css_path));}
				$css_hash_file = file_exists($css_path) ? hash_file('CRC32', $css_path, false) : 0;
			$css_url = str_replace($fonts_base->dir,$fonts_base->url ,$css_path);
			$retval = sprintf('<link id="ma-customfonts" href="%s?ver=%s" rel="stylesheet" type="text/css" />%s',$css_url, $css_hash_file, $builder_style?'<style>'.$builder_style.'</style>':'');
		if (self::$cssoutput == 'html') {
			// option: write CSS to html
			$retval = '<style id="ma-customfonts">'.'/* Version: '.$version.' */'.PHP_EOL.$style.PHP_EOL.$builder_style.'</style>';
		if ($plaincss) {
			$retval = $style.PHP_EOL.$builder_style;

		$et = microtime(true);
		if (WP_DEBUG && self::$timing) {error_log(sprintf('%s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
		return $retval;
	// parses font file url from CSS block
	static function get_font_file_info_from_css($css) {
		$retval = [];
		if (!is_array($css)) {$css = [$css];}
		foreach($css as $css_block) {
			if (preg_match('/url\(\'(.*?)\'\)/',$css_block,$matches)) {
				$retval[] = $matches[1];
		$retval = array_unique($retval); 
		return $retval;
	// returns HTML code to display all registered custom fonts
	// $mode 'admin':		formatting to be displayed on WP Admin > Appearance
	// $mode 'shortcode':	formatting to be displayed as shortcode output
	static function get_font_samples($mode = null) {
		$st = microtime(true);
		$output = '';
		$script_version = self::get_script_version();
		$output = 	'<style>'.
					'.ma-customfonts-test {font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;}'.
					'#ma-customfonts-input-font-size {width:60px;text-align:center;min-height:1em;line-height:1em;padding:0;}'.
					'#ma-customfonts-input-sample-text {width:400px;text-align:left;}'.
					'.ma-customfonts-label {display:inline-block;width:150px;line-height:2em;}'.
					'.ma-customfonts-font-row {display:flex;flex-direction:row;justify-content:space-between;align-items:center;padding:0;line-height:20px;border-bottom:1px solid #e0e0e0;margin:0 1em;}'.
					'.ma-customfonts-font-row:hover {background-color:lightgray;}'.
					'.ma-customfonts-font-info {font-size:10px;line-height:1em;width:100px;}'.
					'.ma-customfonts-font-sample {font-size:16px;line-height:1em;flex-grow:1;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;}'.
					'.ma-customfonts-format-info {font-size:10px;cursor:help;margin-left:1em;}'.
					'.ma-customfonts-simulated {display: none;}'.
					'<div '.($mode=='shortcode'?'class="ma-customfonts-test" style="display:inline-block;border:1px dashed darkgray;padding:10px;"':'').'>'.
						($mode=='shortcode'?'<h2>MA Custom Fonts</h2>':'').
						'<div style="display:inline-block;border:1px solid darkgray;border-radius:10px;padding:10px;">'.
							'<span class="ma-customfonts-label">Version:</span> '.$script_version.'<br/>'.
							'<span class="ma-customfonts-label">Font Families:</span> '.count(self::$fonts).'<br/>'.
							'<span class="ma-customfonts-label">Font Files:</span> '.self::$font_files_cnt.'<br/>'.
							'<span class="ma-customfonts-label">Sample Font Size:</span> '.
								'<input id="ma-customfonts-input-font-size" type="number" value="16" onchange="ma_customfonts_change_font_size();"> px<br/>'.
							'<span class="ma-customfonts-label">Sample Text:</span> '.
								'<input id="ma-customfonts-input-sample-text" value="'.self::$sample_text.'" onkeyup="ma_customfonts_change_sample_text();"><br/>'.
							'<span class="ma-customfonts-label">Simulated:</span> '.
								'<input id="ma-customfonts-input-simulated" type="checkbox" value="simulated" onchange="ma_customfonts_toggle_simulated();"> Show font weights/styles without files as browser would simulate.<br/>'.

		// controls
		$controls_script = <<<'END_OF_CONTROLS_SCRIPT'
		function changeCss(className, classValue) {
			// we need invisible container to store additional css definitions
			var cssMainContainer = jQuery('#css-modifier-container');
			if (cssMainContainer.length == 0) {
				cssMainContainer = jQuery('<div id="css-modifier-container"></div>');
			// we need one div for each class
			var classContainer = cssMainContainer.find('div[data-class="' + className + '"]');
			if (classContainer.length == 0) {
				classContainer = jQuery('<div data-class="' + className + '"></div>');
			// append additional style
			classContainer.html('<style>' + className + ' {' + classValue + '}</style>');
		function ma_customfonts_change_font_size() {
			var $val = jQuery('#ma-customfonts-input-font-size').val();
			changeCss('.ma-customfonts-font-sample','font-size: '+$val+'px;');
		function ma_customfonts_change_sample_text() {
			var $val = jQuery('#ma-customfonts-input-sample-text').val();
		function ma_customfonts_toggle_simulated() {
			var $simulated = jQuery('#ma-customfonts-input-simulated').is(':checked');
		$output .=  $controls_script;
		// prepare tags for every weight/style combination
		$weights = [100,200,300,400,500,600,700,800,900];
		$styles = ['normal','italic'];
		$weights_styles = [];
		foreach ($weights as $weight) { foreach ($styles as $style) { $weights_styles[] = $weight.'/'.$style; } }
		// display fonts in each weight/style combination
		$sample_text = self::$sample_text;

		// build output
		foreach (self::$fonts as $font_name => $font_details) {
			$output .= sprintf('<h3 style="padding-top: 20px;">%1$s</h3>',$font_name);
			foreach ($weights_styles as $weight_style) {
				list ($weight,$style) = explode('/',$weight_style);;
				$font_file_info = '';
				$font_file_list = [];
				if (isset($font_details[$weight_style])) {
					// walk through possible file formats
					foreach (self::$prioritized_formats as $font_ext) {
						// details available for this specific file format?
						if (isset($font_details[$weight_style][$font_ext])) {
							// details content type
							if (isset($font_details[$weight_style]['has_css'])) {	
								// CSS
								$font_file_list[$font_ext] = self::get_font_file_info_from_css($font_details[$weight_style][$font_ext]);
							} else {
								// just file name
								$font_file_list[$font_ext] = [$font_details[$weight_style][$font_ext]];
					// build font file info output
					foreach ($font_file_list as $format => $files) {
						// cut leading path/url from file info
						$files = str_replace(wp_get_upload_dir(),'',$files);
						// decode html entities (e.g. %20) in file path
						foreach ($files as &$file) {$file = implode('/',array_map('rawurldecode',explode('/',$file)));;}
						// convert array to html
						$font_file_list[$format] = sprintf('<span title="%2$s">%1$s</span>', strtoupper($format), implode("\n",$files));
					$font_file_info = '<span class="ma-customfonts-format-info">(' . implode(', ',array_values($font_file_list)) . ')</span>';

				$output .= sprintf(	'<div class="ma-customfonts-font-row '.($font_file_info?'':'ma-customfonts-simulated').'">'.
										'<span class="ma-customfonts-font-info">%2$s %3$s</span>'.
										'<span class="ma-customfonts-font-sample" style="font-family:\'%1$s\';font-weight:%2$d;font-style:%3$s">%4$s</span>%5$s'.
									'</div>',$font_name, $weight, $style, $sample_text, $font_file_info?$font_file_info:'<span class="ma-customfonts-format-info"><em>(simulated)</em></span>');

		$output .= '</div>';

		$et = microtime(true);
		if (WP_DEBUG && self::$timing) {error_log(sprintf('%s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
		return $output;

} // end of class MA_CustomFonts

endif; // end of conditional implementations

// Warn about incompatibilities
	$GLOBALS['ma_customfonts_incompatibilities'] = [];
	if (is_admin()) {
		// Plugin "Elegant Custom Fonts"
		if (function_exists('is_plugin_active') && is_plugin_active('elegant-custom-fonts/elegant-custom-fonts.php'))
			{$GLOBALS['ma_customfonts_incompatibilities'][] = '"Elegant Custom Fonts"';}
		// Plugin "Use Any Font"
		if (function_exists('is_plugin_active') && is_plugin_active('use-any-font/use-any-font.php'))
			{$GLOBALS['ma_customfonts_incompatibilities'][] = '"Use Any Font"';}
		// Plugin "Swiss Knife" with feature "Font Manager" active
		if (function_exists('is_plugin_active') && is_plugin_active('swiss-knife/swiss-knife.php') && (get_option('swiss_font_manager')=='yes')) 														
			{$GLOBALS['ma_customfonts_incompatibilities'][] = '"Swiss Knife" with feature "Font Manager" enabled';}
		if (count($GLOBALS['ma_customfonts_incompatibilities'])) {
			add_action('admin_notices', function(){
				if (WP_DEBUG ) {error_log('MA_CustomFonts / Incompatibilities: '.print_r($GLOBALS['ma_customfonts_incompatibilities'],true));}
				echo '<div class="notice notice-warning is-dismissible">
						<p>The Code Snippet "Oxygen: Custom Fonts" is not compatible with the Plugin '.implode(' or ',$GLOBALS['ma_customfonts_incompatibilities']).'.<br/>
						Please deactivate either the Code Snippet or the Plugin (feature).</p>
	if (count($GLOBALS['ma_customfonts_incompatibilities'])) return;

	// create a primitive ECF_Plugin class if plugin "Elegant Custom Fonts" is not installed
	if (!count($GLOBALS['ma_customfonts_incompatibilities']) && !class_exists('ECF_Plugin')) {
		class ECF_Plugin {
			static function get_font_families() {
				$st = microtime(true);
				$font_family_list = MA_CustomFonts::get_font_families();
				$et = microtime(true);
				if (WP_DEBUG && MA_CustomFonts::$timing) {error_log(sprintf('MA_CustomFonts/%s::%s() Timing: %.5f sec.',__CLASS__,__FUNCTION__,$et-$st));}
				return $font_family_list;

},1000); // hook late to check other plugins!

// Initialize
	if (count($GLOBALS['ma_customfonts_incompatibilities'])) return;
	if (wp_doing_ajax()) return; 		// don't run for AJAX requests
	if (wp_doing_cron()) return; 		// don't run for CRON requests
	if (wp_is_json_request()) return; 	// don't run for JSON requests
	if (is_favicon()) return; 			// don't run for favicon request
	if (WP_DEBUG && (MA_CustomFonts::$debug || MA_CustomFonts::$timing)) {error_log(sprintf('MA_CustomFonts: Request URI="%s" action="%s"', @$_SERVER['REQUEST_URI'], @$_REQUEST['action']));}

	if (is_admin()) {
		// initialize admin menu Appearance > Custom Fonts
		// init custom font functionality only when needed
		global $pagenow;
		if ( 	($pagenow === 'themes.php' && @$_REQUEST['page'] === 'ma_customfonts') 	// custom font test 
			||	($pagenow === 'post-new.php')											// new post
			||	($pagenow === 'post.php' && @$_REQUEST['action'] === 'edit')			// edit post
		) {
	} else {
		// frontend
},1001); // hook after incompatibility check
First published: Sep 15, 2020 on Code Snippet: Integrate Custom Fonts into Oxygen