gutenberg / lib / experimental / fonts-api / class-wp-fonts-provider.php

class-wp-fonts-provider.php in Gutenberg 17.2.1, at lib/experimental/fonts-api/class-wp-fonts-provider.php

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1	<?php
2	/**
3	* Fonts API: Provider abstract class.
4	*
5	* Individual fonts providers should extend this class and implement.
6	*
7	* @package WordPress
8	* @subpackage Fonts API
9	* @since X.X.X
10	*/
11
12	if ( class_exists( 'WP_Fonts_Provider' ) ) {
13	return;
14	}
15
16	/**
17	* Abstract class for Fonts API providers.
18	*
19	* The starting point to building a font service provider.
20	*
21	* What is a Provider?
22	*
23	* A provider contains the know-how (business logic) for how to
24	* process its specific font service (i.e. local or remote)
25	* and how to generate the `@font-face` styles for its service.
26	*
27	* It receives a collection of fonts from the Controller
28	* {@see WP_Fonts_Provider::set_fonts()}, and when requested
29	* {@see WP_Fonts_Provider::get_css()}, it transforms them
30	* into styles (in a performant way for the provider service
31	* it manages).
32	*
33	* @since X.X.X
34	*/
35	abstract class WP_Fonts_Provider {
36
37	/**
38	* The provider's unique ID.
39	*
40	* @since X.X.X
41	*
42	* @var string
43	*/
44	protected $id = '';
45
46	/**
47	* Fonts to be processed.
48	*
49	* @since X.X.X
50	*
51	* @var array[]
52	*/
53	protected $fonts = array();
54
55	/**
56	* Array of Font-face style tag's attribute(s)
57	* where the key is the attribute name and the
58	* value is its value.
59	*
60	* @since X.X.X
61	*
62	* @var string[]
63	*/
64	protected $style_tag_atts = array();
65
66	/**
67	* Sets this provider's fonts property.
68	*
69	* @since X.X.X
70	*
71	* @param array[] $fonts Registered fonts.
72	*/
73	public function set_fonts( array $fonts ) {
74	$this->fonts = $fonts;
75	}
76
77	/**
78	* Prints the generated styles.
79	*
80	* @since X.X.X
81	*/
82	public function print_styles() {
83	printf(
84	$this->get_style_element(),
85	$this->get_css()
86	);
87	}
88
89	/**
90	* Gets the `@font-face` CSS for the provider's fonts.
91	*
92	* This method is where the provider does it processing to build the
93	* needed `@font-face` CSS for all of its fonts. Specifics of how
94	* this processing is done is contained in each provider.
95	*
96	* @since X.X.X
97	*
98	* @return string The `@font-face` CSS.
99	*/
100	abstract public function get_css();
101
102	/**
103	* Gets the `<style>` element for wrapping the `@font-face` CSS.
104	*
105	* @since X.X.X
106	*
107	* @return string The style element.
108	*/
109	protected function get_style_element() {
110	$attributes = $this->generate_style_element_attributes();
111
112	return "<style id='wp-fonts-{$this->id}'{$attributes}>\n%s\n</style>\n";
113	}
114
115	/**
116	* Gets the defined <style> element's attributes.
117	*
118	* @since X.X.X
119	*
120	* @return string A string of attribute=value when defined, else, empty string.
121	*/
122	private function generate_style_element_attributes() {
123	$attributes = '';
124	foreach ( $this->style_tag_atts as $name => $value ) {
125	$attributes .= " {$name}='{$value}'";
126	}
127	return $attributes;
128	}
129	}
130