Load fonts from style variations in the editor and the admin

src/wp-admin/includes/admin-filters.php

@@ -172,3 +172,4 @@
 
 // Font management.
 add_action( 'admin_print_styles', 'wp_print_font_faces', 50 );
+add_action( 'admin_print_styles', 'wp_print_font_faces_from_style_variations', 50 );

src/wp-includes/block-editor.php

@@ -366,6 +366,7 @@ function _wp_get_iframed_editor_assets() {
 	ob_start();
 	wp_print_styles();
 	wp_print_font_faces();
+	wp_print_font_faces_from_style_variations();
 	$styles = ob_get_clean();
 
 	if ( $has_emoji_styles ) {

src/wp-includes/fonts.php

@@ -54,6 +54,22 @@ function wp_print_font_faces( $fonts = array() ) {
 	$wp_font_face->generate_and_print( $fonts );
 }
 
+/**
+ * Generates and prints font-face styles defined the the theme style variations.
+ *
+ * @since 6.7.0
+ *
+ */
+function wp_print_font_faces_from_style_variations() {
+	$fonts = WP_Font_Face_Resolver::get_fonts_from_style_variations();
+
+	if ( empty( $fonts ) ) {
+		return;
+	}
+
+	wp_print_font_faces( $fonts );
+}
+
 /**
  * Registers a new font collection in the font library.
  *

src/wp-includes/fonts/class-wp-font-face-resolver.php

@@ -36,6 +36,38 @@ public static function get_fonts_from_theme_json() {
 		return static::parse_settings( $settings );
 	}
 
+	/**
+	 * Gets fonts defined in style variations.
+	 *
+	 * @since 6.7.0
+	 *
+	 * @return array Returns an array of font-families.
+	 */
+	public static function get_fonts_from_style_variations() {
+		$variations = WP_Theme_JSON_Resolver::get_style_variations();
+		$fonts      = array();
+
+		if ( empty( $variations ) ) {
+			return $fonts;
+		}
+
+		foreach ( $variations as $variation ) {
+			if ( ! empty( $variation['settings']['typography']['fontFamilies']['theme'] ) ) {
+				$fonts = array_merge( $fonts, $variation['settings']['typography']['fontFamilies']['theme'] );
+			}
+		}
+
+		$settings = array(
+			'typography' => array(
+				'fontFamilies' => array(
+					'theme' => $fonts,
+				),
+			),
+		);
+
+		return static::parse_settings( $settings );
+	}
+
 	/**
 	 * Parse theme.json settings to extract font definitions with variations grouped by font-family.
 	 *

tests/phpunit/tests/fonts/font-face/wp-font-face-tests-dataset.php

@@ -403,4 +403,94 @@ public static function get_custom_font_families( $key = '' ) {
 
 		return $data;
 	}
+
+	public static function get_custom_style_variations( $key = '' ) {
+		static $data = null;
+
+		$uri                    = get_stylesheet_directory_uri() . '/assets/fonts/';
+		$expected_font_families = array(
+			array(
+				array(
+					'src'          => array(
+						'/var/www/tests/phpunit/data/themedir1/fonts-block-theme/assets/fonts/dm-sans/DMSans-Regular.woff2',
+					),
+					'font-family'  => 'DM Sans',
+					'font-stretch' => 'normal',
+					'font-style'   => 'normal',
+					'font-weight'  => '400',
+				),
+				array(
+					'src'          => array(
+						'/var/www/tests/phpunit/data/themedir1/fonts-block-theme/assets/fonts/dm-sans/DMSans-Bold.woff2',
+					),
+					'font-family'  => 'DM Sans',
+					'font-stretch' => 'normal',
+					'font-style'   => 'normal',
+					'font-weight'  => '700',
+				),
+			),
+			array(
+				array(
+					'src'          => array(
+						'/var/www/tests/phpunit/data/themedir1/fonts-block-theme/assets/fonts/open-sans/OpenSans-VariableFont_wdth,wght.ttf',
+					),
+					'font-family'  => 'Open Sans',
+					'font-stretch' => 'normal',
+					'font-style'   => 'normal',
+					'font-weight'  => '400',
+				),
+				array(
+					'src'          => array(
+						'/var/www/tests/phpunit/data/themedir1/fonts-block-theme/assets/fonts/open-sans/OpenSans-Italic-VariableFont_wdth,wght.ttf',
+					),
+					'font-family'  => 'Open Sans',
+					'font-stretch' => 'normal',
+					'font-style'   => 'italic',
+					'font-weight'  => '400',
+				),
+			),
+			array(
+				array(
+					'src'          => array(
+						'/var/www/tests/phpunit/data/themedir1/fonts-block-theme/assets/fonts/dm-sans/DMSans-Medium.woff2',
+					),
+					'font-family'  => 'DM Sans',
+					'font-stretch' => 'normal',
+					'font-style'   => 'normal',
+					'font-weight'  => '500',
+				),
+				array(
+					'src'          => array(
+						'/var/www/tests/phpunit/data/themedir1/fonts-block-theme/assets/fonts/dm-sans/DMSans-Medium-Italic.woff2',
+					),
+					'font-family'  => 'DM Sans',
+					'font-stretch' => 'normal',
+					'font-style'   => 'italic',
+					'font-weight'  => '500',
+				),
+			),
+		);
+
+		$expected_styles = <<<CSS
+@font-face{font-family:"DM Sans";font-style:normal;font-weight:400;font-display:fallback;src:url('{$uri}dm-sans/DMSans-Regular.woff2') format('woff2');font-stretch:normal;}
+@font-face{font-family:"DM Sans";font-style:normal;font-weight:700;font-display:fallback;src:url('{$uri}dm-sans/DMSans-Bold.woff2') format('woff2');font-stretch:normal;}
+@font-face{font-family:"Open Sans";font-style:normal;font-weight:400;font-display:fallback;src:url('{$uri}open-sans/OpenSans-VariableFont_wdth,wght.ttf') format('truetype');font-stretch:normal;}
+@font-face{font-family:"Open Sans";font-style:italic;font-weight:400;font-display:fallback;src:url('{$uri}open-sans/OpenSans-Italic-VariableFont_wdth,wght.ttf') format('truetype');font-stretch:normal;}
+@font-face{font-family:"DM Sans";font-style:normal;font-weight:500;font-display:fallback;src:url('{$uri}dm-sans/DMSans-Medium.woff2') format('woff2');font-stretch:normal;}
+@font-face{font-family:"DM Sans";font-style:italic;font-weight:500;font-display:fallback;src:url('{$uri}dm-sans/DMSans-Medium-Italic.woff2') format('woff2');font-stretch:normal;}
+CSS;
+
+		if ( null === $data ) {
+			$data = array(
+				'expected'        => $expected_font_families,
+				'expected_styles' => $expected_styles,
+			);
+		}
+
+		if ( isset( $data[ $key ] ) ) {
+			return $data[ $key ];
+		}
+
+		return $data;
+	}
 }

tests/phpunit/tests/fonts/font-face/wpFontFaceResolver/getFontsFromStyleVariations.php

@@ -0,0 +1,55 @@
+<?php
+/**
+ * Test case for WP_Font_Face_Resolver::get_fonts_from_style_variations().
+ *
+ * @package    WordPress
+ * @subpackage Fonts
+ *
+ * @since 6.7.0
+ *
+ * @group fonts
+ * @group fontface
+ *
+ * @covers WP_Font_Face_Resolver::get_fonts_from_style_variations
+ */
+class Tests_Fonts_WPFontFaceResolver_GetFontsFromStyleVariations extends WP_Font_Face_UnitTestCase {
+	const FONTS_THEME = 'fonts-block-theme';
+
+	public static function set_up_before_class() {
+		self::$requires_switch_theme_fixtures = true;
+
+		parent::set_up_before_class();
+	}
+
+	public function test_should_return_empty_array_when_theme_has_no_style_variations() {
+		switch_theme( 'block-theme' );
+
+		$fonts = WP_Font_Face_Resolver::get_fonts_from_style_variations();
+		$this->assertIsArray( $fonts, 'Should return an array data type' );
+		$this->assertEmpty( $fonts, 'Should return an empty array' );
+	}
+
+	public function test_should_return_all_fonts_from_all_style_variations() {
+		switch_theme( static::FONTS_THEME );
+
+		$actual   = WP_Font_Face_Resolver::get_fonts_from_style_variations();
+		$expected = self::get_custom_style_variations( 'expected' );
+
+		$this->assertSame( $expected, $actual, 'All the fonts from the theme variations should be returned.' );
+	}
+
+	public function test_should_replace_src_file_placeholder() {
+		switch_theme( static::FONTS_THEME );
+
+		$fonts = WP_Font_Face_Resolver::get_fonts_from_style_variations();
+
+		// check that the there is no theme relative url in the src list.
+		foreach ( $fonts as $family ) {
+			foreach ( $family as $font ) {
+				foreach ( $font['src'] as $src ) {
+					$this->assertStringNotContainsString( 'file:./', $src, 'Font src should not contain the "file:./" placeholder' );
+				}
+			}
+		}
+	}
+}

tests/phpunit/tests/fonts/font-face/wpPrintFontFacesFromStyleVariations.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * Test case for wp_print_font_faces_from_style_variations().
+ *
+ * @package    WordPress
+ * @subpackage Fonts
+ *
+ * @since 6.7.0
+ *
+ * @group fonts
+ * @group fontface
+ *
+ * @covers wp_print_font_faces_from_style_variations
+ */
+class Tests_Fonts_WpPrintFontFacesFromStyleVariations extends WP_Font_Face_UnitTestCase {
+	const FONTS_THEME = 'fonts-block-theme';
+
+	public static function set_up_before_class() {
+		self::$requires_switch_theme_fixtures = true;
+
+		parent::set_up_before_class();
+	}
+
+	public function test_should_not_print_when_no_fonts() {
+		switch_theme( 'block-theme' );
+
+		$this->expectOutputString( '' );
+		wp_print_font_faces_from_style_variations();
+	}
+
+	public function test_should_print_fonts_in_style_variations() {
+		switch_theme( static::FONTS_THEME );
+
+		$expected        = $this->get_custom_style_variations( 'expected_styles' );
+		$expected_output = $this->get_expected_styles_output( $expected );
+
+		$this->expectOutputString( $expected_output );
+		wp_print_font_faces_from_style_variations();
+	}
+
+	private function get_expected_styles_output( $styles ) {
+		$style_element = "<style id='wp-fonts-local' type='text/css'>\n%s\n</style>\n";
+		return sprintf( $style_element, $styles );
+	}
+}