Extracts font definitions from theme.json and style variations.

Since: 6.4.0
Source: wp-includes/fonts/class-wp-font-face-resolver.php
Access: Private (internal core usage)

Description

This class abstracts the processing of different data sources (such as theme.json) for font face processing. It converts theme.json font definitions into the format expected by WP_Font_Face.

Methods

get_fonts_from_theme_json()

Gets fonts defined in the active theme.json.

public static function get_fonts_from_theme_json(): array

Returns: Array of font families with their font-face variations.

Process:

1. Retrieves global settings via wp_get_global_settings()
2. Extracts typography.fontFamilies
3. Parses and converts to font-face format

Example Return:

[
    [
        [
            'font-family' => 'Inter',
            'font-weight' => '400',
            'font-style'  => 'normal',
            'src'         => ['https://example.com/fonts/inter.woff2'],
        ],
        [
            'font-family' => 'Inter',
            'font-weight' => '700',
            'font-style'  => 'normal',
            'src'         => ['https://example.com/fonts/inter-bold.woff2'],
        ],
    ],
]

get_fonts_from_style_variations()

Gets fonts defined in theme style variations.

public static function get_fonts_from_style_variations(): array

Since: 6.7.0

Description:

Style variations are JSON files in the theme’s styles/ directory. Each variation can define its own fonts. This method collects fonts from all variations.

Private Methods

parse_settings()

Parses theme.json settings to extract font definitions.

private static function parse_settings( array $settings ): array

Iterates through typography.fontFamilies and converts each definition.

maybe_parse_name_from_comma_separated_list()

Extracts the first font name from a comma-separated font-family list.

private static function maybe_parse_name_from_comma_separated_list( string $font_family ): string

Example:

// "Inter, sans-serif" → "Inter"
// "'Open Sans', Arial" → "Open Sans"

convert_font_face_properties()

Converts font-face properties from theme.json format.

private static function convert_font_face_properties( 
    array $font_face_definition, 
    string $font_family_property 
): array

Transformations:

1. Adds font-family property to each font face
2. Converts file:./ placeholders to theme file URIs
3. Converts camelCase properties to kebab-case

to_theme_file_uri()

Converts file:./ placeholders to theme file URIs.

private static function to_theme_file_uri( array $src ): array

Example:

// Input:  ['file:./assets/fonts/inter.woff2']
// Output: ['https://example.com/wp-content/themes/my-theme/assets/fonts/inter.woff2']

Uses get_theme_file_uri() for the conversion.

to_kebab_case()

Converts array keys from camelCase to kebab-case.

private static function to_kebab_case( array $data ): array

Example:

// ['fontWeight' => '400'] → ['font-weight' => '400']
// ['fontStyle' => 'normal'] → ['font-style' => 'normal']

theme.json Font Format

Input format from theme.json:

{
  "settings": {
    "typography": {
      "fontFamilies": [
        {
          "fontFamily": "Inter, sans-serif",
          "slug": "inter",
          "name": "Inter",
          "fontFace": [
            {
              "fontFamily": "Inter",
              "fontWeight": "400",
              "fontStyle": "normal",
              "src": ["file:./assets/fonts/inter.woff2"]
            }
          ]
        }
      ]
    }
  }
}

Output format for WP_Font_Face:

[
    [
        [
            'font-family' => 'Inter',
            'font-weight' => '400',
            'font-style'  => 'normal',
            'src'         => ['https://example.com/.../inter.woff2'],
        ],
    ],
]

Usage

This class is used internally:

// Called by wp_print_font_faces() when no fonts provided
$fonts = WP_Font_Face_Resolver::get_fonts_from_theme_json();

// Called by wp_print_font_faces_from_style_variations()
$fonts = WP_Font_Face_Resolver::get_fonts_from_style_variations();